[ARC5] ARC-5 and SCR-274-N IF Transformers

[D. Platt]

On 4/16/2014 4:32 PM, Kenneth G. Gordon wrote:
> On 16 Apr 2014 at 15:46, D. Platt wrote:
>
>> indeed, the Navy used dual-tapped transformers in the 2nd and 3rd IFs.
> Tapped. In what way? Center-tapped? What? Are the taps connected to
> anything? If so, what?
One or both coils have a tap near the "top" end of the coil.  The entire 
coil is the tuned circuit but the primary tap goes to the plate and the 
secondary goes to the next stage.
>    
>> crossed over with no noted issues.  Now.. on another tack, I said I
>> thought one could probably modify the 40 meter (6.9.1 MHz) receivers in
>> the same manner as the 80 meters receivers.
> I thought I had mentioned some time ago that this was, more than likely, not
> possible.
That's what I sincerely thought.  However, looking at the books, not the 
radios, themselves, it appears the coil structure may be different.  One 
would have to have a look and see.
>
>>   Looks like that's not the
>> case.  Looking at the various mechanical drawings, the SCR-274-N
>> receivers appear to have a one-piece coil form,
> Yes.
>
>> and are not eligible for
>> the mod, as written.
> No.
>
>>   The Navy units, on the other hand, look like they
>> still have the split coils and ceramic spacers.
> Some do, some don't.
That is good to know.  Again, each receiver would need to be inspected 
for its suitability.
>
>>   Ted's having a look at
>> his 40 meter receivers to see what's the real story.  The thing is, why
>> would the manufacturers use a different methodology for the two
>> services?
> I wondered the same thing...
>
>>   Makes no sense, to me.  If anyone else has any info, it would
>> be good to know what you've found out.  At least the 80 meter rigs are
>> good to go.
> Yes.
>
> BTW, I have quite a number of "loose" IF transformers here. If it got right
> down to it, I could dismantle a bunch and check them.
>
> I also have a list somewhere of the IF can numbers and to which receivers
> they belong. I'll try to dig it out.
Your input, vis-a-vis the coil structure, would be a real asset.
>
> Kenneth G. Gordon W7EKB
>
> "Courage is being scared to death but saddling up anyway."--- John   Wayne
>
>
> ---------------------------------------------------------------------------------------------------
> Text inserted by Panda IS 2014:
>
>   This message has NOT been classified as spam. If it is unsolicited mail (spam), click on the following link to reclassify it: http://localhost:6083/Panda?ID=pav_32042&SPAM=true&path=C:\Documents%20and%20Settings\Doran\Local%20Settings\Application%20Data\Panda%20Security\Panda%20Internet%20Security%202014\AntiSpam
> ---------------------------------------------------------------------------------------------------
>
>