R.F choke - Printable Version
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: R.F choke (/showthread.php?tid=20341)
+- The PHILCO Phorum (https://philcoradio.com/phorum)
+-- Forum: Philco Radio Discussions (https://philcoradio.com/phorum/forumdisplay.php?fid=5)
+--- Forum: Philco Electronic Restoration (https://philcoradio.com/phorum/forumdisplay.php?fid=8)
+--- Thread: R.F choke (/showthread.php?tid=20341)
R.F choke - Arohn19 - 08-28-2019
Ive actually got 2 questions on this topic. I think I read somewhere that a RF choke isn’t really needed today… Is that true or should I put one back in? Also, it’s a .2 MFD and the closest cap I have is a .05 MFD so, should I install that in its place?
RE: R.F choke - Radioroslyn - 08-28-2019
I think you should a couple of .1 use two in parallel (=.2mfd). No you don't need to recreate the coil around the .2 cap.
RE: R.F choke - Arohn19 - 08-29-2019
Unfortunately the container holding the caps fell off my table and spilled a few weeks ago and thought for sure I found all of them but apparently not because I’m missing the 3 .1’s you gave me and the .15. I’m a little frustrated at the moment at myself because you were so kind to send me them for nothing and I’ve gotta order them because
RE: R.F choke - Arohn19 - 08-29-2019
I did manage to find 3 .1 caps, I forgot they were marked 304K. I’m at a loss of where the other 2 are since they’re so big. So I ordered 2 of those and the .015 I’m missing
RE: R.F choke - Phlogiston - 08-29-2019
Why wouldn't an RF choke be needed today?
The RF chokes found in the antenna circuit, to filter out 455khz aren't needed (mostly). But the chokes used to keep RF out of an amplifier are still useful.
RE: R.F choke - Arohn19 - 08-30-2019
I’m not talking about a amp though
RE: R.F choke - Arohn19 - 08-30-2019
Terry,
Where does the other end of it go. One lead goes to 7C6 according to my pics (I’m not trying to map things out on the schematic because it’s mostly hard for me to follow. I tried but my learning disability is fighting me) but, the other lead is missing totally. (Still trying to figure out why some of them had missing 2nd leads and others didn’t but that could explain partly why the previous owner got the pilot light to light but the radio didn’t make any noise
RE: R.F choke - Phlogiston - 08-31-2019
In this case I was referring to any tube/stage that provides signal gain and might amplify unwanted RF.