Date   

Re: Resurecting Pulse ...

Clive Elliott GW4MBS
 

On Tue, Jun 2, 2020 at 04:08 PM, Chris Bartram G4DGU wrote:
Like you I can't claim to have any real interest in HF, although I do occasionally operate there to remind myself of how to operate on that mode!
Chris I used to live under the G3JVL-G3YGF path so it seemed a shame not to join in. So I built a memory keyer & left it running for hours on end. It still annoys me to this day when Class A licensees would imply that I merely held a novice licence. How dare they! My retort used to be ok let's talk about it on 10GHz SSB, oh can't you manage that?

Having said that I do go on 80m every day but just for CW practice.

 
--
Clive GW4MBS (ex-G8ADP)
Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a triumph of optimism over geography!


Re: Activity List for the UK Microwave Group 5.7/10GHz Contests - 31 May

Nick Gregory G0HIK
 

I wonder how people found conditions on 10G at the weekend?

I went out for the first time this year, I had limited time available.

I only managed to complete with one station ODX 250Km, but it was difficult.

All the other tests were a failure.

Were Condx terrible or does my kit need a looking at ? 

BTW this was from around 11:00 to 13:00 Local.

Nick G0HIK IO84


Re: Resurecting Pulse ...

Chris Bartram G4DGU
 

Thanks for posting that paper. It and some of the cited references look very interesting indeed.

73

Chris G4DGU

On 02/06/2020 16:16, Dave G8KHU wrote:
There's this ready to go on 23cms ...
https://lss.fnal.gov/archive/2016/conf/fermilab-conf-16-685-ad.pdf
Dave
_._,_._,_


Re: Resurecting Pulse ...

Dave G8KHU
 


Re: Resurecting Pulse ...

Chris Bartram G4DGU
 

On 02/06/2020 15:14, Clive Elliott GW4MBS via groups.io wrote:
The only reason I took out a Class A licence was to legally use CW on 10GHz. It was a chance remark by G3YGF that it would be helpful for our tropo-scatter tests that finally spurred me to get on with it. I have no interest in HF - honestly.
Hello Clive,

As a 'jait' I was reported by a local (I think I know who ...) to the local GPO inspector for using CW to test with G3JVL on 1296. Fortunately, I knew the inspector from another activity, and his comment was 'you can obviously use morse, so go and take the test'. I did, and passed. Like you I can't claim to have any real interest in HF, although I do occasionally operate there to remind myself of how to operate on that mode!

73

Chris G4DGU


Re: Resurecting Pulse ...

KENT BRITAIN
 

Throw in antenna pointing plus frequency and we have
pretty much eliminated any random QSO's. 

Back to low power CW and long time duration integrating.

Cheers Kent

On Tuesday, June 2, 2020, 9:27:07 AM CDT, Andy G4JNT <andy.g4jnt@...> wrote:


You would use GPS/GNSS locking, good for 10ns pulse-to-pulse repeatability, then search over time to cater for path length unknowns.  You could programme-in the path length to give the search algorithm a starting point.   A bit like setting an FSK demodulator to roughly the right frequency then letting it search for the exact tuning point. 



On Tue, 2 Jun 2020 at 14:40, KENT BRITAIN <WA5VJB@...> wrote:
The SDR's are pretty good a integrating average power.   i.e. Waterfall displays.

Unless the pulse and the SDR samples were timed together (Very difficult with
unknown path lengths) there would be no advantage.  At the time of that ruling
most aircraft Radar rec's were just a 1N23 in waveguide with a 2K25 klystron
to convert it down to 30 MHz.   Near zero rejection of pulses in the ham bands.

And I won't even go into the fun of building Multi KV VCO's to control
the Mags!   Probably have better luck with injection locking.

73 Kent WA5VJB


On Tuesday, June 2, 2020, 8:21:51 AM CDT, Chris Bartram G4DGU <chris@...> wrote:


All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Re: Resurecting Pulse ...

KENT BRITAIN
 

Death wish is a good point.

He had used the high voltage regulators from a 32 KV Colour TV
CRT power supply.in his VCO circuit.    Written up in 73 Magazine as I recall.

Kent WA5VJB

On Tuesday, June 2, 2020, 9:21:58 AM CDT, Andy G4JNT <andy.g4jnt@...> wrote:


And talking of magnetrons:
There have been a number of discussions in the past about locking microwave-cooker magnetrons, but the consensus was that as they were not very high Q, it would need some tens of watts to injection lock properly.  But now those 'tens of watts' are commonplace.  So for someone with a kW rated circulator and a death wish ...
 


On Tue, 2 Jun 2020 at 14:21, Chris Bartram G4DGU <chris@...> wrote:
All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Re: Resurecting Pulse ...

Chris Bartram G4DGU
 

Hello Andy

I once, several decades ago, had a job designing RF diathermy equipment, and I was amazed at the ease with which it was possible to generate several hundred watts of 2.45GHz using a cheap magnetron. Locking of 'maggies' has been a topic of speculation for as long as I've been interested microwaves. At that time the PSUs were crude, although I was able to set that company on their path to the use of switchers before I moved-on.

