Heterodyne conversion crystals
 

I am looking for some Heterodyne conversion crystals for a receiver I am
making.
The frequencies a 5 MHz, 7 MHz, 10.5 MHz, 13.5 MHz, 17.5 MHz and 21.5
MHz.
The variable mixing frequency will be from 3 to 3.5 MHz. I would prefer all
the same type holder.


TNX de Gary, KF9CM

Heterodyne conversion crystals
 

Hey Gary,

Rocks aren't cheap he http://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.
I recall grinding some of these to get them into the novice band back
40 yrs ago.
And putting a pencil mark on the quartz to get them to go down in
frequency.
FT243 style can be found here maybe still: http://www.af4k.com/crystals.htm


73 OM

n8zu

On Sep 2, 4:12 pm, Gary@ removenospamandputkf9cm.com wrote:
I am looking for some Heterodyne conversion crystals for a receiver I am
making.
The frequencies a 5 MHz, 7 MHz, 10.5 MHz, 13.5 MHz, 17.5 MHz and 21.5
MHz.
The variable mixing frequency will be from 3 to 3.5 MHz. I would prefer all
the same type holder.

TNX de Gary, KF9CM

Heterodyne conversion crystals
 

On 2 Sep, 21:12, Gary@ removenospamandputkf9cm.com wrote:
I am looking for some Heterodyne conversion crystals for a receiver I am
making.
The frequencies a 5 MHz, 7 MHz, 10.5 MHz, 13.5 MHz, *17.5 MHz and 21..5
MHz.
The variable mixing frequency will be from 3 to 3.5 MHz. I would prefer all
the same type holder.

TNX de Gary, KF9CM

The Si570 will generate those frequencies, apart from the 5 MHz.

Leon

Heterodyne conversion crystals
 

On Wed, 3 Sep 2008, raypsi wrote:

Hey Gary,

Rocks aren't cheap he http://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.

And you can't grind them unless they are quite close to the desired
frequency. Grinding by hand will be too uneven, so the crystal will
stop working if you try to grind it more than a tiny bit.

It also relies on a big stock of crystals spread around so you can
find one sufficiently close enough, something that did seem possible
in the years after WWII, but after all this time attrition may have
reduced the stock considerably.

And realistically, they also have to be bulky FT-243 holders, since
those you can open by removing screws, and the blank is held in place
with pressure. More recent holder types require desoldering the case,
and figuring out how to remove the blank and then get it back in place
when it's soldered in place (or something like that I can't remember how
the blank is connected).

One of the odd things is that if one has to buy new crystals, a
synthesizer will likely be far cheaper. In the early seventies,
synthesizers made a big splash because everyone wanted lots of channels
on 2m FM, and the need to have them ground to frequency (and to equipment)
made it all very costly, so synthesizers despite their cost and bulk
became the norm.

Almost forty years later, a synthesizer for a handful of crystals would
still be comparatively bulky, but would be even cheaper than in the early
seventies.

Michael VE2BVW

Heterodyne conversion crystals
 

On Wed, 3 Sep 2008, Leon wrote:

On 2 Sep, 21:12, Gary@ removenospamandputkf9cm.com wrote:
I am looking for some Heterodyne conversion crystals for a receiver I am
making.
The frequencies a 5 MHz, 7 MHz, 10.5 MHz, 13.5 MHz, *17.5 MHz and 21.5
MHz.
The variable mixing frequency will be from 3 to 3.5 MHz. I would prefer all
the same type holder.

TNX de Gary, KF9CM

The Si570 will generate those frequencies, apart from the 5 MHz.

Leon


Of course, 5MHz is the one in the bunch that is bound to be easy
to get (and if it's not, 10MHz makes it almost as easy) and
would provide the clock for the synthezier if it needs an external
one.

Michael VE2BVW

Heterodyne conversion crystals
 

On Wed, 3 Sep 2008 14:54:17 -0400, Michael Black wrote:

On Wed, 3 Sep 2008, raypsi wrote:

Hey Gary,

Rocks aren't cheap he http://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.

And you can't grind them unless they are quite close to the desired
frequency. Grinding by hand will be too uneven, so the crystal will
stop working if you try to grind it more than a tiny bit.

My personal experience is an FT-243 crystal's frequency can be
increased by several hundred kilohertz through grinding. A more
abrasive media is needed for the slurry than scouring powder can
provide. Permatex 34A valve grinding compound works FB. Most of my 80M
rocks (26 between 3.5 & 3.6 MHz) were originally cut for 3237 kHz.
Many of my 40M crystals were moved several hundred kHz as well.

The key to grinding is not to try doing too much at once. Let the
abrasive do the cutting, no downward pressure is need from the
fingers..

It also relies on a big stock of crystals spread around so you can
find one sufficiently close enough, something that did seem possible
in the years after WWII, but after all this time attrition may have
reduced the stock considerably.

There are still a lot of them out there and they can be most
inexpensive if the actual frequency isn't too important.

73 de n4jvp

Heterodyne conversion crystals
 

In message , Registered User
writes
On Wed, 3 Sep 2008 14:54:17 -0400, Michael Black wrote:

On Wed, 3 Sep 2008, raypsi wrote:

Hey Gary,

Rocks aren't cheap he http://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.

And you can't grind them unless they are quite close to the desired
frequency. Grinding by hand will be too uneven, so the crystal will
stop working if you try to grind it more than a tiny bit.

My personal experience is an FT-243 crystal's frequency can be
increased by several hundred kilohertz through grinding. A more
abrasive media is needed for the slurry than scouring powder can
provide. Permatex 34A valve grinding compound works FB. Most of my 80M
rocks (26 between 3.5 & 3.6 MHz) were originally cut for 3237 kHz.
Many of my 40M crystals were moved several hundred kHz as well.

