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

Antenna couplers used on 1940s Philco radios
#4

Without the coupler I've tried connecting a long antenna to it and it worked BUT the image rejection was poor on my 41-300. As for the resistors I would say that higher values are more likely to drift but that doesn't preclude checking the lower one's values. If you have some time to kill you can use these: https://philcoradio.com/library/index.ph...-envelope/  to put your resistor in.

Now you do realize that this set was never designed to receive signals from what is known as the fm 100 band just the fm 50 band. It tune from 42-50mc. This means that ant and rf circuits are not going to be resonant at the fm 100 band. Nor is the local oscillator. So what is happening is that your incoming signal @ 84-100mc has to have enough power to plow thru ant and rf stages because they are passing signal @ 50mc or so. Then the mixer has to try to mix with the 2nd harmonic of the oscillator (this is why the sensitivity sucks) so the it can tune the lower half of the fm band. So unless you have a second mixer that converts the 42 to 88mc. With that the set only tunes 8mc it would tune 88-94mc.

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


Messages In This Thread
RE: Antenna couplers used on 1940s Philco radios - by Radioroslyn - 10-25-2023, 10:22 AM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco model 38 code 121 not receiving signal.
Thanks Arran. Yeah this plastic is pretty thin. It's a little thinner than the original stuff. It kinda reminds me of p...Stormlord5500 — 04:37 PM
Testing a speaker and output transformer Trutone A2-G
The equivalent of one short turn is basically the same as that of a shorted load. If it is the primary's turn, then the ...morzh — 03:53 PM
Testing a speaker and output transformer Trutone A2-G
I've never had an output transformer become shorted, the failure mode is usually an open primary, or in a center tapped ...Arran — 03:52 PM
Philco model 38 code 121 not receiving signal.
As long as the plastic sheeting isn't too thick, I think that the thickness of photographic film would be just about rig...Arran — 03:19 PM
Philco model 38 code 121 not receiving signal.
Well why not! :lol:Stormlord5500 — 03:14 PM
Philco model 38 code 121 not receiving signal.
Good luck next thing you know you will be winding coils just for the fun of it. DavidDavid — 11:29 AM
Testing a speaker and output transformer Trutone A2-G
morzh Short-circuited turns can be considered as a half-dead transformer. But on this case transformer will hot and s...Vlad95 — 11:01 AM
Testing a speaker and output transformer Trutone A2-G
I am not sure how a transformer could be weak. It could be inadequate, but only when you replace the original with somet...morzh — 09:56 AM
Philco model 38 code 121 not receiving signal.
Good news everyone! I think I have found everything I need for rewinding the antenna coil primary. I found some pla...Stormlord5500 — 09:40 AM
Philco Battery-WWII vintage
My younger sister went to SUNY Plattsburg NY, (BS, MS, RN) in the late 1970sabout 10 min from the Northern NY / Canada b...MrFixr55 — 07:59 AM

[-]
Who's Online
There are currently 1753 online users. [Complete List]
» 4 Member(s) | 1749 Guest(s)
AvatarAvatarAvatarAvatar

>