[ARC5] The value of MO and PA tank components.

[john rose]

How much precision do you need? The condensers have been measured and reported about a half zillion times, mostly on eBay.  Someone going to estate sales or flea markets looking for old electronics "stuff" will find one of these and list it as 'old variable cap' or some such. Nominally the reported value is about 35 mikeymikes to about 150 mickeymikes. Check out this example.
eBay item number:252316803695
This value is what was reported in 'the literature of the day', ie conversion manuals.

I don't recall anyone listing the coils and transformers values and that is where the 'fun stuff' starts. C63, tuning, is in parrallel with C60, padder, and C68, fixed 3 mikeymikes temperature compensation. The Army manual lists 4 (count 'em) different rotor/stator angles, one for each of the transmitters, from 77 1/4 degrees (yeah, right!) to 95 1/2 degrees. That implies there is 'a heap of mathamagic' in trial and error calculations. Good luck. I am thinking I might take time out to physically measure the coils and see what my ARRL slide rule tells me.
________________________________________
From: ARC5 <arc5-bounces at mailman.qth.net> on behalf of Leslie Smith <vk2bcu at operamail.com>
Sent: Wednesday, March 23, 2016 2:57 AM
To: ARC-5 List
Subject: [ARC5] The value of MO and PA tank components.

To all:

I wish to learn the values of the oscillator and PA tank components in
the ATA, SCR and ARC-5 transmitters.

These are, for the oscillator:  T53, C60, C63 (M.O. turning) and C68.

For the PA Tank circuit: T54A & B, C65 (PA tuning), C66 and C67.

The manual gives the following information for T54:

    Frequency          Dwg #  (from WECO)
     3 to 4 MHz        7347
     4 to 5.3             7248
     5.3 to 7             7249
     7.0 to 9             7250

Information is given in Table #20, page 126 in hard copy. (or page #141
in PFD numbers) about these items, but not the value (uH, pF).  I
presume this is because different values are used for the different
frequency range in each type of transmitter.

I searched the tech manuals to my best ability.  My point here is that
I'm writing AFTER making a diligent search, rather than trying to avoid
this work.

If anyone on the list can advise where I might find component values for
the tank components I'll be grateful.

Thank you,

Les

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