UPDATE: DECEMBER 12, 2018
Writing Book About Verticals from a Salt Marsh Next to the Sea
No antennas up yet, but with 1/4 vertical mounted on the deck with 2 radials thrown over the railing I can hear Europe at 2 PM in the afternoon on 3.5 and 7 Mhz, and easily listen to AM broadcast radio stations in Chicago after sunset.
We will now continue our antenna experiments, striving to achieve the following scenarios:
Phase I: 7 MHz vertical on the salt marsh without any radials, using only ground rods to collect return currents.
We want to see if there is any truth to the wive's tail that you don't need any radials in salt water.
Phase II: 7 MHz Phased verticals on the salt marsh.
Let's see if there is any improvement in their performance compared to their use at the previous location inland.
Phase III: Elevating Radials for The Skin-effect.
We will elevate the radial system to see if we can get them submerged at the same time 1" to 3" to capture "The Skin Effect".
UPDATE: DECEMBER 18, 2018
Outstanding Initial Transmitting Session!
Incredible evening barefoot with 100 Watts. The MFJ Analyzer tells me the 1/4 WL vertical is good for transmitting, which I did not expect; I only put it up to be able to listen to the bands. So I tuned up into it and enjoyed a 7+ hour session on the air from the saltwater marsh using 100 Watts. I worked into Europe until noon, European local time. Thank you everybody for the enormous pile-ups! We're going to have fun from this location.
When I woke up for work, it was blowing heavily -- gusts coming in from all directions, causing the 1/4 wavelength vertical to dance like a VooDoo Child. I guyed it with parachute cord to insulators to cable ties.
Not much, but it works great. And, again, that's because of the location; this thing doesn't even have a serious ground radial system, as illustrated below.
What a Mess
Only 4 or 5 ground radials wires have been unrolled and thrown over the deck railing so far.
The radials and ring are from the phased verticals detailed down the page.
***
All I got out is four or five of these radials unwound and thrown off the ends of the deck. Since this produces a feedpoint impedance of 66 Ohms, and the optimum 1/4 WL vertical feedpoint impedance being 36 Ohms, that means we got about 50% efficiency with this contraption on the deck. When I deliver 100 Watts to it, the far field gets 50 Watts to sculpt. For it is in the far field that the radiation pattern of an antenna is shaped, not the near field immediately surrounding the antenna. And this includes the final take-off angle, which many operators strive to keep low to maximize their signal reports at distant locations.
When we take a look at the mess underbneath the vertical, above, we realize there are no means to effectively collect return currents emitted by the monopole radiator. Despite this fact, the signal reports being received and sent are astonishing. This is likely because the far field is a saltwater march adjacent to the Atlantic Ocean to the South and a mile to the East. That is the first lesson we are learning in this second phase of our antenna experiments. Should you come across this signal on 40 Meters, remember it is being radiated by an aluminum pole stuck out on the deck with the mess seen above serving as the counterpoise. In a moment we will install the second vertical in the salt marsh and A/B between the two antennas to see if there is any difference.
UPDATE: DECEMBER 20, 2018
55 Degrees in December? Time for Antenna Work!
Super warm today. Did a lot of work out on the deck preparing the second vertical for installation out in the saltwater march using four (4) ground rods stuck in the mud, rather than a radial system. Let me take you through the progress made today, as photographed below. And, yes, it was fun!
New Coax Connectors
Finally learned how to use an RG-8X coax adaptor.
***
I got a bunch of new coaxial connectors and installed them on the ends of the RG-8X feedlines we were using with the phased verticals at the previous QTH. That was a good thing to do because you can experience significant losses through bad connectors. And it was about time to replace the ones we had been using: God knows how far they were degraded by all the RF we had been pumping through them. We also finally installed the RG-8X adaptors, which makes the connection more robust and weatherproof. A lot neater way to make the connection. And one which lessens the likelihoood of melting the insulating material in the PL-259, which I often do by applying the soldering iron to it too long.
Unused RG-8X Discovered in Storage
Extra cable always a pleasure to discover.
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Below is the center guy ring for the second vertical made from a PVC tube with cable ties epoxyed to it.
Guy Ring. Patent Not Pending!
Cable ties epoxyed to PVC tube.
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We're going to need that, and probably a second, higher one, on the vertical in the marsh. The winds off the ocean are not abated by any structures or local topography. Below is way of securing the junctions in aluminum verticals when you don't have the right series of tapering tubes. In this case I have a smaller diameter tube inserted between two larger ones, which butt together under the hose clamp. Set screws prevent vertical sliding after final install and support electrical conductivity.
Detail of Vertical Junction
A hose clamp squeezes slits cut in the end of aluminum tubing butted together over a third piece inserted between them.
Sheet metal screws help with maintaining electrical conductivity and prevent vertical slippage..
***
This is the almost-completed reassembly of the second vertical.
33' Test Vertical Nears Completion
Base insulators made from PVC tubes ($2.89/10') and electrical conduit hanger brackets ($0.89/ea.)
***
The base insulators are PVC tubes fastened to the base pipe with electrical conduit hangers. You can easily detach the verticals after install. It is a strong and cheap way of securing vertical radiators. Here's the ground rods being prepared.
Preparation fo Ground Rods
10 foot long 1/2" copper tubing cut in 2.5' lengths, drilled and wires attached.
Liquid Electrical Tape prolongs good RF connection in salt marsh conditions.
Copper wire to copper tube produces a better "non-bi-metalic" electrical connection than using a spade terminal.
***
I use Liquid Electrical Tape to protect the connection from the weather to keep Ohmic losses down. I'd solder the sumbitches but I don't have a propane torch right now. Here's the fitting of the current bead balun to the base support pipe. The balun is one sold by The Wireman ($14) consisting of 50 ferrite beads strung along a piece of RG-173 super thin, albeit high-power, coax.
Detail of Current Balun "Capsule" Mounting
An electrical conduit bracket fastens the PVC tube to the base pipe.
The PVC tube contains a Wireman current (bead) choke ($14)
***
UPDATE: DECEMBER 22, 2018
Second Vertical in the Salt Marsh.
Experimental 1/4 WL Vertical Installed in Salt Marsh Without Any Ground Radials
Uses four (4) ground rods spaced 4' around base.
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First off, check out the view from the operating position and deck this morning! Lots of rain yesterday.
Early Morning View Out the Operating Position
High tide at Succotash Marsh, Matunuck, R.I.
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Second Vertical Installed • No Radials • Only Four 2.5 Foot Long Ground Rods
52 Ohm Feedpoint Impedance • 4 Ohms Reactance • Resonant at 7.190 Mhz!
We were able to install the second vertical in the saltwater marsh this afternoon. She went up beautifully, despite strong winds, and rides well after being guyed. The ground system consists of the four ground rods depicted in the previous update, slammed down into the mud. AWG #10 wires bond the ground rods back to the support pipe. She tuned to a 52 Ohm input impedance with 4 Ohms of reactance at 7.190 Mhz! An hour later everything changed as the water receded with the tide, apparently causing the vertical to resonate at 8 Mhz! I guess we need to just install the ground radials tomorrow!
The Next Day...
