Thermometer antenna?

Computer, engineering, and other technical assistance.

Moderators: genlock, sportsvoice

Post Reply
CoolBreeze
Member
Member
Posts: 2060
Joined: Mon Sep 05, 2005 10:30 am

Thermometer antenna?

Post by CoolBreeze »

Some of you may know that I'm a huge fan of the country of Estonia. I've been there many times and I have studied their history every day for the last 6 years.

Estonia was unique in the 70s and 80s because it's capitol Tallinn, is only 50 miles from Finland, a westernized country. The U.S. government helped to set up high power TV there, just to broadcast Westernized television shows towards Estonia. One of the most popular was "Dallas". The Soviet Union tried everything in their power, including jamming, to keep these shows from being received. Over time, due to the ingenuity of the Estonians and their ability to build indoor antennas, they finally gave up and knew it was just a matter of time that the Soviet Union would be no more anyway due to a variety of issues..

Here's why I'm posting: In a documentary I just watched, one of the most popular secret antennas for receiving TV broadcasts was a mercury thermometer. Once it was discovered that you could build a reliable antenna from a thermometer, the entire city of Tallinn's stores were emptied, and the Soviets wondered why.

According to the inventor in the documentary, he simply cut off the top of a large mercury thermometer and stuck a small wire into it... then pulled it out just a little. That wire was attached to the TV set. He stated that the only problem of using this was that it also became a jamming device. He said that none of his close neighbors in his condo could receive TV when he had it connected. There was a missile site not too far away and their sensitive equipment also picked up the jamming and came to his building looking for the signal, but didn't find it because he unplugged it when he saw them outside his window,

Has anyone here heard of such a thing... or tried it.... or can even explain how such a device might work?
"I know I've got a lot against me: I'm White, I'm Protestant, I'm hard working. Don't you have an Amendment to protect me"? Archie Bunker
User avatar
genlock
Moderator
Moderator
Posts: 8982
Joined: Fri Dec 21, 2001 4:09 pm
Location: OW

Re: Thermometer antenna?

Post by genlock »

I really don't know why a mercury thermometer would be a more effective antenna than a simple piece of wire.
The jamming tho could be caused by the interaction of dissimilar metals (mercury-copper) causing mixing
of signals from inside the tv set and the air defense radar transmitters. Other transmitters could also be
involved like Estonian state TV, police and whatever. When the wire was pulled, the chemical action stopped
and then no interference. What was the frequency/channel of the broadcast from Finland? High-VHF?
That would make sense as the quarter wave length at those frequencies would be about as long as the thermometer.
Crappy Soviet era TV's might have had a lot of local oscillator leakage back to the antenna terminals too.
"Everyone Should be aware that you're just a screen grab away from infamy."
CoolBreeze
Member
Member
Posts: 2060
Joined: Mon Sep 05, 2005 10:30 am

Re: Thermometer antenna?

Post by CoolBreeze »

I think the main reason for even using it was that it was small, and could be disposed of quickly should the KGB come knocking.

You right about the electronics at the time. They were pretty crappy. Some Estonian engineers even sold homemade converters to attach to the TVs because while the Estonians could get a picture, they could not get the Finnish audio without the converter. I 'think" this was due to Soviet jamming.
"I know I've got a lot against me: I'm White, I'm Protestant, I'm hard working. Don't you have an Amendment to protect me"? Archie Bunker
User avatar
genlock
Moderator
Moderator
Posts: 8982
Joined: Fri Dec 21, 2001 4:09 pm
Location: OW

Re: Thermometer antenna?

Post by genlock »

More than likely the lack of sound was due to the differences in the Finnish system of TV.
Different sound intercarrier or FM instead of AM sound or something.
I will look it up.
"Everyone Should be aware that you're just a screen grab away from infamy."
User avatar
genlock
Moderator
Moderator
Posts: 8982
Joined: Fri Dec 21, 2001 4:09 pm
Location: OW

Re: Thermometer antenna?

Post by genlock »

Estonia used the PAL system.

from wiki.

On RF (i.e. through a modulator or TV aerial) the difference between I, D/H and B/G is audio. These use different audio subcarriers, so with mismatch on Modulator Settings or an imported TV there will be perfectly normal Colour Video, but possibly no audio. Some TVs and VHS tuners have multiple filters in parallel or switched for the 6 MHz, 5.5 MHz, 6.5 MHz or 4.5 MHz sound carriers. NICAM is an additional 6.5 MHz offset carrier carrying stereo digitally, on 6.0 MHz PAL-I systems. Germany particularly uses two separate analogue FM sound carriers on PAL-B/G. (Stereo FM Radio uses a mono signal with a DSBSC L-R audio centred on 38 kHz with a 19 kHz pilot to aid decoding. Hence the German analogue Zweikanalton and the digital NICAM both give better performance than FM Radio).
"Everyone Should be aware that you're just a screen grab away from infamy."
CoolBreeze
Member
Member
Posts: 2060
Joined: Mon Sep 05, 2005 10:30 am

Re: Thermometer antenna?

Post by CoolBreeze »

Of course! :wink:
"I know I've got a lot against me: I'm White, I'm Protestant, I'm hard working. Don't you have an Amendment to protect me"? Archie Bunker
Post Reply