Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
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: 1 Guest(s)
[-]
Recent Posts
6TPZ and 5TPO Radio Help
Welcome to the Phorum, R3Sons! I have very limited experience with car radios other than installing custom radios back ...GarySP — 01:08 PM
462ron
OK, I need to rename this thread to say..Eico 368 TV/FM Sweep Generator instead of the current title..Heathkit Sweep Gen...462ron — 12:49 PM
6TPZ and 5TPO Radio Help
Hello, I have a Philco (Ford) 6TPZ and a 5TPO radio.  I replaced the electrolytic capacitors in both.  I have the SAMS m...R3Sons — 12:29 PM
The list of my radio & TV collection!
Hello Peter, Thank you for posting that !! Sincerely Richardradiorich — 09:40 AM
Eico 232 VTVM Schematic
It's a microwave antenna. ?;-p?. I substituted 1N4002s off the 6.3 vac winding for the 1.5 volt battery. Uniprobe is the...RodB — 05:50 PM
Eico 232 VTVM Schematic
Try BAMA for a schematic. Looks like a replacement power source for the D battery has been installed. The tube may be...Chas — 04:51 PM
Eico 232 VTVM Schematic
Is that a battery holder?morzh — 04:43 PM
Eico 232 VTVM Schematic
A friend gave me this Eico 232 VTVM and I'm having trouble locating the schematic for it. This one seems to be a later v...RodB — 04:17 PM
Var resistor id
Considering what it is in series with, I doubt there should be any power requirements. Of course, we should know wher...morzh — 03:23 PM
Var resistor id
Trim pot, about 1/2 watt part of focus divider. As stated 2k ohms. This appears to be a rusty chassis, resolder all ...Chas — 03:19 PM

[-]
Who's Online
There are currently 3229 online users. [Complete List]
» 2 Member(s) | 3227 Guest(s)
AvatarAvatar

>