Tuesday, 4 July 2017

Next Project - Spectrumn Analyzer



Been a while since my last post, but while actual bench work has been minimal, I’ve been getting ready for my next projects. In other words, I’ve been noodling a lot.

Attended this year’s FDIM and Dayton. Had a blast and met a few people that made the trip worthwhile on its own.  Nothing like meeting Hans Summers and Ashhar Farhan to get the creative juices going again.

I bought a new scope while at Dayton and the savings put a good dent into the cost of the trip. Now what can I buy next year to save even more money? Hihi.  One thing I’ll do differently this time will be to put together a shopping list.  I couldn’t really remember everything I needed, and walking around seeing things with a somewhat limited budget prevents one from buying stuff on just spec. 

After the trip to Dayton I’ve decided that my next major project will be a Spectrum Analyzer based on a circuit by Wes Hayward W7ZOI and Terry White K7TAU that was further developed by Ashhar Farhan VU2ESE. And likely will be further modified.  After all half the fun is making something your own.

To date, from a practical perspective, I’ve bread boarded the ad8307 chip for some experimentation. I had done this previously and while I have tons of notes and data, lacking was details on why I was doing certain things. So some of the results are really just numbers without a complete understanding.

Good linearity from +5dBm down to -60dBm.  I know I can get down likely to -70dBm with proper construction techniques and maybe even a little better than that.  Further testing will involve seeing how it behave when I connect it up my LBS rig at the crystal if filter.

I’ve completed a design for the 8307 detector board and will etch shortly.  This design incorporates the smd version of the 8307 while experimentation is done with the dip version.




 

73 , Peter

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