Input Needed for RadCom Column


Andy G4JNT
 


Microwave input really ought to go in the uWaves / GHz column,  so John ought to get first dibs on anything.  But as I have three pages every month, and GHz has one, there's space for more so  ....................

It is getting more and more difficult to find interesting RF and Am. Radio related matters to write about for the regular three pages of Design Notes in RadCom every month.  'JNT labs own projects are running out of steam, and to be quite brutal about things, I personally am getting less and less interested in RF related matters altogether.   What interest remains is purely software / DSP and non radio related electronics.  Very little of which will form DN-suitable material.  

SO........

It really would help if I had input from readers.  What are you doing, bright ideas, helpful tips and hints etc.   Pat Hawker's old column, Tech Topics was made up entirely from reader input and stuff blatantly culled from other publications.   The latter is now pointless with 't web and I'm not even going tp consider that route.   So that leaves reader input.

Please send me your input as and when.  Most reader input will be pasted in directly, with a minimum of editing for correctness / grammar etc.   And naturally you'll be credited.

 OR ......

Although it doesn't help with DN, consider writing up your work as a standalone article for RadCom (or ...Plus   or ...Basics)  .  That way you'll see your work in print and get paid for it.    


John Worsnop
 

I should add that any GHz stuff that won't fit in to my 1 page will usually get in to Scatterpoint via me if you don't send it to editor@....

As I've said many times to people, if you want a larger GHz Bands column,  email radcom@... and ask for one. I'm happy to fill a second page.

As Elaine and Giles will tell you, every time I see them (the editors), I ask them for a second page, but the reply is the same.
"The readership doesn't demand it, "our recent survey" showed that GHz Bands is not widely read and was a minority interest....... but you can always write us stand alone articles" (Which I do!)

73

John   

On Tue, 21 Jan 2020 at 17:25, Andy G4JNT <andy.g4jnt@...> wrote:

Microwave input really ought to go in the uWaves / GHz column,  so John ought to get first dibs on anything.  But as I have three pages every month, and GHz has one, there's space for more so  ....................

It is getting more and more difficult to find interesting RF and Am. Radio related matters to write about for the regular three pages of Design Notes in RadCom every month.  'JNT labs own projects are running out of steam, and to be quite brutal about things, I personally am getting less and less interested in RF related matters altogether.   What interest remains is purely software / DSP and non radio related electronics.  Very little of which will form DN-suitable material.  

SO........

It really would help if I had input from readers.  What are you doing, bright ideas, helpful tips and hints etc.   Pat Hawker's old column, Tech Topics was made up entirely from reader input and stuff blatantly culled from other publications.   The latter is now pointless with 't web and I'm not even going tp consider that route.   So that leaves reader input.

Please send me your input as and when.  Most reader input will be pasted in directly, with a minimum of editing for correctness / grammar etc.   And naturally you'll be credited.

 OR ......

Although it doesn't help with DN, consider writing up your work as a standalone article for RadCom (or ...Plus   or ...Basics)  .  That way you'll see your work in print and get paid for it.    


Adrian G4UVZ
 

A question rather than an answer!  A couple of years ago, as beacon keeper for GB3KBQ I wanted to bring the beacon into the 21st century. Whilst the existing system is very frequency stable using 35 year old  a Pye HS400  https://uhf-satcom.com/misc/hs400-reference-oscillator  and multiplying it's 27MHz o/p up to 10368.87 MHz . The FSK keying is very agricultural using a reed relay to offset the 5MHz TCXO. Having seen the benefits of JT4G modulation system in tests with Neil G4DBN, I was hoping that I might be able to get KBQ emitting these tones. Sadly I drew a blank on a suitable design. The beacon requires around 0dBm at 10GHz ..or 108MHz at a similar level.(Tone spacing woud have to be divided by 96)

For avoidance of any doubt ..whilst I can build hardware, measure rf levels and frequency accurately. Programming eproms, flash memory, PICs, programmable arrays etc is beyond my ability!

Perhaps an article addressing the above would be of interest to other beacon keepers?

