Looking to buy a 3395 AM filter as used in early tube Heathkit
receivers..any other suggestions on receiving AM with homebuilt filter
system? TNX 73 Harold

On Mon, 9 Feb 2009, wrote:

Looking to buy a 3395 AM filter as used in early tube Heathkit
receivers..any other suggestions on receiving AM with homebuilt filter
system? TNX 73 Harold

I thought they stuck with the same IF through the SB line. Or maybe
there was a shift, I seem to recall an article in QST where someone
changed the filter in an early Heathkit SSB transmitter and they had
to make some changes because the then current IF frequency was somewhat
different.

For AM, there's probably a lot more possibilities. Pull some ceramic
filters out of a CB set and cascade them, though those will be at
455KHz. All kinds of cordless phones, cb sets, some older cellphones,
49MHz superheterodyne walkie talkies and other consumer items use
double conversion, with the first IF at 10.7MHz (and a wide ceramic
filter there, the type you find in FM broadcast band receivers) and
then a conversion to 455KHz, so they'd supply the needed crystal
for the second conversion.

If you're not stuck on a specific IF frequency, there's bound to
be still lots of AM bandwidth crystal filters floating around, since
after all relatively few were interested in good filters for AM,
while SSB-width filters were very desired.

Michael VE2BVW

"Michael Black" wrote in message
ample.net...

For AM, there's probably a lot more possibilities. Pull some ceramic
filters out of a CB set and cascade them, though those will be at
455KHz. All kinds of cordless phones, cb sets, some older cellphones,
49MHz superheterodyne walkie talkies and other consumer items use
double conversion, with the first IF at 10.7MHz (and a wide ceramic
filter there, the type you find in FM broadcast band receivers) and
then a conversion to 455KHz, so they'd supply the needed crystal
for the second conversion.

If you're not stuck on a specific IF frequency, there's bound to
be still lots of AM bandwidth crystal filters floating around, since
after all relatively few were interested in good filters for AM,
while SSB-width filters were very desired.

Digi-Key stocks a number of ceramic and crystal filters that might be
suitable for AM reception for less than $10 each, some for less than $2.
They are willing to sell in small quantity and are one of the better
distributors of electronic parts. Now one of the largest distributors,
they got their start selling kits of parts for an integrated circuit keyer
for hams. See:
http://www.digikey.com/.

--
73, Dr. Barry L. Ornitz WA4VZQ

[transpose digits to reply]

Dr. Barry L. Ornitz wrote:
"Michael Black" wrote in message
xample.net...

For AM, there's probably a lot more possibilities. Pull some ceramic
filters out of a CB set and cascade them, though those will be at
455KHz. All kinds of cordless phones, cb sets, some older cellphones,
49MHz superheterodyne walkie talkies and other consumer items use
double conversion, with the first IF at 10.7MHz (and a wide ceramic
filter there, the type you find in FM broadcast band receivers) and
then a conversion to 455KHz, so they'd supply the needed crystal
for the second conversion.

If you're not stuck on a specific IF frequency, there's bound to
be still lots of AM bandwidth crystal filters floating around, since
after all relatively few were interested in good filters for AM,
while SSB-width filters were very desired.

Digi-Key stocks a number of ceramic and crystal filters that might be
suitable for AM reception for less than $10 each, some for less than $2.
They are willing to sell in small quantity and are one of the better
distributors of electronic parts. Now one of the largest distributors,
they got their start selling kits of parts for an integrated circuit keyer
for hams. See:
http://www.digikey.com/.

It _might_ be possible to shift the frequency of an existing ceramic filter
up somewhat by judicious file and sandpaper work. I am not sure how much
you can cut it before you screw the geometry up too much for it to work,
though.

If you need a weird frequency like this, though, I would first call ICM
and see if they can make you something at a reasonable price. They have
standard crystals for very cheap and I bet they won't charge much for
filter crystals either.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Mon, 09 Feb 2009 19:14:44 -0800, wrote:

Looking to buy a 3395 AM filter as used in early tube Heathkit
receivers..any other suggestions on receiving AM with homebuilt filter
system? TNX 73 Harold

You seem to be asking for two different things.

Do you want to homebrew a radio to receive AM, and are looking for some
candidate filters?

Or do you specifically want to build a Heathkit tube rig or use the
Heathkit SSB and CW filters in a rig, and you want an AM filter to match?

If it's the former, then find out who's selling replacement filters (the
name "Fox Tango" floats up to my consciousness) and see what they have.

If it's the latter -- well, the same place may have what you want, or you
may be out of luck (did the Heath rigs _have_ an AM selection? Mine
certainly didn't), or you may have to mix to some other frequency (i.e.
455kHz), filter, and mix back. Note that my SB-201 didn't have an AM
detector, either, so it may be more than just a filter that you need.

