February 12, 2019

Extremely Low Take-off Experiment

European Pile-up After Local Sunrise

Recordings of the Phased Verticals in Europe here.

Continuing our quest for low elevation angle experimentation 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

 

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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. 

February 9, 2019

Antartic 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. 

 

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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

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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.

 

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Phased Verticals Longpath in Tasmania

Working EU pile-up 1500 EDT on January 31, 2019

Recorded in Tasmania by VK7FRJG, Rod.

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!

 

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Vertical in 80 MPH Winds

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

NOAA Warning

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.

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.

 

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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.

 

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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.

 

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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.

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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.

 

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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.

 

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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: These items were brought together into a phasing & impedance-matching system installed out in The Marsh. 

New Phasing line
& connectors 

We raised it above upcoming Super High Tides (editor: using the elevated counterpoise system shortly described in this blog). 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.

• 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.

 

Phasing & Impedance

Matching System

Waterproofing
Connectors

We installed fresh coaxial connectors and consolidated several integral systems into one mechanism. These items were brought together into a phasing & impedance-matching system installed out in The Marsh. We raised it above upcoming Super High Tides. This field work was installed this 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 erupted 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.

 

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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.