I REALLY LIKE THIS RIG.
IT IS LIKE A MAGIC CARPET THAT CARRIES MY VOICE ACROSS THE SEAS.
Cutting Display Hole sets off smoke alarm.
Reverse Polarity Protection.
IF and Crystal Filter at 21.470 MHz 50 ohms! TRGHS!
Amp for VXO Carrier Oscillator/BFO.
Mic Amp from uBITX.
Transmit/Receive switching from mic connector.
VFO: NO DIE CAST BOXES! HT-37 Variable Cap, Frequency Shift.
BP filters from QRP LABS designs (G0UPL).
TIA amp boards from K7TFC.
Needed RF amp to hear band noise.
BITX40 PA design, but RD006HHF1 instead of IRF510.
Should I run receiver input through LP filter?
Frequency Readout Story: How to use one San Jian counter on two bands.
The horror : a diode for reverse polarity protection. It may blow the fuse but until then it still puts on some reverse magic down the line. Use a P channel FET instead.
ReplyDeletehttps://ph2lb.nl/blog/index.php?page=reverse-voltage-protection
Really nice build, Bill! I really enjoy hearing about your process and your build choices. I've been going through many of the same internal conversations with our club direct conversion receiver project - at a simpler level - but much of the same thinking. Great solution for the frequency counter.
ReplyDelete73,
Dean
KK4DAS
I never cared for reverse polarity diodes. I have repaired many a CB's back in the day where that diode shorted out. I think a better way is to just put the diode in series. Sure, there is a 0.7v drop but you'll never smoke a diode if hooked up backwards, it just wont work.
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