Adrian  G4UVZ


Andy G4JNT
 

I once generated WSPR using a carefully adjusted varicap across a crystal, then drove it with a simple two-bit A/D (two resistors).   JT4x would work just as well (there's not a lot of difference between it and WSPR)

But still needed a PIC to generate the timing and symbols; you can't get away from having to use some sort of controller.   Unless...   You coded it onto a wheel with an opto coupler (dual channel of course for four levels)    But you still need PC software to calculate the symbol pattern and GPS or accurate clock time info.
  


On Wed, 22 Jan 2020 at 15:29, Adrian G4UVZ via Groups.Io <adrianwhatmore248=btinternet.com@groups.io> wrote:
A question rather than an answer!  A couple of years ago, as beacon keeper for GB3KBQ I wanted to bring the beacon into the 21st century. Whilst the existing system is very frequency stable using 35 year old  a Pye HS400  https://uhf-satcom.com/misc/hs400-reference-oscillator  and multiplying it's 27MHz o/p up to 10368.87 MHz . The FSK keying is very agricultural using a reed relay to offset the 5MHz TCXO. Having seen the benefits of JT4G modulation system in tests with Neil G4DBN, I was hoping that I might be able to get KBQ emitting these tones. Sadly I drew a blank on a suitable design. The beacon requires around 0dBm at 10GHz ..or 108MHz at a similar level.(Tone spacing woud have to be divided by 96)

For avoidance of any doubt ..whilst I can build hardware, measure rf levels and frequency accurately. Programming eproms, flash memory, PICs, programmable arrays etc is beyond my ability!

Perhaps an article addressing the above would be of interest to other beacon keepers?

Adrian  G4UVZ


Adrian G4UVZ
 

Whilst the idea of keying the 5Mhz sounds interesting ..I fear that the df/dt of the keying by the time it had gone through the PLL would be  pretty poor..as you can hear the exisiting keying is no wonderful!  https://www.beaconspot.uk/beaconsnd.php?beaconcall=GB3KBQ  


Neil Smith G4DBN
 

It is a GLORIOUS sound Adrian, expecially after it has travelled 342km to reach here, which, as you know, it does quite often. I like PI7RTD as well, and all of the others the whoop and slide and chirp. Perfection is boring, at least for the CWID.

Neil G4DBN

On 22/01/2020 15:56, Adrian G4UVZ via Groups.Io wrote:
Whilst the idea of keying the 5Mhz sounds interesting ..I fear that the df/dt of the keying by the time it had gone through the PLL would be  pretty poor..as you can hear the exisiting keying is no wonderful!  https://www.beaconspot.uk/beaconsnd.php?beaconcall=GB3KBQ  
_._,_._,_



Andy G4JNT
 

So. you're saying, for the olde-mann ident stage, it would be preferable to introduce a carefully designed, non-linear chirp along with a bit of PR noise.   That can be done with a PIC / DDS combination, so a direct upconversion based beacon should be able to manage it.   But a PLL or RDDS based one can't hack it

For all  the use the CW ident is, might as well do something special and use some artistry for its sound.

Now there's a thought for any GB3SC# update - a custom CW ident 



On Wed, 22 Jan 2020 at 17:01, Neil Smith G4DBN <neil@...> wrote:

It is a GLORIOUS sound Adrian, expecially after it has travelled 342km to reach here, which, as you know, it does quite often. I like PI7RTD as well, and all of the others the whoop and slide and chirp. Perfection is boring, at least for the CWID.

Neil G4DBN

On 22/01/2020 15:56, Adrian G4UVZ via Groups.Io wrote:
Whilst the idea of keying the 5Mhz sounds interesting ..I fear that the df/dt of the keying by the time it had gone through the PLL would be  pretty poor..as you can hear the exisiting keying is no wonderful!  https://www.beaconspot.uk/beaconsnd.php?beaconcall=GB3KBQ  


Neil Smith G4DBN
 

Something like the sound of a pump key with a CO/PA two-valve transmitter circa 1956 would do the job. Decent click, bit of droop, gradual drift, good amount of chirp, and a few character spacing and symbol length errors to add some idiosyncratic "swing".  Instant recognition of the "fist" without hearing more than a couple of characters.

Is a CWID actually required at all under the beacon licence?  The beacon could have a theme tune instead.  Local folk song melody, or a nice short ID like the Radio Tirana ident from the 70s.

