junius wrote:
HFguy wrote:

AFAIK, There are no HF transceivers with a sync' detector.


I wonder why it is that none of the big three (Kenwood, Icom, Yaesu)
have included synchronous detection circuitry on their HF transceivers.

Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.

HFguy wrote:


Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.

Sure, I realize and appreciate that. But as I said earlier, these
transceivers have a general coverage receiver section...it's not as
though amateur communications is of any account, for instance, in the
MW BCB or the int'l SW BCBs. Through these online fora, it's apparent
that a significant number of radio amateurs have an interest in the
reception of signals in these bands. Moreover, how much of a further
investment would be required to give a transceiver a greater edge in
this area? From what I can see, this might be done simply with the
addition of AM Sync detector circuitry and the expansion of the DSP
variable bandwidth control from the SSB range on up to 6.0 kHz or so.
The technology already there, so...

junius wrote:
HFguy wrote:


Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.


Sure, I realize and appreciate that. But as I said earlier, these
transceivers have a general coverage receiver section...it's not as
though amateur communications is of any account, for instance, in the
MW BCB or the int'l SW BCBs. Through these online fora, it's apparent
that a significant number of radio amateurs have an interest in the
reception of signals in these bands. Moreover, how much of a further
investment would be required to give a transceiver a greater edge in
this area? From what I can see, this might be done simply with the
addition of AM Sync detector circuitry and the expansion of the DSP
variable bandwidth control from the SSB range on up to 6.0 kHz or so.
The technology already there, so...

Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver. I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

On Fri, 21 Apr 2006 10:14:43 GMT, HFguy wrote:


Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver. I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

Synchronous detection is old enough to be in the public domain.

"HFguy" wrote in message
news:ng22g.739$5z3.735@trndny01...
junius wrote:

Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver.

That's an interesting point, but I think Drake is licensing their sync
detector and I suppose other manufacturers would also license theirs, if
they think it wouldn't take away too many of their own radio sales. That's
assuming that's there's still much worth licensing. Most of those patents
must have been around a while.

Chip fabrication is another issue. ASICs are economical only in large runs.
Motorola used sync detection in it's AM stereo chipset, and I'd guess
adapting it to a stand alone sync detector would be easy enough. They must
have not thought there was enough buyers to bother with.


I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

Speaking only as an occasional hamfest attendee, I've noticed little interst
there concerning international broadcasting even though these guys are very
much SW radio hobbyists.

Frank Dresser

In article ng22g.739$5z3.735@trndny01, HFguy
wrote:

junius wrote:
HFguy wrote:


Because ham's use mostly SSB on the HF bands. A sync' detector is not
useful for that mode.


Sure, I realize and appreciate that. But as I said earlier, these
transceivers have a general coverage receiver section...it's not as
though amateur communications is of any account, for instance, in the
MW BCB or the int'l SW BCBs. Through these online fora, it's apparent
that a significant number of radio amateurs have an interest in the
reception of signals in these bands. Moreover, how much of a further
investment would be required to give a transceiver a greater edge in
this area? From what I can see, this might be done simply with the
addition of AM Sync detector circuitry and the expansion of the DSP
variable bandwidth control from the SSB range on up to 6.0 kHz or so.
The technology already there, so...

Although it doesn't cost that much these days to extend the range of an
HF-transceiver for general coverage, it could be harder to come up with
a good sync' detector that doesn't infringe on another manufacturers
design. Look what happened to the R-75. I'm sure Icom knows how to
design a good sync' detector but there may have been legal limitations
to what they could implement. This could be the main reason the
manufacturers are not interested in adding a sync' detector to a general
coverage HF-transceiver. I also don't think it's really so "apparent
that a significant number of radio amateurs have an interest" in
listening to international shortwave broadcasts. It's been my experience
that few do.

Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit. You can buy this circuit on a
chip with a handful of support components for it to function. Maybe you
have to add a reference oscillator to the circuit with the other support
components. Anyone should be able to buy and use these designs.

--
Telamon
Ventura, California

On Fri, 21 Apr 2006 21:54:39 GMT, Telamon
wrote:

In article ng22g.739$5z3.735@trndny01, HFguy
wrote:

Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit. You can buy this circuit on a
chip with a handful of support components for it to function. Maybe you
have to add a reference oscillator to the circuit with the other support
components. Anyone should be able to buy and use these designs.

A PLL and a Product Detector

David wrote:
wrote:
Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector

You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

--
All relevant people are pertinent.
All rude people are impertinent.
Therefore, no rude people are relevant.
-- Solomon W. Golomb

On Fri, 21 Apr 2006 17:46:36 -0500, clifto wrote:

David wrote:
wrote:
Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector

You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

Does that work when the station carrier fades?

clifto wrote:
David wrote:

wrote:

Are you sure about the patent cost? I thought sync detection was mostly
implemented through a PLL type circuit.

A PLL and a Product Detector


You can do without the PLL, too. You just create the signal with a
separate stage that overamplifies the signal into clipping, then
you have basically a sorta-square wave to feed into the product
detector.

That's the poor man's sync' detector. It works but it's no match for
using a PLL with sideband phase cancellation. That's what made the Drake
system so good.