Kuhne 24 GHz transverter IF


Neil Smith G4DBN
 

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz transverter so I could drive it with 10-15 dBm, but they declined. I guess the majority of customers must still be using ancient superhet IF radios and don't see anything perverse about generating 0.5 to 5W at 144MHz along with lots of nice IMDs, only to dissipate 99% of it in a resistor.  Also not weird using a single IF port rather than separate TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and control system to warm up a resistor, or whip the lid off the new transverter and void yet another warranty by swapping out the dropper resistor.  Either way I still have to add an unwanted IF changeover relay.  I have serious misgivings about using the Kuhne kit in my 24G project at all.  All my other transverters apart from the 13cm one have been butchered to run separate IF tx/rx, (and even that has had the attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN


Andy G4JNT
 

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.



On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:
I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN





militaryoperator
 

guess the majority of customers must still be using ancient superhet IF 
radios

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN
------------------------------------------

I for one would like to apologize to Neil for being a Luddite and still using superhets and FT817's. 

Another reason why I'm left wondering if this hobby really is for me. 

73, Ben G4BXD


Neil Smith G4DBN
 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN


On 19/08/2020 14:25, Andy G4JNT wrote:
A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.



On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:
I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN




Neil Smith G4DBN
 

Nah, it's me that is the odd one out Ben!

On 19/08/2020 14:38, militaryoperator via groups.io wrote:
guess the majority of customers must still be using ancient superhet IF 
radios

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN
------------------------------------------

I for one would like to apologize to Neil for being a Luddite and still using superhets and FT817's. 

Another reason why I'm left wondering if this hobby really is for me. 

73, Ben G4BXD



Steve G4HTZ
 

I’m surprised that KUHNE don’t offer a low level drive on their transverter modules ....they seem to on their ready built plug in and go transverters .....I use mine ...or will be with a IC-9700 .

anyway be good to get you on 24ghz Neil ....my 24ghz KUHNE system is ready to go on the new mast with a elevation.rotaor...mast is from MM0CUG but is currently under lockdown measures in Aberdeen ....hopefully be arriving mid September now .

I believe G4BAO G3XDY and GOJBA in east Kent are all active from home on 24ghz now ..maybe others ??

QTH here only 3m asl , but sea path into Holland and Belgium....hopefully get some activity from there ?
--
Steve G4HTZ 
JO01JN60
Great Wakering, Essex 
24ghz 1.8w 80cm dish 

also known to be active occasionally on 70cms DATV 


Paul G8AQA
 

Not too sure about that Neil but I must confess to using an FT290R on the inherited 24GHz rig.  The next rig will be much better using a K3 and DDK transverter.  Much easier to have separate RX and TX path right up to the feed.  Can't justify an Elad at present.  Should have bought one rather than a KX3.

Paul G8AQA

On 19/08/2020 14:46, Neil Smith G4DBN wrote:

Nah, it's me that is the odd one out Ben!

On 19/08/2020 14:38, militaryoperator via groups.io wrote:
guess the majority of customers must still be using ancient superhet IF 
radios

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN
------------------------------------------

I for one would like to apologize to Neil for being a Luddite and still using superhets and FT817's. 

Another reason why I'm left wondering if this hobby really is for me. 

73, Ben G4BXD




John Lemay
 

Neil

 

Before you get Really Grumpy (darn it, too late!), try the transverter out; Gear that I have from Kuhne requires much less drive than stated, so you may be in luck. Admittedly, I’ve no experience of the 24GHz unit.

 

John G4ZTR

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: 19 August 2020 14:45
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Kuhne 24 GHz transverter IF

 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN

 

On 19/08/2020 14:25, Andy G4JNT wrote:

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.