--
http://www.wescottdesign.com

On Tue, 10 Feb 2009, Tim Wescott wrote:


If it's the latter -- well, the same place may have what you want, or you
may be out of luck (did the Heath rigs _have_ an AM selection? Mine
certainly didn't), or you may have to mix to some other frequency (i.e.
455kHz), filter, and mix back. Note that my SB-201 didn't have an AM
detector, either, so it may be more than just a filter that you need.

If they kept the same IF frequency, and I know the SB line did use
something in the 3MHz range, then there was at least one AM filter, for
the shortwave band version of the SB series receiver, the SB-313 or
something.

There was a Heathkit receiver/transmitter set for AM about the time
of their early SSB rigs, same sort of styling as the SSB rig of
the time. The era of the Indian names. I don't know whether those
used a high IF or used the traditional 455KHz, but if it was the
former, they'd surely use the same 3MHz range scheme as the SSB
equpment.

Michael

On Tue, 10 Feb 2009 11:39:29 -0500, Michael Black wrote:

On Tue, 10 Feb 2009, Tim Wescott wrote:


If it's the latter -- well, the same place may have what you want, or
you may be out of luck (did the Heath rigs _have_ an AM selection?
Mine certainly didn't), or you may have to mix to some other frequency
(i.e. 455kHz), filter, and mix back. Note that my SB-201 didn't have
an AM detector, either, so it may be more than just a filter that you
need.

If they kept the same IF frequency, and I know the SB line did use
something in the 3MHz range, then there was at least one AM filter, for
the shortwave band version of the SB series receiver, the SB-313 or
something.

There was a Heathkit receiver/transmitter set for AM about the time of
their early SSB rigs, same sort of styling as the SSB rig of the time.
The era of the Indian names. I don't know whether those used a high IF
or used the traditional 455KHz, but if it was the former, they'd surely
use the same 3MHz range scheme as the SSB equpment.

Michael

I believe there was a regular brand rig (Kenwood?) of about that era that
also used the same mixing scheme, and had the same frequency fixed IF, if
not all the same matching impedances. I can't really recall, though,
other than I was thumbing through a replacement filter catalog and
noticed it because I had the SB-201.

--
http://www.wescottdesign.com

On Feb 9, 9:14*pm, " wrote:
Looking to buy a 3395 AM filter as used in early tube Heathkit
receivers..any other suggestions on receiving AM with homebuilt filter
system? *TNX 73 *Harold Followup: I am looking for a 3395 KHZ. AM Filter for a Heathkit SB301 .The AM filter was offered as an Option . The SB 301 will not receive AM without the optional filter....It has AM detector and everything but the filter..I thought someone might have worked out a substitute for the Heath filter..like a high Q tuned IF can or whatever... TNX Harold

On Tue, 10 Feb 2009, Tim Wescott wrote:

I believe there was a regular brand rig (Kenwood?) of about that era that
also used the same mixing scheme, and had the same frequency fixed IF, if
not all the same matching impedances. I can't really recall, though,
other than I was thumbing through a replacement filter catalog and
noticed it because I had the SB-201.

That sounds familiar, though I can't remember which brand it was either.

I just did some searching, and I was thrown off by the mention of "early"
in the first post.

I was thinking of the Heathkit Commanche as a small receiver suitable
for mobile operation, and it was used in tandem with the am Cheyenne
transmitter. A check shows that receiver used a 3MHz IF. The Mohawk,
which was a full blown receiver, used 1682KHz and then down to 50KHz,
obviously not a standard combination in Heathkit receivers. The HR-20
Mobile SSB receiver used a 3MHz IF too. A quick search doesn't turn
up what IF's the matching SSB transmitters were using, but I assume
they too were 3MHz.

So then Heathkit moved to 3395KHz, and that was pretty standard for
a really long time. I think even the HW series of monoband SSB
transceivers used the same frequency, though they used multiple
crystals rather than prebuilt crystal filter.

It's all relative, but I think of "early" as the pre-SB line, not
the SB line itself. Heath kept the SB line going into the seventies,
with cosmetic changes but the same basic design.

Michael VE2BVW

Tim Wescott wrote:


I believe there was a regular brand rig (Kenwood?) of about that era that
also used the same mixing scheme, and had the same frequency fixed IF, if
not all the same matching impedances. I can't really recall, though,
other than I was thumbing through a replacement filter catalog and
noticed it because I had the SB-201.

My fuzzy recollection says that 3395 shouldn't be difficult to find. A
check of completed auctions on ebay didn't bear that out. I suppose it
depends on how big of a hurry you're in

-Bill