The key to grinding is not to try doing too much at once. Let the
abrasive do the cutting, no downward pressure is need from the
fingers..

It also relies on a big stock of crystals spread around so you can
find one sufficiently close enough, something that did seem possible
in the years after WWII, but after all this time attrition may have
reduced the stock considerably.

There are still a lot of them out there and they can be most
inexpensive if the actual frequency isn't too important.

73 de n4jvp

All this discussion about crystal grinding is very interesting. From my
far distant experiences, it is indeed a work of art and, more often, an
act of God. If the OP goes down that route, he may never actually get
his receiver built!

Looking at the websites of various manufacturers/suppliers (Google on
"crystal+frequency" and similar), it looks like you should be able to
get custom-made crystals in the required frequency range for less than
$20 each. I'm sure that at least the 5MHz will be available
off-the-shelf for less than $5 so we're talking maybe $100 for the six
crystals.

The alternative is, as has been suggested, a frequency synthesizer.
There are countless circuits available, but care should be taken to use
one where the spectral purity of the output signal is adequate for use
in a communications receiver. In particular, the phase noise has to be
low. One approach would to be look for a kit with a good spec (and
obviously something as simple as possible). A Google on
"frequency+synthesizer+kit" and similar brings up lots of information.
--
Ian

Heterodyne conversion crystals
 

On Thu, 4 Sep 2008, Ian Jackson wrote:

In message , Registered User
writes
On Wed, 3 Sep 2008 14:54:17 -0400, Michael Black wrote:

On Wed, 3 Sep 2008, raypsi wrote:

Hey Gary,

Rocks aren't cheap he http://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.

And you can't grind them unless they are quite close to the desired
frequency. Grinding by hand will be too uneven, so the crystal will
stop working if you try to grind it more than a tiny bit.

My personal experience is an FT-243 crystal's frequency can be
increased by several hundred kilohertz through grinding. A more
abrasive media is needed for the slurry than scouring powder can
provide. Permatex 34A valve grinding compound works FB. Most of my 80M
rocks (26 between 3.5 & 3.6 MHz) were originally cut for 3237 kHz.
Many of my 40M crystals were moved several hundred kHz as well.

The key to grinding is not to try doing too much at once. Let the
abrasive do the cutting, no downward pressure is need from the
fingers..

It also relies on a big stock of crystals spread around so you can
find one sufficiently close enough, something that did seem possible
in the years after WWII, but after all this time attrition may have
reduced the stock considerably.

There are still a lot of them out there and they can be most
inexpensive if the actual frequency isn't too important.

73 de n4jvp

All this discussion about crystal grinding is very interesting. From my far
distant experiences, it is indeed a work of art and, more often, an act of
God. If the OP goes down that route, he may never actually get his receiver
built!

Looking at the websites of various manufacturers/suppliers (Google on
"crystal+frequency" and similar), it looks like you should be able to get
custom-made crystals in the required frequency range for less than $20 each.
I'm sure that at least the 5MHz will be available off-the-shelf for less than
$5 so we're talking maybe $100 for the six crystals.

The alternative is, as has been suggested, a frequency synthesizer. There are
countless circuits available, but care should be taken to use one where the
spectral purity of the output signal is adequate for use in a communications
receiver. In particular, the phase noise has to be low. One approach would to
be look for a kit with a good spec (and obviously something as simple as
possible). A Google on "frequency+synthesizer+kit" and similar brings up lots
of information.

A hundred dollars can be quite a bit, likely the rest of the parts aren't
that much (unless someone is buying all new parts).

The thing about a synthesizer is that the original poster only needs
well spaced frequencies, so the reference frequency can be 500KHz, which
allows for much easier filtering than narrower channels (or, the early
synthesizers in the seventies that replaced 8MHz crystals in 2M FM rigs,
not only did they have to deal with close together channel spacing
of 10 or 15KHz, but since the synthesizer output would be multiplied
up by the transmitter, the reference frequency was the channel spacing
divided by how much the transmitter multiplied, which gave a terribly
low reference frequency.

Plus, these are for changing bands, not tuning a given band. A second
or so of lockup time isn't a problem since changing bands won't happen
often. So the filtering can be better without impacting on tuning. A
main tuning synthesizer with 1KHz steps starts out more complicated
because it's 1KHz steps, but then it has to change frequency rapidly,
which makes it even more trouble to design well.

Michael VE2BVW

Heterodyne conversion crystals
 

What ever happened to that neat list of surplus crystals that JAN
in Fort Myers used to offer? Those were the good old days.

A few of those crystals are available on the Surplus Sales of
Nebraska website. I find two rocks I needed (1.515 kHz for
2nd conversion from 1.6 MHz to 85 kHz) there after searching
for several weeks.

Pete

Heterodyne conversion crystals
 

"Tio Pedro" wrote in message .

I find two rocks I needed

I found two rocks...( Edit..) :)

Heterodyne conversion crystals
 

On Sep 3, 2:54*pm, Michael Black wrote:
On Wed, 3 Sep 2008, raypsi wrote:
Hey Gary,

Rocks aren't cheap hehttp://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.

And you can't grind them unless they are quite close to the desired
frequency. *Grinding by hand will be too uneven, so the crystal will
stop working if you try to grind it more than a tiny bit.

It also relies on a big stock of crystals spread around so you can
find one sufficiently close enough, something that did seem possible
in the years after WWII, but after all this time attrition may have
reduced the stock considerably.

And realistically, they also have to be bulky FT-243 holders, since
those you can open by removing screws, and the blank is held in place
with pressure. *More recent holder types require desoldering the case,
and figuring out how to remove the blank and then get it back in place
when it's soldered in place (or something like that I can't remember how
the blank is connected).

