[ARC5] AN/GRC-109 antenna clamping diodes CR1, CR2

[Tom Lee]

I should've read your subject heading! So they're directly across the 
antenna, I assume from your description. 1N34A's are hardy for their 
size, so they give decent protection on a per pF basis, but they don't 
offer much in the way of protection on an absolute basis. But if they're 
shorted but the receiver otherwise works, that's empirical evidence that 
they protect well enough.

--Tom

-- 
Prof. Thomas H. Lee
Allen Bldg., CIS-205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 2/18/2019 10:17 PM, Tom Lee wrote:
> Hi Bill,
>
> That's a Hughes part number, germanium (I believe). Specs are 60V 
> breakdown, 200mA max forward current. A 1N34A would be a close sub. 
> Where in the circuit are these diodes? That would provide a clue as to 
> whether the 1N34A makes sense.
>
> --Cheers,
> Tom
> -- 
> Prof. Thomas H. Lee
> Allen Bldg., CIS-205
> 420 Via Palou Mall
> Stanford University
> Stanford, CA 94305-4070
> http://www-smirc.stanford.edu
> On 2/18/2019 10:03 PM, Fuqua, William wrote:
>>
>>   I was testing the GRC-109 and found that the TR switch in the 
>> transmitter was not passing any signal.
>>
>> I suspect CR1 and CR2 HD2172 diodes are bad. What would be a good 
>> substitution for these? I can't find any data on them.
>>
>> The receiver works well down to less than a uV on CW with the signal 
>> applied directly to the antenna terminals.
>>
>> 73
>>
>> Bill wa4lav
>>
>>
>>
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