Whoops! Correction. After lengthening the vertical to bring it to resonance, the hose clamp used to tighten the junction slipped, causing the vertical to slip back down in itself, throwing the resonance back up to 8 Mhz. How did this happen? I got so excited after tuning the aerial that I went back inside and tried it out, rather then returning in what available light remained to finish the job by drilling a hole to set in a sheet metal screw. So the vertical slipped back down inside it's telescoping self after a little while in the blowing winds, and raised its resonant frequency by so doing. I realized this the next morning when sipping a cup of coffee on the deck admiring the vertical, and then spitting out a mouthful when I noted the guy lines were all slack. I fucked up on that one.
Am going out to correct this now so we can finally A/B between ground rods and radials this evening.
Guys, Support Post & Ground Rods
Green wires lead to four ground rods made of 1/2" copper pipe 2 and a half feet long.
***
UPDATE: DECEMBER 23, 2018
Experimental Vertical Repaired and Tuned • Experimentation Begins Tonight
This morning I corrected the problem and retuned the test vertical in the marsh, as seen below.
"Radial-less" Saltwater Marsh Vertical SWR Sweep
52 Ohm feedpoint impedance at resonance, 16 Ohms of which being ground loss.
Approximately 50% efficient without any radials. SWR under 1.2 across band.
***
Remember, a 50 Ohm feedpoint impedance on a 1/4 WL vertical means about 14 Ohms of ground loss since the optimum feedpoint impedance for such an aerial is 36 Ohms. So what we learned thus far is that four (4) short ground rods (2.5 feet long) spaced 4' apart around the vertical produced 16 Ohms of ground loss at resonance. Another finding is that it is possible to resonate the vertical against the ground rods, e.g. the reactive component is manageable at resonance. The only other thing to find out is whether or not the aerial will survive high winds. So we are looking forward to A/B comparisons between the two verticals on-the-air..
Once again, here she is. Standing tall and proud. The center of her is double-walled aluminum stiffening her in the winds.
Experimental Vertical Ready for Testing
Let the shootout begin.
***
UPDATE: DECEMBER 25, 2018
Merry Christmas • Laying Ground Radials Down in Salt Marsh
SCIENTIFIC NOTE: A/B comparisons between the reference vertical on the deck and the salt marsh vertical resulted in stateside stations seeing no difference between the two, while long-haul DX stations consistently observing 1 to 3 S-units difference. Especially along long=path, grayline propagation conditions. We think that this means the higher-angle envelopes of both verticals are similar, whereas the experimental vertical in the salt marsh is exhibiting a protrusion in its lower elevation envelope. We would need a couple more hams over here and a drone equipped with a field strength meter to procure serious empirical field data. Since we don;t have these resources, we will follow the Old School example by just having fun collecting our non-empirical data through on-air reports. By the way, if anyone has a drone, try to figure out how to rig it up to make field strength measurements through use of something like an Adrino. That would be a cool tool.
Second Day of Radial Deployment
2nd day of laying 30 ground radials out beneath the experimental vertical in the salt marsh. We are trying to reduce feedpoint impedance to the 36 Ohms exhibited by a 1/4 WL vertical over perfect ground. After laying down 10 ground radials yesterday afternoon we reduced the feedpoint impedance from 52 to 41 Ohms! That's 6 Ohms of ground loss which translates into an efficiency figure of 85%! Working on more radials this afternoon in the mud wearing waders. Continuing A/B testing tonight. Lots of data being collected.
10 Ground Radials • Saltwater Marsh Vertical Resonant Feedpoint Impedance
41 Ohms • Reduced from 52 Ohms provided by four ground rods.
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A few hours later, after installing 10 more ground radials in the marsh...
20 Radials • Saltwater Marsh Vertical Feedpoint Impedance Sweep
38 to 43 Ohms • Total radial field: 20
20 Ground Radials • Saltwater Marsh Vertical Resonant Feedpoint Impedance
Impedance same as 10 radials • Resonant frequency raised 64 Khz.
***
Here's the sweeps for 4 ground rods versus 20 ground radials, which seems to indicate we are headed in the right direction. Note that the readings do not take into account the tide charts. Having said that, both sets of readings were taken at low tide, obviously, since I was working down there. It is impossibel to do so at high tide without waders. And even then one would not undertake such a venture for you cannot tell where you are stepping beneath the water.
SWR & Reactance Sweeps • Ground Rods vs 20 Ground Radials
Low tide
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UPDATE: DECEMBER 26, 2018
Salt Marsh Vertical Begins to Outperform Reference Vertical • Massive European Daylight Pile-ups • VK7 Eavesdrops for 4 Hours
Good morning.
Eastern Grayline
The view from the operating position this morning.
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Salt Marsh Vertical Begins to Outperform Reference Vertical
1 to 2 S-units on Long-Haul Grayline Contacts • No Difference Stateside
The experimental salt marsh vertical has begun to pull away from the reference vertical in terms of signal reports received over grayline propagation paths. This appears to be the result of the continuing addition of ground radials in the marsh. When we arrived at 15 radials, the two aerials were neck-to-neck. After that, by 25 radials, South Africa, for example, is reporting 1 to 2 S-units difference. Meanwhile, stateside stations do not report any significant difference, which suggests both verticals exhibiting identical higher-elevation patterns.
Two, massive European pile-ups have thus far been generated since the last update, the first continuing well past daylight in Europe, as detailed below.
Massive 6-Hour Pile-Up on 7.153 Mhz • December 26, 2018
Working Europeans until 10:30 Central European Time with a VK7 breaking in several times
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Here's the DXSummit data for the EU pile-up the day prior:
DXSummit Data • December 26, 2018
The insanity begins around 6 AM GMT
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Australian Eavesdrops for 4 Hours
QRZ.com reader listens to EU pile-up while working in the shack on a summer afternoon.
During the European Pile-up, Rod, VK7FRJG in Australia, was working in his shack "down under" listening to the fracas for four (4) hours! He was able to break the pile-up a couple times and then sent a nice email, reprinted below. His report gives us a good idea of how the experimental vertical is playing over a period of several hours on the opposite side fo the world.
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Added More Radials to Experimental Marsh Vertical • Station Upgrades
25 Ground Radials At Present • Improving TX Audio • Adding On-Air Recording and Playback Capabilities
W1ZY
Operating position.
***
Did not have much time at the end of the day to do any antenna work, and only managed to lay down five (5) more radials in the marsh. Did work on the audio quality by replacing the ELECTROVOICE stick microphone with a 1960s UHER M517, requiring external equalization to cut lows. After sundown am configuring soundboard to record and playback signals for posting on The Saltwater Vertical Sound Archive. Check it out.
UPDATE: DECEMBER 27, 2018
Matching Vertical Feedline Impedances
L-Match in the Feedline
As we tune the experimental vertical its feedpoint impedance changes, progressing lower as its resonant frequency rises. With 25 radials deployed, the vertical's impedance and resonance is not within comfortable ranges for the amplifier. To temporarily correct for this in the shack, a L-match has been inserted into its feedline allowing a 50 Ohm impedance with zero reactance to be presented to the amplifier.
L-Match for Experimental Vertical Installed in Shack
Shows 50 hm impedance and zero reactance to amplifier when experimental vertical is being fed • No need to re-tune vertical while radials are being deployed.
