1210 AM Signal Problem

[davideduardo]

Actually, a half wave tower has one problem, which is the skywave cancellation of the groundwave signal: a 5/8 wave tower tends to move the cancellation zone out a bit. A higher band (1210 is the highest frequency of the old 1A clear channels) frequency will have the skywave land, at night, closer to the transmitter than a 5/8.

Actually, 1580 was the highest frequency of the Class I clear channels. It is a Canadian clear channel. The highest U.S. clear channel was 1560, occupied by WQXR (now WQEW) in New York City, a Class I-B station. The former WCKY in Cincinnati (now WSAI) was a Class I-A on 1530.

The higest 1A was 1210. Everything above it is a 1B or below in the US under the old classificaitons, and all are directional... 1220, 1500, 1510, 1520, 1530, 1560 and 1540. 1550 is a joint Canadian and Mexican channel. 1540 has LA, Waterloo and the Bahamas, 1570 is a Mexican 1A and 1580 is a joint Mexican (XEDM, 50 kw non-d) and canadian (formerly Chicoutimi).

1560 is shared by Bakersfield (the only 10 kw 1-B) and NY. 1530 in Cincy was a 1-B, shared with KFBK (the only standeing Franklin antenna directional system) in Sacramento. No US staiton above 1210 was a 1 A, and none of the 1Bs was non-directional (1500 DC and MPLS, 1510 Nashville and Spokane, 1520 Buffalo and Oklahoma are the others).

 

[qtpieislit]

And I'll pick up a couple of those batteries for ya, Sam. I'm a member of their battery club.

See if they got a tube checker layin’ around, I need to check a few old tubes to see why I’m not pickin up 1210.

 

[qtpieislit]

And I'll pick up a couple of those batteries for ya, Sam. I'm a member of their battery club.

See if they got a tube checker layin’ around, I need to check a few old tubes to see why I’m not pickin up 1210.

Yo Oak,

Check and see if David Eduardo could use that tube checker for his zip code analyzer.

 

[davideduardo]

WPHT used to be a blowtorch. In that station's earlier incarnation as WCAU, I used to hear it clearly in North Jersey. They need to get an engineer on site to check the base impedance and ground system. South Jersey, where the transmitter is located, has been plagued by copper thefts. Someone may have made off with the ground radials, leaving that 50,000 watt signal to warm up fishing worms.

As a follow-up, I taked with a couple of our RF engineers about different scenarios.

If the ground had been stolen, the base inpedence and reactance of the tower would change significantly. This would create reflected power, and probably shut the transmitter off and be evident in readings.

If the ground had deteriorated over time, readings would change over time, and cause a professional engineering staff to investigate, probably by checking with an OIB at the base and comparing with historical data. The cause would be evident.

Tower corrosion, more common in areas near the ocean with salt mist, would cause high resistence to develop between sections, and also increase the reflected power. In some severe cases, sections are scraped and strapped, but the indication would be that the tower might not be structurally sound at that point.

A half waver has something in the range of 120 ohms base inmedence.... plus whatever reactive componeth there is. As you get down to a quarter wave, you have around 36 ohms; a 100 to 110 wave tower will be around 50 ohms and not require much impedence matching but may be reactive.

Any of these situations, the only ones in WPHT's control, would be noticed very easily via metering. The more severe, the less likely a transmitter would even stay on the air without repairs and retuning the ATU.

 

[chuckydoll]

Not in Central Bucks

... 1210 falls short of West Chester and barely makes it to Doylestown.

I was in Central Bucks County on 9/29. Late that afternoon I tuned in 1210 for the Phillies game as I was driving from Doylestown to Warrington. Signal was loud and clear on my car radio along Route 611 (Easton Road) -- as it should be. Some of the announcers were hard to understand but that was due to the network engineer at the ballpark.

Where 1210 has issues is around Reading, Easton and Bridgeton. That's due to the signals on graveyard channels 1230 and 1240.

 

[amfmsw]

Was WCAU a blowtorch? Absolutely. I remeber being in Bermuda in 1971. On a simple Panasonic AM/Cassette Recorder (no FM), We could listen to the local ZFB, as well as KYW, WABC and WCAU anytime 24/7. Night brought us WBT, WKBW, WCBS, WSM, WNBC and more.

