[ARC5] "Curing Chirp in Command Transmitters"

[Mike Hanz]

Ignore it indeed.  That seems like sage advice.  I always scratch my 
noggin when I read solutions like that, since they reveal nothing of the 
analysis process that led them to the particular solution presented.  
When faced with a similar chirp problem, KB4DMF did it the right way - 
put an oscilloscope on the transmitter to characterize the chirp and 
started zeroing in on the cause, which then naturally led to the 
solution.  I really don't understand how presumably technical people can 
agonize over solutions without a scope to give them a view into the 
innards of the physics.  It makes trying fixes so simple.

For more on Steve's particular system and its resolution, see 
http://aafradio.org/docs/Relay_timing_issues_-_SCR-274N.html

I hasten to add that he makes no claim that it is the grand solution for 
everyone, and documents the boundary conditions for the system and 
problem.  For me, the main takeaway was the process.  It would have been 
refreshing if others back in the day had done the same.

            73,
  - Mike   KC4TOS

On 10/5/2014 1:19 AM, WA5CAB--- via ARC5 wrote:
> My thoughts are that the filament voltage in a BC-459 is 24-28 VDC. As his
> isn't, there is no telling what other probably unnecessary mods had been
> done to the transmitter. As has been demonstrated numerous times, Command Sets
> (and many other military sets) work quite well in the unmodified state when
> operated as designed. The H&K is worthless as he gives no information about
> what else had been done to the transmitter to screw it up. Ignore it.
>
> Robert D.
>
> In a message dated 10/4/2014 6:38:13 PM Central Daylight Time,
> r390a.urr at gmail.com writes:
>> One of my 'finds' at Shelby last month was a 1947 edition of "Hints and
>> Kinks for the Radio Amateur." In the 20 page "Converting War Surplus"
>> section, I found the following:
>>
>> <begin quotation>
>>
>> Curing Chirp in Command Transmitters
>> Alfred Scott Cline, W6LGU