 

 

 

On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN

 


Virus-free. www.avg.com


Neil Smith G4DBN
 

My current episode of grumpiness was triggered when some (relatively) young tech hobbyists gave me incredulous stares when I tried to explain why all the pics of microwave activity are folks in laybys with dishes on tripods rather than the cool and exciting stuff they had been expecting.  It is all very nice, and I don't mind a bit of that myself, but it doesn't seem to inspire potential new recruits, who know about SDRs and deep tech, but haven't heard of superhets and are only vaguely aware of the existence of quaint old radio designs which aren't digital, system-on-chip and software-defined.

I tore the lid off my MKU23 G4 the day it arrived, and swapped the dropper resistor, but there isn't exactly any spare space to fit an IF RX socket without serious microsurgery. The alternative is to go REALLY old-school and build a gasfet waveguide preamp and use one or two of Kuhne's ancient PCBs to make a last-century-tech transverter, seeing as I'd have to muck about with implementing an LO anyway.  I'd have to machine up some very good cavity filters, but I know a man with a mill. Doing something more sensible with nice modern up/downconverter chips is a step too far in terms of time expended versus results achieved.

Andy's right though, I should just hold my nose and sort out a very linear 2m booster amp and send Kuhne all my pocket-money, horrible though that solution might be. At least then I could sell the un-butchered Kuhne if I ever get round to making something spiffy.  Or if Kuhne come up with a G5 with separate low-level IF input.

Neil G4DBN

On 19/08/2020 14:57, John Lemay wrote:

Neil

 

Before you get Really Grumpy (darn it, too late!), try the transverter out; Gear that I have from Kuhne requires much less drive than stated, so you may be in luck. Admittedly, I’ve no experience of the 24GHz unit.

 

John G4ZTR

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: 19 August 2020 14:45
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Kuhne 24 GHz transverter IF

 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN

 

On 19/08/2020 14:25, Andy G4JNT wrote:

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.

 

Andy

 

 

 

On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN



John Fell
 

You are probably ahead of the curve Neil .

Looking at my ELAD DUO I realise it is the same form factor as my 1977 202S - some progress then .

Mind you the 202S with replacement front end was a good rig for me and it was used in VHF NFD to come 3rd in the Open section one year last Century . The add on board gave me 2 port capability , so I use that on my 24GHz /P kit to save finger trouble.

Incidentally , this morning I checked GB3SCK on 24,048.905MHz , using my fixed AZ  sectoral horn and found it at just 10dB/noise .Thinking it was my end I checked the system and eventually decided that the 22km LOS signal was actually down .

I then noticed that the 10GHz signal from co-sited GB3SCX was heavily RS but the rain induced Doppler was equally displaced around the nominal carrier frequency - most unusual .Over next 2 hours the 24GHz signal recovered slowly as the rain went North and it is now back to just over +40dB/noise as measured on the Airspy R2 ( quite loud) .

Something very soggy got less so ?

73
John
G0API


On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:
I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN





Andy G4JNT
 

What's non-superhet about mixing down from RF (as a digitised stream of wideband samples)  using a mixer (I/Q multiplication), passing though a roofing filter (decimation) then passing the downconverted IF through a bandpass filter (FIR filtering the decimated data stream)   applying AGC, noise blanking etc, then into a product detector (another I/Q mixer) and out to a speaker (via D/A)




On Wed, 19 Aug 2020 at 15:59, Neil Smith G4DBN <neil@...> wrote:

My current episode of grumpiness was triggered when some (relatively) young tech hobbyists gave me incredulous stares when I tried to explain why all the pics of microwave activity are folks in laybys with dishes on tripods rather than the cool and exciting stuff they had been expecting.  It is all very nice, and I don't mind a bit of that myself, but it doesn't seem to inspire potential new recruits, who know about SDRs and deep tech, but haven't heard of superhets and are only vaguely aware of the existence of quaint old radio designs which aren't digital, system-on-chip and software-defined.

