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Messed-Up Radials Can Generate Spurious Emissions
Messed Up Ground Radials Can Generate Spurious Signals
In 1948 I was the consulting engineer for the proposed first AM broadcast station in Mt. Pleasant, Michigan, obtaining a construction permit and license for WCEN, 500 watts on 1150 KHz. Using a National HRO receiver, I was performing a hands-on search for an available frequency for the new station, when I encountered an interesting and unusual signal that was entirely out of place in the AM broadcast band-a CW Morse-code station illegally transmitting five-letter-word code groups at 30 words per minute. The illegal signal was S9 +40 dB on 1297.8 KHz, producing a 2200 Hz beat-note with the 1300 KHz frequency of WOOD, Grand Rapids, thus producing a an audible CW signal with the receiver BFO disabled. The format of the coded messages appeared to be military, IDing as NSS. We know that NSS is the flagship station of the U.S. Navy in Annapolis, MD, but in the AM broadcast band? It appeared that either an NSS transmitter was producing a spurious emission, or a station using NSS as a fraudulent call sign was operating clandestinely in the AM broadcast band. I deemed it important to find out which. As a former FCC monitoring officer at the Allegan, Michigan monitoring station, the next step was to report the situation to the Allegan station. Although Allegan was 90 airline miles away, the monitoring personnel there could not hear the spurious signal, even though it was S9 +40 dB at Mt. Pleasant. I let the FCC monitors hear the signal through the telephone, but they still heard nothing on their receivers tuned to 1297.8 KHz. Thus the signal must be of local origin near Mt. Pleasant, and not from NSS. However, to be on the safe side, FCC notified the Navy of the spurious signals, and the NSS operators began combing all their transmitters for spurious signals, and found none. The situation is now becoming even more strange. I then copied five minutes of the coded text and sent a copy to the FCC, who relayed it to NSS for comparison to their transmissions. The situation is now both perplexing and frustrating, because the text I copied on 1297.8 KHz agreed exactly with a transmission that had been made by NSS. How could that signal have been transmitted on 1298.7 KHz if no spurious signals were emanating from NSS? But it's not likely to have been a fraudulent station. What then? A partial answer came shortly thereafter. As I resumed the search for a useable frequency for the new station, I proceeded downward from 1298.7 KHz, going through 1280 KHz and hearing WFYC, Alma, 1000 watts, 15 miles away, also S9 +40 dB. But on continuing further downward I immediately came across another S9 +40 dB thumping CW signal. I switched on the BFO and discovered the CW was also a five-letter-word coded transmission at about 30 wpm, the same as NSS. I retuned to 1298.7 KHz and the NSS signal was also there, as before. So I cranked up a second receiver to monitor both frequencies simultaneously. Surprise! Both frequencies were showing identical simultaneous transmissions. I then measured the frequency of the lower-frequency signal-1262.2 KHz. Voila! The higher CW frequency was 17.8 KHz above WFYC's 1280 frequency and the lower CW frequency was 17.8 KHz below WFYC's frequency. A quick reference to the Berne frequency listing showed NSS assigned to 17.8 KHz. This situation now appeared to indicate something very wrong going on at WFYC. The low-frequency world-wide ground-wave signal from NSS was apparently somehow mixing with the signal from WFYC, and producing the 1297.8 and 1262.2 sum and difference frequencies. But what non-linear device in WFYC's system could perform that mixing? Don't know, but I reported this new information to the FCC and that was the last I heard of the situation…until… Fast forward now to 1955. I was now employed as an electrical engineer at the RCA Laboratories, the David Sarnoff Research Center in Princeton, NJ. An assignment took me to Washington, D.C. to attend the annual conference of the NAB, the National Association of Broadcasters. President Dwight D. Eisenhower gave the keynote address. However, one of the technical forums was presented by Jack Young, Chief Engineer of the RCA Broadcast Division. His topic was on the solution of mutual interference between two broadcast stations in Los Angeles, KFI and KNX. It seems that in a section of the Los Angeles area it was impossible to hear one of these stations without hearing both simultaneously-when tuned to 640 KHz for