I understand that the 6kW device used by the Bochum group to receive Venusian echoes was a phase locked, as opposed to injection locked, magnetron; it would be interesting to research that one day ... However, with the exception of 2.4GHz it seems likely that the sticking point would be locating a suitable tube tuned to an amateur frequency, unless, of course, somebody wishes to try making one!

73 Chris G4DGU


On 02/06/2020 15:21, Andy G4JNT wrote:
And talking of magnetrons:
There have been a number of discussions in the past about locking microwave-cooker magnetrons, but the consensus was that as they were not very high Q, it would need some tens of watts to injection lock properly.  But now those 'tens of watts' are commonplace.  So for someone with a kW rated circulator and a death wish ...
 


On Tue, 2 Jun 2020 at 14:21, Chris Bartram G4DGU <chris@...> wrote:
All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Re: Resurecting Pulse ...

Andy G4JNT
 

You would use GPS/GNSS locking, good for 10ns pulse-to-pulse repeatability, then search over time to cater for path length unknowns.  You could programme-in the path length to give the search algorithm a starting point.   A bit like setting an FSK demodulator to roughly the right frequency then letting it search for the exact tuning point. 



On Tue, 2 Jun 2020 at 14:40, KENT BRITAIN <WA5VJB@...> wrote:
The SDR's are pretty good a integrating average power.   i.e. Waterfall displays.

Unless the pulse and the SDR samples were timed together (Very difficult with
unknown path lengths) there would be no advantage.  At the time of that ruling
most aircraft Radar rec's were just a 1N23 in waveguide with a 2K25 klystron
to convert it down to 30 MHz.   Near zero rejection of pulses in the ham bands.

And I won't even go into the fun of building Multi KV VCO's to control
the Mags!   Probably have better luck with injection locking.

73 Kent WA5VJB


On Tuesday, June 2, 2020, 8:21:51 AM CDT, Chris Bartram G4DGU <chris@...> wrote:


All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Re: Resurecting Pulse ...

Andy G4JNT
 

And talking of magnetrons:
There have been a number of discussions in the past about locking microwave-cooker magnetrons, but the consensus was that as they were not very high Q, it would need some tens of watts to injection lock properly.  But now those 'tens of watts' are commonplace.  So for someone with a kW rated circulator and a death wish ...
 


On Tue, 2 Jun 2020 at 14:21, Chris Bartram G4DGU <chris@...> wrote:
All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Re: Resurecting Pulse ...

Clive Elliott GW4MBS
 

The only reason I took out a Class A licence was to legally use CW on 10GHz. It was a chance remark by G3YGF that it would be helpful for our tropo-scatter tests that finally spurred me to get on with it. I have no interest in HF - honestly.
--
Clive GW4MBS (ex-G8ADP)
Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a triumph of optimism over geography!


Re: Resurecting Pulse ...

Ron
 

Still there on 1981 issue.

Ron, G6BMY

On 02/06/2020 14:47, Clive Elliott GW4MBS via groups.io wrote:
On Tue, Jun 2, 2020 at 02:31 PM, Andy G4JNT wrote:
ANyone have a copy of the licence pre 1976 ish?
This is from my 1964 Class B Licence

 
--
Clive GW4MBS (ex-G8ADP)
Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a triumph of optimism over geography!


Virus-free. www.avg.com


Re: Resurecting Pulse ...

John E. Beech
 

At one time G8's weren't even allowed to send a K-tone at the end of their transmissions because that was Morse! The licence contradicted itself, because it also said you were allowed to use radio as part of self training, which could be interpreted as sending & receiving Morse. I got told of for doing exactly that by a Class A licensee who queried my callsign. My Morse was obviously good enough for him to read me, so what was the problem?! Anyway I gave up after that; never did pass a Morse test. I could send & receive Morse better when I was eleven than I can now at 71!

de John G8SEQ

-------Original Message-------
From: Andy G4JNT <andy.g4jnt@gmail.com>
To: UK Microwaves groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Resurecting Pulse ...
Sent: Jun 02 '20 14:55

That's interesting.
2.5kW DC input, magnetrons were quite efficient so perhaps 2kW at 1%
duty cycle

According to that schedule, SSB is permitted on 432 and higher, but
not CW ? Is that because you were a jait, and weren't allowed to use
it even if you could or wanted to


Andy
www.g4jnt.com

On Tue, 2 Jun 2020 at 14:47, Clive Elliott GW4MBS via groups.io
<humber1ton=btinternet.com@groups.io> wrote:

> On Tue, Jun 2, 2020 at 02:31 PM, Andy G4JNT wrote:
>
>> ANyone have a copy of the licence pre 1976 ish?
> This is from my 1964 Class B Licence
>
> --
> Clive GW4MBS (ex-G8ADP)
> Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a
> triumph of optimism over geography!


Re: Resurecting Pulse ...

Andy G4JNT
 

That's interesting.
2.5kW DC input, magnetrons were quite efficient so perhaps 2kW at 1% duty cycle

According to that schedule,   SSB is permitted on 432 and higher, but not CW ?     Is that because you were a jait, and weren't allowed to use it even if you could or wanted to
?



