AM Stations That Have Moved To On Or Near Their Image Frequency

[Schroedingers Cat]

I can think of two stations that moved to near their 455 kHz IF Image Frequency.
One is WMIC, Sandusky, MI which moved from 1560 kHz to 660 kHz, and the other is CHYM/CKGL, Kitchener, ON, which moved from 1490 kHz to 570 kHz. Can you think of any others? I wonder whether the GM came in one day and asked the CE, "Why can you hear our station in a much lower place on the dial? Is something wrong with our transmitter?" And then, getting the idea that it would be cool to move way down the dial and have a much better signal. Oh, I just thought of another one, WESK/WCHT, Escanaba, MI, which moved from 1490 kHz to 600 kHz, but that was back in the 1950s. Not sure that this station was continuously licensed though, but WLST 600 came on the air about the time WESK 1490 left the air.

 

[Schroedingers Cat]

Thought of another one. CFOS Owen Sound, ON moved from 1470 kHz to 560 kHz in 1958. So far, the only exact 455 kHz IF Image move.

 

[Ai4i]

Have you ever heard a station on 910 zero beating with itself on a very poorly constructed receiver?
The signal on 910 KHz mixes with the local oscillator on 1365 KHz
and produces the IF frequency of 455 KHz which doubles and finds its way back to the front end.

Is it just me, or has anyone else ever wondered why stations that are 450 KHz or 460 KHz apart are allowed to overlap unrestrictedly?
If they get into your front end and mix, you will hear them across the dial.

 

[Steve Green NEPA]

I'm not sure where to place this somewhat-off-topic question, but this image/harmonic thread might be a start. The matter is more 'nostalgia' than anything, but when it was a current event it had all of us DXers stumped.

Into the 90's, WGLI was this Long Island station on 1290. Since they had 3 towers in a line, I'm speculating that their directional pattern was symmetrical, like a Rorschach/inkblot* image. The sticks were slightly northwest of the
COL (Babylon) and they'd shoot their 5000 daytime watts straight down the spine of the Babylon USPO postmaster and
then out into Great South Bay and then the ocean. The station actually got some steady manner of response from Bermuda, even when no sensible normal person in Commack or Massapequa -- either side of the implosive main nulls -- could tune in the station at night despite being able to see the three towers blinking!

Anyway .... For a few years, 1290 WGLI also was placing a small signal on 1160. It HAD to've emanated from WGLI itself, as it had the identical directional characteristics as the big parent 1290, plus could be heard at night. The only other area stations signed off at sunset back then, so the nighttime 1160 signal could not have been the consequence like those incestual Meadowlands tower-jungle matings (such as WINS 1010 and WHN 1050 popped up as WHN PLUS WINS on 1090).

So, whence 'WGLI 1160' ?

* * * * * * *

* @ Engineers: Is it true that the resultant 3-towers-in-a-line signal has no choice but be destined by physics to have the same 'information' on both sides of the axis? And that to drop one of those minor side jowls a 4th tower is needed? I never was very far into electronics and theory after escaping high school with a '66' on my Physics II regents.

 

[ContinuousWave]

* @ Engineers: Is it true that the resultant 3-towers-in-a-line signal has no choice but be destined by physics to have the same 'information' on both sides of the axis? And that to drop one of those minor side jowls a 4th tower is needed? I never was very far into electronics and theory after escaping high school with a '66' on my Physics II regents.

My three towers are close to but not exactly in line but the pattern is not symmetrical....

 

[Ai4i]

My three towers are close to but not exactly in line but the pattern is not symmetrical....

There is no way that your pattern could be symmetric if the towers are,
"close to but not exactly in line", however:
Perfect linearity equals perfect symmetry.
Of course, ground conductivity will also distort that perfect symmetry.

 

[Schroedingers Cat]

Theoretical and Standard Patterns are Symmetrical if the towers are in a line. The Augmented Pattern could be Asymmetrical. If the towers are not in a line, but if there is an axis of symmetry, the Theoretical and Standard Pattern COULD be Symmetrical. If the tower arrangement has NO axis of symmetry, the pattern is asymmetrical. The pattern may be so close to symmetrical, it may appear that way. Asymmetrical phasing of a tower arrangement that has an axis of symmetry may also make the pattern asymmetrical. Good question.