I tore the lid off my MKU23 G4 the day it arrived, and swapped the dropper resistor, but there isn't exactly any spare space to fit an IF RX socket without serious microsurgery. The alternative is to go REALLY old-school and build a gasfet waveguide preamp and use one or two of Kuhne's ancient PCBs to make a last-century-tech transverter, seeing as I'd have to muck about with implementing an LO anyway.  I'd have to machine up some very good cavity filters, but I know a man with a mill. Doing something more sensible with nice modern up/downconverter chips is a step too far in terms of time expended versus results achieved.

Andy's right though, I should just hold my nose and sort out a very linear 2m booster amp and send Kuhne all my pocket-money, horrible though that solution might be. At least then I could sell the un-butchered Kuhne if I ever get round to making something spiffy.  Or if Kuhne come up with a G5 with separate low-level IF input.

Neil G4DBN

On 19/08/2020 14:57, John Lemay wrote:

Neil

 

Before you get Really Grumpy (darn it, too late!), try the transverter out; Gear that I have from Kuhne requires much less drive than stated, so you may be in luck. Admittedly, I’ve no experience of the 24GHz unit.

 

John G4ZTR

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: 19 August 2020 14:45
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Kuhne 24 GHz transverter IF

 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN

 

On 19/08/2020 14:25, Andy G4JNT wrote:

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.

 

Andy

 

 

 

On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN



Neil Smith G4DBN
 

Heh heh, touché. Sometimes I wish there was a LIKE button on groups.io

Neil G4DBN

❤️️ This ⬇️⬇️⬇️⬇️⬇️

On 19/08/2020 16:25, Andy G4JNT wrote:
What's non-superhet about mixing down from RF (as a digitised stream of wideband samples)  using a mixer (I/Q multiplication), passing though a roofing filter (decimation) then passing the downconverted IF through a bandpass filter (FIR filtering the decimated data stream)   applying AGC, noise blanking etc, then into a product detector (another I/Q mixer) and out to a speaker (via D/A)




On Wed, 19 Aug 2020 at 15:59, Neil Smith G4DBN <neil@...> wrote:

My current episode of grumpiness was triggered when some (relatively) young tech hobbyists gave me incredulous stares when I tried to explain why all the pics of microwave activity are folks in laybys with dishes on tripods rather than the cool and exciting stuff they had been expecting.  It is all very nice, and I don't mind a bit of that myself, but it doesn't seem to inspire potential new recruits, who know about SDRs and deep tech, but haven't heard of superhets and are only vaguely aware of the existence of quaint old radio designs which aren't digital, system-on-chip and software-defined.

I tore the lid off my MKU23 G4 the day it arrived, and swapped the dropper resistor, but there isn't exactly any spare space to fit an IF RX socket without serious microsurgery. The alternative is to go REALLY old-school and build a gasfet waveguide preamp and use one or two of Kuhne's ancient PCBs to make a last-century-tech transverter, seeing as I'd have to muck about with implementing an LO anyway.  I'd have to machine up some very good cavity filters, but I know a man with a mill. Doing something more sensible with nice modern up/downconverter chips is a step too far in terms of time expended versus results achieved.

Andy's right though, I should just hold my nose and sort out a very linear 2m booster amp and send Kuhne all my pocket-money, horrible though that solution might be. At least then I could sell the un-butchered Kuhne if I ever get round to making something spiffy.  Or if Kuhne come up with a G5 with separate low-level IF input.

Neil G4DBN

On 19/08/2020 14:57, John Lemay wrote:

Neil

 

Before you get Really Grumpy (darn it, too late!), try the transverter out; Gear that I have from Kuhne requires much less drive than stated, so you may be in luck. Admittedly, I’ve no experience of the 24GHz unit.

 

John G4ZTR

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: 19 August 2020 14:45
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Kuhne 24 GHz transverter IF

 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN

 

On 19/08/2020 14:25, Andy G4JNT wrote:

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.