Now 1210 can barely make it to the Jersey Shore. It went from a blowtorch to a Bic lighter.

 

[davideduardo]

Was WCAU a blowtorch? Absolutely. I remeber being in Bermuda in 1971. On a simple Panasonic AM/Cassette Recorder (no FM), We could listen to the local ZFB, as well as KYW, WABC and WCAU anytime 24/7. Night brought us WBT, WKBW, WCBS, WSM, WNBC and more.

Now 1210 can barely make it to the Jersey Shore. It went from a blowtorch to a Bic lighter.

You are comparing groundwave with skywave, which is hardly appropriate. The 5 mv/m listenable contour of that station, now or in the past, is about a 26 mile radius of the transmitter.

I got WCAU frequently in Puerto Rico and even on occasion in Ecuador (in the 60's) but that was skywave. It's meaning less for comparisons with local service areas.

I wonder how you got WCAU in Bermuda on 1210 with an extreme local on 1235? By the way, that station was a blowtorch in the early 60's. Listenable nearly any night except summer in Ohio.

 

[davideduardo]

AM stations are still required to measure their occupied bandwidth and harmonic emissions once a year.

But that is just a tiny part of what the annual proof used to be.

[/quote]If an AM station makes any changes in its antenna system, it must do an antenna proof of performance by sending people with field strength meters out along radials drawn on a map from the transmitter site.[/quote]

An antenna proof is not the annual proof of performance which was essentially an audio and transmission test set.

Unless I am mistaken (I have not been at a non-D since being Chief Operator at one in 1970-72), a non-directional station uses the electrical height of the radiator to determine field strength at a kilometer, and does not do an antenna proof. Field strength may be measured in certain circumstances, such as nonconforming radiators and where a station wishes to demonstrate lower than the FCC chart shows for ground conductivity, thus allowing for a higher efficiency antenna.

For directionals, and there is a proposal to use modeling in place of field readings. I have never seen a non-directinal station with a field strength meter.

If the station is directional, the engineers must make these measurements for each pattern, plus a nondirectional pattern. That certainly cannot be done on a desktop.

And that is not a proof of performance. That is a directional proof, and it is supplemented with a partial proof annually. Again, all this may go away soon by use of modeling. If you don't know the difference between a Proof of Performance and a directional proof, you do ill in lecturing anyone.

Even FM stations are required to check their bandwidth on a spectrum analyzer if they replace a transmitter or exciter or if a subcarrier has been added.

This is usually done by a monitoring service, as many stations do not have a spectrum analyzer. And, again, it is not the Proof of Performance that used to be required where you tested everything from the console to the transmitter and did response curves and various tests like distortion, etc.

 

[oaktree]

The only batteries available were all "Copper Tops", Sam. Now, you know where that ground system went...

A zip code analyzer. That depends on whether it is the old-fashioned "analogue" one or "digital" one me thinks ...

 

[amfmsw]

I had no problem seperating ZFB 1235Kc's narrowband audio (no splatter) with 1210.

It was 5Kc MORE seperation than 1230 WCMC Wildwood here at the shore. There's no problem seperating CMC - CAU unless you're in sight of WCMC's stick. And WCMC has much wider bandwidth than ZFB did at the time.

 

[BRNout]

Re: Not in Central Bucks

Where 1210 has issues is around Reading, Easton and Bridgeton. That's due to the signals on graveyard channels 1230 and 1240.

Um, add much of the Main Line to that list. The static and inability to overcome normal RF from electrical lines renders the signal unlistenable in patches of Paoli, Malvern and Berwyn. Farther west, in Downingtown and Exton, these issues get even worse in built-up areas. Same is true in Phoenixville. The signal ain't great in the central and western portions of Montgomery County either.

The last time I checked, Chester County was in the Philadelphia market and is - in fact - the market's fastest growing and wealthiest county (yes, a higher PCI than Bucks). That doesn't bode well for WPHT unless they do something to boost their signal into the area. It may be fine in Bucks County (which is not far from their tx site) but it is crappy to the west.

 

[PhilGalasso]

I wonder how you got WCAU in Bermuda on 1210 with an extreme local on 1235? By the way, that station was a blowtorch in the early 60's. Listenable nearly any night except summer in Ohio.

