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AM Stations heard on Longwave

I get a weak KTCT 1050 on 150 KHz
KCBS 740/KDYA 1190 on 450 KHz
KDYA 1190 on 290 KHz
Click to expand...

Radios (and TV's) convert all incoming frequencies to a common I.F. (intermediate frequency)s further amplification and processing. Basic AM radios most commonly use 455 KHz or something close to 455 for the I.F. Conversion uses the principle that when 2 frequencies are mixed, the result is the original frequencies, plus the sum and difference frequencies. An adjustable locally generated signal, 455 KHz above the desired signal, produces the 455 KHz I.F. common frequency.

Your radio probably uses an I.F. of 450 Khz. When you tune to 150 KHz, the locally generated signal is at about 600 KHZ (450 KHz above 150 KHz). This produces a 450 KHz I.F. signal. It also happens to be 450 KHz below KTCT at 1050 KHz - so you hear that also. KTCT's much higher frequency should be rejected by other circuitry, but in most radios it is only partially blocked. The same is true for KDYA (290 + 450 + 450 = 1190). KCBS and KDYA are also directly mixing to produce 450 (1190 - 740 = 450)
 
I get IFs from KKNW on 250.
KKNW and KIXI sometimes mixed on 270 khz.
KXPA and KIXI mixed on 660 in the daytime (1540-880=660).
Then KIXI bleeds on 610, 760, 1270 and 1420 in the daytime. Plus IF on 640 from KXPA destroys KFI at night.

-crainbebo
 
Depending on conditions, I get some of the bigger flamethrowers on LW as well.

Some months back, several folks on here explained this same stuff to me too!
 
How about getting longwave on your AM dial? ;)

It's happened to me. When I lived in a small Mississippi town with a big airfield (Grenada) I used to drive by the LW beacon station nearby and it was audible on 1230 kHz… The beacon was on 235 kHz.
 
I get locals, though barely above the threshhold, on at least 2 of the commercial longwave frequencies.

Spent a few minutes trying to I.D. the new longwave catch, until I heard local mentions. :-[
 
How about longwave beacons heard on the AM Broadcast Band? I used to hear harmonics of the UIZ beacon at 215 kHz at two of more places on the AM dial. One was the third harmonic at 645 kHz and another at the sixth harmonic at 1290 kHz. Since Berz Airport was torn down and replaced with a subdivision, the beacon is now gone. Seeing that airport disappear was almost as sad as seeing all the proud impressive old AM arrays of WSNL, WFDF, WWJ, WXYT, and WOOD torn down. All of them were in sweet spots for conductivity, at least when they were built. Of course the NIMBYs were happy, but I don't think any of the new arrays are in areas with as good conductivity like the old arrays, except possibly WWJ.
 
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