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 Post subject: philco 48- 482
PostPosted: May Sat 15, 2021 3:30 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 272
Location: angeles city.philippines,2009
im getting down to the end of this set and in a way im reasonably impressed with it. the only thing left to do is recap the detector and those caps will get here this week. ive replaced all the resistors and all the paper caps and ecaps, aligned the am and the fm i.f. section. in the course of listening to the fm,i noticed that it would only pull in 2 local fm stations but hooking the long wire into the external socket pin 2,really woke that thing up. in the philco repair manual it briefly mentions an external connection to a z100. i googled z100 several different ways i cant find it,also it seems its a reference number and not a part number.does anyone know what it is??? the '49 catalog does seem to have it unless i just dont recognize it.


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 Post subject: Re: philco 48- 482
PostPosted: May Sat 15, 2021 5:06 am 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 17148
Location: Mountains of Mourne. Ireland.
It's a power line antenna.

It's pin 2 on the small four prong jack at the back of the chassis.
https://philcoradio.com/phorum/showthre ... #pid130423

I cut a piece of copper sheet about 1/4" wide and long enough to wrap around the power cord. I put a piece of fish paper between the copper and the cord and soldered a lead to the copper. It works pretty well.
https://www.philcoradio.com/phorum/show ... 5#pid12415

Service manual: https://philcoradio.com/library/downloa ... 8-1949.pdf
from: https://philcoradio.com/library/


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 Post subject: Re: philco 48- 482
PostPosted: May Sat 15, 2021 10:06 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 272
Location: angeles city.philippines,2009
yeah i get it. i cut a piece of sheet brass and made a clip to go around the ac line and it does seem to work. i did this on the outside and its not permanent yet. you think it would work as well under the chassis???


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 Post subject: Re: philco 48- 482
PostPosted: May Sat 15, 2021 12:37 pm 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 272
Location: angeles city.philippines,2009
i did however notice some distortion using this set up.but i still need to recap the discriminator and do the rf alignment. the long random wire works very well but not so much with am oddly enough if hooked to terminal 1 of the loop antenna. am amazed at the shortwave reception with just a loop of wire.


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 Post subject: Re: philco 48- 482
PostPosted: May Sat 15, 2021 3:31 pm 
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Joined: Jan Tue 31, 2012 1:55 am
Posts: 17148
Location: Mountains of Mourne. Ireland.
The power line act as an antenna and transfers the signal to the antenna coil. There is no physical connection between the metal wrap and the copper wire of the line cord, but there is a small amount of capacitance.

It works best in strong FM signal area.
In weak areas an outside antenna is essential.

https://worldradiohistory.com/BOOKSHELF ... -Vol-2.pdf


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 Post subject: Re: philco 48- 482
PostPosted: May Sun 16, 2021 1:43 am 
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Joined: Dec Sat 24, 2011 9:17 pm
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Location: Vancouver Island, Canada
I saw a note once that recommended stretching the power cord out full length when using the power cord antenna. So I tried adding a 6 foot extension cord and pulled in some distant FM stations, a bit louder with the power cord and extension cord stretched out, Zenith C845.

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 Post subject: Re: philco 48- 482
PostPosted: May Sun 16, 2021 3:06 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 272
Location: angeles city.philippines,2009
big problem here is that while the terrain is relatively flat most of the fm stations are in manila about 40 miles away but as its a big city its anyones guess where the transmitters are. and lets face it the technology is pretty old. worse my house has a metal roof! and no extension cord can be as good as long wire 20' in the air. im in reality asking the set to do what its probably not designed to do. it certainly puts my low range zenith of the same era to shame! the way the schematic was laid out i totally missed what z100 was and its location as i had no need to look at the rectifier circuit. i also noticed that depending on the function setting this set doesnt like a true earth ground. im still trying to figure out the pushbutton switching in the antenna circuit that grounds out parts of the antenna coil. i just noticed that as a result of the z100 business. and then theres the 3-4 pins that at times go to pin antenna pin 1 connection,how its all used is mystery to me,unless z100 is a bit more than a line cord antenna tap.


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 Post subject: Re: philco 48- 482
PostPosted: May Sun 16, 2021 7:17 am 
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Joined: Jan Tue 16, 2007 7:02 am
Posts: 4496
Location: Lexington, KY USA
For FM, you will probably be better off with a folded dipole, or even a non-folded one. 300 ohm twinlead, 75 ohm coax for a lead-in. A balun or two may or may not help.

If you can get a real outdoor FM antenna, that will be even better. These now seem to be hard to find in the US.

It is possible to make one. There are construction articles to be found online.

Ted


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 Post subject: Re: philco 48- 482
PostPosted: May Sun 16, 2021 7:54 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 38396
Location: SoCal, 91387
Actually a VHF TV antenna should work well. The FM band is located just above TV channel 6.

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 Post subject: Re: philco 48- 482
PostPosted: May Sun 16, 2021 11:33 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 272
Location: angeles city.philippines,2009
yeah i know about the tv antenna i have one that was on a tower unused when i moved in. i use it on my pioneer stereo.and yes i did try it but did so before i studied the antenna circuit so it ended up being hooked up to 1-3 on the antenna terminal strip via an old matching transformer as the lead in is coax. this of course is only for am and sw. ive got to get some hardware to engineer a hookup to that goofy round socket. i was looking at one on ebay for sale and i could make out an old fashioned twin lead stuffed into the cabinet so it must of had the tv antenna treatment.


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 Post subject: Re: philco 48- 482
PostPosted: May Sun 16, 2021 3:41 pm 
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Joined: Oct Wed 14, 2009 6:36 am
Posts: 6474
Location: New York USA
These FM dipole antennas will work on any set, sold in pairs https://www.amazon.com/dp/B01IFO17CW


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 Post subject: Re: philco 48- 482
PostPosted: May Mon 17, 2021 8:33 am 
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Joined: Aug Wed 14, 2019 6:56 am
Posts: 272
Location: angeles city.philippines,2009
i have one those from a pioneer receiver.they work, but not nearly as effective as that old tv aerial.but the dipole allows for easier placement in the house. as its on the bench waiting for mica caps it plays reasonably well with an alligator clipped wire from the concertina wire atop the wall.!!!


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