hallicrafter 455 filter and xtals
 

Came across a jar of old crystals at a garage sale today. I saved them
from being tossed into the garbage. The home owner says they were in the
house when they moved in and were about to toss it.

I'm going to take them to a swap meet next weekend but there is one item
in the bunch that looks unique. It's a hallicrafter 455Khz crystal filter
in a holder. Looks like one of the crystals except the top is rounded.

http://www.vambo.org/tmp/OldXstals.jpg

I suspect whomever gets the crystals would not have a use for the filter
and it would site on someones shelf. So, I would like to see if anybody
here has a use for it before I take it to the ham fest.

hallicrafter 455 filter and xtals
 

yea right ) writes:
Came across a jar of old crystals at a garage sale today. I saved them
from being tossed into the garbage. The home owner says they were in the
house when they moved in and were about to toss it.

I'm going to take them to a swap meet next weekend but there is one item
in the bunch that looks unique. It's a hallicrafter 455Khz crystal filter
in a holder. Looks like one of the crystals except the top is rounded.

http://www.vambo.org/tmp/OldXstals.jpg

I suspect whomever gets the crystals would not have a use for the filter
and it would site on someones shelf. So, I would like to see if anybody
here has a use for it before I take it to the ham fest.


Huh?

Up until the mid to late fifties, the only crystal filters you'd see in
equipment consisted of a single crystal. Even after mechanical filters
came along, and even after crystal lattice filters made it into ham
equipment, there were still those filters made with single crystals.

Chances are pretty good that whateve you have, it's merely a crystal.

Michael VE2BVW

hallicrafter 455 filter and xtals
 

On Sun, 05 Aug 2007 03:40:44 +0000, Michael Black wrote:

yea right ) writes:
Came across a jar of old crystals at a garage sale today. I saved them
from being tossed into the garbage. The home owner says they were in
the house when they moved in and were about to toss it.

I'm going to take them to a swap meet next weekend but there is one item
in the bunch that looks unique. It's a hallicrafter 455Khz crystal
filter in a holder. Looks like one of the crystals except the top is
rounded.

http://www.vambo.org/tmp/OldXstals.jpg

I suspect whomever gets the crystals would not have a use for the filter
and it would site on someones shelf. So, I would like to see if anybody
here has a use for it before I take it to the ham fest.


Huh?

Up until the mid to late fifties, the only crystal filters you'd see in
equipment consisted of a single crystal. Even after mechanical filters
came along, and even after crystal lattice filters made it into ham
equipment, there were still those filters made with single crystals.

Chances are pretty good that whateve you have, it's merely a crystal.

Michael VE2BVW

It says filter. Here is a much better picture..

http://www.vambo.org/tmp/Hallicraftt...stalFilter.jpg

hallicrafter 455 filter and xtals
 

yea right wrote:

SNIPPED

It says filter. Here is a much better picture..

http://www.vambo.org/tmp/Hallicraftt...stalFilter.jpg


Yep! It is a single 455 KHz crystal in a standard FT-243 [if I recall correctly]
size case.

This type "filter" is very common in radios well into the 60s. It is used in
it's series resonant mode in the first 455 KHz i.f. amplifier tuned circuit. The
technique did a fairly good job of sharpening the selectivity of the older
moderately priced AM type receivers.

hallicrafter 455 filter and xtals
 

"yea right" wrote in message
...
Came across a jar of old crystals at a garage sale today. I saved them
from being tossed into the garbage. The home owner says they were in the
house when they moved in and were about to toss it.

I'm going to take them to a swap meet next weekend but there is one item
in the bunch that looks unique. It's a hallicrafter 455Khz crystal filter
in a holder. Looks like one of the crystals except the top is rounded.

http://www.vambo.org/tmp/OldXstals.jpg

I suspect whomever gets the crystals would not have a use for the filter
and it would site on someones shelf. So, I would like to see if anybody
here has a use for it before I take it to the ham fest.



I have several Hallicrafters that use similar filters. How much are you
asking for it?

Peter

hallicrafter 455 filter and xtals
 

On Sat, 04 Aug 2007 20:58:00 -0600, yea right wrote:

Came across a jar of old crystals at a garage sale today. I saved them
from being tossed into the garbage. The home owner says they were in the
house when they moved in and were about to toss it.

I'm going to take them to a swap meet next weekend but there is one item
in the bunch that looks unique. It's a hallicrafter 455Khz crystal filter
in a holder. Looks like one of the crystals except the top is rounded.

http://www.vambo.org/tmp/OldXstals.jpg

I suspect whomever gets the crystals would not have a use for the filter
and it would site on someones shelf. So, I would like to see if anybody
here has a use for it before I take it to the ham fest.

I HAVE 455 kHz crystals for sale if anyone needs some. I have them
in both the HC6/U cases with straight pins as well as in the wire lead
types of the same size = HC33/U (both have the pin spacing of 0.5
inches.)

See:
http://www.af4k.com/crystals.htm

Thanks for looking & 73

hallicrafter 455 filter and xtals
 

"Deek" wrote in message
. ..
yea right wrote:

SNIPPED

It says filter. Here is a much better picture..
http://www.vambo.org/tmp/Hallicraftt...stalFilter.jpg


Yep! It is a single 455 KHz crystal in a standard FT-243
[if I recall correctly] size case.

This type "filter" is very common in radios well into the
60s. It is used in it's series resonant mode in the first
455 KHz i.f. amplifier tuned circuit. The technique did a
fairly good job of sharpening the selectivity of the older
moderately priced AM type receivers.

Also in higher priced receivers like the SP-600-JX and
51-J series, they work quite well for CW. The original idea
was patented by James Lamb around 1935 and applied first in
National Co's receivers, for instance the famous HRO. A
later version was patented by Hammarlund (can't remember the
inventor's name) and used in their receivers (Super-Pro 100,
200, 400 and others) and some others. The filter in Collins
receivers is of this type. The Hammarlund version allowed a
wider range of bandwidth and also adjustment of the notch
without changing the center frequency. Hallicrafters applied
the Lamb type to all their receivers with an X in the type
number, i.e., SX-28. Earlier crystals were often mounted
between clamps as in the Hammarlund Super-Pro, later
versions were in standard type crystal cases like this one.
Single crystal filters do not have very good skirt
selectivity and were supplanted by various types of
multiple-pole IF filters when methods of producing these at
reasonable prices were developed, and T-type notch filters
operating at the RF frequencies.
The crystal has slightly different characteristics from
those designed mostly for use in oscillators.
I don't know what Hallicrafter's receivers this crystal
fits but there is likely someone out there with a receiver
that needs the crystal.


--
---
Richard Knoppow
Los Angeles, CA, USA

hallicrafter 455 filter and xtals
 

yea right wrote:
Came across a jar of old crystals at a garage sale today. I saved them
from being tossed into the garbage. The home owner says they were in the
house when they moved in and were about to toss it.

I'm going to take them to a swap meet next weekend but there is one item
in the bunch that looks unique. It's a hallicrafter 455Khz crystal filter
in a holder. Looks like one of the crystals except the top is rounded.

http://www.vambo.org/tmp/OldXstals.jpg

I suspect whomever gets the crystals would not have a use for the filter
and it would site on someones shelf. So, I would like to see if anybody
here has a use for it before I take it to the ham fest.



That looks like the one from the SX-16, et al. Very hard to find, too.
Wish I could make your fest!!! de K3HVG