KFI, both KFI and KNX were heard, and when tuned to 1070 KHz for KNX, both KNX and KFI were heard. Young was assigned the task of determining the cause of the interference and eliminating it. To make a long story short, he discovered that there were ancient and rusty oil well derricks in the affected area. Currents from both KFI and KNX transmissions were being induced in the oil well towers, and the rusty joints were acting as mixers for the two frequencies, producing both the sum and difference frequencies, as well as re-radiating both signals on their original frequencies. When the derricks were removed the interference stopped. So how is this incident relevant to the NSS problem? Well, at the conclusion of Young's presentation I had the opportunity to talk with him, and because of the similarity of the problems, I told him of my discovery of the NSS signals appearing in the AM broadcast band. Talk about coincidences! He was surprised and excited to learn that I had discovered the NSS problem at WFYC, because he was the one assigned to determine the cause of the problem. He had never been told how that problem originated, or how the problem had been discovered. He then explained that he had found the ground radial system under the WFYC antenna a horrible mess. Cold solder joints throughout, and far ends of the radials hanging loose in the water of the nearby Pine River, establishing the non-linear mixer condition that resulted in the sum and difference frequencies being generated between the NSS and WFYC signals. Cleaning up the messed-up radials ended the appearance of the NSS signals in the AM broadcast band, thus concluding an interesting journey. Walt, W2DU |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 14:57:21 -0400, Walter Maxwell
wrote: thus concluding an interesting journey. Hi Walt, I want to point out that your story has all the elements demanded of a well written English composition. Some engineers who've been horse-whipped through bone-head grammar classes bristle at the topic. However, one simple lesson was probably lost (given it appears so seldom here) in that punishment. A story (or any posting) needs: a beginning; a middle; an end; and should be have no spelling errors to speak of. You've surpassed those simple elements by a consistently engaging in good yarns. Thanx, Richard Clark, KB7QHC, B.A. |
Messed-Up Radials Can Generate Spurious Emissions
Richard Clark wrote:
SNIPPED story (or any posting) needs: a beginning; a middle; an end; and should be have no spelling errors to speak of. I just recently read that a good Preacher should follow a similar structu A Good beginning A Good ending And as little as possible in the middle Oh well !!! |
Messed-Up Radials Can Generate Spurious Emissions
Walter Maxwell wrote:
Messed Up Ground Radials Can Generate Spurious Signals Walt, Keep up the stories. They are very interesting.... 73, Larry, W0QE |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 12:20:35 -0700, Richard Clark wrote:
On Thu, 20 Oct 2005 14:57:21 -0400, Walter Maxwell wrote: thus concluding an interesting journey. Hi Walt, I want to point out that your story has all the elements demanded of a well written English composition. Some engineers who've been horse-whipped through bone-head grammar classes bristle at the topic. However, one simple lesson was probably lost (given it appears so seldom here) in that punishment. A story (or any posting) needs: a beginning; a middle; an end; and should be have no spelling errors to speak of. You've surpassed those simple elements by a consistently engaging in good yarns. Thanx, Richard Clark, KB7QHC, B.A. Richard, your approval of my writings is like receiving a million-dollar jack pot. Words cannot descibe how much your approval as an English major is appreciated. Walt, W2DU, B.S. |
Messed-Up Radials Can Generate Spurious Emissions
Amos Keag wrote:
Richard Clark wrote: SNIPPED story (or any posting) needs: a beginning; a middle; an end; and should be have no spelling errors to speak of. I just recently read that a good Preacher should follow a similar structu A Good beginning A Good ending And as little as possible in the middle Oh well !!! I'm a part-time GED teacher. Writing is one of the most difficult GED tests as it is not multiple choice. We teach the following format for the writing test. A beginning - a one paragraph statement of a principle or premise A middle - three paragraphs based on three major points of argument An end - A one paragraph conclusion summarizing the three points The people in Austin who grade the GED writing tests like that format. -- 73, Cecil, http://www.qsl.net/w5dxp |