I should put it at the feedpoint to get a flat SWR down the feedline, but am too lazy to scrounge the weather-proof box. Besides, its temporary.
***
Another L-Match in the Other Feedline
A second L-match has been constructed to take care of the impedance transformation for the reference vertical. Matching the impedances of the two verticals to 50 Oms and zero reactance eliminates the possibility that a mismatch to the amplifier affects results of A/B comparison of the verticals.
L-Match for Reference Vertical Constructed & Installed
Provides 50 Ohm impedance and zero reactance to amplifier when experimental vertical is being fed.
***
System Used to Switch Between the Verticals
Both vertical feedline impedances can be independently set to 50 Ohms before being switched to the amplifier
***
More comparisons performed tonight. A71AM reported 3 S-units in Qatar. Ireland reported no difference and then 2 S-units differnce over span of 20 minutes. DX data below.
DXSummit Spots • December 27, 2018
NOTE: Propagation fluctuated from low to high angle in a matter of minutes.
Check out the wide variety of compass headiings reporting in, characteristic of an omnidirectional radiator.
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UPDATE: DECEMBER 28, 2018
Experimental Vertical Takes Her First Storm
The experimental vertical is experiencing her first gale-force winds. 
Experimental Vertical in Her First Storm
Riding beautifully likely due to double-walled center tubing.
***
She is riding 35 Knot sustained winds beautifully due to doubling-up her center section with two lengths of aluminum tubing, one inserted inside the other. From now on I will always double-up the tubing in vertical antennas at seaside locations. The reference vertical is holding her own, as well. But is whipping around more, which is her nature, since she is uniformly-tapered.
NEW ON-LINE AUDIO ARCHIVE
Listen to A71AM in Qatar Booming into the USA at 1 PM in the Afternoonon on 40 Meters
Audio archive now available on freesound.com for saltwater vertical recordings. Click here to go there, or on the image below to check it out.
***
Tide Chart, Matunuck, R.I.
How deep are the experimental vertical radials in the saltwater right now?
At high tide the experimental vertical's radial system is 3 to 8 inches under saltwater. At low tide its raidals are stretched across the marsh grass.
UPDATE: DECEMBER 30, 2018
Phase II: Phased Verticals in Salt Marsh
We now initiate the second phase of the saltwater marsh experiments: phased verticals! We removed the reference vertical from the deck, along with its radial system, so that both can be installed in the salt marsh 60˚ to the northeast of the experimental vertical. A pole was machined to accept the brackets used to foot the second vertical, and a PVC tube was procured to support the relay box. Branches with "Y" junctions collected from the local woods and stuck into the mud serve as an environmentally-friendly means of supporting the feedline and DC control cable above the water at high tide. The vertical base support was driven into the mud 34.4 feet away from the experimental vertical, with the remote relay post sited halfway between the two.
Phase II: Phased Verticals in the Salt Marsh
Support poles prepared and installed.
***
Work performed in the marsh this afternoon was prematurely curtailed because the high tide caused problems navigating in the muck underfoot, necessitating the donning of waders. Upon my return to the shack at 1:30 PM, Europeans running modest stations were booming in. I listended to them on the house speakers while dismantling the reference vertical out on the deck, and retrieving the radials I had so nonchalantly cast out a few, short weeks ago.
UPDATE: DECEMBER 31, 2018
Ground System Shootout Tonight
Today we built and installed the remote relay box needed to alternate between the four ground rods and 25 ground radials underneath the experimental vertical. All that remains to be done is to wire the control cable to the toggle switch here in the shack, which will be done after finishing this update (0100Z). We will then perform a comparison between the two ground systems later tonight in the general portion of the 40 Meter SSB band. A schematic appears below.
Remote Selection of Ground Systems Underneath Experimental Vertical
A/B testing tonight.
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New Feedline • Insertion of Grounded 1:1 Balun • Control Line Management
Upon arrival at the base of the house, a 1:1 balun was inserted into the feedline with the shield of the antenna-side coax earth-grounded. On the other side of the balun the coax runs up to the shack. This reduces the receiver noise floor 1 S-unit.
Shack Entry Isolation & Control Strip
Mitigate common-mode current & facilitate addition of control lines.
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Below is the present state of the feed and control lines in the field, which are in a state of flux as we prepare for the second phase of experimentation.
Today's Feed & Control Line Status
A work-in-progesss
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As part of this process, the feedline to the experimental vertical has been replaced with an 82˚ run to the remote phasing box that was installed between the vertical and the NE vertical support post. To the remote box a 1.2 WL section of coax was attached and run to the balun, as just described. A/B testing will commence tonight after checking the impedance of the feedline in the shack when the ground rod state is selected.
UPDATE: JANUARY 1, 2019
Beautiful New Year's Day
New Year's Day Spent Doing Antenna Work
A blustery day with temperatures in the low-60s.
***
Following a torrential rain storm last night, the new year day emerged blustery and clear with temperatures rising to the low-60s, affording a full day of antenna work. We concentrate on the second vertical, opting to install installing a second set of guys after watching the experimental vertical ride in heavy gusts. Here's how we do it using PVC tubes, cable ties and epoxy.
Adjustable Guy Sleeves for Vertical Radiators
PVC tubes, cable-ties and epoxy.
***
First you set the pvc sleeve to the location you want to guy the vertical; a self tapping screw fixing the sleeve to the spot. In our case it is just below a junction, which is a good place to guy a vertical if you have the option. Then you slip on the cable ties -- the ones with the holes in their tabs. After spacing them 120˚ apart they are epoxyed in place forever. We are using 1/8" parachute cord as guys lines.
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Favorite New Tool
The Hose Clamp Wrench
This is the tool I use to tighten hose clamps. I like it so much I epoxyed the hex key into the socket!
Hose Clamp Wrench
Not (yet) sold by commercial vendors at an exorbitant price
***
UPDATE: JANUARY 2, 2019
Some Initial Thoughts About the Ground System Shootout
Good morning.
View from the Operating Position This Morning
I wake up to this every morning.
***
The A/B testing of the ground rods vs. radial field has produced interesting results; namely, most stateside stations report no difference between the two. Taken on its own, this would appear to corroborate more than refute the contention that, in a salt marsh at least, four (4) ground rods work as well as 25 ground radials. I do not think this is true for the following reasons.
Firstly, when we had the reference vertical up, it was at parity with, or slightly outperformed, the marsh vertical with four ground rods stateside. When we added ground radials to the marsh vertical, we then saw an increase in stateside performance over the reference vertical, and 1 to 3 S-units better performance on longpath/grayline contacts. We would therefore assume that quickly alternating between the marsh vertical's two ground systems would merely reproduce what we saw when each ground system was the only one being used with the vertical. vertical. But this is not the case. What's up with that?
We think that it means that ground currents collected by the ground radial system are coupled to the ground rods via the salty marsh mud. In other words, when we laid-down the ground radials within the near field of the marsh vertical, we altered the ground rods' environment. We increased the density of return currents in the salty marsh mud around the base of the vertical in which the gorund rods were sunk. Thus, the ground rods behaved differently; they were able to transfer more ground current to the vertical than when they were the only ground system installed underneath the vertical.
