Acceptable registrations in the queue through March 16 at 11:00a ET have now been activated. Enjoy! -M.W.

Terms of Use have been amended effective October 6, 2019. Make sure you are aware of the new rules! Please visit this thread for details: https://www.mibuzzboard.com/phpBB3/view ... 16&t=48619

Old Sony FM Table Radio IF Rejection

The technical side of broadcasting. Think IBOC is a sham? Talk about it here! How about HDTV? Post DX reports here as well.
User avatar
Ben Zonia
Posts: 2143
Joined: Sat Jun 03, 2006 10:35 pm
Location: Honor

Old Sony FM Table Radio IF Rejection

Post by Ben Zonia » Wed Jun 30, 2021 5:27 pm

Has anyone here had a problem with IF rejection from strong FM signals 10.4 or 11.0 MHz apart?

I had a professor who was within a mile of two stations 10.4 MHz apart at his office, and he had a Sony Table radio where he had all kinds of blanketing and overload problems. The engineering tech put two LCs on the back of the radio connected to each side of the 300 Ohm antenna input. He had a double folded dipole turnstile antenna on the roof. The engineer detuned both sides with the LCs on the balanced antenna input. But it occurred to me that if the receiver had a really wide IF stage, 10.4 and 11.0 MHz might be a problem in such cases. The radio was from the late 1960s. It looked SOMETHING like this.

Image


"I had a job for a while as an announcer at WWV but I finally quit, because I couldn't stand the hours."

-Author Unknown

User avatar
TC Talks
Posts: 10103
Joined: Wed Oct 26, 2005 2:41 am

Re: Old Sony FM Table Radio IF Rejection

Post by TC Talks » Wed Jun 30, 2021 5:46 pm

No, but I did sleep at a Holiday Inn Express last night.


“The more you can increase fear of drugs, crime, welfare mothers, immigrants and aliens, the more you control all of the people.”
― Noam Chomsky

Posting Content © 2024 TC Talks Holdings LP.

User avatar
Ben Zonia
Posts: 2143
Joined: Sat Jun 03, 2006 10:35 pm
Location: Honor

Re: Old Sony FM Table Radio IF Rejection

Post by Ben Zonia » Wed Jun 30, 2021 5:53 pm

As irrelevant and impertinent as your comment seems, I did stay at a Holiday Inn near LAX once, and I couldn't get KOST 103.5 on the hotel alarm clock radio, because the 103.1 and 103.9 transmitters were so close. It was within the Los Angeles City Limits, and clearly LOS from Mt. Wilson.


"I had a job for a while as an announcer at WWV but I finally quit, because I couldn't stand the hours."

-Author Unknown

User avatar
SolarMax
Posts: 702
Joined: Sat Dec 04, 2004 5:59 pm
Location: 313

Re: Old Sony FM Table Radio IF Rejection

Post by SolarMax » Wed Jun 30, 2021 10:32 pm

Sometimes, a simple inline attenuator like the "DX/Local" switch available on some (but too few) radios, will knock the stronger offending signals down just a few dB, enough to allow copy of the station you actually want to hear. Or, if there's a wire for an FM antenna, shorten it as much as needed to keep the good, reject the bad.



k8jd
Posts: 603
Joined: Fri Jun 28, 2013 3:35 pm
Location: Commerce, MI

Re: Old Sony FM Table Radio IF Rejection

Post by k8jd » Sat Jul 03, 2021 7:15 pm

Sounds like his antenna system for the table radio was overkill for local reception and probably overloading the thing.



User avatar
WOHO
Posts: 820
Joined: Thu Dec 16, 2004 12:05 am
Location: 2965 Pickle Rd.

Re: Old Sony FM Table Radio IF Rejection

Post by WOHO » Wed Jul 14, 2021 9:05 am

Have a Sony very similar, just 2 pieces of #12 wire 15" long make a pretty dandy FM antenna on a tabletop radio (although not pretty).
Japanese quality, which means it still works, but has the scratchy controls, including tuning cap.
Using it in a basement, so no overload issues there.



Post Reply Previous topicNext topic