[R-390] Orange Drop vs ceramic disc

[Jerry K]

I realize this happens often on this list, and it's sometimes fun. But 
you guys are definitely trying to pick fly poop out of the pepper, 
collect it in a sock, and beat a dead horse with it. After working on 
military receivers, transmitters, radars, and such since 1960--mostly 
Navy, I've personally yet to see a single disk ceramic OR orange drop 
(that was subjected to normal operating voltages) fail. Ever. Not once. 
It's possible, and it might even happen on super rare occasions 
somewhere, but the average MTBF on both types must be an astounding 
number. And with the FCC limiting U.S. broadcast stations to a 10 KHz 
bandwidth, and hams limited to 6 KHz (LOL!) worrying about a falloff in 
response at 20 KHz is a bit beyond reasonable. I personally like disks, 
mainly because they are cheap as dirt and OD's are increasingly 
expensive for reasons unknown. And disks have worked perfectly in the 
R-390A's I've put them in. The main advantage I can see for OD's is you 
can flip a module over and tell instantly if and where it's been 
recapped, since they stand out like a neon sign.

Kielbasa, anyone? :)

73 Jerry W5KP (USN Retired)



On 4/1/2011 9:58 AM, Ben Loper wrote:
> I may try something this weekend.  I have an HP audio osscilator and a two
> trace scope, so maybe just start feeding a signal through a cap and watch on
> the scope.  I don't remember the top end but I think 20 khz for the audio
> oscillator.  I can listen also but my ears crap out at about 10 khz last
> time I checked..
>
> On Fri, Apr 1, 2011 at 9:36 AM, Barry<n4buq at knology.net>  wrote:
>
>>   On Fri 01/04/11  9:05 AM , rbethman rbethman at comcast.net sent:
>>> The difference in performance between the two R-390A/URRs that you did
>>> have so many variables that it is impossible to say why.  Could be the
>>> difference in alignment, methodology of restoration, or different
>>> manufacturer of the actual radio.
>>>
>>> You have been using HP equipment lately.  What did you use before that?
>> At that time, I was using an HP410B, a General Radio GR1001A with a Fluke
>> 1920 counter .  The 1001A was replaced with an HP606A and now an HP8640B.  I
>> still have an HP410B and an HP410C.
>>
>> Barry - N4BUQ
>>
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