SolderSmoke Podcast #190 is available:
http://soldersmoke.com/soldersmoke190.mp3
Pilgrims' Progress: Inspiring words from G3RJV
BENCH REPORTS on JUNKBOX RIGS:
Pete describes his beautiful 40 meter blue transceiver (video above)
Bill describes his "Armand HROish" receiver
BANDSWEEP!
Bill needs small (yellow slug) 455 kc transformers.
We need a good user-friendly 40673 SPICE model.
SEND US YOUR BENCH REPORTS!
The BD139 transistor
Ferrite Core Matching Transformers
QSO Reports: Getting on the air with HB rigs
Bill's new FeelTech Signal Generator
MAILBAG
Posts
It's worth noting that Mouser (still!) sells the "Yellow" 455 kHz IFTs (42IF101) along with four other models (search for "42IF"). Alas, they dropped the 10.7 MHz versions (usable from at least 5 MHz to 15 MHz) some time ago.
ReplyDeleteThe lowest impedance of the bunch is for the 42IF102 (White - 30k:500Ohms) with an 8.1:1 ratio between the centertap/end and secondary (66:1 impedance transformation). A series of these with the properly-selected coupling capacitors can be made to provide a custom bandpass response (e.g. a transformer in/out, 2-3 units in the middle using only the resonated winding.)
To be sure, they can be run at different-than-intended impedances, but expect things to happen like lowering of Q, increasing of loss, etc. - but it can still be useful - particularly at <$1 each if you buy 10...
73
Hi Bill,
ReplyDeleteI seen these 455khz IF transformers on EBAY. I doubt you need 20 of them.....
http://www.ebay.com/itm/COILS-MITSUMI-AM-455khz-FI-20-PCS-YELLOW-MADE-IN-JAPAN-/172351382030?hash=item2820f1620e:g:oXcAAOSwAuNW5fcV
I probably have a couple in junk box, but stuff is still in storage. :(
Great broadcast as always....
73's
Dean AC9JQ
While part for projects are important, the photo tells the most important story.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteBG Micro has a 3 set of coils similar to the old coil set from Radio Shack. $1.80 with data sheet - http://www.bgmicro.com/set-of-3-if-transformers-50a01-a02-a03.aspx
ReplyDeleteThanks
Michael N9XYP