The local station in Bermuda had moved to 1230 by the 1970s. At the time, its callsign was ZBM-1.

 

[PhilGalasso]

AM stations are still required to measure their occupied bandwidth and harmonic emissions once a year.

But that is just a tiny part of what the annual proof used to be.

If an AM station makes any changes in its antenna system, it must do an antenna proof of performance by sending people with field strength meters out along radials drawn on a map from the transmitter site.[/quote]

An antenna proof is not the annual proof of performance which was essentially an audio and transmission test set.

Unless I am mistaken (I have not been at a non-D since being Chief Operator at one in 1970-72), a non-directional station uses the electrical height of the radiator to determine field strength at a kilometer, and does not do an antenna proof. Field strength may be measured in certain circumstances, such as nonconforming radiators and where a station wishes to demonstrate lower than the FCC chart shows for ground conductivity, thus allowing for a higher efficiency antenna.

For directionals, and there is a proposal to use modeling in place of field readings. I have never seen a non-directinal station with a field strength meter.

If the station is directional, the engineers must make these measurements for each pattern, plus a nondirectional pattern. That certainly cannot be done on a desktop.

And that is not a proof of performance. That is a directional proof, and it is supplemented with a partial proof annually. Again, all this may go away soon by use of modeling. If you don't know the difference between a Proof of Performance and a directional proof, you do ill in lecturing anyone.

Even FM stations are required to check their bandwidth on a spectrum analyzer if they replace a transmitter or exciter or if a subcarrier has been added.

This is usually done by a monitoring service, as many stations do not have a spectrum analyzer. And, again, it is not the Proof of Performance that used to be required where you tested everything from the console to the transmitter and did response curves and various tests like distortion, etc.
[/quote]

Dave,
As an engineer of 35 years standing, I know the difference between the audio proof of performance, which was formerly required, and the bandwidth measurements, which are mandatory for AM stations on an annual basis and mandatory for FM whenever a new transmitter or exciter is installed. To do FM bandwidth measurements, a spectrum analyzer must be used and stations can rent them or have an outside engineer do them for the station. The annual AM measurements can be taken on a Delta Electronics Splatter Monitor and the harmonic measurements for AM can be taken on a field strength meter that covers frequencies above the AM broadcast band.

The "antenna proofs" that I discussed are proofs of performance, with the word "proof" being a slang term. See the FCC Rules that I cited for clarification. And, yes, they are different from audio proofs. The FCC mentioned several types of "proofs of performance" in its Rules. Look them up for yourself! ¿Metiste la pata en este asunto?

 

[davideduardo]

Dave,
As an engineer of 35 years standing, I know the difference between the audio proof of performance, which was formerly required, and the bandwidth measurements, which are mandatory for AM stations on an annual basis and mandatory for FM whenever a new transmitter or exciter is installed. To do FM bandwidth measurements, a spectrum analyzer must be used and stations can rent them or have an outside engineer do them for the station. The annual AM measurements can be taken on a Delta Electronics Splatter Monitor and the harmonic measurements for AM can be taken on a field strength meter that covers frequencies above the AM broadcast band.

The "antenna proofs" that I discussed are proofs of performance, with the word "proof" being a slang term. See the FCC Rules that I cited for clarification. And, yes, they are different from audio proofs. The FCC mentioned several types of "proofs of performance" in its Rules. Look them up for yourself! ¿Metiste la pata en este asunto?

As an engineer of 43 years standing, I can say the audio and system proof, which is not required, was always called The Proof or abbreviated as the PoP. An antenna proof was always referred to as a directional proof, with no amiguity. Having been though a number of these, there can be no confusion at all... a PoP could be done in one long experimental period session, while a directional proof took days if not weeks. It sometimes took helicopters and boats, too.

Today, at all but the largest stations, the annual tests are done by outsiders, just like frequency checks used to be done. PoPs, though, generally required more than one person, especailly for separate xmtr and studio locations. It was usual in markets I was in for engineers to help other engineers in exchange for reciprocity when the next proof was due. Of course, we all had to have a 1st to sign the papers, too.

In the case of this discussion of the WPHT signal, we are touching on things a PoP would reveal. As a non-D, 1210 does not have to do an antenna proof and has no monitor points.

