Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco 38-116 antenna question
#1

Hi Guy's
Have a really mint 38-116 that I got from a pro that restored it completely.
This guy is very thorough when he does one.
Just wondering what most people think is an adequate single wire antenna for the antenna hog?
Has about a 10 ft wire on it now and it works, but not as good as most of my other radios.
Unless you are dialed into a strong local station, you get alot of static and backround noise.
Picks up stations all up and down the dial, but unless they are really strong stations, you have to deal with the static.
I thought maybe a little alignment issue, but I don't want to mess with the re-builders alignment unless I can improve it with more antenna.
If I grab the end of the single wire, it does not seem to improve reception.
Any thoughts from the Philco Pro's?
murf
#2

If it has a 2-prong power plug, try connecting the chassis to earth ground.
#3

Hi Kevin,
10'  isn't very much at all !!! If we were to do the math for the broadcast band just in rough numbers you figure wavelength in meters x3 to = feet and that will give you an idea. So 1600kc= 200mtrs = abt 600' , 10' your cute!

Here's the practical side of things. A single wire ant will work but it's not the greatest thing since sliced bread. A better way to go is a dipole ant if you have the space. It is two wires that are connected to the radio thru a feed line at it's mid point. Ignore the 1/4 wave length, if you can get 50 or 60' each side of center that's fine. Insulators can be a short piece of 1/2" pvc pipe a hole drilled in each end. I put up one here that is 125' long and is up 8'. Wish it was up 80' but I'm on the small lot so five 1"x2"x8' furring furring strips were the supports. They were tethered with rope to the fence which borders the lot. 60' across the back and about 35' up each side of the lot. Have about 40' from the back of the house to the antenna so I used RG-58 coax. For your application it's ok but it does offer a bit of an impedance mismatch. It's 50 ohms and the set is about 300 ohms. In the big scheme of thing it pretty negligible but if you can't sleep at night over it you can build or buy a transformer called a balun. It's simple and cheap.





[Image: https://www.kingscountyradioclub.com/wp-...Dipole.png]

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#4

Holy scrap, I have been meaning to put an outside line up, but its winter now here .
If I did something like that, I would run it into a control so I could run a line to a couple different rooms.
I do have a lot of trees here, so I could probably utilize them to as long as I don't attach the wires to the trees.
Murf
#5

Hi again Terry,
So the leads on the coaxial cable are going to both be attached to the antenna terminal on the chassis?
What would be ideal lengths on each end of the dipole?
Could this be run under the eaves on the house?
Would need to protect from lightning with a ground rod also.
Murf
#6

Don't think have room for 600 ft.
I assume the copper stranded wire is in shielded?
Murf
#7

>So the leads on the coaxial cable are going to both be attached to the antenna terminal on the chassis?
Correct. Center conductor connects to the ant post and the shield connects to the gnd or chassis.

>What would be ideal lengths on each end of the dipole?
Well there is ideal and practical. Ideal would be about 1500' up about 150' in the air but it's not very practical for many reasons. Practical is what you can do with what you have. If you can get a total of 100 or 150' in length you're doing good. Height the higher the better.

>Could this be run under the eaves on the house?
You could. The only thing to watch out for is metal. Things like flashing and stuff can degrade the performance so if you can keep it several inches away from the metal that's great.

>Would need to protect from lightning with a ground rod also.
It's probably not a bad idea. I don't over here in PA. My ants aren't very high and we don't get much lightning. A ground rod is a good idea not necessarily for lightning but being isolated from the noise of the house's ground system.

>Don't think have room for 600 ft.
I don't know that most of use do... I'm on a 100'x60' lot so putting up anything that is resonant below about 3.5 mc. is tough.

>I assume the copper stranded wire is in shielded?
Ok the basics are this. Two kind of wire solid just one piece of solid copper like the wire use when wiring a house. Stranded no it doesn't mean it's stuck and can't get off the island. Sorry just a little wire humor. It has many small thin pieces of copper wire to make up one larger diameter piece, typically twisted together. In the case of coax the center conductor can be solid or stranded it varies. The outside shield is stranded but is woven like a shoe lace. This permits the center conductor to be thru the shield aka braid. But no the wire that is used from the insulator to the center that sez stranded wire is not shielded.

With all of the dipole stuff being said here's something that is simple that can be put together in an afternoon. There are LOTS of different designs for antennas. But here is the practical side of things. Outside wire ants are great for picking up massive amounts of signals. Now at the outset that sound good. But what if some of those signals are interfering with the signals you want to hear?? Some folk have wire antennas that favor different directions. One ant favors n/s the other e/w. It's a barrel of laffs fixing them after a wind storm or a fallen branch or two.
This might be something fun to tryout. I wound downsize it by 30% or so as it's resonant frequency is abt 950kc. The deal is this you can add capacitance to lower the resonant frequency. This one has too many turns if you add capacitance it just lowers the frequency. Plus the fact it ginormous. Does a good job at nulling weaker stations on the same frequency. https://philcoradio.com/phorum/showthread.php?tid=19735

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!

Terry
#8

Thanks for all the info Terry!
You seem to have it down pat!
Will have to work on it.
Murf




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 38-7 Speaker
4-ohm speaker. Black, Green leads.tludka — 07:00 PM
Philco 42-390, code 121 speaker
#87 on the schematic.  This radio had a 8" Zenith  speaker attached to it when I got it. I do don't know the hist...Stevelog — 06:39 PM
Philco 60 Squealing
I'm pretty sure I now have the litz wire soldered. This did not make any difference. Back in April I rewound the seconda...dconant — 06:25 PM
Philco 38-7 Speaker
Just to make sure, you chose either 4 ohm into 5K or into 10K? (blk-org or blk-grn)morzh — 06:23 PM
Philco 38-7 Speaker
I have let this one sit because of other duties. Now I am back, and I have a couple of questions. I hooked up a Hammond ...tludka — 05:34 PM
Philco 42-390, code 121 speaker
>>A closer examination of the very small print schematic indicates that the speaker is a PM type. This shows a ...morzh — 05:18 PM
Philco 60 Squealing
Litz is typically tinned by simply rubbing it with the soldering iron tip while immersed in solder (and a bit of rosin f...morzh — 05:14 PM
Philco 6K7
The suppressor grid (if by G3 you mean the S) is usually at the Cathode potential, which in this caes is GND. I am not ...morzh — 05:10 PM
Philco 16B Parts
Thanks for the reply. Unfortunately the radio was removed before bidding was over so I didn't get a chance to bid.dconant — 04:10 PM
Philco 16B Parts
Hi Dan, Mike is correct, there's a lot of painted stuff on the chassis but it looks pretty good. The sm is all there,sp...Radioroslyn — 03:50 PM

[-]
Who's Online
There are currently 3853 online users. [Complete List]
» 1 Member(s) | 3852 Guest(s)
Avatar

>