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

Philco 38-10 Antenna input
#1

While restoring my 38-10,I noticed in my Riders that that when using the factory supplied "All Wave Antenna" (basically a dipole) one side of the antenna is always at chassis ground potential regardless of band switch position (The black lead) .IMHO,this renders half of the antenna useless for reception.Is this a factory goofup or is there a reason for this? 73 de Bill
#2

W4NJF,

It apparently is just like a half-wave ham dipole. The 'active' side is a quarter-wave. The other side is basically serving as a counterpoise.

This arrangement allows for resonance and a low impedance feedpoint. Look at the SO-239 on the back of your ham gear. Its at ground. Icon_smile

Some sets do this arrangement using a balanced feedline and/or balun/xfmr. Not sure if one is any better than the other in this application (broadband).
#3

hI EXRAY,Gotta disagree with you on this one,in the 1937 Philco models that used the same antenna,the primary antenna windings were center tapped to ground and the antenna itself was switched to "T" configuration on the BCB and operated as half wave dipole on SW.The exact resonant frequency of the antenna was dependent on how long you cut each leg-usually about 12 Mhz (25 meters).So why put a dipole for 40 meters in length when one for 20 would do?(for rx purposes only!).I can see your take on the counterpoise,but I'm not talking verticals here.
#4

The bandswitch does the balaned/un-bal switching, I believe.

Chuck
#5

Bill Fulling Wrote:hI EXRAY,Gotta disagree with you on this one,in the 1937 Philco models that used the same antenna,the primary antenna windings were center tapped to ground and the antenna itself was switched to "T" configuration on the BCB and operated as half wave dipole on SW.The exact resonant frequency of the antenna was dependent on how long you cut each leg-usually about 12 Mhz (25 meters).So why put a dipole for 40 meters in length when one for 20 would do?(for rx purposes only!).I can see your take on the counterpoise,but I'm not talking verticals here.

If its a question of length then they were possibly operating the dipole at both 1/2-wave and 3/2-wave lengths. Using a freq 12 Mhz (25 m) just for example...a dipole of 37.5 meters in length will work as well if not a tad better than one of a 12.5 m length PLUS the 37.5 m one has the advantage of working at 4 MHz (75 m wavelength) as well.

I have no idea if thats what they had in mind but a dipole would work that way.

-Bill




Users browsing this thread: 3 Guest(s)
[-]
Recent Posts
Hickok AC51 tube tester
Note that no power cord, power switch, or power transformer switch are shown. That (along with my experience with full s...DaleHCook — 07:09 AM
IF can wire size and Rubber mounts?
A pair of wire strippers can give you an idea of what the existing gauge of the wire leads are in the IF can, I think it...Arran — 06:07 AM
My last cabinet for this year
Hello Dan, That is really beautiful what great looking radio you have ! I have friends who live in Calgary and the wea...radiorich — 01:51 AM
12' Philco
Not anymore Mike. Andre The Giant Born: May 19, 1946, Coulommiers, France Died: Jan 28, 1993 (46 years), Paris, Fran...RodB — 11:53 PM
IF can wire size and Rubber mounts?
Renovated Radios do carry what you need. As for the voltage, a wire should be at least 300V-rated.morzh — 11:13 PM
12' Philco
Andre the Giant got 2" on Kareem :lol:morzh — 11:11 PM
IF can wire size and Rubber mounts?
Thanks for the info but I doubt that a hardware store would be carrying the proper tuner assembly support mountings for ...georgetownjohn — 10:38 PM
12' Philco
Perhaps Kareem Abdul Jabbar?GarySP — 10:33 PM
My last cabinet for this year
Outstanding work, Dan! Take care and BE HEALTHY! GaryGarySP — 10:31 PM
My last cabinet for this year
They are a nice looking radio, Stromberg. I have a small tabletop octagon-dial one. It sounds surprisingly nice. And t...morzh — 09:40 PM

[-]
Who's Online
There are currently no members online.

>