The PHILCO Phorum

I just finished another restoration on a Model 89 cathedral with the 36 autodyne. I know I have probably beat the oscillator tickler coil thing to death. But this time I got it to work first time. Maybe this posting will help someone in the future.

27 turns starting from pin 1 ending on pin 2, turning clockwise looking from the bottom of the coil form, using #38 wire. Pin 1 is the first one to the right of the mounting clip looking from the bottom. Worked perfectly and oscillates across the entire band.

In the past, I tried #34 and #36. I know people will say that the wire size is not critical for a ticker coil, but only, only after I went to #38 wire did I get it to work. With this number of turns, and the very thin #38 wire, the resistance measured about 5 ohms, which is very close to what it says on the schematic. I took this as a good sign.

When I brought it up, it squealed like the dickens. But the tube shields were missing. I found a tube shield for the the 75 tube, and that fixed that.

Mark K8KZ

Congratulations, and thanks for the information. Always good to learn from others' experiences.

One more thing, it is always a good idea to bake the coil form at 200 degrees for about 30 minutes. 

Steve  

Mark,
What do you recommend I use as an insulator between the two coils? I'm talking about the tickler coil being wound on top of the other coil. From what I've read there's a lot of differences of opinion on what material should be used.

I'm just starting an 89. Do you have any advice on the antenna call?

Hugh, Welcome to the Phorum!


I edited the two posts you made to combine them into the one you see here.

(02-16-2016, 01:33 PM)Hugh C Wrote: [ -> ]What do you recommend I use as an insulator between the two coils?

For an insulator, I just used scotch frosted tape. I lay in on backwards with the sticky side out. This holds the wire in place as I wrap each turn. In order to hold the tape in place, I tape it down with some tiny pieces of additional tape around the perimeter.

Mark K8KZ

Mark, do you cover or coat the tape and tickler coil with anything?  I was concerned about the edges of the sticky tape attracting dirt or metal filings.

HI Dave,

No I haven't been doing that. I understand your concern, but I haven't found it to be a problem. Ron has suggested spraying the finished coil with clear lacquer. That would negate the stickiness, but I have not resorted to that.

Mark K8KZ

Ok so I gave your method a try and it came out pretty good.  I used some polyimide tape that I found on Amazon that has really good dielectric and temperature specs.  I used 27 turns of #38 like you suggested and I'll be testing it soon.

Wow that looks great Dave!

Mark K8KZ