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Philco Boomerang antenna coil
#1

Hi.
I bought a Philco Boomerang, but without the back cover and the antenna coil.
I would like to know how many turns the antenna coil has and what is the diameter of the wire.
If you have a photo, with that detail, I would appreciate it.


Attached Files Image(s)
   

Regards from Portugal,
Carlos
#2

A link to the sch from riders  http://www.nostalgiaair.org/Resources/659/M0013659.htm     The Philco part number is 32-4052-19 the same part was also used on model number 49-505. David
#3

First, you are going to need to make a new back for the radio. You can do this easily enough by gluing several layers of card stock type cardboard together, 4 should be enough depending on what you use. One good and cheap source is the front and back panels of large cereal boxes if they are big enough. If not, go to an office supply store and buy a couple of sheets of the white cardboard type poster board. Whatever you use cut 4 pieces the same size and shape so you can easily stack them, and larger than the backside of the radio. Next glue the sheets together with 2 part epoxy glue. Spread it on liberally between the layers all over. Stack the sheets with glue between each layer but NOT ON THE OUTSIDE of the bottom and top layers. If you use cereal boxes make sure you have the UN-PRINTED side of the card stock facing outward. Put a piece of newspaper below the stack, and one on top of the stack, and then put a piece of plywood or a large book big enough to cover the whole stack on top of the stack and paper covering, and add more weight, more books or the like, to press the sheets of card stock together while they dry. When the stack is dried well, remove it, and then spray it with polyurethane on both sides to help it resist water and moisture. When the poly is dry, then put the radio on top of the stack, back side down, and trace all around it. Cut out the back just to the inside of the line you traced so it will fit nicely into the little edge on the back of the cabinet, using an Exacto knife. Then, using the Exacto, cut ventilation holes near the upper part of the back and near the lower part of the back to allow air circulation to dissipate the heat from the tubes. Also cut a slit for the power cord, and an oval hole over the place where the loop antenna socket and external antenna wire come out of the back of the chassis. That will get you a good, workable back for this radio.

Now, as to the antenna loop, here is a link which describe the process of making one which you can then attach to the new back you just made above...
http://www.sparkbench.com/loopante2.html
Once you make it, run a wire from each end to the two terminals of the plug on the back of the chassis. One of these wires will be permanent, one may not be. Test the radio. If it seems weak, remove 1/2 a turn but do not cut what you removed. At this shorter point reconnect that wire, see if it improves. If it does, keep removing 1/2 turn at a time, until you find the ideal length. The cut off the excess you removed, solder the connector wire, and that's it. Just glue the loop to the new back.
#4

Hi David,

Many thanks.

Regards from Portugal,
Carlos
#5

Hi  mikethedruid.

Many thanks for your  excellent explanation of how to make the back panel.

The original loop antenna it is not glued to the back panel, but to the inside of the radio.

In this photo, it sees clearly.


Attached Files Image(s)
   

Regards from Portugal,
Carlos
#6

There's an old Rolling Stones song, "You Cant Always Get What You Want." The method I described will get you a working radio. Also, I realize now that plug on the back is an accessory plug, and the loop appears to be hard wired into the circuit. Good luck. Download the Rider's information from that link and read through it carefully. Lots of good information there. Let us know how things turn out.
#7

Looking at Beitmans the ant is 2.8 ohms that is not listed on  Riders, enjoy your project looking forward to updates. David
#8

Many thanks Mike and David.

I'm finishing up restoring an RCA 128, and then I start on this Philco.
When I start, I'll let you know.

Regards from Portugal,
Carlos
#9

To make your antenna ....

Set the radio onto a thick (1"+) piece of wood (anything will work, softer is easier to cut) and trace the pattern.
Knowing the thickness of the cabinet, redraw your tracing, but smaller to take the cabinet into account.
Cut the pattern with a band or jig saw and use this wood as the pattern
Put double sided tape around the pattern
Wrap your wire around the wood pattern and stick it to the tape
When you have more than enough wraps (based on your photo) stop./
Put strips of hot glue or similar across the windings to hold them in place.
Cut the wood out or slide the loop off , wrap it in several places with clear tape to keep it together and install it inside the cabinet.
If your pattern was properly cut, the coil should be a tight press fit.
Test the set and reduce the number of wraps until the set works best.
#10

hello Edison,
I just bought myself a Philco Flying Wedge and it also is missing the back .
I normally use 1/8 Masonite to make mine with.
this time thinking of trying our new "glow forge pro" laser engraver that we have in the classroom where I teach.
Sincerely Richard
P.S. I am looking for a photo too.
#11

Somewhere, somebody, has a box of those foolish internal philco antennas, I have only seen that type of antenna that runs the rim of a radio in Philco's. Most others have it on the back or attached to chassis. Those make an easier chassis to pull. Good luck

Paul

Tubetalk1
#12

Hi John.

Your idea is very good.

Many thanks.

Regards from Portugal,
Carlos
#13

Hi radiorich.

In this link, you have one photo of the back wall.

https://www.radiomuseum.org/r/philco_48_230.html

Regards from Portugal,
Carlos
#14

Thanks Paul.

Regards from Portugal,
Carlos
#15

One thing that nobody has mentioned is that there are actually two windings in the loop antenna coil, one acts as the antenna to the set, the other is to connect an external antenna. I can't remember the ratio but I think it's 3:1, they may give a DC resistance of each coil in the service literature. I think that the best course of action is to make a form out of some plywood, or lumber, by tracing out the inside of the cabinet, and cutting out the shape, including the ribs that the back attaches to, but you will have to make it smaller to accommodate the wire, this is if you want to make a facsimile of the original loop antenna. Otherwise you could just make a electrically similar coil and mount it to a replacement back, which is likely the easier route.
Regards
Arran




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