Messed-Up Radials Can Generate Spurious Emissions
Walter Maxwell wrote:
Richard, your approval of my writings is like receiving a million-dollar jack pot. Words cannot descibe how much your approval as an English major is appreciated. Y'all shudda did ah reright in Suthurn so us Texians kud unnerrstan. -- 73, Cecil, http://www.qsl.net/w5dxp |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 20:26:55 GMT, Cecil Moore wrote:
Walter Maxwell wrote: Richard, your approval of my writings is like receiving a million-dollar jack pot. Words cannot descibe how much your approval as an English major is appreciated. Y'all shudda did ah reright in Suthurn so us Texians kud unnerrstan. Cecil, shud I huv writ my last 3 emales ta ya in Suthurn so ya kud of unnerrstud em sufeeciently ta reeplie? Waalltre |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 12:20:35 -0700, Richard Clark wrote:
Richard, in my previous post I intended to say that my last story I sent to you was the first rough draft. Unfortunately, my first drafts are disasters, and after cleaning it up I submitted it to QST, who has promised to review it. Walt |
Messed-Up Radials Can Generate Spurious Emissions
Cleaning up the messed-up
radials ended the appearance of the NSS signals in the AM broadcast band, thus concluding an interesting journey. ......................... I think a lot of the MW garbage I receive on 160m, etc, is generated much the same way. I've even seen people say that semi corroded stranded copper wire, even insulated can cause problems like that. And...I've been seeing stronger and stronger MW energy here every year it seems... I'm starting to wonder if the standed wire theory may not be too far fetched, as most all my wire is stranded, and most is getting some age on it. I also seen to notice even the water heater or pipes seem to generate spurious MW energy.. Been driving me crazy the last few years, and seems to be slowly getting worse. Not to mention all the other sources of trouble like fences, guy wires, bad connections, etc. I don't doubt bad radials could cause that for a minute...I've seen things like that around here in mildew city from all kinds of bad connections.. Once had a bad "rf in the shack" problem...Turned out to be nothing more than corroded/rusted balun hardware at the antenna feedpoint. Cleaned that up, bingo, all gone. MK |
Messed-Up Radials Can Generate Spurious Emissions
Walter Maxwell wrote:
Cecil, shud I huv writ my last 3 emales ta ya in Suthurn so ya kud of unnerrstud em sufeeciently ta reeplie? Walt, I received your .doc attachment at work and I only work two days a week so it wasn't until today that I could actually read it. Sorry, I'll probably reply tonight. -- 73, Cecil, http://www.qsl.net/w5dxp |
Messed-Up Radials Can Generate Spurious Emissions
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Messed-Up Radials Can Generate Spurious Emissions
Very interesting. Are these stories from a book you may have published?
"Walter Maxwell" wrote in message ... Messed Up Ground Radials Can Generate Spurious Signals In 1948 I was the consulting engineer for the proposed first AM broadcast station in Mt. Pleasant, Michigan, obtaining a construction permit and license [cut] |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 17:31:59 -0500, "John N9JG"
wrote: Very interesting. Are these stories from a book you may have published? No, John, but the story about the FCC RID saving lives by locating lost aircraft over the Pacific has been submitted to QST. We'll have to wait and see if they publish it. Walt "Walter Maxwell" wrote in message .. . Messed Up Ground Radials Can Generate Spurious Signals In 1948 I was the consulting engineer for the proposed first AM broadcast station in Mt. Pleasant, Michigan, obtaining a construction permit and license [cut] |
Messed-Up Radials Can Generate Spurious Emissions
Good story - I'm impressed. I struggle trying to copy 20 wpm, and you were
copying @ 30 wpm. I noticed also you referred to frequencies in KHZ. But shouldn't that have been "KC" or for historic accuracy. ;-) |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 21:05:31 -0400, "Hal Rosser" wrote:
