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

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

RF Choke and Condenser -42-PT-7
#2

OK, well,

This seems like a wave trap and is not even important. You could simply remove it.
As for the value of the cap:

Let's assume 2cm diameter (if it is 2uF, it is large), and 1cm the length of the winding.
We will also assume air core.
It is just the first order calcs:

The inductance is:

Mu-zero (air dielectric const) * A (area) * N-square (turns) / l (length)

L = 4*3.14 * 10^-7 * 49 * 3.14 * 10^-4 = 2uH

Now the resonant frequency for 2uF is:

1/ (2 * Pi * SQRT (LC)) = 1/(6.28 * SQRT (0.000002 * 0.000002)) = 79 kHz.

For 0.2uF:

We will also assume the cap is 1/2 the other one's diameter, which will decrease L by 4.
But in the Frequency it is SQRT, so it is factor of 2.

So it is 500kHz.

It is pretty close to 455 kHz IF frequency.


So, my vote is for 0.2uF.


----------------------------



And, again - this is not important. This LC could be removed.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.


Messages In This Thread
RF Choke and Condenser -42-PT-7 - by Masonparker - 11-11-2024, 10:03 AM
RE: RF Choke and Condenser -42-PT-7 - by morzh - 11-11-2024, 12:28 PM
RE: RF Choke and Condenser -42-PT-7 - by RodB - 11-11-2024, 02:21 PM
RE: RF Choke and Condenser -42-PT-7 - by morzh - 11-11-2024, 02:51 PM
RE: RF Choke and Condenser -42-PT-7 - by MrFixr55 - 11-12-2024, 06:04 PM
RE: RF Choke and Condenser -42-PT-7 - by Arran - 11-13-2024, 07:00 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 42-345 Restoration/Repair
Today I've been reading through the site trying to learn more about this radio. I also soldered the lose power cord cabl...osanders0311 — 08:24 PM
Philco 610B oscillator wiring
Thanks David! I do have that same later prodution model 610 schematic. I've also studied the Philco service bulletins fo...Tubester — 08:12 PM
Philco 610B oscillator wiring
Some info from Beitmans says late production. David   David — 06:06 PM
Restoring Philco 96
Oh wow! Just found this thread.  Brings me back to early days on this phorum.  I did a 96 back in 2017.  Thread here: ...rfeenstra — 06:05 PM
Philco 610B oscillator wiring
Thanks for the replies. It's not the really the hum that I am after. Just trying to understand why only the shortwave ba...Tubester — 04:01 PM
Restoring Philco 96
70 and 90 are Superhets, but at least the 2x45 model of 90 uses the Plate detector (and so does 70). Also the Atwaters,...morzh — 03:28 PM
Restoring Philco 96
Morzh, Prayers for your mom. I am sure that there was enough pain living through the Holocaust as a child. I pray dail...MrFixr55 — 02:19 PM
Philco 610B oscillator wiring
Hi Dan, Divide and conquer. First off trry to differentiate between 60Hz and 120 Hz hum. 120 Hz hum has a higher pit...MrFixr55 — 01:49 PM
Restoring Philco 96
Yes, other than takin a toll on your back, they are undeed way more repair friendly than many other Philcos. To me, som...morzh — 01:04 PM
Philco 610B oscillator wiring
If the wires look like they were this way from the factory (very neat and very dull soldering joints), I'd leave them be...morzh — 12:58 PM

[-]
Who's Online
There are currently 1586 online users. [Complete List]
» 1 Member(s) | 1585 Guest(s)
Avatar

>