One of the odd things is that if one has to buy new crystals, a
synthesizer will likely be far cheaper. *In the early seventies,
synthesizers made a big splash because everyone wanted lots of channels
on 2m FM, and the need to have them ground to frequency (and to equipment)
made it all very costly, so synthesizers despite their cost and bulk
became the norm.

Almost forty years later, a synthesizer for a handful of crystals would
still be comparatively bulky, but would be even cheaper than in the early
seventies.

* * Michael *VE2BVW

Believe it or not I was making a living sell rocks HI HI back forty
years ago.
It was like there was a freaking crystal company on every corner.
There was so
much competition back then the prices was chump change. The crystal
companies
could have put the big hurt on PLL or programmable dividers. I know
the real
reason crystals took a back seat, and it;s not what anybody thinks
happened.

73 OM

n8zu

Heterodyne conversion crystals
 

Believe it or not I was making a living sell rocks HI HI back forty
years ago.
It was like there was a freaking crystal company on every corner.
There was so
much competition back then the prices was chump change. The crystal
companies
could have put the big hurt on PLL or programmable dividers. I know
the real
reason crystals took a back seat, and it;s not what anybody thinks
happened.

73 OM

n8zu

It would be my guess to do away with technicians that tune up radios and fix
things.

Heterodyne conversion crystals
 

"JB" wrote in message
news:g_bwk.563$1a2.176@trnddc04...
The crystal
companies
could have put the big hurt on PLL or programmable dividers. I know
the real
reason crystals took a back seat, and it;s not what anybody thinks
happened.

73 OM

n8zu

It would be my guess to do away with technicians that tune up radios and
fix
things.


I've been racking my brain trying to figure out a reason.
But, I think you hit the nail on the head. It fits right in
with the obsolescence of the FCC 1st and 2nd Class
Radiotelephone tickets.

Pete

Heterodyne conversion crystals
 

"Ralph Mowery" wrote in message
m...

"Tio Pedro" wrote in message
...

I've been racking my brain trying to figure out a reason.
But, I think you hit the nail on the head. It fits right in
with the obsolescence of the FCC 1st and 2nd Class
Radiotelephone tickets.

Pete

They may as well have done away with the FCC tickets. I passed the 1st
class test at 22 years of age in 1972 on the first try for the ticket. I
had never seen a TV transmitter, but had the ticket to work on them.
Maybe
years ago it was differant and a harder test.
Thought I wanted to get into the 2 way repair business, but never did.
When
I took the test it was only one dollar more for the first class, so took
it
and passed
Most of the tests are made so any idiot can pass them.


*Mamas don't let your babies grow up to be radio techs.*

I did the Advanced Ham ticket, then 2nd phone when I was 17 and got sucked
into MNSO immediately.

Nobody cares about the FCC tickets but the Gov't. The private industry
actually holds it against you because you have rules and they don't.
And I'm worn out from always being threatened by people with guns and billy
clubs who's first instinct is to smash something if it seems uncooperative.
Then there's the hams "bless their hearts" who put me out of business by
doing free work. Retirement is sweet but I'm dirt poor.

Heterodyne conversion crystals
 

"Tio Pedro" wrote in message
...

I've been racking my brain trying to figure out a reason.
But, I think you hit the nail on the head. It fits right in
with the obsolescence of the FCC 1st and 2nd Class
Radiotelephone tickets.

Pete

They may as well have done away with the FCC tickets. I passed the 1st
class test at 22 years of age in 1972 on the first try for the ticket. I
had never seen a TV transmitter, but had the ticket to work on them. Maybe
years ago it was differant and a harder test.
Thought I wanted to get into the 2 way repair business, but never did. When
I took the test it was only one dollar more for the first class, so took it
and passed.
Most of the tests are made so any idiot can pass them.

Heterodyne conversion crystals
 

"Ralph Mowery" wrote in message
...

"JB" wrote in message
news:_6wwk.729$393.65@trnddc05...

"Ralph Mowery" wrote in message
m...

"Tio Pedro" wrote in message
...

Nobody cares about the FCC tickets but the Gov't. The private industry
actually holds it against you because you have rules and they don't.
And I'm worn out from always being threatened by people with guns and
billy
clubs who's first instinct is to smash something if it seems
uncooperative.
Then there's the hams "bless their hearts" who put me out of business by
doing free work. Retirement is sweet but I'm dirt poor.


That is why I did not go into the radio business. Friend told me of a job
opening. I was making about $ 2 an hour more at the time and had a good
retirement package.
The job I was doing did not require any special license or anything.
Working for a large company as an electrician/instrument technician.
Did not have to have an electrical license as large companies don't
require it and neither does the government.


I got my FCC 1st in high school after working tobacco for one
summer. The remainder of my summer vacations were spent
tending AM/FM/TV transmitter sites as summer replacement.
Paid was good for a kid, and I didn't get dirty :) One of my first
interim "career" jobs was a field tech for RCA/Univac mainframe
systems. I'm not sure which career (broadcasting or mainframe
computer) careers faded into oblivion first. Both are rght up
there with coal delivery techicians and icemen.

Pete

Heterodyne conversion crystals
 

Tio Pedro wrote:
One of my first
interim "career" jobs was a field tech for RCA/Univac mainframe
systems. I'm not sure which career (broadcasting or mainframe
computer) careers faded into oblivion first. Both are rght up
there with coal delivery techicians and icemen.

Pete



Damn! I just got my degree in coal delivery. I guess I always am a day
late and a dollar short! ;) Guess I'll have to keep my day job (radio
tech...VHF up through 7 GHz)

Scott
N0EDV

Heterodyne conversion crystals
 

"JB" wrote in message
news:_6wwk.729$393.65@trnddc05...

"Ralph Mowery" wrote in message
m...

"Tio Pedro" wrote in message
...