Good story - I'm impressed. I struggle trying to copy 20 wpm, and you were copying @ 30 wpm. I learned the code at a very early age. When I was an op at AM BC station WMFJ Daytona Beach in 1940 we had no teletype for gathering news, but had a contract with Press Wireless for copying WCX/WJS Brentwood, NY. I copied the news every day for broadcast. The code speed was 35 to 38 wpm. I noticed also you referred to frequencies in KHZ. But shouldn't that have been "KC" or for historic accuracy. I understand your thoughts on this, but if I had used KC in a current piece like this one, someone would surely say I should have used KHz. So either way someone would say I should have used the other form. Walt |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 21:05:31 -0400, Hal Rosser wrote:
I noticed also you referred to frequencies in KHZ. But shouldn't that have been "KC" or for historic accuracy. ;-) Well, it should've been "kc/s". More 'short-handedly': "kcs". A Hertz is a "cycle per second". Jonesy W3DHJ |
Messed-Up Radials Can Generate Spurious Emissions
On 21 Oct 2005 02:50:10 GMT, Allodoxaphobia wrote:
On Thu, 20 Oct 2005 21:05:31 -0400, Hal Rosser wrote: I noticed also you referred to frequencies in KHZ. But shouldn't that have been "KC" or for historic accuracy. ;-) Well, it should've been "kc/s". More 'short-handedly': "kcs". A Hertz is a "cycle per second". Jonesy W3DHJ Then I should have said KHz/s, or KHzs, right? Walt |
Messed-Up Radials Can Generate Spurious Emissions
Walter Maxwell writes:
Messed Up Ground Radials Can Generate Spurious Signals ....[snip].... So can a weak alligator clip on a simple homebrew antenna tuner! Several years ago I was operating CW while my wife was using a "glass TTY" to a remote computer (that shows how long ago this was), when a policeman (who was NOT a ham) knocked on our door and said I was causing lots of RFI and TVI. After thinking "I'm on CW; who would have been able to identify me?", I called a nearby ham. Yep, he said I was inter- ferring on EVERY frequency he could check (AM, FM, TV, ham, etc.!), and since he couldn't phone me, he had called the police. So I got back on the air and, with his help, started wiggling everything from the transmitter output toward the antenna. The culprit was a rather weak alligator clip in my homebrew antenna tuner, and that poor joint was producing harmonics from DC to daylight! --Myron, W0PBV. -- --Myron A. Calhoun. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
Messed-Up Radials Can Generate Spurious Emissions
LOTS SNIPPED
I just recently read that a good Preacher should follow a similar structu A Good beginning A Good ending And as little as possible in the middle Or: Stand up. Speak up. Shut up! -- --Myron A. Calhoun. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
Messed-Up Radials Can Generate Spurious Emissions
On 20 Oct 2005 23:53:05 -0500, wrote:
that poor joint was producing harmonics from DC to daylight! Hi Myron, Early Cold Fusion. 73's Richard Clark, KB7QHC |
Messed-Up Radials Can Generate Spurious Emissions
Cecil Moore wrote:
I'm a part-time GED teacher. Writing is one of the most difficult GED tests as it is not multiple choice. What's a "GED"... when translated into English? :-) Yet another version of 1-2-3: 1. Tell 'em what you're going to tell 'em. 2. Then tell 'em. 3. Tell 'em what you've told 'em. -- 73 from Ian G/GM3SEK |
Messed-Up Radials Can Generate Spurious Emissions
Walter Maxwell wrote:
SNIPPED I understand your thoughts on this, but if I had used KC in a current piece like this one, someone would surely say I should have used KHz. So either way someone would say I should have used the other form. Walt C'mon Walt, you can do better than this 'weak' response. You could define a new term. One that includes CPS for historical accuracy, and also includes Hz for contemporary usage. What about combining both into a new contraction, 'CZ' ? ;-) |
rust?Messed-Up Radials Can Generate Spurious Emissions
In article ,
Cecil Moore wrote: hmm this kinda makes me wonder about my tvi as my antenna is near the building master tv antenna which is pretty rusty espically on the coax to antenna lugs never saw so much rust surpirzed i can see any station and it's missing a few elements that broke off i've been afraid to change it since a new antenna just might be worse then again it could be much better wish there was a way to test if the interference was strictly due to proximity/master amp or tv overload etc or 'sperious emissions' caused by the tv antennas rust i need a rust spurious emissions meter m |
Messed-Up Radials Can Generate Spurious Emissions
Ian White G/GM3SEK wrote:
What's a "GED"... when translated into English? :-) Sorry, that's a USA term - stands for General Education Development. It's a high school equivalency certificate issued by the state, after passing a battery of 5 exams, to people who didn't graduate from high school for whatever reason. -- 73, Cecil http://www.qsl.net/w5dxp |
