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SW on Philco 60B
#1

Just finished a model 60 and have a question about short wave. This is a later run where the LF compensating condenser was replaced with a 1400pF mica cap. However the actual cap in the radio is 2100pF. After alignment, the AM plays strong and is quite sensitive, but SW seems weak with low sensitivity. Could the value difference of this mica cap be the culprit? The 2100pF cap looks original, but I am not sure. Is there anything else that could cause low sensitivity on the SW band?
  Thanks,
Tim
#2

Try another oscillator tube for starters. What kind of antenna are you using?

Good luck with the project and all of us here are expecting a full report when you're finished.
#3

(02-11-2017, 01:42 PM)Jim Koehler Wrote:  Try another oscillator tube for starters. What kind of antenna are you using?

Thanks Jim, I will try another tube. I have about 45' of wire as an antenna, but it goes around the perimeter of the room, up and down a hallway about 16' above ground.
#4

(02-11-2017, 02:31 PM)tiloco Wrote:  
(02-11-2017, 01:42 PM)Jim Koehler Wrote:  Try another oscillator tube for starters. What kind of antenna are you using?

Thanks Jim, I will try another tube. I have about 45' of wire as an antenna, but it goes around the perimeter of the room, up and down a hallway about 16' above ground.

Alas, well I tried two different 6A7s and neither seemed to make much of a difference. SW still very weak. Could I have screwed something up when aligning the set? I would think that with the fixed cap for LF that there is not much one can do about the SW band on this set. Should I replace the 2100pF with the 1400pF the schematic calls for, or is that just chasing my tail?
#5

Just for grins you could try a .004mfd cap in series w/ the 2100mmfd cap. That will give you abt 1399mmfd.

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




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