[Chas]

Mineral spirits should dissolve away the pitch and wax slowly but leave any paint code dots or coil sealants intact.

By description, seems the contents is a pair of tuned loading coils to broaden the response of each leg of the antenna wire.

It is also possible that there are resonances setup for the shortwave bands, popular and solar active at the time. Reviewing the solar cycle activity charts of that era may reveal that shortwave radios were built to favor those band openings.

[GarySP]

Hello Simon. To answer the question about making changes (#40) after posting. The answer is yes. After signing in, go to the post you want to correct. At the bottom of the post is an Edit bar. Click on that, go to quick edit, make your changes, then hit save changes.
As far as the lightning strike question, does anything really survive a lightning strike? And even if it didn't look like any damage was done, I sure wouldn't trust it until completely checking it first.
Since you don't want to try a toaster oven and "Cooking with Ron", perhaps a heat gun could soften the tar enough to help remove it.
I've rambled enough. Take care and BE HEALTHY! Gary

[poulsbobill]

Sign me up for what really is in that "PHILCO HIGH-EFFICIENCY AERIAL".

Thanks

Bill

[Simon Wa3uay]

All good advice, very smart bunch here; I don't have a toaster oven but am using heat gun to soften...they seem to be mica condensers, and some of the paint dots are already history but I should be able to measure them when I lift one of the legs...I still hold down a full time job but still time for fun!
-Simon
Oh, and I think Chas is right; there also seems to be a bigger coil down in there, too......

[Chas]

My theory, without consulting my files full or antenna documentation I have. Is that the Philco antenna as well as antennas marketed by other radio manufactures during the "heyday" of shortwave. Are, aperiodic, such an "antenna" will have a high feedpoint impedance and wont match any feedline. So such feedpoint devices suit that purpose. What cannot be discounted that the "action" of the match system may include using the feedline as part of the reception as a vertical component. At certain times of the day and at lower wavelengths the short range of ground signal is very dominant. IMHO the antenna will be a compromise, that is not bad as a resonant antenna performs poorly off resonance.

Interestingly, RCA had an antenna FWIR called a "Spider-Web" I may be wrong in the terms but it looks a lot like the lower half of a spider web. What I believe it does with wire and a Delta match is to achieve a certain "broadbandedness" as well.

Such broadband, well, multi-band antennas are being built today, wire construction, awkward to hang and not at all stealth but they are resonant and matched to coax feedline for use with a transmitter. I salvaged at least two of these and did have one hung long ago. The other from an estate in 2007 I have rolled up in storage. I think it is a commercial unit or one that someone has put considerable labor into. Both these antenna are copper-weld wire, very strong because of the weight of the entire antenna system.

A word Simon:

Avoid manipulating the mica condensers by twisting, the clip the attaches the wire to the stack of metal plates can partially open and disconnect, making the cap go lower in capacity.

Good Work!

Chas

[Simon Wa3uay]

Lest ye think I've been slacking, we have been soaking this thing in a jar of mineral spirits, and it's just about clean now -even the interior which was plugged up
We have broken some one the fine magnet wire the tar was stuck to, but maybe we can count the turns....
   
actually, I have been slacking.

[David]

One has to wonder if their was a connection between Philco and one of the oil companies the way Philco like to coat things with tar!

[Simon Wa3uay]

Sept 4
We are finished with this (for now), and I haven’t made sense to how all these little tuned circuits are supposed to work together to make a “noise reducing” “More than double the number of stations you can get and enjoy” signal measured in microvolts. There must be some magic in the coils that are in series (L3,L4,L5,L6), plus the “Grnd” lead-in adds its own flavoring.

L1c, I could not find a termination. I broke 4 or 5 wires getting the tar off, and the Mica’s don’t measure right after being soaked and moved around.

Haven’t had this much fun since I slipped and twisted my knee while running in the rain with my arms full of tomatoes from the garden 10 years ago, the tomatoes were ok.
Simon

   


   

   

[thirtiesradio]

Very interesting seeing inside the antenna can!

Quite a few years back I bought a storage full of audio items, tubes, advertising and a lot of items from a Philco radio shop that was active in the 1920's and at least through the 1960's.

In with the items I found two of the 1930's Philco antennas still in their boxes. Since I have a 37-690, and was getting noise and static in my 40 miles south of Los Angeles area, I decided to try one of the antennas. I knew they were designed for Philco sets and was hoping they were what I needed. Using the installation instructions in the box I found I didn't have any better reception than with other wire or balum antennas I had tried. Still had a lot of noise. I was about to try another antenna when I came across and started reading one of the hundreds of paper items that were in the lot.

What I read was a 26 page book Philco and the Radio Manufacturers Service made for dealers (installers) on noise elimination in antenna systems. This book was put out in the same year that my antennas were made as there is a photo of the box and details of how to use what is inside. The book goes into great details on how to correctly install this particular antenna and its attachment on any radio made. I followed their directions and ended up using this antenna for 3 years. I had to take it down every year when I had my trees trimmed and never put it up after the third year. It was the quietest and most sensitive wire antenna I had ever used! I ended up using the radio with one of my several Wellbrook antennas as in the last photo. With the loop I no longer needed the trees as a mount. Since the Wellbrook is not on a rotator like the ones I use with my communication receivers I'd say the 1930's Philco antenna is easily as quiet and was a bit more sensitive as the Wellbrook. If on a rotator I'd have to say the Wellbrook is more sensitive as you can null out signals from any direction. 

When correctly installed the Philco Aerial is really a great antenna.

[Ron Ramirez]

Simon,

Thank you for all the work you have done thus far in trying to take the "mystery" out of the Philco High Efficiency Aerial. I hope your experiments will eventually lead to a successful conclusion.

[Ron Ramirez]

thirtiesradio

Man, those Wellbrook loops are expensive!

[thirtiesradio]

Hi Ron,

Yes they are expensive new. I have only bought one new as I wanted the low noise version. The other 3 I bought as I found them for under $150 each locally.

They are the best I've found at reducing local noise. I can almost completely null it out.

[Simon Wa3uay]

Thank you all; I suspect the old Philco "aerials" nulled out certain known (at the time) interfering frequencies with all those little resonant circuits, thereby making it "noise-reducing", I don't know. Yes, antennas can get expensive, but they are important because they are the 'first stage' of the radio preceding the amplifier or first detector and tuned properly can hear (and transmit) around the world!
Regards,
Simon

[GarySP]

Excellent work, Simon! Now, when do you think you can start mass-producing them? (just kidding!) Take care and BE HEALTHY! Gary

[Simon Wa3uay]

Gary, I will leave that up to you!
Simon