Nobody cares about the FCC tickets but the Gov't. The private industry
actually holds it against you because you have rules and they don't.
And I'm worn out from always being threatened by people with guns and
billy
clubs who's first instinct is to smash something if it seems
uncooperative.
Then there's the hams "bless their hearts" who put me out of business by
doing free work. Retirement is sweet but I'm dirt poor.


That is why I did not go into the radio business. Friend told me of a job
opening. I was making about $ 2 an hour more at the time and had a good
retirement package.
The job I was doing did not require any special license or anything.
Working for a large company as an electrician/instrument technician.
Did not have to have an electrical license as large companies don't require
it and neither does the government.

Heterodyne conversion crystals
 

JB wrote:
snip
Then there's the hams "bless their hearts" who put me out of business by
doing free work. Retirement is sweet but I'm dirt poor.
============================================
Hams are radio AMATEURS so it is logical that they do work for free,
since they are involved in a hobby.

Frank GM0CSZ / KN6WH

Heterodyne conversion crystals
 

"Highland Ham" wrote in message
...
JB wrote:
snip
Then there's the hams "bless their hearts" who put me out of business by
doing free work. Retirement is sweet but I'm dirt poor.
============================================
Hams are radio AMATEURS so it is logical that they do work for free,
since they are involved in a hobby.

Frank GM0CSZ / KN6WH

That's why they have to learn to seperate their hobby from the pecuniary
interests of others. So they don't become a target for commercial
interests.

If some one or group should be buying or renting radios or systems because
their entity has regular need for radio dispatch or communications of a
non-hobby nature, they should seek professional help while it exists rather
than exploiting the ham.

Of course if we all join the Communist Party and the government volunteers
to provide us with free food, housing, clothing, medical and other basic
subsistence needs, we should do whatever they want after we finish our
compulsory rice picking for the day.

Heterodyne conversion crystals
 

"JB" wrote in message news:g5Dwk.762

That's why they have to learn to seperate their hobby from the pecuniary
interests of others. So they don't become a target for commercial
interests.

If some one or group should be buying or renting radios or systems because
their entity has regular need for radio dispatch or communications of a
non-hobby nature, they should seek professional help while it exists
rather
than exploiting the ham.

Of course if we all join the Communist Party and the government volunteers
to provide us with free food, housing, clothing, medical and other basic
subsistence needs, we should do whatever they want after we finish our
compulsory rice picking for the day.


It was the same in broadcasting. There was always a person
willing to DJ for free, just for the fun of it, at the smaller
stations. Folks who were trying to make a meager living
behind the mikes were at the mercy of hobbyists.

Heterodyne conversion crystals
 

On Sep 4, 9:11 pm, raypsi wrote:
On Sep 3, 2:54 pm, Michael Black wrote:



On Wed, 3 Sep 2008, raypsi wrote:
Hey Gary,

Rocks aren't cheap hehttp://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.

And you can't grind them unless they are quite close to the desired
frequency. Grinding by hand will be too uneven, so the crystal will
stop working if you try to grind it more than a tiny bit.

It also relies on a big stock of crystals spread around so you can
find one sufficiently close enough, something that did seem possible
in the years after WWII, but after all this time attrition may have
reduced the stock considerably.

And realistically, they also have to be bulky FT-243 holders, since
those you can open by removing screws, and the blank is held in place
with pressure. More recent holder types require desoldering the case,
and figuring out how to remove the blank and then get it back in place
when it's soldered in place (or something like that I can't remember how
the blank is connected).

One of the odd things is that if one has to buy new crystals, a
synthesizer will likely be far cheaper. In the early seventies,
synthesizers made a big splash because everyone wanted lots of channels
on 2m FM, and the need to have them ground to frequency (and to equipment)
made it all very costly, so synthesizers despite their cost and bulk
became the norm.

Almost forty years later, a synthesizer for a handful of crystals would
still be comparatively bulky, but would be even cheaper than in the early
seventies.

Michael VE2BVW

Believe it or not I was making a living sell rocks HI HI back forty
years ago.
It was like there was a freaking crystal company on every corner.
There was so
much competition back then the prices was chump change. The crystal
companies
could have put the big hurt on PLL or programmable dividers. I know
the real
reason crystals took a back seat, and it;s not what anybody thinks
happened.

73 OM

n8zu

You don't see any newbies on here making any rock controlled hets..
It's like vinyl records or CD's
they is all gone. They don't want you to know about crystals there is
to much
power in that knowledge. They want everyone dumbed down so they can be
controlled,
that's why they did away with code, nobody will ever know it ever
existed in 5 years time.

73
n8zu

Heterodyne conversion crystals
 

On Sep 2, 4:12�pm, Gary@ removenospamandputkf9cm.com wrote:
I am looking for some Heterodyne conversion crystals for a receiver I am
making.
The frequencies a 5 MHz, 7 MHz, 10.5 MHz, 13.5 MHz, �17.5 MHz and 21.5
MHz.
The variable mixing frequency will be from 3 to 3.5 MHz. I would prefer all
the same type holder.

Once source of crystals is eBay. Another is AF4K (google his call), he
has quite a stock in various holders.

But be prepared to pay more than a few dollars per crystal!

Actually, when you adjust for inflation, crystals cost about as much
now as they did 30-40 years ago. Three dollars back in 1965 is the
equivalent of about twenty dollars today.

You can also do things like use harmonics and overtones of the
crystals to get the higher frequencies.

--

But before you start building, I suggest you reconsider that mixing
scheme.

As I understand it, the receiver will consist of a tunable section
that covers 3 to 3.5 MHz, and a converter section which converts the
various ham bands to that tuning range.