I'd certainly be keen to have a decent slow mode like JT4F/G or PI4 which would work via rainscatter as well as weak troposcatter, but also a fast mode like JT9F-fast that would work off aircraft, and some plain carrier to look at the shape of the troposcatter spectrum over 20s or so.

Neil G4DBN

On 22/01/2020 17:09, Andy G4JNT wrote:
So. you're saying, for the olde-mann ident stage, it would be preferable to introduce a carefully designed, non-linear chirp along with a bit of PR noise.   That can be done with a PIC / DDS combination, so a direct upconversion based beacon should be able to manage it.   But a PLL or RDDS based one can't hack it

For all  the use the CW ident is, might as well do something special and use some artistry for its sound.

Now there's a thought for any GB3SC# update - a custom CW ident 



On Wed, 22 Jan 2020 at 17:01, Neil Smith G4DBN <neil@...> wrote:

It is a GLORIOUS sound Adrian, expecially after it has travelled 342km to reach here, which, as you know, it does quite often. I like PI7RTD as well, and all of the others the whoop and slide and chirp. Perfection is boring, at least for the CWID.

Neil G4DBN

On 22/01/2020 15:56, Adrian G4UVZ via Groups.Io wrote:
Whilst the idea of keying the 5Mhz sounds interesting ..I fear that the df/dt of the keying by the time it had gone through the PLL would be  pretty poor..as you can hear the exisiting keying is no wonderful!  https://www.beaconspot.uk/beaconsnd.php?beaconcall=GB3KBQ  
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>


Andy G4JNT
 

Unfortunately, the old people who run the system still mandate CW idents.  I see no point whatsoever in them, but whatevs...

The period of plain carrier, also mandated,  is essential as it gives a constant measure for any beacon.

But the proper modulation type is a free-for-all.  So a combination of fast mode plus slow mode is quite possible.   JT9 woul dbe good for that as it can have a lot of generator code in common, just changing the symbol rate and tone shift .  In fact for uWaves,  the same tone shift for fast and slow mode could even be maintained.



On Wed, 22 Jan 2020 at 17:25, Neil Smith G4DBN <neil@...> wrote:

Something like the sound of a pump key with a CO/PA two-valve transmitter circa 1956 would do the job. Decent click, bit of droop, gradual drift, good amount of chirp, and a few character spacing and symbol length errors to add some idiosyncratic "swing".  Instant recognition of the "fist" without hearing more than a couple of characters.

Is a CWID actually required at all under the beacon licence?  The beacon could have a theme tune instead.  Local folk song melody, or a nice short ID like the Radio Tirana ident from the 70s.

I'd certainly be keen to have a decent slow mode like JT4F/G or PI4 which would work via rainscatter as well as weak troposcatter, but also a fast mode like JT9F-fast that would work off aircraft, and some plain carrier to look at the shape of the troposcatter spectrum over 20s or so.

Neil G4DBN

On 22/01/2020 17:09, Andy G4JNT wrote:
So. you're saying, for the olde-mann ident stage, it would be preferable to introduce a carefully designed, non-linear chirp along with a bit of PR noise.   That can be done with a PIC / DDS combination, so a direct upconversion based beacon should be able to manage it.   But a PLL or RDDS based one can't hack it

For all  the use the CW ident is, might as well do something special and use some artistry for its sound.

Now there's a thought for any GB3SC# update - a custom CW ident 



On Wed, 22 Jan 2020 at 17:01, Neil Smith G4DBN <neil@...> wrote:

It is a GLORIOUS sound Adrian, expecially after it has travelled 342km to reach here, which, as you know, it does quite often. I like PI7RTD as well, and all of the others the whoop and slide and chirp. Perfection is boring, at least for the CWID.

