Antennas-shortwave.

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Antennas-shortwave.

Postby mike43 » Sun Jul 15, 2018 3:38 pm

Hello....I have a question to ask of the knowledgeable forum members regarding having two antennas going into my radio. I Have a random wire antenna about about 25 feet in the air from the chimney pot to a pole at the end of the garden, overall length 40 or so feet plus 15 or so feet down into my loft. The antenna wire is all one piece but it goes into the loft from the middle of the wire, sort of a "T" shape as it is the only way too get it into the loft. I also have a 50 Ohm Discone antenna about 30 feet in the air for my scanner. My receiver is a Tecsun S2000 with two inputs for shortwave, a 500 Ohm and a 50 Ohm. This morning I tried an experiment by plugging the random wire antenna via my homemade "L" match ATU into the 500 Ohm socket, and plugging the Discone antenna into the 50 Ohm socket. The reception was stronger and clearer than either one of the antennas on their own. I got many radio stations coming in with this setup plus many SSB stations. I have often used my Discone antenna on it's own and it has got me to Radio Habana and beyond without any problems. I was told some time ago on this forum that the Discone is just another wire in the sky. I am just a shortwave listener and enjoy making FM antennas just for the hell of it and am amazed at the results. I am not into antenna equations and the like but just enjoy the bits and pieces of radio fiddling around without complications. (Getting a bit long winded this). I would like to know firstly is it safe to use both antennas plugged into two different sockets (500 Ohm and 50 Ohm). Does the ATU bring the random wire antenna down to 50 Ohms. Hope you can enlighten me on this.
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Re: Antennas-shortwave.

Postby G4RMT » Sun Jul 15, 2018 7:13 pm

It's perfectly safe. I also suspect that your discone is indeed a bit of metal in the sky - but it's also a long length of wire. Chances are what you are hearing is beening picked up on the screen of the cable. Nothing wrong within that. Your other antenna is also a random length. A good motto is don't knock it, if it works. The physics makes it clear that the discone is pretty useless at HF as anything remotely efficient - but it will still capture something. Something else could be loads better - but keep in mind that in the 50s and 60s people were listening to shortwave for entertainment, and had no knowledge of how it worked, so long strings of wire and a local earth were pretty much what everyone used to listen to other countries - especially when things like radio Luxembourg popped up with music!
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Re: Antennas-shortwave.

Postby m0lsx » Sun Jul 15, 2018 9:04 pm

Have you tried a shorter wire on your radio?
I use longer wires on short Wave receivers, for example on my old Trio. But on portable radios I find a shorter wire works best & looking at the radios of those who contribute to the British DX Clubs magazine, I have noticed many others use short wires on their portable RX's too.
I tend to use 10 meters or less of something like bell wire. With a crocodile clip at the end & then I just clip it to my Eaton's telescopic antenna. I listen to the weekend hobby free radio stations on 48 meters etc. So largely low power stations that are in the noise.
My personal experience is that radios designed to work on a small telescopic whip, tend to overload quickly.
If you listen around Medium Wave the look at getting yourself a small loop & using it via induction. I use a Tecsun AN-200 & have had some very good logs with it.
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Re: Antennas-shortwave.

Postby Chris P » Mon Jul 16, 2018 8:59 am

G4RMT wrote:It's perfectly safe. I also suspect that your discone is indeed a bit of metal in the sky - but it's also a long length of wire. Chances are what you are hearing is beening picked up on the screen of the cable. Nothing wrong within that. Your other antenna is also a random length. A good motto is don't knock it, if it works. The physics makes it clear that the discone is pretty useless at HF as anything remotely efficient - but it will still capture something. Something else could be loads better - but keep in mind that in the 50s and 60s people were listening to shortwave for entertainment, and had no knowledge of how it worked, so long strings of wire and a local earth were pretty much what everyone used to listen to other countries - especially when things like radio Luxembourg popped up with music!





I used my bed spring as an aerial to listen to Radio Luxembourg in the 50`s & 60`s not realising that the aerial socket was live with HT voltage on some of the broadcast radios
Regards Chris aka G8FFF nipper or tazmin88
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Re: Antennas-shortwave.

Postby mike43 » Tue Aug 07, 2018 10:05 am

Thanks for all your inputs, very helpful. Mike
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