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Antenna wire
#46

Murf and Other Philco-ists,

Here is my contribution for a quick, versatile and effective antenna.  Last winter I worked on a radio that didn't have a loop or long wire.  When it came time to test I couldn't find the wire I normally used for an antenna so I started looking around for something else.  The first thing I looked at was a short ethernet cable hanging on the wall.  I looked at the 6 foot cable and it was an older, outdated one so I cut the connectors off,  removed an inch and a half of insulation.
[attachment=20157]

After stripping a quarter inch of insulation from each of the eight wires on one end, I joined each pair; orange with orange stripe, blue with blue stripe, etc.
[attachment=20158]

On the other end I stripped the wires but connected each wire to a non-corresponding wire creating three separate pairs leaving the forth pair unconnected.  I now have a continuous wire looping through the cable. Attach two gator clips to the unconnected wires and I now have a forty-eight foot loop.
[attachment=20159]

It worked great.  I used it on the next radio and it worked for that one too.  The next radio I worked on needed an internal antenna loop so I coiled another ethernet antenna into the top of the cabinet with great results.  Try one of these and let us know how it goes.

Rod
#47

Effective and novel.

Paul

Tubetalk1
#48

Another thing you could do with this setup is join wires between the two ends. That would give a multi-turn coil - and a tuning capacitance could be used to bring it to resonance.

There are many fun projects with wire antennas Icon_smile

I don't hold with furniture that talks.
#49

Considering that I use the rails on my vert.-lift garage door - 20 ft. up and 20ft down - just about anything will work. Somethings even work well.

"I just might turn into smoke, but I feel fine"
http://www.russoldradios.com/
#50

...and don’t forget the rain gutters (if they are not vinyl) but you can lay wire inside if they are! Attic is even better....
#51

OK, much promised, I have got a fair way sketching up the methods I like to use for external antennas. Here's a sneak preview. If desired, I can make this a thread all of its own. Remember, even if you don't have much room for external aerials, the techniques can still apply.

General good way to connect a radio to a "Long Wire" or "Random Wire"
   

Connecting a dipole or doublet antenna
   


Simple Signal transformer, indicating connections. The builder can experiment with different ratios of turns. 
   


Toroid cores, or "binocular" cores are great for this application. Type 73 ferrite is very good, but other types seem to work well for receive applications, e.g. parts salvaged from old computer/switching power supplies.
   

Another good feature of using isolating transformers is that any static build up on the antenna wire is prevented by the dc path to ground. Additionally, any voltage that may unintentionally appear on the terminals of the radio (e.g. AC/DC sets, or the case of a bad cap somewhere) is prevented from reaching the external wire, further guarding against shock hazard.

As mentioned, I have used these methods for long,  medium and shortwave receiving aerials, and they are very good at blocking domestic noise that otherwise can get to the antenna system along the ground side of the feed between the radio and antenna. 

Let me know what you think, and if more info or illustration would be helpful.

Let me know what you think so far Icon_smile

Cheers

Ed

I don't hold with furniture that talks.
#52

Regarding the use of two of the unused wires in a telephone cable, do you get noise, especially the cable where the other two wires are still in use?
This is all great information, keep it coming.
Keith
#53

Keith,

I think the answer to "do you get noise" is - possibly. I'd want to be sure the wires could not get energised, and would still place a small capacitor in series between the wire and antenna connection on the radio - a ceramic type of a few hundred pF would be appropriate.

Ed

I don't hold with furniture that talks.
#54

Thank you Ed.
Keith




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