[Lowfer] Re: AMRAD Probe antenna part needed

[jrusgrove at comcast.net]

Jim

Built a half dozen e probes a few years back for a mil project and had a 
chance to evaluate some variations. The following chart shows performance 
with the CP666 and a standard old J310. Performance of the J310 improved 
with higher voltage - the J310 was biased for 15 - 25 mA idling current. No 
other changes to the existing circuit are necessary.

Results: http://www.w1vd.com/E%20probe.pdf

I've been planning a test to evaluate two or three J310s in parallel to see 
if  the 1 dB compression can be brought up to CP666 levels. I'll post the 
results here when the tests are completed.

Since the closest broadcast stations to me are 1) a 50 kW at 11 miles and 2) 
a couple kW at 3 miles the J310 is perfectly adequate - no unexpected 
signals are received.

Instead of an NE2 bulb I use a Bourns 2035-09-B two pole gas discharge tube 
and haven't experienced any failures even with nearby lightning strikes. 
These are available from Mouser and DigiKey.

Jay W1VD  WD2XNS  WE2XGR/2