Messed-Up Radials Can Generate Spurious Emissions
Cecil Moore wrote:
Ian White G/GM3SEK wrote: What's a "GED"... when translated into English? :-) Sorry, that's a USA term - stands for General Education Development. It's a high school equivalency certificate issued by the state, after passing a battery of 5 exams, to people who didn't graduate from high school for whatever reason. Thank you - and well done, Cecil, for being part of that program. -- 73 from Ian G/GM3SEK |
Messed-Up Radials Can Generate Spurious Emissions
Ian White G/GM3SEK wrote:
Thank you - and well done, Cecil, for being part of that program. There's a fringe benefit. Some of those kids have pretty cute grandmas. :-) -- 73, Cecil, http://www.qsl.net/w5dxp |
Messed-Up Radials Can Generate Spurious Emissions
Hi Walt,
Enjoyed reading the story. Thanks! I live about 1/2 mile from a 50 kW broadcast station on 1360 kHz here in West Phoenix/Glendale and am within 5 miles of another half-dozen running 5 - 20 kW. Recently I became quite aware of a bad splice in the wires on my 80/40-meter dipole through the appearance of mixing products from the broadcasters all up and down both bands. Of course, I also saw the problem on transmit, having one value of SWR at 5 watts and an entirely different one at 500 watts. I hate to think of how many "mystery signals" I was generating in the process of getting that bit of test data! I keep telling people I am going to cut that bad splice out and patent it. How many mixer diodes do you know about that can handle half a kilowatt. 73, Jim, K7JEB |
Messed-Up Radials Can Generate Spurious Emissions
On Thu, 20 Oct 2005 23:00:49 -0400, Walter Maxwell wrote:
On 21 Oct 2005 02:50:10 GMT, Allodoxaphobia wrote: On Thu, 20 Oct 2005 21:05:31 -0400, Hal Rosser wrote: I noticed also you referred to frequencies in KHZ. But shouldn't that have been "KC" or for historic accuracy. ;-) Well, it should've been "kc/s". More 'short-handedly': "kcs". A Hertz is a "cycle per second". Jonesy W3DHJ Then I should have said KHz/s, or KHzs, right? _That_ would be doubly redundant. :-) It would be the equivalent to saying "kilo-cycles per second per second". Some sort of "FM propagation", I suppose. Jonesy -- Marvin L Jones | jonz | W3DHJ | linux Pueblo, Colorado | @ | Jonesy | OS/2 __ 38.24N 104.55W | config.com | DM78rf | SK |
Messed-Up Radials Can Generate Spurious Emissions
On Fri, 21 Oct 2005 07:14:31 -0700, "K7JEB" wrote:
Hi Walt, Enjoyed reading the story. Thanks! I live about 1/2 mile from a 50 kW broadcast station on 1360 kHz here in West Phoenix/Glendale and am within 5 miles of another half-dozen running 5 - 20 kW. Recently I became quite aware of a bad splice in the wires on my 80/40-meter dipole through the appearance of mixing products from the broadcasters all up and down both bands. Of course, I also saw the problem on transmit, having one value of SWR at 5 watts and an entirely different one at 500 watts. I hate to think of how many "mystery signals" I was generating in the process of getting that bit of test data! I keep telling people I am going to cut that bad splice out and patent it. How many mixer diodes do you know about that can handle half a kilowatt. 73, Jim, K7JEB Interesting, Jim, I believe the US Patent Office is open for business. Looks like I've started something. Walt |
Messed-Up Radials Can Generate Spurious Emissions
Cecil Moore wrote:
Ian White G/GM3SEK wrote: Thank you - and well done, Cecil, for being part of that program. There's a fringe benefit. Some of those kids have pretty cute grandmas. :-) Do you teach them to spell "incorrigible"? -- 73 from Ian G/GM3SEK |
Messed-Up Radials Can Generate Spurious Emissions
I think a lot of the MW garbage I receive on 160m, etc, is
generated much the same way. I've even seen people say that semi corroded stranded copper wire, even insulated can cause problems like that. And...I've been seeing stronger and stronger MW energy here every year it seems... I'm starting to wonder if the standed wire theory may not be too far fetched, as most all my wire is stranded, and most is getting some age on it. I also seen to notice even the water heater or pipes seem to generate spurious MW energy.. Been driving me crazy the last few years, and seems to be slowly getting worse. Not to mention all the other sources of trouble like fences, guy wires, bad connections, etc. I don't doubt bad radials could cause that for a minute...I've seen things like that around here in mildew city from all kinds of bad connections.. Once had a bad "rf in the shack" problem...Turned out to be nothing more than corroded/rusted balun hardware at the antenna feedpoint. Cleaned that up, bingo, all gone. MK I had a similar problem with a W2AU balun. AM stations all over the place. The balun "eye" bolts were severely corroded. Replacing the balun with a stainless steel version eliminated all the AM junk. I notice that W2AU baluns are now advertised as having all "Stainless steel" hardware. Frank |