Secondly, and perhaps more empirically, when the marsh vertical had only the four ground rodsas its ground system, it exhibited a 50 Ohm impedance at resonance, as seen below.
7.0 to 7.3 MHz Experimental Vertical Sweep
Only 4 ground rods underneath the vertical.
***
This is no longer the case after we laid-down the 25 ground radials.
7.0 to 7.3 MHz Experimental Vertical Sweep
4 ground rods & 25 radials underneath the vertcal.
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***
Heading out to the marsh to reorient the feedline perpendicular to the line formed between the two verticals, and to straighten out the ground raidals by anchoring them in the mud with these bamboo skewers procured at Walmart for $0.89/dozen!
Eco-friendly Ground Radial Stakes
$0.89 per dozen.
***
UPDATE: JANUARY 3, 2019
Second Vertical Installed
Just got back in from the marsh. Gotta go back out before tide gets any higher and patch in cables, drive ground rods and deploy some radials. But just wanted to share a couple snapshots taken of the "Twins". They look good. Second one is double-guyed. It's incredibly well-sited. Can't wait for the first Noreaster...
Phased Verticals
Succotash Salt Marsh, Matunuck, R.I.
***
The place is starting to look like a NATO listening post...
UPDATE: JANUARY 4, 2019
Tuning Phased Verticals
Waited for low tide at noon before venturing out to tune the two verticals. The process is to disconnect the verticals from their feedlines and attach the MFJ analyzer to the base of one of the verticals. Walk the resonance (lowest reactance) to the design frequency by adjusting the length of the vertical. When done, move over to the other vertical and do the same thing. Today, here in the salt marsh, we hope there is enough ground conductivity to allow each vertical to exhibit a feedpoint impedance (at resonance) close to 36 Ohms.
When we measured the experimental vertical (hereafter called the "Southwest Vertical"), it was resonating at 7.3 Mhz -- 200 Khz above our design frequency. This means we have to take it down and lengthen it by about 6". After completing this task, and reinstalling the vertical, the MFJ analyzer showed the following readings.
Southwest Vertical: 37 Ohms
Resonating on 7.1 Mhz with a 37 Ohm feedpoint impedance and 7 Ohms reactance.
Purfect!
***
The Southwest vertical ends up resonating at the 7.1 Mhz design frequency with a feedpoint impedance of 37 Ohms and 7 Ohms reactive. This is outstanding since the theoretically-ideal impedance is 36 Ohms. I can bring out the reactance by dismantling the vertical, cleaning its junctions and put them back together with dielectric grease (Editor: This is exactly what happens when the vertical junctions are cleaned a few weeks later. See the February 18 update for details). So we now off in the muck over to the Northeast vertical to see what's up with it. Remember, the Southwest vertical remains unattached to its feedline to render it invisible to the Northeast vertical.
Northeast Vertical: 41 Ohms
Resonating on 7.2 MHz with a 41 Ohm feedpoint and 6 Ohms reactance.
***
With only 3 ground rods, the Northeast vertical resonates at 7.195 Mhz with a feedpoint impedance of 41 Ohms and 6 Ohms reactive. Not bad! The resonant frequency needs to be brought down 100 Khz to the 7.1 Mhz design frequency. This would entail shortening the vertical radiator if it was not for the fact that the addition of its ground raidals will likely change the resonant frequency. So we hold off and leave the vertical as is. Obtaining 41 Ohm feedpoint impedance with only three 2.5' ground rods testifies to the conductivity and permitivity of the salt marsh, and is close to the 37 Ohms exhibited by the other (Southwest) vertical. We're psyched as we slosh through the muck back to the shack to check out what the feedline reads when the array is run through its three phasing states.
Wet Boots in the Shack • Checking the Feedline Numbers
***
Removing our waders at the sliding glass door, we attach the MFJ analyzer to the coax feedline and measure the three phasing states: Northeast, Southwest and Broadside (Omni). We should take these readings at the remote phasing relay box in the salt marsh but the tide is rising too fast. We also note that losses incurred in lengthy coaxial runs mitigate high SWR readings, making things look a lot better in the shack than they are at the feedpoint. We hope for as little change as possible in the MFJ analyzer readings as we toggle between NE and SW positions because this indicates the system is balanced, e.g. the two verticals exhibit identical impedance and reactance sweeps across the 40 Meter band.
Northeast: 37 Ohms
7.1 Mhz design frequency resonance • 37 Ohms feedpoint impedance • 5 Ohms reactance.
***
In the shack, the system reasonates at the design frequencey exhibiting a 37 Ohm feedpoint impedance with 5 Ohms reactance. This will likely change after deployment of ground radials under the Northeast vertical as discussed. Obviously we are pleased. Now, the moment of truth. What are the readings after we flip the system to the Southwest? Drum roll, please...
Southwest: 41 Ohms
7.1 Mhz design frequency resonance • 41 Ohms feedpoint impedance • 3 Ohms reactance.
***
We are pleased to see that the numbers show 41 Ohms with 3 Ohms reactance. They, too, will change after we install radials under the NE vertical and tune it to the 7.1 Mhz design frequency. We then check the third, "Broadsude" position achieved when the phasing line is shortd causing the verticals to in-phase. This condition always exhibits a problematic impedance in the Christman phasing system.
Broadside (Omni): 41 Ohms
7.1 Mhz design frequency resonance • 41 Ohms feedpoint impedance • 20 Ohms reactance.
***
NOTE: These readings, however encouraging, are taken from the shack. True system readings are obtained at the remote relay switching box in the field. Once we install the ground radials under the Northeast vertical, we will remeasure all readings.
UPDATE: JANUARY 7, 2019
Phased Verticals: Tweaking the F/B
Ocean Fog Envelopes Succotash Salt Marsh
January 7, 2019
***
Walking the F/B Down to 7.150 Mhz
Thanks for all the F/B reports, everybody. They give us an idea about the phased verticals' stateside and DX coverage when oriented NE (60˚) / SW 240˚). I am using these reports, along with monitoring foreign broadcast stations above 7.2 Mhz, to walk the maximujm Front-to-Back Ratio down to 7.150 Mhz by lengthening the phasing cable in the field. This is why I keep on asking for F/B reports in pile-ups. Perhaps not ironically, I found myself using the same jumpers to lengthen the phasing as were used in the previous installation of these verticals, detailed down this QRZ.com page. (Editor: In a moment we will learn that the phasing line needs to be lengthend several, additional inches for this salt marsh installation).
Populating Radial Field Under Northeast Vertical
I am laying down radials under the Northeast vertical, which until now has been using three ground rods. So far have laid down 8 in all directions, with 22 more to go. This will require re-tuning the vertical, and hopefully an increase in overall performance, expecially F/B, which is the most distinctive aspect of this array.
UPDATE: JANUARY 9, 2019
Phased Verticals: Re-Resonating NE Vertical • F/B Locks In
Re-resonated Northeast vertical this afternoon, dropping it from 7.5 Mhz to 7.15 Mhz -- requiring 1.5 feet lengthening. Added a RF choke to base of Southwest vertical to bleed static build-up from it.
Homemade Static Bleed Choke
AWG #16 enamel copper wire wrapped around 3/4" PVC tube • bleeds static off vertical
***
Upon return to the shack the following readings were taken at the feedline.
