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Author Topic: Question on Using a Junker Straight Key  (Read 298 times)

KM6ZX

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Question on Using a Junker Straight Key
« on: June 11, 2021, 09:17:38 PM »

I recently acquired a very nice Junker straight key, in almost mint condition. It was manufactured in 1987, so is one of the later ones.

I wired up the key with my modern solid state transceiver and noticed a serious lag between key down and the transmitter actually keying. On further inspection, I noticed an LCR circuit under the key, so when the key makes contact, the switch actually closes a LCR circuit, and not a straight connection. It appears to be some kind of electrical filter or damper. Anyways, I carefully removed the resistor and capacitor part of the circuit and it now works perfectly. I left the inductor in place. Does anyone know the purpose of this circuitry? Is it for older high-voltage rigs? It seems to cause problems with my modern transceiver.

I made sure anything I do to the key is easily reversible, as I don't want to ruin a historical key.

73 - Brian KM6ZX

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ZL1BBW

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Re: Question on Using a Junker Straight Key
« Reply #1 on: June 11, 2021, 11:48:54 PM »

Ah, back in the old days, we used to shape our keying with a filter on the key, it also helped get rid of the clicks.

The really wide awake ops were inevitably using cathode keying, where if you fingers trayed there was often a 100 or so volts ac  ross the key contacts, that certainly improved your focus.

Cheers.
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ex MN Radio Officer, Portishead Radio GKA, BT Radio Amateur Morse Tester.  Licensed as G3YCP ZL1DAB, now taken over my father (sk) call as ZL1BBW.

W6MK

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Re: Question on Using a Junker Straight Key
« Reply #2 on: June 12, 2021, 04:04:19 PM »

I made sure anything I do to the key is easily reversible, as I don't want to ruin a historical key.

The LCR network I removed from my Junker IS history.

The Junker is unlikely to be used for cathode or grid block keying in the future.
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AC2EU

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Re: Question on Using a Junker Straight Key
« Reply #3 on: June 13, 2021, 07:53:58 AM »

Quote
It was manufactured in 1987, so is one of the later ones. I made sure anything I do to the key is easily reversible, as I don't want to ruin a historical key.

I doubt that a key manufactured in 1987 has any historical value...or did you mean 1887?
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