[Milsurplus] PTOs

[Jim Whartenby]

Rob
Good to hear from you.
I found it chore to find a schematic for the TBK,  Still a secret after all of these years?  Finally found one on page 286 at: http://www.navy-radio.com/manuals/rm1c-10229-1950.pdf  As I see it, the master oscillator in the TBK uses a tapped inductor to set the coarse frequency and a variable capacitor to set fine frequency.
I think of permeability tuning as inserting a ferrite core into a coil so that inductance is variable, not stepped.    From what I have found on the history of ferrite, it seems that Panasonic gets the credit for being the first to use permeability tuning in 1940 Japan, well after the TBK was designed.  
Don't know offhand about ferrite use in IFT's.  It seems that ferrite use was rapidly accepted and developed during WW2.  I think that the Hallicrafters SX-28 was produced with both types of IFT's during WW2?
Collins might not be the first to use permeability tuning of an oscillator but I've got to give them credit for being among the first to do so.
Jim

Too much agreement kills a chat.  E. Cleaver

-----Original Message-----
From: Rob Flory <farmer.rob.flory at gmail.com>
To: milsurplus <milsurplus at mailman.qth.net>
Sent: Fri, May 14, 2021 11:29 am
Subject: [Milsurplus] PTOs

Jim, I think Navy TBK transmitter uses permeability tuning, quite a few years before the one you are looking at.

What others?  I think there are more shipboard transmitters that have pro.
RF


______________________________________________________________
Milsurplus mailing list
Home: http://mailman.qth.net/mailman/listinfo/milsurplus
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Milsurplus at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20210514/b5fb50e9/attachment-0001.html>