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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

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Old 20th Nov 2018, 12:14 am   #1
JohnBG8JMB
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Default 80/160m solid state AM TX

Can anyone provide info or a link to a 80/160m solid state AM TX?
In effect, today's [or at least the 1970's] version of the codar AT5
minimum 5W output
vfo tuned
adjustable aerial matching
no unobtanium
NO CLASS E ie not a FAT5- tuneup with multimeter or built in metering, no scope needed!!



73
john
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Old 20th Nov 2018, 7:50 am   #2
G3VKM_Roger
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Default Re: 80/160m solid state AM TX

Maybe something like this? See attached:

I'm afraid I don't have the circuit diagram but maybe another group member might.

73

Roger/G3VKM
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Old 20th Nov 2018, 9:02 am   #3
Bazz4CQJ
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Default Re: 80/160m solid state AM TX

Have you had a look here https://www.americanradiohistory.com/Short_Wave_UK.htm and searching the indexes to SWM? I'd guess the earliest time would be late sixties? I'm sure I recall features from about that time, but stopped buying it after ~1975.

B
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Old 20th Nov 2018, 10:28 am   #4
G3VKM_Roger
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Default Re: 80/160m solid state AM TX

That's a good suggestion. A search on that site "Transistor Transmitter" entitled shows a lot of hits and around the early 50s there was a monthly column by G3HMO. if you really want to go back to the early uses of transistors by amateurs.

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Roger
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Old 20th Nov 2018, 3:55 pm   #5
David G4EBT
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Default Re: 80/160m solid state AM TX

You might find the PW 'Dart' Top Band double-sideband-supressed-carrier transmitter which featured in PW Nov Dec 1983 of interest. It was a popular QRP project in its day and received favourable reports. It's fairly simple, built of several small modular PCBs, much favoured by George Dobbs, G3RJV (the co-designer, along with Colin Turner, G3VTT), who always adopted the 'build a bit - test a bit' approach, and it has no hard to get components.

Amateurs are still building it today - well at least one has done in 2018 - G4AQB. Here's a snippet from his website:

Quote:

8-<

After thinking about my next construction project, I decided to have a go at building from scratch the old P.W. Dart Double Sideband Topband Transmitter, which came from Practical Wireless in Nov / Dec 1983. The components were all easy to find and I already had most of the small components.

8-<

https://g4aqb.wordpress.com/2018/03/...itter-project/

The two issues of PW covering the 'Dart' can be found here:

https://www.americanradiohistory.com...01983%2011.pdf

https://www.americanradiohistory.com...01983%2012.pdf

Hope that's of interest.
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Old 22nd Nov 2018, 1:33 am   #6
JohnBG8JMB
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Default Re: 80/160m solid state AM TX

Thanks for them replies
The CSE_2A10.jpg looks good - cct would be great.
PW dart - 2W of dsb that needs ext atu does not really meet the need...

All suggestions welcome...

73
John
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Old 22nd Nov 2018, 8:15 am   #7
G3VKM_Roger
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Default Re: 80/160m solid state AM TX

John,

Take a look at a previous discussion on the CSE rig:-

https://www.vintage-radio.net/forum/...d.php?t=147547

73

Roger
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Old 22nd Nov 2018, 10:17 am   #8
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Default Re: 80/160m solid state AM TX

Around 1970-72 I think it was, I built a 160M AM solid state mobile in a 12x6x2 inch approx diecast box. I think it used a BD123 PA, VFO as well. It would have been from an article, probably Shortwave magazine or maybe PW as they were all I bought then. Maybe try a search in those publications around that era and see if anything. For rx I used an Echelford converter into my car radio.
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Old 22nd Nov 2018, 10:39 am   #9
G6Tanuki
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Default Re: 80/160m solid state AM TX

There were a few circuits in "PW" in the late-70s/early-80s that used power-FETs [VN66AF / IRF510] as the PA stage, running up to 10W or so. These FETs were originally designed as audio-amps/switching transistors but worked OK at low-RF, just as originally designed-as-audio-amp valves such as the 6BW6 and EL84 were found to be great as low-RF PA stages.

The modulation for these little FET transmitters was usually by way of one of the similar-era audio ICs (TBA810 TDA2030 or TA7205) with the tapped secondary of a loudspeaker 100V-line transformer as the 'modulation transformer'.

At least one such desigtn was intriguing in that the VFO covered 3.5-4MHz and to obtain 1.8-2.0MHz coverage it used a divide-by-two CMOS chip interposed between the VFO and PA - a nice reversal of the old approach of running the VFO at the lower frequency and doubling....

For ideas, see the "PW Chatterbox" - https://www.robkalmeijer.nl/techniek...e19/index.html
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