AM Jammers

[MarioMania]

Right about now on 819 KHz on the Deajeon, Rep. of Koea SDR

I can hear the South Korean Jammer mixing with the 819 from the North

Like 4:25am KST/12:25pm PST

 

[kevtronics]

North Korea is also one of the few places left with a cable radio (rediffusion) network.

 

[Kelly A]

Yes, just as the stations being jammed have transmitters. That's how radio works: Receivers receive what transmitters transmit. Silly question, unless your difficulties in "wording stuff" are obscuring your true meaning.

Consumer products with switching power supplies, flat panel displays, LED and florescent light bulbs, neon signs, aging utility infrastructure, brushed electric motors, lithium ion battery chargers, lightning or static discharge. All these things and more cause noise to the AM/MW broadcast band. When you think about it, there's never a need to jam stations on the band. Consumer products and Mother Nature already do.

 

[CTListener]

Consumer products with switching power supplies, flat panel displays, LED and florescent light bulbs, neon signs, aging utility infrastructure, brushed electric motors, lithium ion battery chargers, lightning or static discharge. All these things and more cause noise to the AM/MW broadcast band. When you think about it, there's never a need to jam stations on the band. Consumer products and Mother Nature already do.

True but the original question was about what the Cuban government was using to impede reception on 870. Setting up huge installations of LEDs or battery chargers for that purpose is highly unlikely.

Also, apologies to MarioMania for my initial reply. As the others have said, keep on posting. I'll definitely try to be more patient.

 

[Schroedingers Cat]

The way the FM Band has been "jammed" with Docket 80-90 stations, translators, LPFMs, international drop ins, and IBOC sidebands, you could regard it as a form of jamming. Especially with translators, there have been many cases of competitors putting a translator on a frequency that interferes with a competitors' signal in a fringe area of service that used to be clear. Stations in neighboring markets with similar formats used to compete with larger market stations, regularly shaving a few tenths of a rating point. Translators have been put on those neighboring market frequencies, obliterating competition. Good receivers used to be able to tune first adjacent signals to fairly strong local signals. Now IBOC sidebands obliterate those, even on the most expensive tuners. This is common for old 3 kW Class As 65 miles away from Metro stations in many markets, and they really get ripped up by IBOC.

There have been around 12 full power stations that have been dropped in near the US Canadian Border near Metro Detroit over the last 25 years or so, on second adjacent frequencies, which use a lot of allotment loopholes in the US Canada Agreement. This does not theoretically cause interference to US stations around Detroit, that compete with US stations in Canada, which is fine and dandy, but they de facto interfere with neighboring market fringe area signals which used to be clear.

 

[Kelly A]

True but the original question was about what the Cuban government was using to impede reception on 870. Setting up huge installations of LEDs or battery chargers for that purpose is highly unlikely.

The point of intentionally jamming anything on the AM/MW,or SW bands anywhere in the world would be completely pointless. Nobody is bothering to go the extra mile to hear broadcasts from the U.S. or anywhere else. Include the overall noise floor increase from old utilities, congestion plus consumer products, and the bands are a wasteland.
Over the past ten years alone, I've been to many cities in the Middle East, Europe, Asia and North Africa. In my travels, I've sampled what's on the radio and have found mainly nothing more than noise and co-channel congestion. Not unlike the U.S. and Europe, residents moved to FM years ago.

 

[ZantennaG1]

The way the FM Band has been "jammed" with Docket 80-90 stations, translators, LPFMs, international drop ins, and IBOC sidebands, you could regard it as a form of jamming. Especially with translators, there have been many cases of competitors putting a translator on a frequency that interferes with a competitors' signal in a fringe area of service that used to be clear. Stations in neighboring markets with similar formats used to compete with larger market stations, regularly shaving a few tenths of a rating point. Translators have been put on those neighboring market frequencies, obliterating competition. Good receivers used to be able to tune first adjacent signals to fairly strong local signals. Now IBOC sidebands obliterate those, even on the most expensive tuners. This is common for old 3 kW Class As 65 miles away from Metro stations in many markets, and they really get ripped up by IBOC.

There have been around 12 full power stations that have been dropped in near the US Canadian Border near Metro Detroit over the last 25 years or so, on second adjacent frequencies, which use a lot of allotment loopholes in the US Canada Agreement. This does not theoretically cause interference to US stations around Detroit, that compete with US stations in Canada, which is fine and dandy, but they de facto interfere with neighboring market fringe area signals which used to be clear.

I would say IBOC is a form of jamming, because it uses up valuable space on both AM and FM, even considering stations are spaced out anyways. Having adjacent frequencies in use is not necessarily jamming unless one station is a lot more powerful than the other, or in certain circumstances. The downtown Cheyenne FM mess is an accidental form of jamming as harmonics destroys locals down there. If the FCC determined that KXKL was desirable in Cheyenne, then KRRR would be considered a jammer. However, KVXO/KUWY are not jammers of each other.

 

[boombox4]

Fascinating video of the Australian guy's trips inside North Korea. I read that there are indeed radios in rural North Korea, but they are tuned to one station only, i.e. no variable tuner, just a one-channel only AM or FM receiver. Any tampering can get you an extended prison sentence.

 

[Schroedingers Cat]

Fascinating video of the Australian guy's trips inside North Korea. I read that there are indeed radios in rural North Korea, but they are tuned to one station only, i.e. no variable tuner, just a one-channel only AM or FM receiver. Any tampering can get you an extended prison sentence.

