[ARC5] Question on IF transformers...

[Kenneth G. Gordon]

On 18 Oct 2014 at 11:16, Dennis Monticelli wrote:

> Ken,
>  
> Hard to tell without getting into the designer's head. 

Yes. I had thought the same...
  
> The tap is a "free variable" for the designer.  It costs nothing to take
> advantage of it...or not.  The designer can use it to achieve max power
> transfer if his IF gain is on the low side or he can throw away gain if he wants
> to promote IF strip stability in the face of component/tube variations or if he
> wants to achieve unloaded Q for max selectivity.  Exact positioning of the taps
> is often one of the last choices made in the overall design optimization and it
> was probably not a critical decision with some of the stages in some of the
> receivers.  In other words, we may be overthinking this a bit.

I suspect you're correct, Dennis.

The reason I asked is that in my pile of parts, I have quite a number of IF 
transformers for 239 Kc, but all are IF transformer #3, and I have only one 
"complete set".

I have at least 3 and possibly 4 semi-restorable BC band ARC-5s, but only 
the one set of all three of the correct transformers.

I have another two chassis which will require quite a bit of JB Weld to plug all 
the "idiot holes", but may also be "restorable" to working condition.

What I am looking forward to is to try to set up a working ARR2 type of "find 
your way back to the carrier" setup as someone else did.

I think that entire system was very unique and a real technological wonder, a 
master-piece of design and original thinking.

Ken W7EKB