 

Andy

 

 

 

On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN


-- 
Neil
http://g4dbn.uk


Andy G4JNT
 

The real challenge is a TRF digital receiver.   AM only of course, as a TRF radio with a BFO for SSB isn't a TRF radio any more.

Filtering at the full sampling rate is, well,  I suppose possible if you use big fast FPGAs
AM demod without mixing on a bandpass filtered stream - the diode detector becomes SQRT(I^2 + Q^2)

It could be done - now there's a thought to ponder on ...



On Wed, 19 Aug 2020 at 16:55, Neil Smith G4DBN <neil@...> wrote:

Heh heh, touché. Sometimes I wish there was a LIKE button on groups.io

Neil G4DBN

❤️️ This ⬇️⬇️⬇️⬇️⬇️

On 19/08/2020 16:25, Andy G4JNT wrote:
What's non-superhet about mixing down from RF (as a digitised stream of wideband samples)  using a mixer (I/Q multiplication), passing though a roofing filter (decimation) then passing the downconverted IF through a bandpass filter (FIR filtering the decimated data stream)   applying AGC, noise blanking etc, then into a product detector (another I/Q mixer) and out to a speaker (via D/A)




On Wed, 19 Aug 2020 at 15:59, Neil Smith G4DBN <neil@...> wrote:

My current episode of grumpiness was triggered when some (relatively) young tech hobbyists gave me incredulous stares when I tried to explain why all the pics of microwave activity are folks in laybys with dishes on tripods rather than the cool and exciting stuff they had been expecting.  It is all very nice, and I don't mind a bit of that myself, but it doesn't seem to inspire potential new recruits, who know about SDRs and deep tech, but haven't heard of superhets and are only vaguely aware of the existence of quaint old radio designs which aren't digital, system-on-chip and software-defined.

I tore the lid off my MKU23 G4 the day it arrived, and swapped the dropper resistor, but there isn't exactly any spare space to fit an IF RX socket without serious microsurgery. The alternative is to go REALLY old-school and build a gasfet waveguide preamp and use one or two of Kuhne's ancient PCBs to make a last-century-tech transverter, seeing as I'd have to muck about with implementing an LO anyway.  I'd have to machine up some very good cavity filters, but I know a man with a mill. Doing something more sensible with nice modern up/downconverter chips is a step too far in terms of time expended versus results achieved.

Andy's right though, I should just hold my nose and sort out a very linear 2m booster amp and send Kuhne all my pocket-money, horrible though that solution might be. At least then I could sell the un-butchered Kuhne if I ever get round to making something spiffy.  Or if Kuhne come up with a G5 with separate low-level IF input.

Neil G4DBN

On 19/08/2020 14:57, John Lemay wrote:

Neil

 

Before you get Really Grumpy (darn it, too late!), try the transverter out; Gear that I have from Kuhne requires much less drive than stated, so you may be in luck. Admittedly, I’ve no experience of the 24GHz unit.

 

John G4ZTR

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: 19 August 2020 14:45
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Kuhne 24 GHz transverter IF

 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN

 

On 19/08/2020 14:25, Andy G4JNT wrote:

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.

 

Andy

 

 

 

On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN


-- 
Neil
http://g4dbn.uk


Chris Bartram G4DGU
 

Hello Neil

I have a totally Kuhne-free station and always have had. So I'm free to choose my IF levels - which on TX are 144MHz/0dBm (from guess where !!!) on 10368, and 438MHz on 24048 obtained by carefully up and down converting 38MHz.   144 does present a few problems,  largely due to potential breakthrough and radiation problems asI'm near a flight path to Newquay Airport and try to be responsible.These which are eliminated  byusing decent coax (FSJ2/50) for the IF runs from my shack to the dish. If I wanted to generate more IF power, I know how to achieve very high linearities, but that would be a bit too much like the work I retired from!