So for 160, you would take the 2 to 1.5 MHz range, subtract it from 5
MHz, and get 3 to 3.5 MHz

For 80, you would take the 4 to 3.5 MHz range, subtract it from 7
MHz, and get 3 to 3.5 MHz

For 40, you would take the 7.5 to 7 MHz range, subtract it from 10.5
MHz, and get 3 to 3.5 MHz

For 30, you would take the 10.5 to 10.0 MHz range, subtract it from
13.5 MHz, and get 3 to 3.5 MHz

For 20, you would take the 14.5 to 14 MHz range, subtract it from 17.5
MHz, and get 3 to 3.5 MHz

For 17, you would take the 18.5 to 18 MHz range, subtract it from 21.5
MHz, and get 3 to 3.5 MHz

I guess you don't plan on 15, 12 or 10 meters.

The main problem I see with this design is on 80 meters. On that band,
the tunable frequency is too close to the band being covered, and
you'll likely have troubles with feedthrough. For example, when you
are trying to listen to a signal on, say, 3.6 MHz, the tunable section
will be on 3.4 MHz, and the front-end selectivity probably won't be
able to stop strong signals from leaking through.

I suggest you look at other heterodyne schemes, because 80 meter
operation will be compromised using the scheme you describe.

Here's one to consider, from G2DAF:

Tunable range is 5 to 5.5 MHz

For 160, you would take the 2 to 1.5 MHz range, subtract it from 7
MHz, and get 5 to 5.5 MHz

For 80, you would take the 4 to 3.5 MHz range, subtract it from 9
MHz, and get 5 to 5.5 MHz

For 40, you would take the 7.5 to 7 MHz range, subtract it from 12.5
MHz, and get 5 to 5.5 MHz

For 30, you would take the 10.5 to 10.0 MHz range, subtract it from
15.5 MHz, and get 5 to 5.5 MHz

For 20, you would take the 14 to 14.5 MHz range, subtract 9 MHz from
it, and get 5 to 5.5 MHz (Note that the 9 MHz xtal works on two bands)

For 17, you would take the 18 to 18.5 MHz range, subtract 13 MHz from
it, and get 5 to 5.5 MHz

For 15, you would take the 21 to 21.5 MHz range, subtract 16 MHz from
it, and get 5 to 5.5 MHz

For 12, you would take the 24.5 to 25 MHz range, subtract 19.5 MHz
from it, and get 5 to 5.5 MHz

So you cover 8 ranges below 25 MHz with 7 xtals

Ten meters is left as an exercise for the reader.

For the higher frequencies, harmonics of the can be used. For example,
an 8 MHz xtal could be used for 15 meters by doubling.

Here's another one:

Tunable range is 3.5 to 4.1 MHz

For 160, you would take the 2 to 1.4 MHz range, subtract it from 5.5
MHz, and get 3.5 to 4.1 MHz

For 80, the conversion section is bypassed and you use the basic
tuning range

For 40, you would take the 7.5 to 6.9 MHz range, subtract it from 11
MHz, and get 3.5 to 4.1 MHz (Note that the second harmonic of the 5.5
MHz xtal used for 160 is 11 MHz)

For 30, you would take the 10.6 to 10.0 MHz range, subtract it from
14.1 MHz, and get 3.5 to 4.1 MHz

For 20, you would take the 14 to 14.6 MHz range, subtract 10.5 MHz
from it, and get 3.5 to 4.1 MHz

For 17, you would take the 17.6 to 18.2 MHz range, subtract 14.1 MHz
from it, and get 3.5 to 4.1 MHz (Note that the same xtal that gives
you 30 meters also works on 17 meters)

For 15, you would take the 21 to 21.6 MHz range, subtract 17.5 MHz
from it, and get 3.5 to 4.1 MHz

For 12, you would take the 24.5 to 25.1 MHz range, subtract 21 MHz
from it, and get 3.5 to 4.1 MHz (Note that the second harmonic of the
10.5 MHz xtal used for 20 is 21 MHz)

So you cover cover 8 ranges below 25.1 MHz with 6 xtals. If you use
harmonics of certain xtals, those 8 ranges can be covered with just 4
xtals.

Ten meters is left as an exercise for the reader.

There are lots of other schemes.

73 de Jim, N2EY

Heterodyne conversion crystals
 

The real reason for the popularity of synthesizers is cost. When you
need a new rock for every band they get costly, but a synthesizer
doesn't. This wasn't practical until chips that could do most of the
work became cheap.

The main reason for eliminating the commercial operator licenses was
cost too. Here's what happened:

There was a time, not so long ago, when there were a large number of
tasks that could only be performed (legally, anyway) by a person with
an FCC Commercial Operator license. No others need apply, regardless
of experience, education or background. Either you were a Radio
Operator of a certain class, or you weren't.

Those licenses meant that a person with a high-school education and
some smarts could have a good middle-class income if they had the
license. Not that all the jobs were easy, or that you didn't need a
certain amount of knowledge to do them, but that the Commercial
license became the equivalent of a union card, and the jobs were, in a
way, protected by FCC regulations.

In other words, the Commercial licenses protected a craft known as
Radio Operators, with a set of skills and knowledge specific to them,
and jobs only they could do.

The masters of industry didn't like that, so they prevailed on the FCC
to reduce the requirements and eliminate most of the licenses and the
requirements for tasks to be done only by Radio Operators. The jobs
went with them.

This is also why the maritime services went to satellite-based comms
rather than HF and MF radio and Morse Code - it eliminated the need
for ships to carry licensed Radio Operators.

Oddly enough, FCC still issues Commercial RadioTelegraph licenses,
both First and Second Class, though I don't know where in the USA you
can get the required experience for a First Class.

73 de Jim, N2EY

Heterodyne conversion crystals
 

On Sep 6, 7:38�pm, raypsi wrote:

They want everyone dumbed down so they can be
controlled,
that's why they did away with code, nobody will ever know it ever
existed in 5 years time.

They didn't do away with Morse Code. They did away with the test for
it. It was done a little at a time over the past 30 years.

