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Fw: First QSO with the BITX20 Transceiver

Ashhar Farhan <farhan@...>
 

dear pete,

very good on your efforts. which crystals are you using? the Cb crysals
available for 9MHz are quite cheap. i am using a PC-based AGC system with
some kind of noise blanker and even squelch. it work smuch better than
analog systems. i will post the program soon.

can you resend the pcitures pse? guys on the group would love to see the
pics. send it to me on this email of mine. i am cross posting this to the
BITX group for others to know of your excellent success.

- farhan

On Sat, 19 Jun 2004, Pete Juliano wrote:



Hi Ashhar,

I sent you a series of photos to the phonestock email. I don't think hotmail likes big photo files.

Have now had about 5 QSO's with the rig and have made a few modifications.

For my crystals which are 9.0 MHz --seems like 100PF works best for all capacitors. That made the audio sound better. I also tried substituting a commercial 9.0 Mhz filter in the radio and while there was some improvement --the homebrew filter is quite good.

I added a small 25K pot as a mic gain control. seems like I could overdrive the radio with the microphone I am using.

I also had to add a second relay. There is a dpdt relay at the linear board just like on the schematic. However I was getting stray RF feedback --so I added a second spst relay right at the bandpass network on the mainboard-- now there is no rf feedback.

Have you given any thought to adding a simple AGC system. Loud stations really play havoc on receive -- some sort of system to change the bias level on the Rcv IF amp might be easy to implement.

I hope to get it in a metal box this next week.

Thanks again for such a neat project.