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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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20th Nov 2018, 12:14 am | #1 |
Pentode
Join Date: May 2006
Location: Poole, Dorset, UK.
Posts: 129
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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 G8JMB |
20th Nov 2018, 7:50 am | #2 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 772
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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 Last edited by G3VKM_Roger; 20th Nov 2018 at 7:51 am. Reason: sp |
20th Nov 2018, 9:02 am | #3 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
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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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20th Nov 2018, 10:28 am | #4 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 772
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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.
73 Roger |
20th Nov 2018, 3:55 pm | #5 |
Dekatron
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
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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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David. BVWS Member. G-QRP Club member 1339. Last edited by David G4EBT; 20th Nov 2018 at 4:02 pm. |
22nd Nov 2018, 1:33 am | #6 |
Pentode
Join Date: May 2006
Location: Poole, Dorset, UK.
Posts: 129
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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 |
22nd Nov 2018, 8:15 am | #7 |
Heptode
Join Date: Jun 2012
Location: Southeast Norfolk, UK.
Posts: 772
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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 |
22nd Nov 2018, 10:17 am | #8 |
Nonode
Join Date: Jun 2010
Location: Spalding, Peterborough, Cambridgeshire, UK.
Posts: 2,851
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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.
Rob
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22nd Nov 2018, 10:39 am | #9 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
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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 |