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 1968 Homebrew HF SSB transceiver
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 Return to top of page · Post #: 1 · Written at 12:55:41 PM on 7 September 2014.
Art's Gravatar
 Art
 Location: Somewhere, USA
 Member since 22 October 2013
 Member #: 1437
 Postcount: 895

Hi Guys,
I'm keen to get started since I wanted to see a vintage AR forum Smile
I'll go easy for starters since it's the first time I've emailed photos in to Brad for the forum.

1968 homebrew HF SSB transmitter/receiver (split VFO) 20/40/80 meters - VK4QT silent key.
This, among some other older gear was donated to my club after the original owner's passing, and in turn donated to me to get running although I'm not licensed to the level of transmitting into the air with a homebrew transmitter yet. Tho I'm asking if the freq is in use on the YouTube video, I was talking to myself. It didn't go out into the air.
This is probably among the first SSB homebrew in my area.

This one is just a bit of depressionary era show & tell.. hard to beat the charm of this.

Home Made HF SSB Tranceiver
Home Made HF SSB Tranceiver


No restoration other than new electrolytics needed, and I can receive off the air,
and verified transmit into dummy load while monitoring with a coupled modern receiver.
It only requires a little adjustment for carrier suppression (balanced modulator).
The schematic was provided, and dated Nov 1968 (transmitter), and Dec 1968 (receiver).
25 valves total, and four solid state diodes! The schematic sample of the PA section is just an idea of what it looks like.

Home Made HF SSB Tranceiver


Receiver test on YouTube:
https://www.youtube.com/watch?v=7sJWXOYXItU.

Transmitter test on YouTube:
https://www.youtube.com/watch?v=x1x-WJsGtvY.

The unit came with a GDO dated right there on the label May 1965 and works unmodified.

Home Made HF SSB Tranceiver


I found out later that this was a project day done at my club, and there are other identical units around, including an incomplete one still sitting at my club.
Grid Dip Oscillator test on YouTube:
https://www.youtube.com/watch?v=Ch_MHJSHnIA.

Later, the owner makes this replacement, but it's 40 meter only. It still has a valve power amplifier similar in style to the above unit.

Home Made HF SSB Tranceiver


Since this needed little work, I didn't learn much other than how someone can care about quality of construction using any old parts available, and how difficult the rig would be to use practically today!
When my licensing is up to advanced, I aim to lock the entire rig to freq digitally, and host a net with it.
Since this thread might be Google searchable, greetings to the current VK4QT, and respect for the former VK4QT's work.

Want to see more? Let me know, next up is complete restoration of a commercial transceiver Smile
Cheers, Brek (VK4FAST) - VK4WIP Ipswich & District Radio Club.


 
 Return to top of page · Post #: 2 · Written at 5:12:06 PM on 19 October 2014.
Art's Gravatar
 Art
 Location: Somewhere, USA
 Member since 22 October 2013
 Member #: 1437
 Postcount: 895

I'll bet he never imagined it would end up with an atomic frequency reference.
Still a way to go on software and hardware, but yeah!

https://www.youtube.com/watch?v=jU2I2OEoEAo.


 
 Return to top of page · Post #: 3 · Written at 8:47:03 PM on 19 October 2014.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 5262

I'll bet he never imagined it would end up with an atomic frequency reference.

I think that would be the mother of all safe bets.


 
 Return to top of page · Post #: 4 · Written at 11:27:20 PM on 19 October 2014.
Art's Gravatar
 Art
 Location: Somewhere, USA
 Member since 22 October 2013
 Member #: 1437
 Postcount: 895

Don't worry it doesn't get mutilated ;) It has to work with or without the unit.

There are another 3 bargraphs to go to make eight decade digits that I will alternate with the gate timer to work like the old HP counters that alternate between counting and displaying with each gate time interval.

The first decade counter has to be a specialty 50 MHz Texas Instruments chip, and after it's divided by ten once,
the cheap 5 MHz chips are fine for the rest of the display. Then it's an absolute count with no prescaling for freqs up to 50 MHz Smile


 
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