AM Frequency of the Week - 700 kHz

[dave73]

I usually get a faint signal from WLW Cincinnati during the day (when not getting splattered by IBOC from WGN-AM on 720. It comes in better once local sunset arrives.

 

[rbrucecarter5]

A modern, consumer-level AM broadcast receiver sold in the US has an RF/IF bandwidth of maybe 6 kHz at the -3 dB points, that is, 3 kHz above and below an analog carrier frequency centered in its passband.

WRONG! This is what is inside virtually all radios manufactured in the last 30 years: http://earmark.net/gesr/Current_Radio_Design.htm

One lousy, horrible, cheap 455 kHz IF filter. I've seen them as wide as +/- 40 kHz. I've seen radios that skip the ceramic filter and just bypass the IF with a ceramic cap. If there is any roll-off - and remember that takes a few pennies - so lots of radios leave it out, it is done in the audio section which is usually equalized for speech, NOT in the IF bandwidth. What I don't see is any more of the all Japanese / American 6 transistor baseline with three IF cans and an IF bandwidth of +/- 4 kHz. I've tried - I've bought cheap radios trying to get an IF can set to replace a defective one in an antique - yes I said antique - 6 transistor radio. These cans are too big to fit on small boards, too expensive, and too unreliable. That crappy radio board I analyzed above is industry standard now. That was a $100 radio, you can imagine what compromises are made for a $10 radio. Even "good" radios in cars only dedicate 3 or 4 square inches at most to both AM and FM, so they can squeeze in satellite, CD, MPS, Pandora, bluetooth, etc. You are lucky these days to find tuned RF on AM and more than two ceramic filters on FM. So - yeah - the AGC of a modern AM radio is going to get fooled by sidebands - big time. FM isn't much better, usually there is a single junky 280 kHz ceramic filter there. Ultimate stop band rejection of only 40 to 50 dB. So - lots of potential for overload, crosstalk, and the AGC getting fooled by HD sidebands there, too.

Don't buy iBiquity propaganda and bad science. They looked long and hard to find a set of radios with antique circuitry inside to justify their foregone conclusion. I can do bad science, too, if I am forced to. But I have more integrity than to do it for money or to keep a job.

 

[schmave]

If WLW were ever to be off the air for any reason, what do you think might come in in its place? (Day or night)

If you're asking me, great question. Everything else on 700 (thinking Salt Lake City, Houston and Dallas off the top of my head) directs away from our region at night. One night about three years ago, I heard a station that was unidentifiable beating up on WLW in its cancellation zone, but there was no way to tell what it was. I hadn't heard it before then and have never heard it since.
Maybe some foreign station would sneak its way in?

 

[Cincinnati Kid]

If WLW were ever to be off the air for any reason, what do you think might come in in its place?

This reminds me of a time in the summer of 1962 when I had a very small AM transmitter (three tubes and 1/2 watt or something, maybe made by Heathkit) where you could set the frequency you were going to broadcast on. In addition to the ten-foot long wire aerial that came with it, I connected it to a long wire in my backyard and connected that to a strand of copper wire. In order to know it was that transmitter that was being heard while driving around, I connected a reel-to-reel tape recorder to it and would broadcast events such as the recent high school variety show which let you know it was that transmitter that was being heard. Even at night, you could pick up its signal close to 1/4 mile away. For a couple of late nights that summer, WLW indicated the station would be off for several hours to do some kind of maintenance. I and a couple of friends got the bright idea to set that small transmitter for 700 k.c. after WLW went off and see how far it might be heard. We also thought of persons in the immediate area who might tune into WLW by habit in their homes or cars and hear the output of that small transmitter. Unfortunately, we had a problem knowing when we had the transmitter exactly on 700 k.c. (the setting was done using a small screwdriver). At the same time, it was raining on the night we attempted this "great broadcast" making it a little harder to run back and forth from the house to the car to see how it sounded, if it was on 700, etc. I'm sure that Marconi faced much greater obstacles, but it is fun remembering it all now.

 

[schmave]

I usually get a faint signal from WLW Cincinnati during the day (when not getting splattered by IBOC from WGN-AM on 720. It comes in better once local sunset arrives.

When did WGN turn IBOC back on? It's been off for a couple years from everything I've heard.

 

[Time Traveler]

In Saratoga Springs, NY....either nothing or faint WTUB-Orange, Ma.....during the day....and of course WLW clearly at night. During the 1990's......There was a country station from New Brunswick or Nova Scotia that would mix with WLW at night. That station is long gone....Does anybody remember what it was?

 

[jd]

During the 1990's....There was a country station from New Brunswick or Nova Scotia that would mix with WLW at night. That station is long gone....Does anybody remember what it was?

That would be CHSJ, Saint John NB. They raised power from 10kW day/5kW night to 25/10kW in 1993. CHSJ-FM came on in early 1998 and the AM signed off a few months later.

 

[purpledevil]

Well there are only 2 700's within 500 miles of me, KSEV and KHSE, so if our local KSEV and WLW were both off, I'd love to catch XEDRD from the in-law's hometown of Durango, but at only 500w at night from around 700 miles away that's probably going to remain a log unfulfilled.

 

[ftballfan]

Well there are only 2 700's within 500 miles of me, KSEV and KHSE, so if our local KSEV and WLW were both off, I'd love to catch XEDRD from the in-law's hometown of Durango, but at only 500w at night from around 700 miles away that's probably going to remain a log unfulfilled.

You can't predict AM reception

 

[cyberdad]

I usually get a faint signal from WLW Cincinnati during the day (when not getting splattered by IBOC from WGN-AM on 720.  It comes in better once local sunset arrives.

When did WGN turn IBOC back on? It's been off for a couple years from everything I've heard.

Its off.

 

[Time Traveler]

During the 1990's....There was a country station from New Brunswick or Nova Scotia that would mix with WLW at night. That station is long gone....Does anybody remember what it was?

That would be CHSJ, Saint John NB. They raised power from 10kW day/5kW night to 25/10kW in 1993. CHSJ-FM came on in early 1998 and the AM signed off a few months later.

Thanks...I remembered that I had an old NRC AM log book right after I posted the question. I was getting something else under WLW last night...But when ever I tried to null WLW...the frequency was overwhelmed by WOR's IBLOCK hiss....