[Hammarlund] HQ-215

[rbethman]

Well, Hallicrafters came up with a different solution.   The components 
used for the oscillation circuitry are built into the Tuning Units.  I 
could place the previously mentioned TUs in the three slots set up for 
the three bands that you select from on the front panel.

All I have to do is change the PA Coil, and place the crystal in the TU 
for the band I want.

Bob - N0DGN

On 6/16/2010 2:42 PM, Bob Macklin wrote:
> Classically this is done by using the screen of the oscillator tube as 
> the plate for the oscillator circuit (oscillating at the fundamental) 
> ant then the real plate of the tube is tuned to the desired harmonic.
>
> Bob Macklin
> K5MYJ
> Seattle, Wa.
> "Real Radios Glow In The Dark"
> ----- Original Message ----- From: "rbethman" <rbethman at comcast.net>
> To: <hammarlund at qth.net>
> Cc: "Bob Macklin" <macklinbob at msn.com>; "Dan Cotsirilos" 
> <k9dtc at comcast.net>
> Sent: Wednesday, June 16, 2010 11:34 AM
> Subject: Re: [Hammarlund] HQ-215
>
>
>> The real oddball thing is that the Tuning Units for the BC-610 will 
>> either use a crystal at its fundamental, the nest TU will use it, and 
>> be a doubler, while a third one will use the original crystal and 
>> will be a tripler.
>>
>> IOW - The 3Mc TU will use the 3945Kc crystal in the fundamental 
>> freq., the 7Mc TU will use it and double it, and the one covering 12 
>> Mc will triple it.
>>
>> The oscillator circuitry has the 6V6 and 6L6 tubes to do the doubling 
>> and tripling, driving a pair of 807s that push the circuitry feeding 
>> the grid of the 250TH.
>>
>> Bob - N0DGN