My personal theory on why it was eliminated is this:

Since the early 1980s, the FCC has been required to do more and more
stuff with less and less resources. So they have constantly sought out
ways to reduce their workload, particularly for radio services that
don't bring in $$, like ham radio.

That's why they turned over the job of amateur license testing to the
QPC and VECs back in 1983 or so. Instead of paid FCC employees making
up and conducting amateur license tests, unpaid volunteers do almost
all the work. It's also why they doubled the license term to 10 years
about that same time - reduces the number of renewals by half.

Reducing the number of license classes reduces the number of tests and
the number of upgrade applications to process. In the old days when
there were six license classes, a ham who went from Novice or Tech to
Extra could upgrade as many as four times. Now there are only two
steps.

Eliminating the Morse Code test means one less license test. Less
work.

But even though the last remnants of the Morse Code test were removed
back in February 2007, there are still plenty of hams using it on the
air. This past Field Day, for example, the group I went with had one
Morse Code station and three voice stations, all similarly equipped.
There were three Morse Code operators and far more voice ops, yet the
Morse Code station made more QSOs than all the voice stations
combined. This wasn't a surprise, either.

73 de Jim, N2EY

Heterodyne conversion crystals
 

On Sep 6, 9:03*pm, wrote:
They didn't do away with Morse Code. They did away with the test
for
it. It was done a little at a time over the past 30 years.
hey jim:
Sorry I wasn't talking Morse code, .
Real Morse code nobody knows. That is lost already gone kaput history.
Vail invented the code you so aptly call Morse, So it's not real Morse
code
it's Vail code. What is really lost: everybody still calls it Morse
code.

I think I could make some money fire up the ole solar powered kiln and
start growing quartz.
I break out that old ARRL handbook that tells you exactly how to cut
the crystals
for the desired frequencies and sell them for 50 cent apiece.
I'd make so much money in volume sales.

73 OM
n8zu

Heterodyne conversion crystals
 

On Sep 6, 8:31*pm, wrote:
On Sep 2, 4:12 pm, Gary@ removenospamandputkf9cm.com wrote:

I am looking for some Heterodyne conversion crystals for a receiver I am
making.
The frequencies a 5 MHz, 7 MHz, 10.5 MHz, 13.5 MHz, 17.5 MHz and 21.5
MHz.
The variable mixing frequency will be from 3 to 3.5 MHz. I would prefer all
the same type holder.
.

73 de Jim, N2EY

What you ain't got no IF?
All those fine numbers and no IF
You know what the image frequency is with no IF?

I think he can get's 12 and 15 meters.
21.5+3.39=24.89 the bottom of the 12 meter band.
21.5+3.49=24.99 the top of the 12 meter band
17.5+3.5=21.0 the bottom of 15 meters for an extra
squeeze the tuning range to 3.95 and
17.5+3,95 =21.45 the top of the 15 meter band.

Back in the day the reason for Heterodyne was simple
to get a lower frequency at which you could amplify the signal
more readily getting you more SN ratio and selectivity.


73 OM

n8zu

Heterodyne conversion crystals
 

On Sun, 7 Sep 2008, raypsi wrote:

On Sep 6, 9:03*pm, wrote:
They didn't do away with Morse Code. They did away with the test
for
it. It was done a little at a time over the past 30 years.
hey jim:
Sorry I wasn't talking Morse code, .
Real Morse code nobody knows. That is lost already gone kaput history.
Vail invented the code you so aptly call Morse, So it's not real Morse
code
it's Vail code. What is really lost: everybody still calls it Morse
code.

I think I could make some money fire up the ole solar powered kiln and
start growing quartz.
I break out that old ARRL handbook that tells you exactly how to cut
the crystals
for the desired frequencies and sell them for 50 cent apiece.
I'd make so much money in volume sales.

Nobody has ground their crystals from scratch since about the 1930's,
if even then. I've been licensed since 1972 and in all the time since
then I've never seen anything about it, not in magazines and books
going back to the late 1940's and not in more recent material. I do
recall the 1964 article in QST about a buy in SOuth America who made
his own tubes.

Go back far enough, and hams just needed crystals within the band.
They had relatively little need for exact frequencies.

I suspect even if the Handbook did give such details at one time,
little bits may be lost since when something is current, "everyone
knows" things that may not be obvious to someone who comes later.

Now, they need them on exact frequencies, and they want them in
nice small packages, none of those FT-243 ones that were held together
with pressure.

Even if you can so easily grind a piece of quartz to frequency, packaging
them will be problematic, since a sealed metal case is going to be a lot
more trouble than an FT-243 package.


Michael VE2BVW

Heterodyne conversion crystals
 

"Michael Black" wrote in message
ample.org...
On Sun, 7 Sep 2008, raypsi wrote:

On Go back far enough, and hams just needed crystals within the band.
They had relatively little need for exact frequencies.

And Novice regulations required the use of Xtal control, a ready
market...

I suspect even if the Handbook did give such details at one time,
little bits may be lost since when something is current, "everyone
knows" things that may not be obvious to someone who comes later.

Tools, techiques, sources for raw or processed materials. WWII
end provided what seemed to be an endless supply of radio
related parts and equipment. Tons of FT-243 xtals, ready to
use or to regrind, etc. I remember when one could find surplus
455kc xtals to make SSB filters; they are unobtanium now.

Pete, k1zjh

Michael VE2BVW

Heterodyne conversion crystals
 

On Sep 7, 2:43�pm, Michael Black wrote:

Nobody has ground their crystals from scratch
since about the 1930's,
if even then. �I've been licensed since 1972 and in all the time
since
then I've never seen anything about it, not in magazines and books
going back to the late 1940's and not in more recent material.

There were articles in QST in the 1920s about cutting and grinding
your own crystals from the raw quartz, making holders, etc. A lot of
work and specialized equipment. The market was such that the
specialists quickly took over in the early 1930s.

