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Old 11th May 2021, 1:04 pm   #9
mole42uk
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Join Date: Aug 2010
Location: Resolven, Wales; and Bristol, England
Posts: 2,613
Default Re: DIY Spectrum Analyser

Quote:
Originally Posted by Radio Wrangler View Post
If that crystal has three legs, it's likely to be a two-pole monolithic crystal filter <snip>
David
Yes, it has three legs and yes, it is the 10.7MHz filter, not a crystal. It was late when I took the lid off the box and I was both surprised and excited to find what was inside! Looking at it again this morning, it is exactly the SSA by Roger Blackwell.

I must have made more boards than I remembered, I sold a couple a few years ago. My business used to be involved in frequency scanning at model aircraft displays (health and safety!) so I remember we made a few specialised scanners for 27, 35 and 459MHz. We probably used the Blackwell design as a shortcut....
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Richard

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