On Tue, 2 Jun 2020 at 14:47, Clive Elliott GW4MBS via groups.io <humber1ton=btinternet.com@groups.io> wrote:
On Tue, Jun 2, 2020 at 02:31 PM, Andy G4JNT wrote:
ANyone have a copy of the licence pre 1976 ish?
This is from my 1964 Class B Licence

 
--
Clive GW4MBS (ex-G8ADP)
Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a triumph of optimism over geography!


Re: Resurecting Pulse ...

Clive Elliott GW4MBS
 

On Tue, Jun 2, 2020 at 02:31 PM, Andy G4JNT wrote:
ANyone have a copy of the licence pre 1976 ish?
This is from my 1964 Class B Licence

 
--
Clive GW4MBS (ex-G8ADP)
Pottering on 6m - 3cm in a valley in IO71XW where any QSO is a triumph of optimism over geography!


Re: Resurecting Pulse ...

KENT BRITAIN
 

The SDR's are pretty good a integrating average power.   i.e. Waterfall displays.

Unless the pulse and the SDR samples were timed together (Very difficult with
unknown path lengths) there would be no advantage.  At the time of that ruling
most aircraft Radar rec's were just a 1N23 in waveguide with a 2K25 klystron
to convert it down to 30 MHz.   Near zero rejection of pulses in the ham bands.

And I won't even go into the fun of building Multi KV VCO's to control
the Mags!   Probably have better luck with injection locking.

73 Kent WA5VJB


On Tuesday, June 2, 2020, 8:21:51 AM CDT, Chris Bartram G4DGU <chris@...> wrote:


All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Re: Resurecting Pulse ...

John E. Beech
 

I think I've got my old paper licence from 1978 somewhere.

de John G8SEQ

-------Original Message-------
From: Andy G4JNT <andy.g4jnt@gmail.com>
To: UK Microwaves groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Resurecting Pulse ...
Sent: Jun 02 '20 14:32

I was about to say that there's now nothing to stop us doing pulse
operation if we wanted to, provided bandwidth is controlled.
Then remembered the old licence was based on short radar type pulses,
and that kilowatt pulses were permitted. ANyone have a copy of the
licence pre 1976 ish?

So I see what you're getting at.

Wasn't pulse-position modulation used on some of the early microwave
links ?
An old radar magnetron phase locked to GPS - now there's a thought

Andy
www.g4jnt.com

On Tue, 2 Jun 2020 at 14:21, Chris Bartram G4DGU
<chris@chris-bartram.co.uk> wrote:

> All of this talk of klystrons leads me to wonder what we might have
> been
> able to do had the UK Amateur licence had not been amended to
> remove the
> provision for pulse operation? A medium-sized magnetron, phase
> locked
> and suitably modulated could well make quite an impression,
> particularly
> now that good receivers and DSP are available ... Please discuss,
> dismiss, laugh, or cry as appropriate!
>
> 73 Chris G4DGU


Re: Resurecting Pulse ...

John E. Beech
 

Hi Chris,
I did dream up a scheme for frequency modulating a microwave oven magnetron. The idea was to wind a coil of several hundred turns between the two magnets and driving it with an audio power amplifier of (say) 10 Watts. This would modulate the static magnetic field to give nbfm. I haven't done any calculations as to how many turns/power (current) required. With a modern solid state amp it might be necessary to use some form of auto transformer to match the impedance.

de John G8SEQ

-------Original Message-------
From: Chris Bartram G4DGU <chris@chris-bartram.co.uk>
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: [UKMicrowaves] Resurecting Pulse ...
Sent: Jun 02 '20 14:21

All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Re: Resurecting Pulse ...

Andy G4JNT
 

I was about to say that there's now nothing to stop us doing pulse operation if we wanted to, provided bandwidth is controlled.
Then remembered the old licence was based on short radar type pulses, and that kilowatt pulses were permitted.  ANyone have a copy of the licence pre 1976 ish?

So I see what you're getting at.

Wasn't pulse-position modulation used on some of the early microwave links ?
An old radar magnetron phase locked to GPS - now there's a thought



On Tue, 2 Jun 2020 at 14:21, Chris Bartram G4DGU <chris@...> wrote:
All of this talk of klystrons leads me to wonder what we might have been
able to do had the UK Amateur licence had not been amended to remove the
provision for pulse operation? A medium-sized magnetron, phase locked
and suitably modulated could well make quite an impression, particularly
now that good receivers and DSP are available  ... Please discuss,
dismiss, laugh, or cry as appropriate!

73 Chris G4DGU






Resurecting Pulse ...

Chris Bartram G4DGU
 

All of this talk of klystrons leads me to wonder what we might have been able to do had the UK Amateur licence had not been amended to remove the provision for pulse operation? A medium-sized magnetron, phase locked and suitably modulated could well make quite an impression, particularly now that good receivers and DSP are available  ... Please discuss, dismiss, laugh, or cry as appropriate!

73 Chris G4DGU

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