How do they enforce that? Neighbors spying on neighbors and informing? Or doing a frequency sweep scan to make sure nobody has a different oscillator frequency?

A decent TRF set would get you freedom without an oscillator for the AM. Use earphones so the informants can't hear.

Funny thing. The Board of Education used to have those radios in the classrooms that only tuned in their educational radio frequency. I suppose the teachers would have gotten into trouble if they changed it. But no extreme or capital punishment for it.

 

[gr8oldies]

True but the original question was about what the Cuban government was using to impede reception on 870. Setting up huge installations of LEDs or battery chargers for that purpose is highly unlikely.

Also, apologies to MarioMania for my initial reply. As the others have said, keep on posting. I'll definitely try to be more patient.

I just don’t believe that that is intentional interference. But as generally, at least since the high power transmitters went away, hasn’t bothered trying to jam English language stations, especially from as far away as New Orleans

 

[Schroedingers Cat]

The situation with WWL 870 was complicated by operating AUX facilities of reportedly 5 kW or 10 kW during the power outages from the hurricane. So the Wobbler was relatively stronger.

 

[kevtronics]

Why would Cuba jam WWL? Just on the off chance that they might say something bad about the Cuban government?

And technology moves on. People in North Korea who want to listen to (or watch) foreign programming are now doing so via USB thumb drives distributed on the black market, not by radio.

 

[oldradiotapes]

And technology moves on. People in North Korea who want to listen to (or watch) foreign programming are now doing so via USB thumb drives distributed on the black market, not by radio.

"Frontline" ran a documentary a few months before Mr Fahey's presentation at HOPE, which discussed that quite extensively.

Secret State of North Korea (~1 GB download; be patient)
(Transcript: Secret State of North Korea - Transcript)

They have 8 "Joson Jung-ang Pangsong" AMs, ranging from a 2 kw secondary service in Pyongyang, to 500 kw. There are two 500 kw station, 3 with 250 kw and 2 with 50 kw on AM.

Pyongyang Pangsong on 657 is (perhaps incorrectly) reported on Wikipedia as "1500 kW" (one and one-half megawatts) though DXing on the Tokyo Kiwi SDR sometime last year, it appeared to be putting a really crappy signal into southern Japan. I don't know whether it was the orientation of that person's receiving aerial or if they were operating at reduced output power (and how much South Korean jamming was affecting it). But I tried DXing it locally at sunrise a couple years ago during a massive transpacific skip opening extensively documented by crainbebo on the DX forum in late 2018, and only heard a faint drifty heterodyne whistle. If it was making the trip, I suppose CFFR and KTNN were probably taking it out.

 

[crainbebo]

If you build yourself a 2 1/2 or 3-foot box loop with several turns of wire, it all works out. I lugged the 3-foot loop out to a local park right before sunrise, went into the trees to avoid looky-loos, and DXed that spectacular multiple-morning TP sequence. The signals were louder than I had ever heard them before, and being out of most of the RFI helped. I successfully copied KICY's sign-on at least twice in that late October-early November 2018 propagation period. I heard Taiwan, multiple Chinese stations (love that I can use CNR1 on 6175 as a parallel), and a few new Japanese/Korean stations.

 

[wildthangjim]

In my experience in western Australia, the key to receiving distant signals is low RF noise level and fewer competing signals. In the early morning, after the rest of Australia was in daylight, I could easily receive many of the high power stations in the Middle East, plus VOA Sao Tome, Vesti FM in Moldova, etc., using a PR-D5 barefoot or with an AN-200 loop. I'm sure a big loop would have helped, but the impact of RF and interference reduction was immense.

 

[SomeRadioGuy]

Why would Cuba jam WWL? Just on the off chance that they might say something bad about the Cuban government?

And technology moves on. People in North Korea who want to listen to (or watch) foreign programming are now doing so via USB thumb drives distributed on the black market, not by radio.

i dont think theyre intentionally jamming WWL.. its just shitty transmitter gear

 

[oldradiotapes]

If you build yourself a 2 1/2 or 3-foot box loop with several turns of wire, it all works out. I lugged the 3-foot loop out to a local park right before sunrise, went into the trees to avoid looky-loos, and DXed that spectacular multiple-morning TP sequence. The signals were louder than I had ever heard them before, and being out of most of the RFI helped.

That would have made a difference. As I remember I was sitting half-awake in bed plugged into a DX-390 that morning. It was also in early 2019, a couple months after your log, so maybe by that point the tide had started going back out, so to speak. RFI wasn't as bad of a problem as it had been earlier. I had recently decommissioned my TV set and ATSC receiver (that set was a horrendous buzzomatic) and my computer power supplies (Corsair) are fairly well filtered and still turned off at that point in the morning, so that cut it down quite a bit.

I had a Selectatenna once upon a time but I have no idea where it vanished to....

 

[cyberdad]

i dont think theyre intentionally jamming WWL.. its just shitty transmitter gear

That seems to have been the consensus opinion. At least until someone comes along and demonstrates/proves otherwise. Which, I'd say, is unlikely. (Even given that one never knows what the Cubans might do or try next.)

 

[MarioMania]

Right now on the Key West SDR

On 870, I don't hear the Wobble

But, I do hear a Beep once in a while, It's weak

 

[davideduardo]

Right now on the Key West SDR

On 870, I don't hear the Wobble

But, I do hear a Beep once in a while, It's weak

If the beep is like an old-fashioned news "stinger" or "separator", that is Cuba.