System Feedline Sweeps
Northeast, Southwest & Broadside (Omni)
7.04 Mhz
Northeast, Southwest and Broadside
7.15 Mhz
Northeast, Southwest and Broadside
7.3 Mhz
Northeast, Southwest and Broadside
***
We are clearly pleased with these data, especially the exhibition of 38 Ohms in all three phase states on 7.150 Mhz. These readings confirm the NE vertical would require retuning after addition of radials to the three ground rods. We also note an increase in F/B ratio on receive and transmit in the several contacts made after completing field work in the salt marsh.
UPDATE: JANUARY 9, 2019
Fine-Tuning the Christman Phasing System
Now the Hard Part
Tuning the array is the last task.
***
From flipping back and forth between NE and SW for a day or so, it has been determined that the F/B is maximized around 7.280 Mhz. Now that the NE vertical has radials and has been re-resonated, I will now walk the F/B curve down in frequency and park it where I want it, which is 7080 Mhz. This will afford excellent F/B in the CW and DX phone sub-bands between 7.2 Mhz and 7.0 Mhz. To do this I have to add a tiny bit of coax into the 71˚ phasing line out at the remote relay box. I am able to do this now because both verticals are exhibiting nearly-identical impedance and reactance sweeps.
Methodology: Moving the F/B Ratio Curve Up and Down in Frequency by Adjusting the Christman Phasing Line Length
- First we have to calculate how long 71-degrees of RG-8X is at two frequencies: where it is presently maximized and where we want it to be maximized.
- Once we do that, we subtract the length of the shorter coax (71˚ @ 7.280 Mhz) from the longer coax (71˚ @ 7.080 Mhz) to see how much coax to add to the shorter piece to make it as long as the longer piece.
- Then we cut a piece of coax that length and solder PL-259s on each end.
- We then put on the waders, go out into the salt marsh and insert the little patch cable into the phasing line using a barrel connector.
Calculating Christman 71˚ Phasing Lines
- [300/frequency] x feet/meter x velocity factor of coax = 1 wavelength of coax at frequency specified.
- Since that length represents 360˚ of the frequency's sinewave, we multiuply this length by how much 71˚ is of 360˚. This is, of course, the fraction: 71/360.
- So we multiply the 1 WL coax by 71/360 to arrive at how long 71˚ of it is.
The 7.280 Mhz and 7.080 Mhz calculations are provided below:
[(300 / 7.280) x 3.28 x 0.82 x (71/360)] = 21.859 Feet @ 7.280 Mhz
[(300 / 7.080) x 3.28 x 0.82 x (71/360)] = 22.476 Feet @ 7.080 Mhz
We now subtract the longer coax from the shorter coax to see how much coax to add to the shorter coax to make it as long as the longer coax.
This will lower the frequency of the F/B ratio curve from 7.28 Mhz to 7.08 Mhz. Or so I think. Thus,
22.476 - 21.859 = 0.619 feet or 7.4"
So the next step is to prepare the little piece of RG-8X coax, and solder a couple PL-259s on the ends.
Fine-Tuning the Christman Phasing Harness
7" of RG-8X
***
Believe it or not, this is all that is called for according to our observations switching the array back and forth for a day or so, as derived by our mathematical calculations. Seven (7) puny inches of coax inserted into the Christman phasing line out in the marsh. At times like this we think we might be crazy to think such a simple thing will walk the perceived F/B down 200 Khz to the design frwquency of 7.1 Mhz. But then we recall the original spark gap operators of a century ago, and the spirit they had for experimentation and for giving things a try based on their own observations. We put on the waders and head out to what several on the air inadvertantly refer to as "The Swamp". Let's see what happens after this simple adjustment. If anything, this constitutes one of the finer points of tuning phased verticals which, hopefully, others will perform. Remember, at this point we have received some fairly good F/B reports.
QRZ.com Readers Check-in via Email
Hank, K3YDX and Mike, VE3MEU
***
UPDATE: JANUARY 10, 2019
The Thrill of Empirical Confirmation
All I can say is BiNgO! After the installation of the 7" piece of coax, the F/B has not only been walked down to 7.1 Mhz, but is presaent throughout the 40 Meter band! I never thought that would be within the realm of the possible. But all indications on receive indicate a significant expansion of the F/B in absolute terms, as well as its manifestation across a wide sweep of frequencies: 7.0 Mhz to 7.3 Mhz. It's everywhere! I perform some random tests between 7.130 Mhz and 7.180 Mhz, and all reports surpass ones previously collected a day or so before when the extra 7" of coax were not in place. The next day I plan to conduct an extended F/B check on the air with amateurs who are following all of this on this QRZ.com page.
After installing the 7" of coax into the phasing line, the numbers read by the MFJ analyzer at the remote switching relay box locked into textbook purfection. 37 Ohms+j7 for Northeast, 38 Ohms+j7 for Southwest and 41 Ohms+j17 for Broadside (Omni). Awesome! When I saw the numbers in the field, I knew something "was up". It was not until I got back into the shack and started flipping the verticals NE/SW that I realized the extent to which the entire system had locked-in to itself.
Perfect Readings: Northeast, Southwest & Broadside (Omni)
Measured at the remote relay switch box after lengthening phasing line 7".
***
UPDATE: JANUARY 10, 2019
Checking the F/B on 7.220 Mhz
Tonight we ran F/B checks on 7220 Mhz during which about 50 amateurs, who presumably follow events posted on this QRZ.com page, provided F/B reports. In addition, and quite to my delight, several hams who could not wait through my slow pile-up operating style opted to email me in their F/B impressions! Thank you, guys! Below we see the operating position at the height of taking F/B reception reports, as well as the desk notes this session produced during its three-hour duration.
QRZ.com Readers Submit F/B Reception Reports in Massive 3-Hour Pile-Up on 7.220 Mhz.
The operating position at the height of the 3-hour session, and the desk notes it produced subsequently collated into the table appearing below
***
I added the 6" segment of coax to the phasing line to "walk" its maximum F/B down from about 7280. However, and as detailed in previous updates, this locked the phased verticals into one another producing prodigious F/B over a wide swath of frequencies, from the CW portion of the 40 Meter band all the way up above 7.2 Mhz. Thus I selected 7.220 Mhz to check the F/B to see how the verticals were performing so far above the design frequency of 7.1 Mhz. The results were fascinating, the highlight perhaps being Canadian maritime stations reporting the exact opposite results from those submitted from amateurs situated to the Southwest. Of course, this is what is supposed to happen, according to theory. But it is always exhilerating to see theory confirmed empirically. After the F/B ratio reports were written down in the "scientific notebook" maintained in the shack, I looked up each station on QRZ.com and recorded their azimuth bearings in for inclusion in the table submitted below for your hopefully enjoyable review. Thanks everybody!
