I had our friend Grayson (in Turkey) in mind when I put Eddy's messages about this "thermitron" receiver on the blog.
Hi Bill,
Many thanks for the FB note...
Well, I think my buddy VE3CSK is 99% "hooked" on the notion of making an MFTMM receiver for himself---and that's a good thing. That rascal of a rig is pretty much fool-proof, & the design sure does lend itself to no end of enhancements / improvements / changes / mods! I should know: with my set-up here I added AVC, and extra IF stage, an extra stage of AF, more pre-selection, etc. etc. etc.
As for selectivity, I simply incorporated regeneration in the 2nd IF stage: with judicious tweaking of the BFO, one can achieve a near single-signal selectivity effect that is GLORIOUS on CW. I guess one can make these things as complicated---or as simple!---as we might chose to do, yet further proof of the flexibility of this receiver.
I've taken some jpegs of my set-up here, and am attaching them herewith for your perusal. I like the notion of using these rigs on 80- and 40-meter AM, too---but am presently somewhat "distracted" with the task of re-inking my main tuning dial for my 1929-style superhet.
I think my next step in my MFTMM receiver here will be the addition of an internal 125 VDC power supply---most likely will mount the components inside, on one of the vertical sides (still LOTSA room there!). I have a FB Hammond power transformer that'd be perfect for the job, & I won't have to connect / dis-connect / re-connect its current out board power supply (that I use with other peripherals, too---a REAL pain by times).
~73~ de Eddy VE3CUI - VE3XZ
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"FB receiver Eddy. Glad more people are doing thermatron projects!
ReplyDeleteFrom Grayson:
Great idea on the regeneration on the IF. an "oldie but goodie" trick.
Like to know more. Why second IF?
Where did you get the tuning dial? Looks like a real nice one. HB?
Keep up the good work!"
Grayson
TA2ZGE - Ankara, Turkey
KJ7UM