EMRFD Message Archive 10943

Message Date From Subject
10943 2015-03-28 13:03:03 n0ksf 10.7 mhz if transformer 7-8341

I was going to build a band pass filter for 40 meters and I have a bunch of these IF cans type 10.7 mhz if transformer 7-8341. I have seen filters made out of the Mouser type 42IF123 type. When I went to use these I realized they do not seem to have a primary and only a secondary output. I am sure a little confused what these cans were used for. I could sure use some help. Thank you and 73's

Jack N0KSF


10944 2015-03-28 14:25:26 Kirk Kleinschmidt Re: 10.7 mhz if transformer 7-8341

Many "can coils" are just that -- adjustable coils :) 

And not transformers.

A popular configuration was an adjustable coil to make the 455-kHz oscillator in an AM broadcast band radio without using a crystal (just an L-C tank).

Many adjustable coils are built on the same "chassis" as the multi-winding transformers, so in many cases it's possible to add a second winding of your own choosing.

Of course, the coil's ferrite material must be suitable for whatever frequency range you're interested in.

Look closely with magnification to see if your "can" has any markings that might identify it. Some do, some don't.


--Kirk, NT)Z

My book, "Stealth Amateur Radio," is now available from
www.stealthamateur.com and on the Amazon Kindle (soon)

10945 2015-03-28 17:02:47 Jack Boswell Re: 10.7 mhz if transformer 7-8341
Hi Kirk, thank you for the info that sure cleared a few things up. I will try and open one soon and see if I can add primary with out damaging the packaging.
Thank you for the help
73's Jack N0KSF

10948 2015-03-29 19:28:37 biastee Re: 10.7 mhz if transformer 7-8341
Aside from the 455 kHz oscillator mentioned by Kirk, the coil for the FM quadrature demodulator also has a single winding. The FM quad coil is typically 450 nH and is connected in parallel with 490 pF cap externally.   

73, Chin-leong, 9W2LC