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Thanks for reply all. I have the equivalent drive level resistor. ?The procedure call for pre setting the IRF 510s to 50 ma each, and then adjusting the drive level pot until the increase in voltage

bitx 40 Liner Amp Key.jpg Here is my solution to the PTT Mute and the addition of a Linear Amp keying circuit. I just dead bugged the H11AV1 Opto coupler on top of the LM386 to make the connections

Could you post a drawing please?

None BiTX, but hope it is of interest to others if it hasn’t been mentioned elsewhere. QRP Labs are in the process of kitting up a new Mono Band 5W CW Kit for the HAM Bands. A great feature for

p.s. no extra bits really needed for my unit, transistors just what was to hand (scrapped from a PC PSU). If Ted has put in extra caps it would likely be to keep it muting a few milliseconds after PTT

Hi Ted and all ... back from having my tea ... that V3 circuit is my choice, *BUT* connect to pin 3 (across the input instead of pin 7. Pops all gone, PTT press *and* release! 73 ...

This is the version I used. I see when I have another look it is version3 anyway it seems to work for me. circuit as below. I added at the junction of the 1k resistor and the emiter of the 2N3906 a

Hi Ted,, Pl post the Version 5 circuit diagram..Your HB assembly nice construction...tnx n 73 de Raj ,VU2SMM

Hi all I have made up and installed version5, now all I hear is the relay clicks. Photo of board attached. Ted ZL1BQA

Hi Dexter,? Which version of Gian's schematic were you changing? My add-in board with his mod is currently at "Trial 5." Whatever you suggest, I will try tomorrow after work. I want to remove this

Hi Jonathan Read later entries here - search on Gian's call or "PTT". My contribution: Gian's circuit except wire to pin 7 goes to pin 3. Try it, you'll like it. 73 de ZL2DEX ...

Buonasera Gian, I did not have any luck with this mod. While I tried the previous versions as well, the clicks remain throughout testing. I did get the LM386 to mute properly by using a modified

R136 is "drive level". Over-driving can produce distortion at the driver stage (cause of "barely intelligible audio", likely mistaken as FMing?), and if it continues can burn out the driver's emitter

Thank you Giuseppe, I will have a look at the code and see if I can make it work for me. -- Mike VK3XL

I had similar audio reports on a BITX40 kit.? What I believe fixed the problem was to adjust R136.? If you can find the comparable variable resistor on your kit, it may help. It is at the base of

The BitX40 with no mods is ready to be powered...except for the microphone. Today I worked on the PTT bar. A parallel pair of switches should take care of me pushing on one end of the bar or the other

A 1206 surface mount resistor like that is typically rated for 1/4 watt. ?Might seem high, as a 1/4 watt axial lead resistor is considerably larger. ?But the 1206 can can better dump heat into the

I have a Hendrix kit built Bit-x 20 (assembled myself) and after about a year of playing with it, finally started making contacts. It has the 10K pot mod instead of a tuning cap. and tunes from 3.152

BITX QSO Night, Sunday, August 20, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere Join us as we make contacts from BITX40 to BITX40 on 7.277 MHz in 40 meters! To participate, call CQ

Soundar VU2RJW wrote… Thank you very much for posting that! As I mentioned previously I had already replaced Q15 and then Q13 before seeing your post. I took a close look at R141 and it did look