"Joel" wrote in message
...
That "Steve Nosko" wrote in message
...

Steve,
Although I didn't figure it out at the time, my Knight-Kit Space
Spanner
circa 1960 had terrible microphonics - very noisy. I cleaned the entire
chassis & rewired it to no avail. Today I suspect a mica cap, the old
square type, since I heard of same thing this some time ago.


Space Spanner.. O'Man, I could only afford the Ocean Hopper.. Man, them
were the days!

Joel AG4QC


Yea! AND, get this, I think I took plates off, or bent some, of the
bandspread cap to reduce its range and calibrated it for 40 M. Every
Saturday morning I'd listen to the same group on SSB talking about their
Collins rigs and inverted Vees.
Wish I still had it and the Knight-Kit crystal set. Had it hooked up to
a loud speaker in my room (course I was in Wood Dale, IL., not too far from
the WBBM and WGN AM transmitters...)
73
--
Steve N, K,9;d, c. i My email has no u's.

Space Spanner.. O'Man, I could only afford the Ocean Hopper.. Man, them
were the days!

Joel AG4QC

"Steve Nosko" wrote in message
...

Steve,
Although I didn't figure it out at the time, my Knight-Kit Space
Spanner
circa 1960 had terrible microphonics - very noisy. I cleaned the entire
chassis & rewired it to no avail. Today I suspect a mica cap, the old
square type, since I heard of same thing this some time ago.

In article ,
Steve Kavanagh wrote:
[...]
I have just been observing the same sort of frequent jumping behaviour
(up to a kHz or so at a time) in another local oscillator (output at
about 10.5 GHz, phase locked to a crystal oscillator around 100 MHz).
I note that this one also has dipped silver mica caps in the crystal
oscillator and I wonder if it too would be improved by replacing them
with NP0 ceramics.

Do the silver mica caps say "made in china" on them? Are they a light tan
color? If either of these are true chances are you will get a better cap
made from ear wax and tin foil. Somewhere in China there was, and perhaps
still is a factory, that made silver mica caps that change value if you
squeeze them between your fingers and go open if you heat cycle them.

I've never had much trouble with CDE caps.

--
--
forging knowledge

On 16 May 2004 07:06:24 -0700 (Steve
Kavanagh) wrote:

The capacitors used in both cases are from unknown sources and were
probably manufactured in the early 1980's.

That may be the secret here. In the past, I've used silver mica caps
in a number of applications with positive results. The only problem
I've ever seen with good quality ones was a single one in a 40 year
old HP amplifier that had become leaky.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"Jim Adney" wrote in message
...
On 16 May 2004 07:06:24 -0700 (Steve
Kavanagh) wrote:

The capacitors used in both cases are from unknown sources and were
probably manufactured in the early 1980's.

That may be the secret here. In the past, I've used silver mica caps
in a number of applications with positive results. The only problem
I've ever seen with good quality ones was a single one in a 40 year
old HP amplifier that had become leaky.

If silvered mica caps are so crappy, why did they ever use them in
the first place?

Thanks,
Rich

"Rich Grise" wrote in message
...
"Jim Adney" wrote in message
...
On 16 May 2004 07:06:24 -0700 (Steve
Kavanagh) wrote:

[snip]

If silvered mica caps are so crappy, why did they ever use them in
the first place?

Thanks,
Rich


Well made, they are very stable & handle considerable current. These were
top of the line. If they make junk now, so be it.

--
Steve N, K,9;d, c. i My email has no u's.

On Tue, 18 May 2004 02:31:08 GMT "Rich Grise"
wrote:

"Jim Adney" wrote in message
.. .
On 16 May 2004 07:06:24 -0700 (Steve
Kavanagh) wrote:

The capacitors used in both cases are from unknown sources and were
probably manufactured in the early 1980's.

That may be the secret here. In the past, I've used silver mica caps
in a number of applications with positive results. The only problem
I've ever seen with good quality ones was a single one in a 40 year
old HP amplifier that had become leaky.

If silvered mica caps are so crappy, why did they ever use them in
the first place?

I was not suggesting that they were crappy. I was suggesting that of
all the high quality ones I have worked with over many years, I've
only seen 1 failure.

His experience may well be due to the fact that his were of unknown
origin and unknown quality.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"Rich Grise" wrote in message
...
"Jim Adney" wrote in message
...
On 16 May 2004 07:06:24 -0700 (Steve
Kavanagh) wrote:

[snip]

If silvered mica caps are so crappy, why did they ever use them in
the first place?

Thanks,
Rich


Well made, they are very stable & handle considerable current. These were
top of the line. If they make junk now, so be it.

--
Steve N, K,9;d, c. i My email has no u's.

On Tue, 18 May 2004 02:31:08 GMT "Rich Grise"
wrote:

"Jim Adney" wrote in message
.. .
On 16 May 2004 07:06:24 -0700 (Steve
Kavanagh) wrote:

The capacitors used in both cases are from unknown sources and were
probably manufactured in the early 1980's.

That may be the secret here. In the past, I've used silver mica caps
in a number of applications with positive results. The only problem
I've ever seen with good quality ones was a single one in a 40 year
old HP amplifier that had become leaky.

If silvered mica caps are so crappy, why did they ever use them in
the first place?

I was not suggesting that they were crappy. I was suggesting that of
all the high quality ones I have worked with over many years, I've
only seen 1 failure.

His experience may well be due to the fact that his were of unknown
origin and unknown quality.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

"Jim Adney" wrote in message
...
On 16 May 2004 07:06:24 -0700 (Steve
Kavanagh) wrote:

The capacitors used in both cases are from unknown sources and were
probably manufactured in the early 1980's.

That may be the secret here. In the past, I've used silver mica caps
in a number of applications with positive results. The only problem
I've ever seen with good quality ones was a single one in a 40 year
old HP amplifier that had become leaky.

If silvered mica caps are so crappy, why did they ever use them in
the first place?

Thanks,
Rich