Fw: [500kc] [Lowfer] Re: AMRAD Probe antenna part needed

[James M. Walker]

> Hi Jay,
> Yes I have an ample supply of the J310 devices here, all in TO-92 package.
> As the AMRAD Probe was a "loaner" for evaluation purposes only, I want
> to repair it to original form before returning it.
>
> As an aside, I also ran some evaluations on "different" devices in RX 
> antenna
> applications and found that, put simply the best approach so far has been 
> to
> "Amplify the Crap" out of the "received spectrum at the antenna" then pipe 
> it
> down to the receiver location, and filter it through band-pass filters to 
> remove
> as much of the unwanted spectrum as necessary, and apply a narrow 
> bandwidth
> amplifier for the segment I want. That is another story altogether.
>
> This request is just to repair back to original components, for return to 
> the
> lender.
>
> Thanks for the info, much appreciated.
> Jim
> WB2FCN
>
> Sent: Tuesday, June 10, 2008 7:32 AM
> Subject: Re: [500kc] [Lowfer] Re: AMRAD Probe antenna part needed
>
>
>> 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