| Call Sign | Northeast | Southwest | F/B vs. Bearing |
|---|---|---|---|
| WE1DEN | 53 | 59+10dB | 52 dB - 270˚ |
| KW4GT | 59 | 59+15dB | 15 dB - 242˚ |
| W4RCT | 57 | 59+10/20dB | 25 dB - 204˚ |
| KN4GCA | 57 | 59+10/15dB | 15 dB - 227˚ |
| WX5J | 55 | 59+10 | 35 dB - 252˚ |
| KK4PIV | 55 | 57 | 10 dB - 237˚ |
| N4RXV | 56 | 59 | 15 dB - 232˚ |
| VE3RFA | 59 | 59 | 0 dB - 293˚ |
| VO1CRP | 59+10/20dB | 57 | 25 dB - 59˚ |
| W3ABA | 51 | 59+5dB | 45 dB - 177˚ |
| N5WVC | 59 | 59+10dB | 10 dB - 260˚ |
| KP4JJO | 53 | 57 | 20 dB - 170˚ |
| N8YYB | 55 | 59+10dB | 30 dB - 252˚ |
| WA4PMK | 53/4 | 59+10dB | 35 dB - 238˚ |
| VE2QGL | 59 | 59+20dB | 20 dB - 329˚ |
| KD9IPO | 55 | 59 | 20 dB - 278˚ |
| KD8YVD | 59 | 59+20dB | 20 dB - 257˚ |
| N4QNT | 57 | 59+10/15dB | 20 dB - 235˚ |
| VE3LRL | 59+40dB | 59+60dB | 20 dB - 290˚ |
| AA4XA | 59 | 59+20dB | 20 dB - 218˚ |
| KC3KRE | 57/9 | 59+30dB | 35 dB - 270˚ |
| K4RCI | 57 | 59+10dB | 20 dB - 232˚ |
| KB1YTO | 55 | 59+30dB | 35 dB - 346˚ |
| WA3RSL | 59+25dB | 59+40dB | 15 dB - 237˚ |
| K5GI | 58 | 59+10dB | 15 dB - 259 |
| N1UJD | 57 | 59 | 10 dB - 003˚ |
| K4JSC | 53 | 59+20dB | 50 dB - 236˚ |
| K3RSJ | 55 | 59+5dB | 25 dB - 240˚ |
| N3OHI | 58 | 59+20dB | 25 dB - 265˚ |
| KC3MIO | 59+10dB | 59+35dB | 25 dB - 263˚ |
| WB8DMX | 33 | 59+10dB | 40 dB - 264˚ |
| VE3MEU | 59+10dB | 59+40/60dB | 40 dB - 289˚ |
| AI8O | 56 | 59 | 15 dB - 233˚ |
| WD9ENB | 55 | 59+10dB | 40 dB - 275˚ |
| KN4ADM | 53 | 59+10dB | 40 dB - 227˚ |
| W1GTA | 57 | 59+20dB | 30 dB - 227˚ |
| KC2WWZ | 35 | 59 | 20 dB - 270˚ |
| W8AVW | 59+5dB | 59+20dB | 15 dB - 244˚ |
| WV4P | 59 | 59+20dB | 20 dB - 250˚ |
| KE2QI | 59+10dB | 59+20dB | 10 dB - 322˚ |
| N4GA | 57 | 59+30dB | 40 dB - 238˚ |
| KB8WPZ | 58/9 | 59+20dB | 20 dB - 271˚ |
| KD5FHW | 55 | 59+10dB | 20 dB - 247˚ |
What we're looking for is the following. Since the phased verticals are sited 60˚ Northeast and 240˚ Southwest, we compare the F/B reports to their compass bearings. The F/B ratio reports from stations situated on or near either of these two bearings, 60˚ and 240˚, are looking directly into the then away from the forward lobe. Their's will be front-to-back observatiuons. Reports received from stations situated 90˚ off these bearings, e.g. 150˚ and 330˚, will be situated perpendicular to the array's F/B pattern, and expected to see no difference at all. From these stations we should see smaller F/B ratio reports. Stations situated about 45˚ +/- the main lobe bearings (60˚, 240˚) might be seen providing the largest F/B reports since they will be seeing the forward lobe and then one of the array's rear-quarter nulls produced to create the small nub off the rear-end due to non-optimum tuning of the F/B. Hence we look to see if stations +/- 45˚ (or so) off-axis from the dead rear-end reporting higher F/B ratios. All of this is, of course, quite subjective. But it is fun to do, and represents the way original spark gap poineers shared with others, through wireless means, the results of their individual tinkerings with the ether. And that is exactly what we are doing here.
UPDATE: JANUARY 13, 2019
2nd Bleed Choke Installed
Installed the second RF choke across feedpoint of Northeast vertical. Both verticals now are so equipped.
Homemade vs. Commercial: Static Bleed Chokes
To the left we see the 2nd homemade choke installed today on the Northeast vertical. Cost: $0.
On the right we see one sold by Array Solutions. Cost: $40. Take your pick.
Since phased verticals requires two, you'll end up sending Array Solutions $90 for two of them.
***
UPDATE: JANUARY 14, 2019
Site Survey
A Shack with a View
Phased verticals always in view from the operating position.
***
Asia, Longpath
Salt marsh extends to seaside homes situated on the Atlantic coast.
***
Ground Systems: Southwest and Northeast Verticals
Hopefully dispelling the notion that the ground system is not important.
Ground rods connect through green wires. Ground radials attach to ring.
Rf choke bleeds static electricity build-up.
***
UPDATE: JANUARY 21, 2019
"AHHhh... Houston... We've got a Problem..." • NE Vertical Submerged in Frozen Salt Water
Dayem! Yesterday's storm surge, combined with the Blood Moon abnormally high tide this morning, swamped Succotash Salt Marsh at 7 AM, submerging the Northeast vertical underwater. Actually, ice. I knew it would happen by monitoring the local tide charts, and attempted to raise the NE vertical yesterday when temperatures were a balmy 28˚.
Huston, We've Got a Problem • Northeast Vertical Submerged
4-foot high Blood Moon tide plus yesterday's storm surge coalesce to swamp the Northeast vertical underwater.
Dropping temperatures freeze Succotash Salt Marsh, locking the vertical into ice.
***
Here's the system impedance and reactance of a pair of submerged saltwater verticals to the Northeast, Southwest and broadside, as measured in the shack this morning.
Feedpoint Impedance and Reactance of Submerged Phased Verticals
Northeast, Southwest and Broadside
***
I am waiting for the tide to drop so I can go out there in 0˚ temperature to attempt to raise the Northeast vertical by several inches. I think I can do this by unguying it and raising the aluminum tube up in the PVC insulator tube, drilling a new hole to set the bottom retaining screw at a new height. Not a problem given the design of the vertical base support scheme. I tried to do it yesterday afternoon, but lost light while raising the more-important remote switching relay box higher above the high tide waterline. She survived without getting swamped. (Editor: actually, this was not the case. As we shall shortly see, the problem was in the switchbox which had been repeatedly subjected to immersion in salt water at previoous high tides). The only problem with doing this is that it is extremely cold outside, and the waders aren't insulated. This morning the air temperature was so cold that The Marsh and Atlantic ocean were steaming like a hot cup of coffee. I shot photos and video which I will edit and post on YouTube later this morning.
Point Judith, Rhode Island
Cold air temperatures caused sea water to steam like hot coffee.