Messed-Up Radials Can Generate Spurious Emissions
I'll only say that it is interesting that the first comments were about the
grammar not the content. Interesting story Walt. That's what I call an ending! Brief story 1 The apollo recovery ships had problems in the radars from high power HF transmitters and the rusty deck railing chains. Brief story 2...well not so brief. To solve a problem in a 150MHz car telephone in a Caddy and one on a motorcycle, I developed a method for finding what I dubbed "environmental desense" of a similar nature. This amounted to the transmitter being modulated, in its _field_ by near-by noisy joints in the car body or the motorcycle seat springs. This produced virtual noise sidebands on the transmitter. This "modulation" extended out to the receiver frequency. The receiver used the same antenna, thus easily picking up this new "noise modulation. This is an extension of what I had called "the Screwdriver Effect" in my early 2-way repair days. you are listening to a rather close transmitter (or maybe not so close) and you simply rub a screwdriver across another nearby piece of metal and you hear noise on the received signal. Same effect - field modulation. To explain in more detail... 1- EVERYTHING conductive is an antenna (receiving). 2- Everything has RF current in it from every transmitter (even YOU). 3- These "everythings" therefore produce small RF fields of their own, from these currents. 4- These fields sum with the original field. 5- If two of these "everythings" come into contact, there can be a change in current due to the new physical arrangement (current through the new connection) 6- This change also changes the resulting fields from the "Everythings" 7- This changes the total resulting field. 8- this is just like a change in the original field and just like a change in the transmitted signal. 9- SO... this is received just like some similar modulation on the original transmitter. Try it, but the screwdriver part has to be near the receive antenna and the main signal not so strong that the noise is too far down. 2M FM may the best place to try. Noisy screwdriver contact...noisy received signal 73, Steve, K,9.D;C'I "Walter Maxwell" wrote in message ... Messed Up Ground Radials Can Generate Spurious Signals In 1948 I was the consulting engineer for the proposed first AM broadcast station in Mt. Pleasant, Michigan, obtaining a construction permit and license for WCEN, 500 watts on 1150 KHz. Using a National HRO receiver, I was performing a hands-on search for an available frequency for the new station, when I encountered an interesting and unusual signal that was entirely out of place in the AM broadcast band-a CW Morse-code station illegally transmitting five-letter-word code groups at 30 words per minute. The illegal signal was S9 +40 dB on 1297.8 KHz, producing a 2200 Hz beat-note with the 1300 KHz frequency of WOOD, Grand Rapids, thus producing a an audible CW signal with the receiver BFO disabled. The format of the coded messages appeared to be military, IDing as NSS. We know that NSS is the flagship station of the U.S. Navy in Annapolis, MD, but in the AM broadcast band? It appeared that either an NSS transmitter was producing a spurious emission, or a station using NSS as a fraudulent call sign was operating clandestinely in the AM broadcast band. I deemed it important to find out which. As a former FCC monitoring officer at the Allegan, Michigan monitoring station, the next step was to report the situation to the Allegan station. Although Allegan was 90 airline miles away, the monitoring personnel there could not hear the spurious signal, even though it was S9 +40 dB at Mt. Pleasant. I let the FCC monitors hear the signal through the telephone, but they still heard nothing on their receivers tuned to 1297.8 KHz. Thus the signal must be of local origin near Mt. Pleasant, and not from NSS. However, to be on the safe side, FCC notified the Navy of the spurious signals, and the NSS operators began combing all their transmitters for spurious signals, and found none. The situation is now becoming even more strange. I then copied five minutes of the coded text and sent a copy to the FCC, who relayed it to NSS for comparison