[Lowfer] 2200m dynamic load

[Michael Sapp]

Brian:

In my back yard, the EWE ground system is about 35~40ft NS and 50 ft E~W 
with 4ft ground
rods, perimeter wire, and X wires connecting the 4 corner ground rods.

https://www.dropbox.com/s/epfdjht9o7rjle0/ewegnd.JPG?dl=0

I just checked the DC return current from the EWE ground system to the bus 
bar trench ground installed for my home AC service 150 feet away and see

80ma with slow drift downward at 12.5V (156 ohms) and  310ma at 25.5V (82 
ohms) with slow drift downward using

17AH 12V batteries as the power source for testing.  I still have frozen 
ground down about 3~4 inches. I expect these resistance readings to be half

of what they are now in another month once the ground thaws completely.  I 
check my DC ground resistance periodically

and clean all my ground connections every few months with Scotch brite pads 
and silicone oil.

I would make sure your ground rod connections are clean and tight and do 
whatever you can to lower the current

density on the ground rods. How many aluminum ladders or chicken wire rolls 
can you lay on the ground and temporarily tie into the ground rods?

73, Mike wa3tts


----- Original Message ----- 
From: "Brian, WA1ZMS" <wa1zms at att.net>
To: "Lowfer" <lowfer at mailman.qth.net>; <rsgb_lf_group at yahoogroups.co.uk>
Sent: Sunday, April 01, 2018 8:39 PM
Subject: [Lowfer] 2200m dynamic load


> While trying to get a bigger PA set-up today on 2200m, I ran into a 
> problem which is rather odd.  It would appear that my ground losses are a 
> function of RF currents flowing.
>
> Has anyone seen such an effect with rather lossy ground at LF?
>
> That fact that the load Z shifts and thus detunes any PA driving it (I 
> have tried two different PAs) makes for more chasing one's own tail when 
> measuring Z both inside and out at the antenna.  My ground losses on 2200m 
> are on the order of 40 ohms so that's part of my root problem!  Time to 
> build a 2200m Scope match I suspect.
>
> Comments?
>
> -Brian, WA1ZMS
> iPhone