After WW2 the enormous amount of surplus dominated the amateur market
for decades. Many of the "new" FT-243 crystals we bought were actually
surplus holders with new crystal inside.

�I do
recall the 1964 article in QST about a buy in SOuth America who
made his own tubes.

There's a guy in France doing it today. Has a movie on his website.
But again, lots of work and specialized equipment.

Go back far enough, and hams just needed crystals within
the band.
They had relatively little need for exact frequencies.

Well, yes and no.

Some xtal frequencies were more prized than others, because the
harmonics fell in higher bands.

I suspect even if the Handbook did give such details at one time,
little bits may be lost since when something is current, "everyone
knows" things that may not be obvious to someone who comes
later.

That's true of many things. Reading older radio books and magazines
can require knowledge of a lot of the jargon and methods of the day.

Now, they need them on exact frequencies, and they want them in
nice small packages, none of those FT-243 ones that were held
together with pressure.

The big difference is plated electrodes vs. pressure electrodes.
FT-243s are capable of quite good accuracy; .005% was common, which
works out to 200 Hz at 4 MHz.

Pre-WW2 xtals were big and rugged, but used a lot of quartz. Radio-
grade natural quartz came almost exclusively from Brazil, and the
difficulty of supply caused US xtal makers to develop xtal designs
that used less quartz. The FT-243 was ultra-miniature in its time!

73 de Jim, N2EY

Heterodyne conversion crystals
 

On Sep 7, 8:46*pm, wrote:
On Sep 7, 2:43 pm, Michael Black wrote:



Nobody has ground their crystals from scratch
since about the 1930's,
if even then. I've been licensed since 1972 and in all the time
since
then I've never seen anything about it, not in magazines and books
going back to the late 1940's and not in more recent material.

There were articles in QST in the 1920s about cutting and grinding
your own crystals from the raw quartz, making holders, etc. A lot of
work and specialized equipment. The market was such that the
specialists quickly took over in the early 1930s.

After WW2 the enormous amount of surplus dominated the amateur market
for decades. Many of the "new" FT-243 crystals we bought were actually
surplus holders with new crystal inside.

I do
recall the 1964 article in QST about a buy in SOuth America who
made his own tubes.

There's a guy in France doing it today. Has a movie on his website.
But again, lots of work and specialized equipment.

Go back far enough, and hams just needed crystals within
the band.
They had relatively little need for exact frequencies.

Well, yes and no.

Some xtal frequencies were more prized than others, because the
harmonics fell in higher bands.

I suspect even if the Handbook did give such details at one time,
little bits may be lost since when something is current, "everyone
knows" things that may not be obvious to someone who comes
later.

That's true of many things. Reading older radio books and magazines
can require knowledge of a lot of the jargon and methods of the day.



Now, they need them on exact frequencies, and they want them in
nice small packages, none of those FT-243 ones that were held
together with pressure.

The big difference is plated electrodes vs. pressure electrodes.
FT-243s are capable of quite good accuracy; .005% was common, which
works out to 200 Hz at 4 MHz.

Pre-WW2 xtals were big and rugged, but used a lot of quartz. Radio-
grade natural quartz came almost exclusively from Brazil, and the
difficulty of supply caused US xtal makers to develop xtal designs
that used less quartz. The FT-243 was ultra-miniature in its time!

73 de Jim, N2EY

Absolutely jim

Looky at the January 1934 issue of QST.it's all there.
A yl friend of mine told me bigger is better, I know she's right
even when it comes to crystals.

As far as accuracy goes you know you can pull it to the frequency you
want
if your'e close enough, it's the oven you need to keep em on
frequency.

73 OM
n8zu

Heterodyne conversion crystals
 

Heterodyne conversion crystals
 

On Sep 8, 1:33�am, AJ Lake wrote:
wrote:
My personal theory on why it [code test] was eliminated is this:
Since the early 1980s, the FCC has been required to do more and more
stuff with less and less resources. So they have constantly sought out
ways to reduce their workload, particularly for radio services that
don't bring in $$, like ham radio.

And another theory is that the code mode is simply obsolete so why test
for it. No more horse driving government tests either. Course
for people who like it, they can still work CW and drive horses.

That theory doesn't hold water because Morse Code isn't obsolete on
the HF/MF ham bands. You hear a lot more hams using Morse Code on
those bands than you see people riding or driving horses.

A much more reasonable theory would be that most states do not test a
driver's ability to operate a manual transmission.

But even though the last remnants of the Morse Code test were removed
back in February 2007, there are still plenty of hams using it on the
air.

Yea, but there's less and less each year as the old guys die off.

That doesn't seem to be happening. Groups such as FISTS and SKCC have
increasing numbers of members. Participation in contests using Morse
Code isn't declining increasing even with terrible sunspot numbers.
Look at the results of the ARRL 160 meter contest for the past several
years - and it's all-CW.

I know
you work CW so you know that the vast majority of your CW QSOs are with
people in their 60's and over.

No, they're not. Sure there are lots of hams who are senior citizens
but there are also a lot who aren't - and who use Morse Code on the
air.

Plus the whole US population is getting older. People are living
longer and having fewer kids, for one thing. The median age for US
residents back in 2000 was 39 years and some months (according to the
Census Bureau). And it keeps increasing.

One foot in the proverbial grave.

How old are *yiu*? I'm 54, been a ham 41 years.

What led me to my theory is that the FCC didn't just drop the Morse
Code tests, they simplified and reduced all the testing as well as the
administrative procedures. For almost 30 years, every change was in
the direction of making less work for FCC, to save resources.

This past Field Day, for example, the group I went with had one
Morse Code station and three voice stations, all similarly equipped.
There were three Morse Code operators and far more voice ops, yet the
Morse Code station made more QSOs than all the voice stations
combined. This wasn't a surprise, either.

