Sunday, January 20, 2013

A special QSO

I had said to myself, long time ago, that I would only consider myself an reasonable amateur if I managed to build and make a QSO with something I built instead of using an appliance. I don't say all ham's should follow my idea, each one should have is own goals.

Keeping short, some time ago I built an VHF FM transceiver (with some small parts designed by me on the reception chain) and made at least 2 QSO's... before reusing some components to another project (a VHF crystal controlled transmitter, unfinished so far). It was a nice feeling of accomplishment but I wanted to make also a QSO in the HF bands using something soldered my me.

Last Friday I was doing some adjustment in the "Speaky" transceiver BFO and band pass filter for the 17m band when I heard someone CQ'ing, I couldn't resist and answered the call, first a brief "QRZ" and finally LX1HD (1600Km from my QTH) managed to decode my call-sign... YES!!! I was so nervous like it was my first ever QSO because I still didn't placed the heath dissipator on the final transistors and they are somehow expensive, kept the QSO very short and asked for an audio report, Henri answered stating some RF present in the signal which latter traced to the audio compression part. I thanked a lot to Henri and said goodbye because I was very afraid of blowing the finals.  Think I even didn't sent Henri his signal report but was at least 59....the s-meter isn't calibrated yet as so is the output power meter...!

 Here it is as when QSO was made:
 Bench testing the unit:

Now some things to do before closing the top lid and have fun QSO'ing:

Add heat dissipation to the final transistors.
Check audio compression/gain issue
Trim PA bias
Calibrate internal power/S-meter
Tighten cables.
Optimize IF filter bandwidth, now its a little wide for my taste.
Rebuild 40m bandpass filter, it works but trimmers are on the lowest capacity setting.
Add 20, 15 and 10m band....

 ...Maybe my next objective could be someday design an built everything from the ground up....maybe

Have a nice week!

1 comment:

PE4BAS, Bas said...

Congrats Ricardo, I can imagine this was a very rewarding QSO. I wish I had the brains and the time to build and design my own trx. But well there are a lot of other things in this hobby. At least I can build my own antenna ;-). Good luck tuning and tweaking your "Speaky". 73, Bas