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I had to re-bias after swapping the TX transistors (Q20, Q21 and Q22) in June. I wondered why TX-power on SSB went down - and the reason was that Q20 was not on the correct operating point. Allisson (

I believe the 12mhz crystals for the Bitx40 are all from the same bin after sorting by frequency. The filter uses them at series resonance, the BFO uses the crystal at the parallel resonant frequency.

my recent ubitx was delivered with the LSB BFO way off, but the USB side okay.? try both USB and LSB on appropriate bands.? when BFO is right, the SSB and CW audio are quite nice.? I am surprised

Built this circuit up, and caught the need to use a 560 ohm resistor to feed the transistor that drives the LED.? Using a orange LED and a LDR with 20k dark resistance.? Only on very high signals do

Finally got my ubitx working mostly correctly. Everything is default, firmware is 2.0. After following tuneup procedures, I'm able to tune to local AM stations and hear properly, audio is great aside

here it is after? a lot of rework with the dual diode pkg as per factory installation . The SX xtal was thrown out an a full HC49U one (Digikey) was put in from the new matched set. As you can see,

He matched the xtals but did not measure the passband as per your above.? I warned him that he would? be fitting xtals of unknown motional params to? a set of capacitors that were not matched.? He

Hmm. Arv asked? JGaffke said that the old style balanced modulator had two discrete diodes and a pot. Which I suspect Arv knows full well because he has built a few Bitx's like that. Old and new

Ah, I do vaguely remember that stuff from long long ago in a thread far away ... Yup, there's a few spots where the currently shipped Bitx40 does not agree with the schematic. That balanced modulator

It has been backed up by J Gaffke on this BBS already (that is the issue of the BM change) The board as photographed (not mine) shows the old style BM with two diodes , a so called half bridge BM with

Timothy But *you* also made some claims that need backing up.? * *HF Signals back ordering...?* Is that really true?? Where did you get that information?? * *On Tue, Nov 6, 2018 at 12:59 PM,

Yes. I was about to put it on eBay. I could ship it tomorrow. Priority or std, it should get to about anywhere in the US within 3-4 days. Priority 3 or less. Sent from Mail for Windows 10 Sent:

The Bitx40 that M Trager (lately of these pages ) rxd was a nightmare and he gave up on it.? I had him search the cct? and he related what J Gaf above has noted.? Trager had changed out the full

That older Bitx40 would have to be at least 2 years old, from before they had a Raduino. The modulator then was two discrete 1n4148a's and a pot. The Bat54s now used has the two diodes on one die and

Huh. Got any more details or sources? Not that I don't believe you, just...trust but verify, right? -- Jon Tabor KI7JYE http://obsolete.site

B Shep ; reading between the lines on some work I did with M Trager , HFSigs seem to have made some hardware mods to the Bitx40 (modulator area and leaving out the trim cap on the BFO OSC which is a

On Tue, Nov 6, 2018 at 12:58 PM, Timothy Fidler wrote: > > B Shep -? reading between the lines on some work I did with M Trager , > HFSigs seem to have made some hardware mods to the Bitx40

Interesting. I bought one (my first!) last week, and it shipped yesterday. Jon KI7JYE

still for sale?

I might be willing to buy it lol!!!