Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 [2]   Go Down
  Print  
Author Topic: Illicit SWLing in North Korea  (Read 4901 times)
W1JKA
Member

Posts: 1800




Ignore
« 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
Member

Posts: 47




Ignore
« 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.
Logged
AA4HA
Member

Posts: 1568




Ignore
« 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.
Logged

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
W0BTU
Member

Posts: 1795


WWW

Ignore
« 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
Member

Posts: 523




Ignore
« 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. 
Logged
Pages: Prev 1 [2]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!