to their transmissions. The situation is now both perplexing and frustrating, because the text I copied on 1297.8 KHz agreed exactly with a transmission that had been made by NSS. How could that signal have been transmitted on 1298.7 KHz if no spurious signals were emanating from NSS? But it's not likely to have been a fraudulent station. What then? A partial answer came shortly thereafter. As I resumed the search for a useable frequency for the new station, I proceeded downward from 1298.7 KHz, going through 1280 KHz and hearing WFYC, Alma, 1000 watts, 15 miles away, also S9 +40 dB. But on continuing further downward I immediately came across another S9 +40 dB thumping CW signal. I switched on the BFO and discovered the CW was also a five-letter-word coded transmission at about 30 wpm, the same as NSS. I retuned to 1298.7 KHz and the NSS signal was also there, as before. So I cranked up a second receiver to monitor both frequencies simultaneously. Surprise! Both frequencies were showing identical simultaneous transmissions. I then measured the frequency of the lower-frequency signal-1262.2 KHz. Voila! The higher CW frequency was 17.8 KHz above WFYC's 1280 frequency and the lower CW frequency was 17.8 KHz below WFYC's frequency. A quick reference to the Berne frequency listing showed NSS assigned to 17.8 KHz. This situation now appeared to indicate something very wrong going on at WFYC. The low-frequency world-wide ground-wave signal from NSS was apparently somehow mixing with the signal from WFYC, and producing the 1297.8 and 1262.2 sum and difference frequencies. But what non-linear device in WFYC's system could perform that mixing? Don't know, but I reported this new information to the FCC and that was the last I heard of the situation.until. Fast forward now to 1955. I was now employed as an electrical engineer at the RCA Laboratories, the David Sarnoff Research Center in Princeton, NJ. An assignment took me to Washington, D.C. to attend the annual conference of the NAB, the National Association of Broadcasters. President Dwight D. Eisenhower gave the keynote address. However, one of the technical forums was presented by Jack Young, Chief Engineer of the RCA Broadcast Division. His topic was on the solution of mutual interference between two broadcast stations in Los Angeles, KFI and KNX. It seems that in a section of the Los Angeles area it was impossible to hear one of these stations without hearing both simultaneously-when tuned to 640 KHz for KFI, both KFI and KNX were heard, and when tuned to 1070 KHz for KNX, both KNX and KFI were heard. Young was assigned the task of determining the cause of the interference and eliminating it. To make a long story short, he discovered that there were ancient and rusty oil well derricks in the affected area. Currents from both KFI and KNX transmissions were being induced in the oil well towers, and the rusty joints were acting as mixers for the two frequencies, producing both the sum and difference frequencies, as well as re-radiating both signals on their original frequencies. When the derricks were removed the interference stopped. So how is this incident relevant to the NSS problem? Well, at the conclusion of Young's presentation I had the opportunity to talk with him, and because of the similarity of the problems, I told him of my discovery of the NSS signals appearing in the AM broadcast band. Talk about coincidences! He was surprised and excited to learn that I had discovered the NSS problem at WFYC, because he was the one assigned to determine the cause of the problem. He had never been told how that problem originated, or how the problem had been discovered. He then explained that he had found the ground radial system under the WFYC antenna a horrible mess. Cold solder joints throughout, and far ends of the radials hanging loose in the water of the nearby Pine River, establishing the non-linear mixer condition that resulted in the sum and difference frequencies being generated between the NSS and WFYC signals. Cleaning up the messed-up radials ended the appearance of the NSS signals in the AM broadcast band, thus concluding an interesting journey. Walt, W2DU |
rust?Messed-Up Radials Can Generate Spurious Emissions
"ml" wrote in message ... In article , Cecil Moore wrote: hmm this kinda makes me wonder about my tvi as my antenna is near the building master tv antenna Mmmmm Bad sign from the beginning. This opens up a large possibility box. IM , spurious, overload, you name it. 73, Steve, K,9.D;C'I |
Messed-Up Radials Can Generate Spurious Emissions
Yous guys krack me up.