You might explain to the PNRs that the reason why we are not sampling microwaves directly, is because it's freakingly expensive to do so. It can be done, but not by the usual monolithic offerings of the semiconductor industry. Perhaps you should challenge them to come-up with a 14 or 16bit sampler capable of directly sampling 10GHz! As I said the other day, most so-called 'SDRs' consist of a relatively low-frequency sampling back-end, preceeded by an image reject up-down converter. That's exactly what we are doing with our FDM-DUOs and transverters; using a better sampler than is contained in most 'SDRs' and certainly very much better up-down converters!

'The semiconductor industry is rather good at generating hype and sometimes quite adequate at product design!'

73

Cynical of mid-Cornwall aka Chris G4DGU


On 19/08/2020 15:58, Neil Smith G4DBN wrote:

My current episode of grumpiness was triggered when some (relatively) young tech hobbyists gave me incredulous stares when I tried to explain why all the pics of microwave activity are folks in laybys with dishes on tripods rather than the cool and exciting stuff they had been expecting.  It is all very nice, and I don't mind a bit of that myself, but it doesn't seem to inspire potential new recruits, who know about SDRs and deep tech, but haven't heard of superhets and are only vaguely aware of the existence of quaint old radio designs which aren't digital, system-on-chip and software-defined.

I tore the lid off my MKU23 G4 the day it arrived, and swapped the dropper resistor, but there isn't exactly any spare space to fit an IF RX socket without serious microsurgery. The alternative is to go REALLY old-school and build a gasfet waveguide preamp and use one or two of Kuhne's ancient PCBs to make a last-century-tech transverter, seeing as I'd have to muck about with implementing an LO anyway.  I'd have to machine up some very good cavity filters, but I know a man with a mill. Doing something more sensible with nice modern up/downconverter chips is a step too far in terms of time expended versus results achieved.

Andy's right though, I should just hold my nose and sort out a very linear 2m booster amp and send Kuhne all my pocket-money, horrible though that solution might be. At least then I could sell the un-butchered Kuhne if I ever get round to making something spiffy.  Or if Kuhne come up with a G5 with separate low-level IF input.

Neil G4DBN

On 19/08/2020 14:57, John Lemay wrote:

Neil

 

Before you get Really Grumpy (darn it, too late!), try the transverter out; Gear that I have from Kuhne requires much less drive than stated, so you may be in luck. Admittedly, I’ve no experience of the 24GHz unit.

 

John G4ZTR

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: 19 August 2020 14:45
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Kuhne 24 GHz transverter IF

 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN

 

On 19/08/2020 14:25, Andy G4JNT wrote:

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.

 

Andy

 

 

 

On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN



Andy G4JNT
 

You don't have to sample at 16 bit resolution when in a normal noise limited environment.    HF requires 16 bits, but even so, it was done successfully at forst 12, then 14 bits with the SDR-14 and SDR-IQ
At microwaves an 8 bit wideband sampling converter, clocked at perhaps 3GHz and using alias products would serve our, and many others' purposes.

But it's still more complex and expensive than a mixer up/downconverter solution or image cancelling baseband direct conversion



On Wed, 19 Aug 2020 at 18:33, Chris Bartram G4DGU <chris@...> wrote:

Hello Neil

I have a totally Kuhne-free station and always have had. So I'm free to choose my IF levels - which on TX are 144MHz/0dBm (from guess where !!!) on 10368, and 438MHz on 24048 obtained by carefully up and down converting 38MHz.   144 does present a few problems,  largely due to potential breakthrough and radiation problems asI'm near a flight path to Newquay Airport and try to be responsible.These which are eliminated  byusing decent coax (FSJ2/50) for the IF runs from my shack to the dish. If I wanted to generate more IF power, I know how to achieve very high linearities, but that would be a bit too much like the work I retired from!

