With some prodding from Pete Juliano, I am moving forward on my next transceiver. Same wood box enclosure (with copper flashing), but this time I am greatly relaxing some of the radical fundamentalist restrictions: Chips will be allowed. VFOs and VXOs will be replaced by an Si5351. Filters will not have to be homebrew. Pete has been putting his CNC machine to use and making me some nice boards with isolation pads already milled in. Oh, the luxury!
I am going to use the Termination Insensitive Amplifiers designed by Wes Hayward and Bob Kopski back in 2009. These are especially useful in bilateral type transceivers because they allow you to nail down the termination impedances on the crystal filter IN BOTH DIRECTIONS. That's is important if you want the same filter shape on both transmit and receive.
But now, with the trauma of my unfortunate IF selection on the BITX 20/40 (now just 20, sniff...) in mind, what filter should I use on this rig? The three main candidates appear above. The 9 MHz Yaesu filter was given to me some time ago by Steve "Snort Rosin" Smith. The Heath filter (3.395 MHz) and the larger silver one (2.215 MHz) were given to me by Armand Hamel. (Thanks Guys!)
My main band of interest for this rig is 40. But if possible, I'd like to be able to use it on 15 and 12 meters, and maybe even 20 and 17, hopefully without having to change filters.
So what say the gurus? Which one should I use? Or should I put two of them in there, with provisions that would make it easy for me to move from one to the other?
Right now my inclination is to go with the 9 MHz filter, perhaps with the 3.395 MHz filter also available.
In response to popular demand, "SolderSmoke -- Global Adventures in Wireless Electronics" is now available as an e-book for Amazon's Kindle.
Here's the site:
For the print version:
For shipping from a printer in the U.S. (probably better for N. American buyers) Click here: SolderSmoke USA Version
For shipping from a printer in the UK, Spain, or the USA (probably better for UK and other European buyers)
Click here: SolderSmoke EU Version
The two versions are identical, except for a minor difference in the paper used. That's why the prices are a bit different.
Bill's OTHER Book (Warning: Not About Radio)
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W4HBK's QRSS Grabber: The Amazing Pensacola Snapper (Live!)