Topband: RX ant-Frozen ground

[Tim Shoppa]

Steve - when I see an increase in Intermod, my mind goes away from poor grounds, and towards oxidized connectors and flaky relay contacts.

Reseat all connectors, tighten all screws, and hot-switch relay contacts till you find the offender.

Tim N3QE

Sent from my iPhone

> On Dec 7, 2016, at 4:35 PM, VE6WZ Steve <ve6wz at shaw.ca> wrote:
> 
> I’m wondering what experiences are out there regarding small vertical array, or beverage performance in the winter over frozen ground.
> 
> The reason for this question is that over the last 2 weeks or so, my HI-z (24’ vertical) SDR skimmer antenna at my remote QTH has shown somewhat diminished performance and a dramatic increase in AM inter-mod byproducts on 160.
> During the somewhat hasty install of this antenna (the SDR “RBN skimmer” antenna was not considered an important part of the station) I had some trouble driving the ground rod for the HI-z amplifier and only ended up with about 3’ of copper pipe driven into the ground. During this past summer and fall the performance was good.
> Winter has been here for a while. Last night it was -28 deg C. Today, that rod is now probably sitting in a block of solid ice. (ok, not solid ice, but the conductive dissociated ions from the native salts distributed within the soil are now locked in ice)
> 
> In truth I am not really concerned about this particular antenna, but I do plan to install an 8 circle array as well as some beverages  this summer and this problem got me thinking about making sure I have a “seasonally stable” ground system up here in the frozen north.
> Some quick research points to potential frost depths ranging from 6’-8’ depending on snow cover and soil type. Perhaps driving deeper rods could help, but it seems to me that there will still be a seasonal change of consequence. Literature associated with various short vertical array products indicate that 3’-4’ rods should be adequate, but is this true in a northern climate?
> For the most part, I could care less whether the array works in the summer…..it’s during our winter DX season that I want performance.
> 
> Perhaps a very carefully designed and symmetrical short ground radial system could stabilize things, but I know with phased rx vertical arrays this can be a big problem and cause phase imbalances. Perhaps on my beverages a small radial system at the termination would be helpful.
> 
> I am not new to rx antennas, having built and used numerous single wire beverages, reversible beverages and end-fire phased beverages as well as passive and active (Hi-z) phased vertical arrays at my home QTH, but have never “noticed” a problem.
> BTW, it is possible that there is something else going on with my SDR antenna other than a ground problem, and I will be checking that out next time I’m at the station. However,  I think I’ll still want to consider the frozen ground impact even if there is something else going on.
> 
> Any experiences, measurements or ideas from those living in places where it snows a lot, you have something called a “block heater” for your car, and when you work outside you last about 5 minutes before your hands and toes are numb??
> 
> de steve ve6wz. 
> 
> 
> Steve Babcock  
> Lead Geologist, Mature
> TAQA North Ltd.
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