You don't really call those guys with the computers and keyboards
who ruin the CW bands on contest weekends CW ops do you ???

Why not? All the computer does is keep the log and maybe call CQ. The
'phone stations had the same computer logging system, all networked to
a central server. Yet the CW ops outdid them easily.

As for "ruining the CW bands" - the only "CW bands" in Part 97 are the
bottom 100 kHz of 6 and 2 meters. All the other bands where CW is
allowed share the space with other modes, such as RTTY and PSK31.

It's just beautiful when the bands are full of hams making QSOs. Not
"ruined" at all.

73 de Jim, N2EY

Heterodyne conversion crystals
 

Heterodyne conversion crystals
 

"AJ Lake" wrote in message
...
wrote:

That theory doesn't hold water because Morse Code isn't obsolete on
the HF/MF ham bands.

The code may be fun to use as a *hobby* but it is obsolete
as in the dictionary definition: to become disused, old fashioned,
and no longer up to date.

The FCC (and the rest of the world) just recognized that
requiring people to become human modems to
get a ham license didn't make sense. Maybe it did in WW2
when a pool of human CW ops was needed, but certainly not now.

Groups such as FISTS and SKCC have
increasing numbers of members.

You won't win this one on the numbers. Do you really
think the number of active CW ops today compares
with the numbers there were in the 50s?

Participation in contests using Morse Code isn't declining...

No unfortunately contests are just as bad as ever.

the only "CW bands" in Part 97 are the
bottom 100 kHz of 6 and 2 meters.

Playing word cop is not your style, sorry to see you do it. The
'CW bands' are common ham jargon not lawyer speak. Just as
using the term CW when you mean the code mode.


You'd think that now that no one is being forced, it shouldn't be an issue.
Maybe the real problem all along was people who really have a problem with
other people's hobbies. You people really need to quit bashing each other's
hobby. What you screw around and loose for someone else, you lose too.
Obsolete is a favorite word of the salesman that wants to con you out of
what you have, to sell you something else. For better or worse. So don't
buy into it. You need to understand that the FCC really doesn't want to be
bothered with Ham Radio at all. That's been motivating nearly everything
they have done since the 70's. But, Ok a bunch of whiners screamed and
cried and held their breath and now even the Extra Class is code free.
Doesn't make much sense because all you get is some CW subbands anyway.

All the Anti-CW arguments could easily be used against Ham Radio in general.
I don't even want to hear obsolete. I still have a manual typewriter to
fill out odd forms and in case power goes out. I still have a VCR because
there are movies that I don't see on DVD yet. I even use CW on VHF and
above to make contacts that can't seem to be done any other way. People
scream about Digital! Digital! OK WHICH DIGITAL do you use. There are more
than a dozen modes out there, so how are you going to make the contact that
is gone in 60 seconds because of propagation? Let me know when you have a
free software package that instantly decodes ANY MODE and doesn't even
require a computer or extra hardware, is operable across all bands and digs
weak signals better than CW, then CW will be obsolete. The fact that CW is
allowed EVERYWHERE and can be received by any SSB RCVR make it a universal
mode of communications. It is also the most useful means of station
identification. Don't tell me it's obsolete if you don't know anything
about it.

There is a rail system in India that was set up in the 20's and is still in
use because it works so well for what they use it for. They would screw up
a good thing to try to replace it with anything more complex.

Heterodyne conversion crystals
 

raypsi wrote:
Hey Gary,

Rocks aren't cheap he http://www.icmfg.com/thruhole_crystals.html
Maybe in 9 land they pave the streets with gold.
Personally I'd go with a programmable divider or PLL.

Maybe you like retro, then I'd get some old rocks the ones
you can take apart and grind them down to git's the freq's you need.
I recall grinding some of these to get them into the novice band back
40 yrs ago.
And putting a pencil mark on the quartz to get them to go down in
frequency.
FT243 style can be found here maybe still: http://www.af4k.com/crystals.htm


73 OM

n8zu

On Sep 2, 4:12 pm, Gary@ removenospamandputkf9cm.com wrote:
I am looking for some Heterodyne conversion crystals for a receiver I am
making.
The frequencies a 5 MHz, 7 MHz, 10.5 MHz, 13.5 MHz, 17.5 MHz and 21.5
MHz.
The variable mixing frequency will be from 3 to 3.5 MHz. I would prefer all
the same type holder.

TNX de Gary, KF9CM

You can use the same grinding powder that ATM's (amateur Telescope
makers) use to grind mirrors for grinding crystals. You want the fine
stuff #400 or finer. www.gotgrit.com has this stuff cheap.
Grind the crystal against a piece of scrap plate glass. I've had mixed
results, I've moved a few rocks a few hundred khz and I've also killed
some trying to move them just a few hundred hz.

Only grind ONE side of the rock, put a pencil mark on the other so you
don't mix this up. Wash the crystal well after each grinding session
and only handle it by the edges, you don't want your finger sweat or
oils getting on the crystal. Grinding motion should be a figure 8, use
light pressure and don't push down on the middle of the crystal, handle
by the edges while grinding.

If you do kill the crystal, you might be able to get it to start again
by light grinding using a different motion. Also try holding the
crystal vertical and grind the edges slightly. Measure the thickness
(carefully!) with a micrometer all around. If you ground a 'wedge'
shape into the rock this will also kill and and the cure is to regrind
putting more pressure on the fatter end.

I have quite a few useless FT243 rocks in the junk box, one of these
days I'll probably try moving a few of them to a more useful frequency.

BTW some of those 'useless' frequency rocks do multiply out into some
ham bands.

A few examples from my junk box:
4845khz - 29070khz (10 meters)
6050khz - 18150khz (17 meters)
6025khz - 18075khz (17 meters)
4785khz - 28710hkz (10 meters)
5300khz - 21200hkz (15 meters)