Antenna for Philco 39-40 - Printable Version
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Antenna for Philco 39-40 - Sourbone - 06-08-2010
I acquired a Philco 39-40. I wondered if there was an optimal antenna for this radio. Any suggestions?
Dave
Re: Antenna for Philco 39-40 - Radioroslyn - 06-08-2010
Well there are two answer to your question. The simple answer is yes there is. The longest highest free from near by buildings and power lines.
The more accurate answer is yes it should be resonant to the frequency that you are tuned to. What you will need to do is convert your frequency from kc or mc to meters. The formula is wavelength in meters is equal to 300,000 over frequency in kc or Wavelength in meters in equal to 300 over frequency in mc.
If you do the math an antenna resonant at the low end of the bc band say 550kc is about 500 meters long. That's pretty long! when you get up to say 6mc it's about 50 meters long.
I took a glance at the diagram of your set. It's a nice one with a rf amp and a real phase inverter something not seen on many Philco's of that vintage. Have you got it working? and working well?
Terry
Re: Antenna for Philco 39-40 - mgutierres - 06-09-2010
I think you're wondering if there was a specific tuned antenna included with the set and the cabinet for this model, like the paper "muffler" antenna on the 1940 console models, or the square loops in the 1941+ models. I don't know, but maybe someone else here does?
Re: Antenna for Philco 39-40 - Ron Ramirez - 06-10-2010
Dave
The 1939 models, for the most part, did not have loop antennas; they still relied on a longwire. (The portable 39-71/39-72 sets were the exception as they did have built-in loop antennas.) A longwire antenna should be, as Terry pointed out, as long and as high as you can put it and as far away from power lines as possible.
Sometimes you have to live with a piece of wire strung around the baseboard of the room the radio is in. But an outdoor longwire, with proper lightning protection, is much better.
Re: Antenna for Philco 39-40 - denver - 06-10-2010
I tried running a long wire 70 foot high 100 foot long . Did not do much. Now i have one about 25 foot up 200 foot long picks up all over the dial .
Make sure you ground your set to the earth . And use lighting aresster . And for safety use a through off switch . If you know a storm is on the way through the switch off , or if your away . Ther are lot of sites show you best way to build a long wire antenna.
Kent.
Re: Antenna for Philco 39-40 - exray - 06-10-2010
denver Wrote:I tried running a long wire 70 foot high 100 foot long . Did not do much. Now i have one about 25 foot up 200 foot long picks up all over the dial .
That's kind of surprising. I'm sure the 200 footer would be the better of the two on the broadcast band but I'd think the 70 foot high 100 footer would be no slouch either.
My 'city lot' is only 40x100 so I'm very cramped. I have about 50-60 feet of flat-top up to a fairly decent tree then dropping down at an angle about 40 feet. I'm pretty happy with it.
All that said, any good length of wire starting at 20 or 30 feet, preferably run outdoors, will suffice for the radio unless you're into DXing
-Bill