[ARC5] First AM QSO with the SCR-274!

[J Mcvey]

OK , the guy was only 40 miles away, but I'll take what I can get!He was familiar with the ARC radios and said it had the classic military audio.The mike I used has a carbon cartridge with the simple 'mike booster" circuit consisting of a transistor and 2.2k resistor.Haven't built my electret circuit into a mike yet, but I will get to it soon. The prototype worked well when I did a live test on the modulator. It has more amplitude/gain  than what I used today.
It worked pretty well well with a 4:1 unun with a series cap to match the 80 meter dipole. Had to experimet with cap but I need about 150 pf on 80 meters  ( it's on a junk box variable cap from a military tuning box, with the plates meshed, so I'll remeasure it to be sure) . Tried 100pf and 40 pf fixed caps, but couldn't get it to load with those.
The power meter says it's a little over 50 watts on CW and maybe 12 watts carrier on AM.
The inductor is happy at  around 1/3 around 3885. 
Interestingly, the current meter reads just under 2 amps on CW but the power meter says >50.  

I have not hooked up the sidetone/receive mute to the receiver rack and the feedback was very bad even with the sensitivity control all the way down.It was usable that way with CW, but not so much with AM!
I'm wondering if the the grounding contact on the T/R relay might need some cleaning or is there really that much leakage into the receivers?
After rewiring everything  into it's "portable radio desk", I'm glad it worked on the first try....

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