You might explain to the PNRs that the reason why we are not sampling microwaves directly, is because it's freakingly expensive to do so. It can be done, but not by the usual monolithic offerings of the semiconductor industry. Perhaps you should challenge them to come-up with a 14 or 16bit sampler capable of directly sampling 10GHz! As I said the other day, most so-called 'SDRs' consist of a relatively low-frequency sampling back-end, preceeded by an image reject up-down converter. That's exactly what we are doing with our FDM-DUOs and transverters; using a better sampler than is contained in most 'SDRs' and certainly very much better up-down converters!

'The semiconductor industry is rather good at generating hype and sometimes quite adequate at product design!'

73

Cynical of mid-Cornwall aka Chris G4DGU


On 19/08/2020 15:58, Neil Smith G4DBN wrote:

My current episode of grumpiness was triggered when some (relatively) young tech hobbyists gave me incredulous stares when I tried to explain why all the pics of microwave activity are folks in laybys with dishes on tripods rather than the cool and exciting stuff they had been expecting.  It is all very nice, and I don't mind a bit of that myself, but it doesn't seem to inspire potential new recruits, who know about SDRs and deep tech, but haven't heard of superhets and are only vaguely aware of the existence of quaint old radio designs which aren't digital, system-on-chip and software-defined.

I tore the lid off my MKU23 G4 the day it arrived, and swapped the dropper resistor, but there isn't exactly any spare space to fit an IF RX socket without serious microsurgery. The alternative is to go REALLY old-school and build a gasfet waveguide preamp and use one or two of Kuhne's ancient PCBs to make a last-century-tech transverter, seeing as I'd have to muck about with implementing an LO anyway.  I'd have to machine up some very good cavity filters, but I know a man with a mill. Doing something more sensible with nice modern up/downconverter chips is a step too far in terms of time expended versus results achieved.

Andy's right though, I should just hold my nose and sort out a very linear 2m booster amp and send Kuhne all my pocket-money, horrible though that solution might be. At least then I could sell the un-butchered Kuhne if I ever get round to making something spiffy.  Or if Kuhne come up with a G5 with separate low-level IF input.

Neil G4DBN

On 19/08/2020 14:57, John Lemay wrote:

Neil

 

Before you get Really Grumpy (darn it, too late!), try the transverter out; Gear that I have from Kuhne requires much less drive than stated, so you may be in luck. Admittedly, I’ve no experience of the 24GHz unit.

 

John G4ZTR

 

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Neil Smith G4DBN
Sent: 19 August 2020 14:45
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Kuhne 24 GHz transverter IF

 

Just because it is popular, doesn't make it less weird though. Just seems like adding unnecessary transmit IMD. I can't imagine a use-case where I'd want to key the transverter from a rig rather than a sequence controller, but I suspect the primary application for their 24 GHz stuff is lovely sepia-tinged nostalgic retro tripod-on-a-hilltop-with-an-817 speakymode rather than EME or home-station terrestrial digimodes with SDRs and it is me that is out of step with commercial reality as usual.

Neil G4DBN

 

On 19/08/2020 14:25, Andy G4JNT wrote:

A single IF port, I guess, is a strongly preferred option, and carrying PTT control with it.   That has become a de-facto standard.   Level, well, yes, it's annoying, but 500mW isn't that much to generate.   Two devices instead of one from the mixer/source, but gain is cheap.

 

Andy

 

 

 

On Wed, 19 Aug 2020 at 14:14, Neil Smith G4DBN <neil@...> wrote:

I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN



neil whiting
 

hi Neil,

I'm completely with you about the IF levels - I use 13dBm for my 2m IF transverters which are old
Kuhne kits in which I had no qualms about modifying the attenuator values. I'd probably go lower still
if I was starting again now.

I do use the single wire TX/RX/PTT scheme though, a bit messier inside the modules to do the switching
but saves a lot of cable hassles and just need a single coaxial switch to choose bands.

