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Author Topic: Illicit SWLing in North Korea  (Read 32552 times)
W1JKA
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Posts: 2099




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« Reply #15 on: November 09, 2014, 02:04:49 AM »

  Simple solution: Repackage the old 1x4 in. red/white "Rocket" crystal radios of the early 60s as a fake small piece of tree branch or dog turd with plug in ear bud, ground wire and ant. along with hi power AM xtmrs. on the S Korean border then smuggle them across the border with specially trained abandoned dogs. If users were in danger of being caught they could throw the radio out into the woods then swallow the ear plug and set up a quick ground snare with ant./ground wire trying to catch a rat for a meal.

   As a young teen with my "Rocket" radio I often listened to Wolf Man Jack on WBZ Boston at night from my bedroom in Maine 220 mi. away with ant. wire hooked to bedspring of my overhead bunk bed and ground wire connected to the steam radiator.
« Last Edit: November 09, 2014, 02:44:16 AM by W1JKA » Logged
VK3DWZ
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Posts: 55




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« Reply #16 on: November 09, 2014, 03:52:56 AM »

The biggest problem with listening to M-W broadcasts in the D.P.R.K., from South Korea, is that those in  the North jam them.  I don't know if the broadcasts from Soth Korea on shortwave are also jammed but I can imagine they are.  Martyn Williams has a good website "North Korea Tech" that talks about the jaming wars between the north and the south.  He is there and provides sound clips recorded in the South.  

If those in the south wish to listen to M-W (and F-M) broadcasts from the north, they can't because they are jammed, but NK's domestic S-W broadcasts are not because few people in  the south listen to shortwave.
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AA4HA
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Posts: 2630




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« Reply #17 on: November 13, 2014, 07:03:40 AM »

I liked the ear-bud concept. You should be able to make a simple regen receiver with a few surface mount transistors, resistors and caps. You tune the radio by placing your finger on your ear and rotating your finger. The top of the ear-bud spins and is the tuning dial.

Make the case out of zinc and have an insulated copper wire maybe 20 cm long with a bare copper strip on the end, about the size of a penny. Put the little copper strip in your mouth. The acids from saliva makes your head into a low voltage battery to run the radio. The 20 cm long wire also doubles as the antenna.

The thing would last forever, be nearly impossible to find and not need batteries.

North Korea is the kind of place that if they found that an AAA battery was being used to power illicit radios, they would make batteries illegal. Let them try to make saliva illegal.

You see people walking down the street, scratching their ear, they are really tuning around for a different station.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
W0BTU
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« Reply #18 on: November 13, 2014, 09:57:48 AM »

You should be able to make a simple regen receiver ... have an insulated copper wire maybe 20 cm long ...

Well, that's an interesting concept. But have you ever tried a regenerative receiver? The difference between maximum sensitivity and oscillation is a very fine line indeed. A misadjusted (that is, oscillating) regen RX is a transmitter, that would be even easier to detect than a superhet. Back in the early days of radio, regenerative receivers were notorious for transmitting a signal that generated an interfering heterodyne in nearby neighbors' receivers.

And I'm not sure that such a short antenna would be sufficient.

EDIT: And separate controls for regeneration and tuning are a must.
Maybe you have some other ideas, such as an RF amplifier (which I have never seen in any regen schematic) with good isolation. But if you can build such a regen receiver, you're a far better electronics technician than I am. :-)
« Last Edit: November 13, 2014, 10:29:47 AM by W0BTU » Logged

K1DA
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Posts: 744




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« Reply #19 on: November 19, 2014, 08:11:38 AM »

Merchant ships at the start of WWII had regen receieves which the German Uboats could DF with ease.  The is some info on boat anchor receiver sites about the later receiver designs  supplied which were built to reduce LO leakage. 
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W1ITT
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Posts: 199




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« Reply #20 on: November 30, 2014, 09:37:03 AM »

A few years ago I was traveling to many sites in Romania, installing new medium wave (AM broadcast) antenna systems, while an associate installed new Harris solid state transmitters.  At one site, I had to retune an existing antenna to 50 ohms, j-zero, from the approximate 75 ohm setup it used previously.  I retuned the network but ended up with a reactance that called for about 18 microhenries of series inductance to cancel.  I asked where I could find such a coil and was directed to a much cannibalized transmitter in a back room, and found a nice rotary inductor that fitted the bill.
It was obviously a short wave transmitter and, when I inquired as to what it had been used for, I was informed that it was a jammer to interfere with Radio Free Europe.  Located right in the city, it would have made life difficult for most people trying to listen.
We put the coil to better use and had a good laugh.
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WA2ONH
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Posts: 532




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« Reply #21 on: November 30, 2014, 10:06:39 AM »

TV's PBS "Fontline" aired this program Jan 14, 2014 ...

Secret State of North Korea

"FRONTLINE shines a light on the hidden world of the North Korean people, drawing on undercover footage from inside the country as well as interviews with defectors who are trying to chisel away at the regime’s"

LINK: http://video.pbs.org/video/2365155890/

53 minute video.
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73 de WA2ONH  <dit dit> ... Charlie
---------------------------------------------------------------------------------
"Never be satisfied with what you know, only with what more you can find out"
Dr David Fairchild 1869-1954 US Scientist
KC5MO
Member

Posts: 51




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« Reply #22 on: January 03, 2015, 09:24:02 AM »

 Simple solution: Repackage the old 1x4 in. red/white "Rocket" crystal radios of the early 60s as a fake small piece of tree branch or dog turd with plug in ear bud, ground wire and ant. along with hi power AM xtmrs. on the S Korean border then smuggle them across the border with specially trained abandoned dogs.

I like it!! It sparked an idea for my next Rockmite 30 housing.
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W7ASA
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Posts: 548




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« Reply #23 on: January 03, 2015, 10:44:18 AM »

I love regens, from my single #30 triode SW/ham receiver to the tiny and thrifty solid state kit variants on the market today.  That being said, the regen is put into oscillation (autodyne) for CW and SSB, but not for the reception of A.M. broadcasts.  When the regen detector is set for A.M. it is not oscillating, so it's not radiating. 'Touchy' receivers that 'plop' into and out of oscillation intermittently are a problem of design and can be solved with good engineering, like the old SW-3 and some of the mil regen sets which were very controllable.


Good discussion -


73 de Ray
W7ASA   ..._  ._
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VK3DWZ
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Posts: 55




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« Reply #24 on: February 05, 2015, 07:56:46 PM »

I have just learned that the B.B.C. might be considering a shortwave service to the D.P.R.K.  I don't think it would worth their trouble tho' as surely the number of SW listeners in that country would be miniscule.  It might be worth it tho' as whilst the number of SW receivers would be low, there  might be enough receivers in the country to encourage their people to encourage others to purchase (illicit) SW receivers and, if enough people listen who knows might happen to their terrible regieme.
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RENTON481
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Posts: 281




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« Reply #25 on: February 07, 2015, 05:15:04 AM »

And there is always the word of mouth factor... although in a police state like North Korea, I suppose those who actually could listen in wouldn't tell others much, for fear of secret police.
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