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. 

20 Ground Radials: Vertical Resonant Feedpoint Impedance 

Impedance same as 10 radials • Resonant frequency raised 64 Khz.

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A few hours later, after installing 10 more ground radials in the marsh...

20 Ground Radials: Resonant Feedpoint Impedance

Impedance same as 10 radials • Resonant frequency raised 64 KHz.

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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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