73,  Neil G4BRK

Virus-free. www.avast.com


On Wed, 19 Aug 2020 at 13:14, Neil Smith G4DBN <neil@...> wrote:
I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN





Robin Szemeti - G1YFG
 

The best solution I have seen is to have two ports .. one for RX out ... and the other a switchable TX in/RXout ... you can then use the device 1 wire or 2 wire,  or use the RX port for a "waterfall" display via a dongle if you wish. Seems to cover all bases.

On Wed, 19 Aug 2020 at 18:54, neil whiting <neil@...> wrote:
hi Neil,

I'm completely with you about the IF levels - I use 13dBm for my 2m IF transverters which are old
Kuhne kits in which I had no qualms about modifying the attenuator values. I'd probably go lower still
if I was starting again now.

I do use the single wire TX/RX/PTT scheme though, a bit messier inside the modules to do the switching
but saves a lot of cable hassles and just need a single coaxial switch to choose bands.

73,  Neil G4BRK

Virus-free. www.avast.com

On Wed, 19 Aug 2020 at 13:14, Neil Smith G4DBN <neil@...> wrote:
I asked Kuhne if they could modify the 144 MHz IF input on their 24GHz
transverter so I could drive it with 10-15 dBm, but they declined. I
guess the majority of customers must still be using ancient superhet IF
radios and don't see anything perverse about generating 0.5 to 5W at
144MHz along with lots of nice IMDs, only to dissipate 99% of it in a
resistor.  Also not weird using a single IF port rather than separate
TX/RX sockets.

All this in a £700 transverter which doesn't even have a local oscillator.

Two choices then: Build a very linear but pointless 144MHz PA and
control system to warm up a resistor, or whip the lid off the new
transverter and void yet another warranty by swapping out the dropper
resistor.  Either way I still have to add an unwanted IF changeover
relay.  I have serious misgivings about using the Kuhne kit in my 24G
project at all.  All my other transverters apart from the 13cm one have
been butchered to run separate IF tx/rx, (and even that has had the
attenuator modified) or are Kuhnes already equipped with low-level inputs.

Am I the one who is out of step here, or are they stuck in the era where
an FT-817 (or IC-202?) was the state of the art for IF radios?

Neil G4DBN





--
Robin Szemeti - G1YFG


David Robinson
 

I have the same experience as G4ZTR, Kuhne transverters require much less drive than the manuals state. My 24GHZ xverter only needs 200mw of drive as now do my other 3  db6nt xverters. My FT817 has had its hidden menus adjusted to produce 200mw on 2m and 70cm irrespective of what output power selection i make on the front panel to avoid accidents.
Looking at the kuhne web pages yesterday i was struck by how the number/range of available products has considerably reduced during this year

Dave
G4FRE


Neil Smith G4DBN
 

I had a note from Kuhne this morning saying they will look into the possibility of a low-power version.  The mod I usually do now is to remove the big power resistor and swap it for an 82 ohm, then change the resistor in series with the 100 ohm pot to a 33 ohm. Still looks like 50 ohm pretty much. On my kit versions, I used 100 ohm parallel and 0 ohm series. I can see it isn't going to be sensible for them to go that far as it might be too easy to cause damage with the pot at max, but we shall see what they say.

Neil G4DBN

On 20/08/2020 07:51, David Robinson wrote:
I have the same experience as G4ZTR, Kuhne transverters require much less drive than the manuals state. My 24GHZ xverter only needs 200mw of drive as now do my other 3  db6nt xverters. My FT817 has had its hidden menus adjusted to produce 200mw on 2m and 70cm irrespective of what output power selection i make on the front panel to avoid accidents.
Looking at the kuhne web pages yesterday i was struck by how the number/range of available products has considerably reduced during this year


militaryoperator
 

I had a note from Kuhne this morning saying they will look into the
possibility of a low-power version. 
----------------------------------------------------


You'd think at £702 a box they would be falling over themselves to sell the stuff. 

Still, guess when your the only player in the game (?) you can do what you like. 

Might be a while till I get operational on 24. 

Ben 
G4BXD