[600MRG] 630 meter Homebrew

[Edward R Cole]

Only 20w?  I had an old DX-100 that used two 1625's in the plate 
modulator and produced 120w at audio.  500-KHz is not that much 
higher in freq.  Two 6146 will do 150w at HF and 110w at 6m (what was 
in my SB-110).  Of course this was class-B in the modulator and class-C at RF.

73, Ed

At 12:37 PM 1/28/2018, Dwight Blevins via 600MRG wrote:
>I see there's an ongoing discussion on a homebrew tube transmitter 
>for 630 meters. I just built one and it was a most rewarding 
>experience. It was a bit more difficult than I expected, but quite 
>doable for the average ham. Mine is a takeoff on one posted online 
>by a ham in Australia (VK1S?). He used a 6AG7 to drive an 807. I 
>used a 1625 for the final, much the same tube as the 6BG6, 807, 
>1625, 6l6, etc. It produces about 20 watts output.
>
>Forget the ease of the old 6V6/6L6 style transmitters, which most 
>all of us have tried at some point in the hobby. The high value L/C 
>configurations of the MF/LF spectrum are something located in the 
>pages of another book that many of us have not yet read. Thankfully 
>the online schematic that I found got me in the ballpark, but I 
>still spent several days of cut and try, getting things to gel for 
>my particular setup. I learned some valuable lessons that I'll not 
>soon forget.
>
>If I had it to do over (and I probably will) I'd have gone for a 
>dual, parallel output in the final. This would produce around 35 to 
>40 watts out, which, based on my experience thus far, I feel is 
>minimal and needful from a practical standpoint. Many of us do not 
>have a very efficient antenna, so I feel that if you don't have at 
>least something close to a minimum power in the 40 to 50 watt range, 
>then you'll have considerable difficulty making contacts with cw. 
>The challenge might be a little less for those living in areas of 
>high population, but there are just not yet that many hams operating 630m.
>
>Living in the high desert of western Colorado, it can be a pretty 
>good challenge trying to work another ham beyond the high Rockies to 
>the east, and the Sierra Nevada to the west. Going north and south 
>there are probably at least 100,000 Jackrabbits between me and the 
>next closest 630m antenna. A couple of hams have copied my signal, 
>including KB5NJD, but I have yet to validate a single two-way QSO.
>Am I discouraged? Of course, not. The challenge just enhances the 
>joy of it all!
>
>To me, 630m is a homebrew tinker's paradise. Right now that's what 
>thrills me the most, so this is where I'll be; pounding the brass 
>and looking for that one and first elusive response to my CQ, which 
>I know lies somewhere on the future horizon.
>
>Ike, KW7T
>
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73, Ed - KL7UW
   http://www.kl7uw.com
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