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Tuesday, November 1, 2016

It's Ugly, But It Gets You There: Pete's Latest Rig

That, my friends is an extreme  example of what we mean when we use the word "rig." This magnificent machine sent Pete's melodious voice across the mighty Pacific several times during the recent CQ WW contest. 

Pete wrote to Jun:

Hi Jun,
This weekend is the CQ World Wide SSB contest and I just worked three JA stations on 40 Meters. The time 1400 UTC. I must confess that I was using 600 watts to my droopy dipole but they came back on the first call. So there are paths open and perhaps 600 watts was overkill but the timing seems like it works for a good path to the west coast. Along the way I also worked a station in Hawaii (KH6).
See if you can find some 813 tubes as they make a great grounded grid linear amplifier tube and a pair will give you 600 watts. see http://www.ohio.edu/people/postr/bapix/813amp.htm
The rig I was using is shown below. The mainboard came from a Hallicrafters FPM 300 (late 1960) to which I added the Rx Tx Mixer (SBL-1), my stock 2N3904 bi-directional amp board, the 2N2222 + BD139 driver stage using the EMRFD circuit and a 2SC2075 final which gives about 3 watts. This in turn drives an intermediate SS amp to 100 watts and then the SB200 to 600 watts. The FPM 300 used a 9.0 MHz IF frequency.
Of course no rig today from N6QW would  be complete without a Si5351 and the color TFT display. Rounding this out is an LM386 audio amp stage. Cosmetically the rig doesn’t look pretty but sure works well.
Pete N6QW

(The comments about the 813s are kind of SHOCKING, coming from a member of the QRP Hall of Fame!)

1 comment:

  1. So OK, take my award away. The rig has been operated at 400 MW and 3 watts so it has made the QRP sojourn. We should not get so hung up --at times with a minimalist approach all you end up doing is talking to oneself. QRO is not a four letter word!

    Pete N6QW


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