[ARC5] Fw: Varying oscillator frequency. re: Anode voltage on tank coils in the GF-11 and SCR-274N series Command transmitters

[Henry Mei'l's]

I wasn't referring to inductors having metal (metallic) cores
BUT don't the Command set transmitter oscillators use a
powdered ferrite adjustment core? Shouldn't a DC current
influence the core mU and thus coil inductance? Though assumedly
not even approach saturation under normal transmitter operating conditions.
(As far as I can see, Magnetrons/Klystrons operate on entirely
different principles so I suppose my comparison was irrelevant.)

Henry



----- Original Message ----- 
From: "Henry Mei'l's" <meils at get2net.dk>
To: <arc5 at mailman.qth.net>
Sent: Sunday, April 17, 2011 12:08 PM
Subject: Varying oscillator frequency. re: Anode voltage on tank coils in 
the GF-11 and SCR-274N series Command transmitters


> Pretty sure I've read that DC coil current flow is actually used to vary 
> oscillator frequency.
> I don't know if this is remotely relevant to klystron and/or magnetron 
> burst pulse operation.
> Back to the theory books for me or maybe some internet research unless 
> someone like
> Dennis, John, Ken, Les, and many more here .... can fill me.
> (BTW if any are tired of my "witty comments" - what about me: I have to 
> hear them
> everywhere I go!  Maybe Mark Twain somehow sneaked into my family tree.)
>
> Henry
> oz3o (oz1uf)  n2nr
>
> ----- Original Message ----- 
> From: "Henry Mei'l's" <meils at get2net.dk>
> To: <arc5 at mailman.qth.net>
> Sent: Sunday, April 17, 2011 9:09 AM
> Subject: [ARC5] Fw: Anode voltage on tank coils in the GF-11 and SCR- 
> seriesCommand transmitters
>
>
>>
>> ----- Original Message ----- 
>> From: Henry Mei'l's
>> Sent: Saturday, April 16, 2011 11:28 PM
>> Subject: Anode voltage on tank coils in the GF-11 and SCR- series Command 
>> transmitters
>>
>>
>>
>> The reason I asked about anode voltage on the GF-ll plug in coils
>> is that in the Command Set transmitter series, the tank coil in the 
>> SCR-274N / BC-xxx
>> units, but NOT the ARC-5 / T-xx units, had anode voltage present on the
>> tank coil.  Which meant I had to be extra cautious when using a neon RF 
>> sniffer
>> or making PA output  adjustments, especially having been most used
>> to adjusting my ARC-5's. All three types could give me an RF burn but all 
>> but
>> the ARC-5 type could also give me a nasty wrap if Iwasn't very cautious.
>> (Pretty sure I also got to close to the DC carrying coils on my GF-11.)
>> Caution and patience were not my strong side in my pre- and teen-age
>> years.  (Hope I've got my Command Series nomencalture straight this 
>> time!)
>>
>> TECHNICAL QUESTION:
>>
>> Doesn't the DC current flow in a coil (including tank coils, of course), 
>> by virtue of its
>> magnetic field affect the actual inductance value?  Meaning that current 
>> magnitude
>> could theoretically influence RF inductance -- I assume this would be 
>> miniscule
>> under normal operating conditions.
>>
>> I could dig around in my basic theory books to check this out  -
>> but there are so many sharp people on this reflector.
>> (Who say's 'Flattery will get you nowhere? ;0)
>>
>> Henry
>> oz3o n2mr
>>
>>
>>
>>
>>
>>
>> ______________________________________________________________
>> ARC5 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/arc5
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:ARC5 at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>