***
I have installed the L-match into a tackle box in order to mount it in The Marsh next to the remote switching relay. This will enable me to establish a 1:1 SWR and zero reactance down the feedline heading back to the shack, as well as install a dozen ferrite beads between the switchbox and the L-match. This might quiet-down even further the common-mode noise on the coaxial feedline heading back to the shack.
L-Match Readied for External Installation
A tacklebox serves as weather-proof enclosure for the L-Match.
Matches 38-Ohm impedance tio 50 Ohms.
***
UPDATE: JANUARY 22, 2019
Salt Water Immersion Blows Out RF Connectors
SO-239 in Remote Relay Switchbox
Here's what happens when Saltwater gets into a RF Connection
After repeated submersion at high tides, the feedline connector finally failed. The mating PL-259 was also destroyed.
***
So today's update reveals my misdiagnosis of the NE vertical feedpoint as the source of the difficulty. Tracing the problem from this starting point led me to the remote switchbox when the NE 84˚ line checked-out good. When removing the box in order to barrel-connect the SW vertical to the feedline, I discovered the SO-239 and PL-259 connectors had ice in them which, when chipped-off, revealed major arcing had been taking place for quite some time. This explained the problem I had been ghaving for several days of RF getting into my audio back in the shack. I removed the switchbox and cables, chipping them out of the ice pack, and connected the SW vertical to a second, back-up feedline pre-installed when I set up the system. This worked and I was back on the air with a single vertical last night, with full control over my audio. I replaced the connectors in the switchbox and on the feedline, slipping some ferrite beads on the latter to further reduce common-mode noise on receive. BooM. DonE.
New Switchbox and Feedline Connectors
Added ferrite beads to main feedline at switchbox end.
***
What we're going to do today is measure the length of the 71˚ Christman phasing line we ended up with and replace it with a new contiguous length of coax. This emancipates the barrel conectors presently tied-up in the lengthening of the phasing line, while making available for use several short patch cables. One of these patch cables will be used to connect the L-match to the remote relay switchbox after I mount both onto the same post.
OK, I just did that.
Measuring the Final Length of the 71˚ Christman Phasing Cable
We finally get to see exactly how long it ended up being.
***
24.5' is the final length that I ended up with to lock the system into its present performance level. Let's compare that to mathematical calculations which set the 71˚ Christman 71˚ phasing line at 22.4' for RG-8X @ 7.1 MHz. This means we are Two Point One (2.1) feet longer, which could partly be due to the actual velocity factor of the coax I am using and partly because of the soil characteristics intrinsic to the salt water installation. However, we note that we had to add 7" to the same 71˚ phasing line used at the previous, inland installation (Editor: using the elevated counterpoise system detailed further down this page). So I would say that the real-world conditions surrounding a phased aerial installation do determine the final dimensions of the Christman phasing lines. In fact, if we subtract the 7" required for our salt marsh installation, we come up with 23' 10" as teh length of the phasing line used at the inland installation which used elevated counterpoise wires. Let's step-back and check out how these numbers crunch, as seen below.
- Mathematically Calculated Length: 22.4'
- Inland Installation Length: 23.8' (106% longer)
- Salt Marsh Installation Length: 24.5' (109% longer)
That's empirical data derived from our own experimental work performed over the past few years. We may not win a Nobel Prize, but we can assuage concerns perplexing others building any phased array about sticking with coaxial lengths mathematically calculated. Any installation has to be tweaked because each one exhibits final qualities unique unto itself. So don't be afraid to deviate from dimensions provided by mathematical formulas or computer modellings. Here's what else we did today.
We installed fresh coaxial connectors throughout the system, and consolidated several integral systems into one mechanism.Some of this work can be seen below.
Massive Retrofitting of Entire System
New Christman 71˚ Phasing line & connectors • New feedline connector and current choke
• Liquid Electrical Tape® oozing into rear of Phasing line connector • More Liquid Electrical Tape® slatehred over main feedline connector
***
These items were brought together into a phasing & impedance-matching system installed out in The Marsh. We raised it above upcoming Super High Tides.
Integrated Phasing and Impedance Matching System
Remote relay phasing box and L-match • Provides 1:1 SWR on feedline leading back to the shack
***
This system was installed in the afternoon and converts the 37 Ohm j7 impedance at the remote switching box into 50 Ohm j0 along the RG-8X feedline run back to the shack. This reduces receiver noise resulting from common-mode ingress along this stretch of the array's cabling system. Ferrite beads were added to the feedline to further decouple it from the array. Upon returning to the shack at sunset, a European pile-up errupted producing numerous 59+10dB to 25dB signal reports and 25db to 30 dB F/B observations.
DXSummit: January 22, 2019
Initial test of system upgrades produces encouraging results.
***
When the system F/B was tested, the average EU report was 25 to 30 dB. I think the installation of new PL-259 connectors with reducers, soldered with an eye on making good shield connections, combined with the removal of several PL-259 & barrel connectors integrated into the phasing line when tuning the array, have improved its overall operation. Up next will be to raise the feedpoint of the NE vertical so that it cannot be shorted-out by super high tides. After that we will relocate the SW vertical deeper into the Marsh so that it becomes the NE vertical. This will allow for the deployment of both ground radial systems (30 radials) in a symmetrical fashion, bring both verticals to the same elevation and cause their ground radial systems to be swamped by salt water at high tides.
UPDATE: JANUARY 23, 2019
Raised Northeast Vertical Above Super High Tide Line • EA5AVL Reports a Whopping 48 dB Front-to-Back Ratio.
DXSummit: January 23, 2019
First session after raising Northeast vertical.
***
UPDATE: JANUARY 24, 2019
Atlantic Storm Makes Landfall, Buffeting Verticals with 80 MPH Gusts • Storm Surge Swamps Northeast Vertical One Day After Raising Its Feedpoint 2 Feet
4' Storm Surge Swamps Northeast Vertical
One day after I raised its feedpoint 2 feet!
***
Outrageously, the day after I raised the Northeast vertical feedpoint 2 feet higher, an unannounced storm off the Atlantic landfalls in Southern Rhode Island, bringing with it sustained windspeeds of 45 MPH, gusting to 80 MPH for several hours. I couldn't believe it as I sat in the ham shack lookinbg out through its sliding glass door watching enormous gusts bend the verticals over despite their 3-point, double-tier guying systems. Many times they were parallel to the horizon, almost as if bowing to the North in supplication to the Gods blowing them from the South. When the gusts subsided, both verticals attempted to resume their vertical positions in winds measured by my anenometer at 45 MPH! I was proud of them, and, of course, of myself, as each attempted to return to their vertical positions under tensions provided by their guys. But then one wind gust arrived, around 5 PM, that pushed the Northeast vertical to the North so extremely that it was permanently bent and could no longer stand up straight.
Northeast Vertical Vertical Succumbs to 80 MPH Gust
Several hours later both verticals will emerge with minor damage..
***
Remember, the Northeast vertical is the one with single-walled tubing, whereas the Southwest vertical has double-walled tubing inside its middle-third. It emerged from the storm without any permanent damage despite the placement of its upper guy ring uo too high. The newly-renovated remote-switching/Z-match box resolutely defied the Atlantic storm, emerging unscathed and bone dry when opened up the next day.
Newly-renovated Remote Switchbox Defies Atlantic Storm
The contraption worked perfectly.