Steve "Walter Maxwell" wrote in message ... On Thu, 20 Oct 2005 20:26:55 GMT, Cecil Moore wrote: Walter Maxwell wrote: Richard, your approval of my writings is like receiving a million-dollar jack pot. Words cannot descibe how much your approval as an English major is appreciated. Y'all shudda did ah reright in Suthurn so us Texians kud unnerrstan. Cecil, shud I huv writ my last 3 emales ta ya in Suthurn so ya kud of unnerrstud em sufeeciently ta reeplie? Waalltre |
Messed-Up Radials Can Generate Spurious Emissions
The singular (implied plural) was well accepted.
100 kc Go up 3 kc, please "Allodoxaphobia" wrote in message ... On Thu, 20 Oct 2005 21:05:31 -0400, Hal Rosser wrote: I noticed also you referred to frequencies in KHZ. But shouldn't that have been "KC" or for historic accuracy. ;-) Well, it should've been "kc/s". More 'short-handedly': "kcs". A Hertz is a "cycle per second". Jonesy W3DHJ |
Messed-Up Radials Can Generate Spurious Emissions
On 21 Oct 2005 14:23:49 GMT, Allodoxaphobia wrote:
On Thu, 20 Oct 2005 23:00:49 -0400, Walter Maxwell wrote: On 21 Oct 2005 02:50:10 GMT, Allodoxaphobia wrote: On Thu, 20 Oct 2005 21:05:31 -0400, Hal Rosser wrote: I noticed also you referred to frequencies in KHZ. But shouldn't that have been "KC" or for historic accuracy. ;-) Well, it should've been "kc/s". More 'short-handedly': "kcs". A Hertz is a "cycle per second". Jonesy W3DHJ Then I should have said KHz/s, or KHzs, right? _That_ would be doubly redundant. :-) It would be the equivalent to saying "kilo-cycles per second per second". Some sort of "FM propagation", I suppose. Jonesy As I see it, Jonesy, kc = kilocycles, but we think of it as kilocycles per sec. kc/s = kilocycles/sec, which accurately specifies it as such, so it is not redundant. Therefore, KHz is also proper, but KHz/s more accurately specifies it, and is also not redundant. But aren't we being a little picky picky? Walt |
Messed-Up Radials Can Generate Spurious Emissions
"K7JEB" wrote in message news:1J66f.3561$i%.2682@fed1read07... Hi Walt, Enjoyed reading the story. Thanks! ...a bad splice in the wires on my 80/40-meter dipole through the appearance of mixing products from the broadcasters all up and down both bands. .... How many mixer diodes do you know about that can handle half a kilowatt. 73, Jim, K7JEB Probably all the ones that are on about 20% of all the ham antennas in the world... (:-) 73, Steve, K,9.D;C'I |
Messed-Up Radials Can Generate Spurious Emissions
"Walter Maxwell" wrote in message
... On 21 Oct 2005 14:23:49 GMT, Allodoxaphobia wrote: As I see it, Jonesy, kc = kilocycles, but we think of it as kilocycles per sec. kc/s = kilocycles/sec, which accurately specifies it as such, so it is not redundant. Therefore, KHz is also proper, but KHz/s more accurately specifies it, and is also not redundant. But aren't we being a little picky picky? Walt Actually, the Hertz is is defined as a unit of frequency equal to one cycle per second. That would mean the KHz/s is redundant. But you're right - it is picky unless the meaning isn't clear from the context. Bob |
Messed-Up Radials Can Generate Spurious Emissions
Bob Spooner wrote: "Walter Maxwell" wrote in message ... On 21 Oct 2005 14:23:49 GMT, Allodoxaphobia wrote: As I see it, Jonesy, kc = kilocycles, but we think of it as kilocycles per sec. kc/s = kilocycles/sec, which accurately specifies it as such, so it is not redundant. Therefore, KHz is also proper, but KHz/s more accurately specifies it, and is also not redundant. But aren't we being a little picky picky? Walt Actually, the Hertz is is defined as a unit of frequency equal to one cycle per second. That would mean the KHz/s is redundant. KHz/s is a sweep rate. ac6xg |
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