[OldRestorer]

I am going through the radios and I found this in my 60. From what I can tell, the guy took the back off a westinghouse radio and rigged it into the 60's antenna.

Not sure if it works but pretty cool thinking.

[bfrohwein]

I wonder how well it works/worked... I keep wondering how well something like this would work with some of my tombstones.

[exray]

Probably not very well. What you have is 60-80 feet of wire in a 1 ft space = a 1 ft wire. The 60 is not setup to use a loop.

[mikethedruid]

Hi Old Restorer,
I remembered seeing this in one of my old radio books, Radio For The Millions, Popular Science Publishing, 1943, on page 86... http://37.media.tumblr.com/58132522349bc...1_1280.jpg ... It may be of help to you. Sorry, exray, but, depending on how it is connected, it is a very effective type of antenna for local and medium distance reception, that is why it was used in so many sets of a later period.

[exray]

Well Mike, a loop is a perfectly fine antenna when applied correctly. In practices later than the Model 60 the tuned loop replaces the on-chassis antenna coil and is tuned by the gang capacitor. That is what is suggested in the Radio for Millions article.

I'll pontificate a bit and say its awful hard to get decent tracking with this method. I tried my damndest to sub one for an antenna coil and although it 'worked' it didn't work satisfactorily. Two main gotchas are the cut of the tuning gang and the self-capacitance of the coil versus the loop.

The photo suggests that this is simply a loop from another radio connected to the antenna terminal. Not the same thing at all. In this sense its nothing more than a wad of wire.

There are ways to couple an ersatz loop to a 'random-wire' input but nothing shown suggests that such was done.

[tom.seeger]

Its hard to see from the single photo, but I agree that this antenna does not appear to be wired in as a loop. I think I see only 1 wire on the back board.
However I have modified 2 Philcos and 1 Stromberg that originally had antenna transformers (and external antennas) and replaced them with home made internal loops. In each case reception was greatly improved. At my location I have large amounts of broadband noise, rendering wire antennas almost useless especially at night. I found radios with loops to be quite a lot quieter. It takes a bit of care to adjust a loops inductance to track properly, but once done it works very well across the entire band.

[exray]

Hi Tom. I imagine a loop *could* be subbed if all of the rules are followed. Unfortunately I've never encountered such a case. Plenty of noise here!
I use my 24" external loop even for day-to-day listening of semi-local stations. Is a DX King! And since I use an external tuning cap its infinitely variable for any application.
To sub an ersatz loop into the Philco 60 would require disconnecting the original ant coil (which could be bad anyway) and not only subbing the AA5 loop to correct inductance at the high end of the trimmer range but adding a precise (unknown) amount of capacitance to get it to track.
Not to say it can't work but it hasn't been shown in this or any other random examples.

[mikethedruid]

I would be very interested to know exactly how this loop is connected to the Philco. Unfortunately, OldRestorer didn't say. In the photos one really cannot see how it is hooked up, but I think I see 2 lighter colored wires there coming from it. I have seen too many of these odd things that actually WORKED over the years to pooh-pooh it before I know how it is connected; and, if it is logically connected, how it actually worked.

[Arran]

I have not found loop antennas to perform any better in terms of gain or noise then a long-wire and a proper antenna coil around here, most of the interference is power line noise and hash that only a power line filter could fix. Whenever I see something like a random loop antenna tacked onto the back of a pre war radio I put that in the same category as most of the aftermarket phono jacks I see, they were usually added by some weekend warrior who assumed that they were making some improvement but didn't really accomplish anything useful.
I'm not arrogant enough to second guess the factory engineers, at least of the larger manufacturers like RCA and Philco, they had all the specs and resources at their disposal to design the tuned circuits in their front ends and knew what to match with what. I know that many like to thing that interference and hash is a new thing but if anything they had more of it 70+ years ago, brush motors, automobile ignitions, diathermy machines, street cars, and to make matters worse most house wiring did not have a ground once you got past the fuse box. To some extent the engineers did take this into account, of course they could not have taken more recent trash like cheap switch mode supplies into account.
Sometimes, then as now, the interference can be caused by defective street lights and pole transformers, such things can be tracked down and reported to the local power company's service department. Usually when a pole transformer starts to cause interference, or produces whacky voltages, it's a sign that something is about to go.
Regards
Arran

[exray]

I have not found loop antennas to perform any better in terms of gain or noise thAn a long-wire and a proper antenna coil around here.

Oh, they can work great. Check this little 30 sec clip of pulling them out of the noise.
https://www.youtube.com/watch?v=EeFl4oWdoGk
I might mention that this is daylight reception of a 10kw station 400+ miles away across salt water. The effect demonstrated here is TUNING the loop, not just the loop itself.
Unfortunately, if you are totally surrounded by artificial noise its a losing battle.

[tom.seeger]

In my particular location an outdoor long wire is really inconvenient. I wont argue weather a good outdoor will or won't beat an indoor loop. But I can say that in my case any radio with internal loop will always provide better reception than a similar radio tied to an indoor random wire layed on the floor, or taped to the ceiling.
As far as constructing internal loops, as long as you get the right inductance for the bottom of the band and adjust the antenna trimmer for the top of the band the performance has been excellent 3 out of 3 times that I tried. To determine the required inductance I found an easy technique using a loopstick with a sliding coil. I temporarily connect the loopstick in place of the original antenna transformer. I slide the ferrite rod in or out of the coil to find the best reception at 570 kHz. Then I adjust the antenna trimmer for best recetion at 1460 khz. (I happen to have radio stations at these 2 frequencies). Then I remove the loopstick, measure its inductance using an inductance meter, and construct an air loop with the same inductance. Then I permanently wire it inside the radio, and tweek the antenna trimmer. It works like a charm. No fuss, no magic. Two of the radios I had, had open circuit antenna transformers, so I felt no guilt in modifying them. I can always restore everything in the future anyway. Tom

[exray]

The last one I had so much trouble with was a Northern Electric Rainbow set, battery version. I have an AADE meter and can also wind my own loops to spec. In this case I peaked the antenna and trimmer with the loop mounted on the back of the radio. It tracked pretty ok at the ends but didn't do well in the middle of the band. Add to that, it also severely detuned the antenna with the back mounted into place since it mounts so close against the radio chassis. Tried over and over to get the loop right but was unsuccessful and put back the original ant coil.

The ferrite antenna is a good option. I had to refurb a little 40s AA5 Belknap that was my daughter-in-laws "family heirloom". Missing loop. I just left the ferrite rod antenna mounted to the top of the cabinet in that one. It worked fine.

[tom.seeger]

I use a 7 inch ferrite loop as my temporary antenna, and you are right they do work very well. Its hard to say if its better than an air loop, but it is less susceptible to nearby objects. I have not experienced the mid band problem you had. But I don't really like to see a ferrite rod in a 1940 radio. But if you do it right, the average person might not know that the radio did not originally have an air loop on the backboard.