 

[davideduardo]

I wonder how you got WCAU in Bermuda on 1210 with an extreme local on 1235? By the way, that station was a blowtorch in the early 60's. Listenable nearly any night except summer in Ohio.

The local station in Bermuda had moved to 1230 by the 1970s. At the time, its callsign was ZBM-1.

And I believe there was another co-owned station on 1340; 960 came sometime in the 70's, too.

 

[PhilGalasso]

I wonder how you got WCAU in Bermuda on 1210 with an extreme local on 1235? By the way, that station was a blowtorch in the early 60's. Listenable nearly any night except summer in Ohio.

The local station in Bermuda had moved to 1230 by the 1970s. At the time, its callsign was ZBM-1.

And I believe there was another co-owned station on 1340; 960 came sometime in the 70's, too.

The co-owned station was ZBM-2. 960 was ZFB. Around 1983, a third broadcaster began operation in Bermuda, VSB on 1450 kHz. It had a country format at the time.

 

[amfmsw]

I know I wasn't going nuts. No, 1230Kc in Bermuda was NOT ZBM-1. It was ZFB. It was July 1971. As far as the 1235Kc frequency, I'm taking DE's word on that. Bermuda was on the European frequency allocations, being aqssociated with the UK.

And the 1210 reception of Philadelphia was constant, even more reliable during the day. It was not skywave until critical hours and overnight. This was on a Halicrafters Receiver with a longwire antenna supplied by the government to the Scout camp outside of Hamilton.

http://en.wikipedia.org/wiki/Bermuda_Broadcasting

 

[w9wi]

I know I wasn't going nuts. No, 1230Kc in Bermuda was NOT ZBM-1. It was ZFB. It was July 1971. As far as the 1235Kc frequency, I'm taking DE's word on that. Bermuda was on the European frequency allocations, being aqssociated with the UK.

I'm pretty sure 1235 wasn't a valid European channel. (the nearest modern European channel is 1233. The European plan has changed since 1971 but I'm pretty sure only by 1KHz so 1235 wouldn't have been valid under the old plan either.)

A fair number of Caribbean stations (and some in South America were quoted in various directories with 5KHz splits - operating midway between the U.S. channels - David E. could probably elaborate - but anyway, I would suggest 1235 would be for this reason, not for anything having to do with Europe.

 

[davideduardo]

I know I wasn't going nuts. No, 1230Kc in Bermuda was NOT ZBM-1. It was ZFB. It was July 1971. As far as the 1235Kc frequency, I'm taking DE's word on that. Bermuda was on the European frequency allocations, being aqssociated with the UK.

I'm pretty sure 1235 wasn't a valid European channel. (the nearest modern European channel is 1233. The European plan has changed since 1971 but I'm pretty sure only by 1KHz so 1235 wouldn't have been valid under the old plan either.)

A fair number of Caribbean stations (and some in South America were quoted in various directories with 5KHz splits - operating midway between the U.S. channels - David E. could probably elaborate - but anyway, I would suggest 1235 would be for this reason, not for anything having to do with Europe.

1235 was an anomaly. It neither matched the US nor Europe. It was widely heard, even to the west coast of the US. Other northeren splits were St. Pierre et Miquelon (off Newfoundland) on 1375, Thule AFB on 1425, and Caribbeans in the Windwards on 535, 545 (for a while 50 kw Jumbo from St Lucia), 555, 995, 705, 1205, etc. Haiti on 1325, 1035, 1375 were common. Costa Rica licensed in the 60's to the 90's every 25 kHz, so 575, 625, 675, etc were all on the air. Panama had many stations ending in 5, like Ondas del Canajagua 1045, and many others. Ecuador licenced every 5... I had 805 in Quito which I always ran, never detected, on 810. Peru had several, including the government station in Lima on 854, I believe. Paraguay and Bolivia had many ending in 5, too. Belize was long on 834 or 835 I think, until they ended all AM radio in that nation. Nicaragua had stations like Radio Managua on 965, and Radio Chinandega on 1475. All were nice DX targets.

 

[mimo]

I thought Belize still had one am left as the info here suggests, unless it's woefully out of date. http://radiostationworld.com/Locations/Belize/Radio.asp If they did finally go off the air, when was that?