***
Succotash Salt Marsh at High Tide
At this point ground conductivity is supplanted by the skin-effect,
rendering the modelling of the phased verticals beyond reach of antenna modelling programs.
***
UPDATE: JANUARY 28, 2019
Extremely Low Take-off Experiment: Working Europe at 2 O'Clock in the Afternoon (1900Z)
Low Take-off Angle: Europe at 2 PM, January 28, 2019
Testing the low take-off angle of the Saltwater Verticals produces interesting results.
***
Phased Verticals Longpath in Tasmania
Working EU pile-up 1500 EDT on January 31, 2019
Recorded in Tasmania by VK7FRJG, Rod.
UPDATE: February 6, 2019
Extremely Low Take-off Experiment: Working Europe After Local Sunrise
We are preparing to test the lowest component of the verticals's take-off angle. The experiment is to call CQ at weird hours of the day in an attempt to get through to different regions before the band would be expected to be open. The mechanical preparation for this experiment began last Sunday with the restringing of 30 ground radials around the Northeast vertical so that they are symmertrical and taut. This detuned the NE vertical by 50 Khz, which was corrected. Next up will be the relocaiton of the Southwest vertical deeper into the salt marsh, siting it to the northeast of the present NE vertical, rendering the latter the southwest vertical. This will be done in order to more fully deploy its 30 ground radials in a symmertric fashion, as well as to (finally) get both verticals at the same elevation. Relocating the vertical in this fashion will allow its entire ground radial fieldl to be swamped at high tides; at present only half of the raidal field (North East South) extends into the marsh.
After restringing the NE vertical radial field, we hailed Europe at 7:15 AM, which is 12:30 PM Zulu. Two stations were worked in the UK, one being a mobile.
Working Europe at 7:15 AM, EDT
February 6, 2019
***
UPDATE: February 9, 2019
Antartica Calling
IA0/IZ1KHY, Danilo in Antartica, responded to a CQ put out this morning around 5 AM EDT. His 1 KW signal peaked at 58. Prior to that, on a relatively dead band, several Middle Eastern stations were presenting significant signals.
Antartica Worked • February 9, 2019
IA0/IZ1KHY, Tony, in Antartica.
***
UPDATE: February 12, 2019
Extremely Low Take-off Experiment: European Pile-up After Local Sunrise • Recordings of the Phased Verticals in Europe here.
Daylight European Pile-up • DxSummit Spots • February 12, 2019
Working Europe Until 12 Noon
***
Continuing our test of the low elevation angle of the phased saltwater verticals this morning by getting up at 4:30 AM to hail Europe before sunrise on the East coast. To our surprise European signals were presenting themselves well over the S9 mark. A massive pile-up ensued, recorded in its entirity here. The QRZ log appears below.
European Daytime Pile-up
February 12, 2019
***
It was surreal working European stations as the edge of the Eastern horizon began to glow the deep reddish-purple of first light, let alone well after the sun emerged over the horizon, bathing the salt marsh in a yellow-orange glow. I used the European SDR in the UK to monitor the phased saltwater verticals in Europe, watching with amazement the S meter readings produced by the aerial. The recordings can be found here. This subjective experiment indicates the take-off angle of the phased saltwater verticals is unusually low.
UPDATE: February 18, 2019
Cleaning the Verticals
Every once in awhile it is best to disassemble a saltwater vertical in order to clean and re-grease its mechanical junctions. This reduces Ohmic losses. The last time I did this, which was when the verticals were installed in the woods with an elevated counterpoise system, it dropped the reactive component at resonance down to 2 or 3 Ohms. I hope it happens this time. The tool kit assembled for this job is depicted below.
W1ZY Vertical Radiator Ohmic Loss Reduction Kit for Suckers • $89.95 + Shipping
Dielectric grease, a copper scouring pad, a (red) mechanic's shop rag and a plummer's pipe brush are all that's needed to reduce Ohmic losses.
Total cost at Home Depot about $8.
***
What I do is start at the top junction, where the tubing is smallest in diameter, and work my way down the vertical. Since I use set screws at the junctions, when I put them back together there is no alteration of the vertical's length. Once I separate two tubes at a junciton, I scour the outside of the smaller diameter tube with a copper pad laden with Brasso®, and then wipe off the residue with a mechanic's shop rag. I then use a plummer's bvrush, available at Home Depot, to burnish the inside of the larger diameter tube. I then lay dielectric grease on the outside of the smaller diameter tube and run it in and oout of the larger tube to distribute the grease throughout the junction. The tubes are then reconnected with hose clamps and stainless steel sheet metal screws which lock them tight. I then move down the vertical to the next junction. The whole process takes about 45 minutes for a 40 Meter 1/4 WL vertical made of 6' sections of telescoping aluminum tubing. Sometimes, if I feel anal compulsive, I will lay a bead of Liquid Electrical Tape around the junction ledge to further prevent water ingress, although this is certaily overkill. I do it mainly becuase I have the Liquid Electrical Tape available in The Shack.
Cleaning the Vertical Junctions
Junction seen after being disassembled, cleaned and refitted after application of dielectric grease.
***
I worked my way down the Southwest vertical in this fashion yesterday afternoon. I then reinstalled the contraption to the ground pipe, which is from a child's swingset. After resetting the two-tiers of three-point guys (1/8" parachute cord), I removed the Northeast vertical radiator from its feedline and used the MFJ Antenna Analyzer to sweep the Southwest vertical's feedpoint. Remember, both verticals have to be detatched from their feedlines in order to tune either of them individually. Check out the reading, provided below.
Southwest Vertical Apparently Detuned 500 Khz After Element Cleaning
At least the reactive component is now down to zero.
***
False Alarm Evoked by Operator Error
Turns out I made a mistake. I overlooked the fact that one of the ends of a hose clamp was touching the Southwest vertical radiator, detuning it in effect. Once bent out of the way, the MFJ Antenna Analyzer readings presented a more reassuring 7.048 MHz resonance with a few Ohms of reactance. Interestingly, this is the same reading presented by the Northeast vertical a week earlier after resetting its ground radial system, as described in a previous update. So now both verticals resonate at 7.050, requiring each to be walked up in frequency about 50 KHz, which means shortening them by about 3". I will hold off doing this because tomorrow I am going to relocate the Southwest vertical even further into the Salt Marsh in order to more symmetrically distribute its ground radial system.
Shortcuts for Builders
For those of you interested in ballpark shortcuts, below we find lengths and corresponding frequency deviations for 1/4 wavelength verticals on 7 MHz. Which means how far you have to adjust the vertical to walk it up or down the corresponding frequency.
- 6" per 100 KHz.
- 3" per 50 KHz.
- 1 1/2" per 25 KHz.
- 3/4" per 12.5 KHz.
UPDATE: February 19, 2019
Reorganizing the feedpoints
Good Omen
Juvenile hawk hanging out before being chased off by sea gulls.
***
Phasing and Switching System
The 38 Ohm feedpoint impedance is transposed to 50 Ohms by an L-match encased in a tackle box before being sent down the feedline.
Homemade remote relay switch box is hermetically sealed to preclude water ingress. Ground radial system underneath the Northeast vertical.
***
