Collins / Thordarson Mod Tranformer?

Discussion in 'Amplitude Modulation' started by KA4KOE, Mar 11, 2021.

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  1. KA4KOE

    KA4KOE Ham Member QRZ Page

    Can anyone offer any more info beyond nameplate data? A friend has this particular unit.


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    WA3JVJ likes this.
  2. K5UJ

    K5UJ Ham Member QRZ Page

    I can't tell you anything about the particular rig it went with; I can only infer the obvious by what's there in the photos, that it isn't a broadcast transformer based on the core gap and power rating and step down. It's certainly not for any Collins ham rig on account of the power rating. Based on the frequency response and everything I've mentioned, it was probably made for a commercial short wave voice communications rig.
    KA4KOE likes this.
  3. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Not a bad turns ratio for headroom when using a common power supply; should be good enough for a little positive peak headroom. Frequency response about on par with that of a T-368 or BC-610; might actually be better than what's shown on the nameplate rating, since that may have been the bare minimum performance specified for its intended use and the manufacturer could have built it beyond that. Power rating plenty for modulating a kw DC input or more. Low frequency response could probably be improved by using it with a reactor to take DC off the secondary. There is no nameplate specification for maximum DC flow through the secondary.

    Looks like typical Thordarson potted end-bell construction, so don't even think about disassembling and cross-laminating the core to get rid of the gap.

    It might work well in a KW-1, but due to the lower primary and secondary impedance specifications it probably wasn't designed for that rig even though the turns ratio is about right.

    What are the physical dimensions and how much does it weigh?
  4. K5UJ

    K5UJ Ham Member QRZ Page

    Good point. I didn't think about that. It looks like a pretty big transformer. I guess for 850 watts with the current through the secondary it would be pretty big for the power. It sure dwarfs the mod. transformer in the BC1G hi hi. I'm using the data plate for scale.
  5. W4ZOR

    W4ZOR XML Subscriber QRZ Page

    Hi Don, Dennis here, formerly known as Zorro WA2ZOR, now W4ZOR, when we met back with Joe, W2WAS my long departed Elmer....the transformer is mine, it's roughly 12" long, 5-6" wide and about 8" high and weighs at least 150 lbs,......
  6. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    Nice transformer. Hope to soon hear it on the air.

    I worked W2WAS many times, and visited him once at his QTH on L.I.
  7. W7TFO

    W7TFO Premium Subscriber QRZ Page

    Funny how iron can hold us all together...

    K5UJ likes this.
  8. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    It's in our blood-Literally! :eek:

    K5UJ, AD5HR and (deleted member) like this.
  9. W7TFO

    W7TFO Premium Subscriber QRZ Page

    Someone ought to start up a ham-oriented transformer outfit called "Geritrans--for iron poor tired transmitters!"

    W3SLK likes this.
  10. K5UJ

    K5UJ Ham Member QRZ Page

    If they just made audio driver transformers I'd be delirious. Line to grid too.

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