Neil G4DBN

On 22/01/2020 15:56, Adrian G4UVZ via Groups.Io wrote:
Whilst the idea of keying the 5Mhz sounds interesting ..I fear that the df/dt of the keying by the time it had gone through the PLL would be  pretty poor..as you can hear the exisiting keying is no wonderful!  https://www.beaconspot.uk/beaconsnd.php?beaconcall=GB3KBQ  
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>


Paul G8KFW
 

Hi Andy

 

Did you receive my email to your email address regarding possible future copy for the  RadCom Column

 

Regards Paul


From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Andy G4JNT
Sent: 22 January 2020 17:09
To: UK Microwaves groups.io
Subject: Re: [UKMicrowaves] Input Needed for RadCom Column

 

So. you're saying, for the olde-mann ident stage, it would be preferable to introduce a carefully designed, non-linear chirp along with a bit of PR noise.   That can be done with a PIC / DDS combination, so a direct upconversion based beacon should be able to manage it.   But a PLL or RDDS based one can't hack it

 

For all  the use the CW ident is, might as well do something special and use some artistry for its sound.

 

Now there's a thought for any GB3SC# update - a custom CW ident 

 

Andy

 

 

 

On Wed, 22 Jan 2020 at 17:01, Neil Smith G4DBN <neil@...> wrote:

It is a GLORIOUS sound Adrian, expecially after it has travelled 342km to reach here, which, as you know, it does quite often. I like PI7RTD as well, and all of the others the whoop and slide and chirp. Perfection is boring, at least for the CWID.

Neil G4DBN

On 22/01/2020 15:56, Adrian G4UVZ via Groups.Io wrote:

Whilst the idea of keying the 5Mhz sounds interesting ..I fear that the df/dt of the keying by the time it had gone through the PLL would be  pretty poor..as you can hear the exisiting keying is no wonderful!  https://www.beaconspot.uk/beaconsnd.php?beaconcall=GB3KBQ  

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.


--
Paul Bicknell G8KFW   South Coast UK


Chris Bartram G4DGU
 

Hello Andy,

There seems to be no restriction on using a tone signaling system with tones or frequency offsets chosen from a series of frequencies related by 2e(1/12). That should give a nice quasi-musical character to beacon idents without upsetting those who run the system.

73

Chris G4DGU


On 22/01/2020 17:35, Andy G4JNT wrote:
Unfortunately, the old people who run the system still mandate CW idents.  I see no point whatsoever in them, but whatevs...

The period of plain carrier, also mandated,  is essential as it gives a constant measure for any beacon.

But the proper modulation type is a free-for-all.  So a combination of fast mode plus slow mode is quite possible.   JT9 woul dbe good for that as it can have a lot of generator code in common, just changing the symbol rate and tone shift .  In fact for uWaves,  the same tone shift for fast and slow mode could even be maintained.



Andy G4JNT
 

Yes, I did. 
'fraid I can't reply to everyone who comments.  Relevent emails will be placed in  their own folder pending...
 


On Wed, 22 Jan 2020 at 17:44, Paul G8KFW <paul@...> wrote:

Hi Andy

 

Did you receive my email to your email address regarding possible future copy for the  RadCom Column

 

Regards Paul


From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Andy G4JNT
Sent: 22 January 2020 17:09
To: UK Microwaves groups.io
Subject: Re: [UKMicrowaves] Input Needed for RadCom Column

 

So. you're saying, for the olde-mann ident stage, it would be preferable to introduce a carefully designed, non-linear chirp along with a bit of PR noise.   That can be done with a PIC / DDS combination, so a direct upconversion based beacon should be able to manage it.   But a PLL or RDDS based one can't hack it

 

For all  the use the CW ident is, might as well do something special and use some artistry for its sound.

 

Now there's a thought for any GB3SC# update - a custom CW ident 

 

Andy

 

 

 

On Wed, 22 Jan 2020 at 17:01, Neil Smith G4DBN <neil@...> wrote:

It is a GLORIOUS sound Adrian, expecially after it has travelled 342km to reach here, which, as you know, it does quite often. I like PI7RTD as well, and all of the others the whoop and slide and chirp. Perfection is boring, at least for the CWID.

Neil G4DBN

On 22/01/2020 15:56, Adrian G4UVZ via Groups.Io wrote:

Whilst the idea of keying the 5Mhz sounds interesting ..I fear that the df/dt of the keying by the time it had gone through the PLL would be  pretty poor..as you can hear the exisiting keying is no wonderful!  https://www.beaconspot.uk/beaconsnd.php?beaconcall=GB3KBQ  

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.


--
Paul Bicknell G8KFW   South Coast UK