Date   

Re: Input Needed for RadCom Column

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  
_._,_._,_



Spectrum Analysers for sale from SK

Neil, G3RIR
 

I have two spectrum analysers for sale on behalf of the widow of an old friend of mine.

One is a Marconi TF2370 110 MHz I believe

The other is Tektronics 7603 with 7L18 plug-in  1.5 - 18 GHz.

I do not know if either are working as I do not know enough about them. Therefore I do not know the value.

Both are heavy so really only collect from my QTH south Leicestershire very near jnctn 20 M!.

If any one is seriously interested I may be able to take them to the Harwell Rally 9th Feb.

Neil G3RIR


Re: Input Needed for RadCom Column

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  


Re: Input Needed for RadCom Column

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


Re: Input Needed for RadCom Column

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


Re: Spectrum Analyser conundrum

geoffrey pike
 

Would you not think of using a YIG oscillator instead of a synth?
cheers
Geoff
GI0GDP

On Tuesday, 21 January 2020, 20:27:05 GMT, Andy G4JNT <andy.g4jnt@...> wrote:


Openly Pondering ...

My Ailtech / Eaton 757   22GHz spectrum analyser has died.   Now, I could just dig inside and repair it - looks like the main PSU has failed somewhere, so probably is repairable, and I hate repairing stuff, especially old tech.   ANd then there's all the niggly faults which appeared over time, probably dried out capacitors to be  replaced.   The thing weighs over 30kg has already hurt my back in days gone by and is too long in the tooth and irritating to drive

I'd buy a half- decent SA but many popular ones only go to a few GHz and 22GHz ones are not cheap. I already have a modern digital radio test set that has a quite good narrow band SA function that goes to 6GHz  with span up to a GHz, so spending a fair bit of money on an SA that doesn't go much beyond this seems totally pointless.

NOW ...

I have two old YIG filters that tune 4 - 18GHz.  The Ailtech will have another one inside it, as well as a harmonic mixer so thoughts are turning to an external converter.    YIG filter, harmonic mixer and integer-N synth LO with some basic drive electronics.   Simple enough.   Could butcher the old SA for it's harmonic mixer, or make one using a uWave DBM with subharmonic LO.  It also has the switchable attenuator going to 20GHz + and possibly other uWave bits that may prove useful

So the decision to repair (tedious and not exciting) or rip apart for bits to make an external converter has to be made,

Has anyone done this - an external SA convertger?   Might generate a bit of interest in building RF stuff again here !

 


Re: 23 cm yagi design

Chris Bartram G4DGU
 

Hello Ben,

AM hi.
Laugh you not! I know I'm by no means alone on this group in having made my first QSOs on 23cm using AM! At that time in the radio medieval (early 1970s) , the kit consisted of a HB valve transmitter on 2m, and two cascaded varactor triplers from 2m. It's was probably a good thing that I didn't then have a spectrum analyser!

Incidentally, I still have some affection for varactor technology. It was much maligned, but used sensibly capable of very good performance. The Russians, in particular, used varactors extensively, and I have some which should allow quite high power on 47 and 76GHz if I ever find time to design and build the kit. Retirement seems to mean that there are even fewer hours in the day to play radio!

73

Chris G4DGU


Re: 23 cm yagi design

militaryoperator
 


73

Chris G4DGU - who you last worked as GW4DGU on 5MHz AM! There's an
admission!


-=-=-=-=-=-=-=-=-=-=-=-

We'll try 23 next Chris, AM hi. 


cheers. Ben


Re: 23 cm Yagi Design

ian hope (2E0IJH)
 

Justin G0KSC has recently been working on 23cm LFA's with promisig results, stuff has been on his Facebook page.
 
Ian
2E0IJH

 
 
Sent: Wednesday, January 22, 2020 at 1:47 AM
From: "Barry VE4MA" <ve4ma@...>
To: UKMicrowaves <UKMicrowaves@groups.io>
Subject: [UKMicrowaves] 23 cm Yagi Design
A corner reflector is a good but low gain option.   Loop yagis of all sizes are the antennas of choice in North America.  Good all weather performance ( yagis are problematic in wet weather).
 
Element kits are available from Directive Systems in the US at reasonable prices
 
73
Barry VE4MA/ K7
 


Re: 23 cm Yagi Design

alwyn.seeds1
 

Dear All,

When I checked the dimensions of the 25ele Wimo 23cm yagis, they appeared to follow the DL6WU design.

Take care in assembly and when connecting the feeder not to place stress on the driven element moulding- cracking of this and consequent problems has been frequently reported. 

Though the Wimos appear fairly fragile, they have now survived some years 24/7 at 32m agl on a hill-top in IO92, defying my rigger’s expectation.

The deterioration in performance with IO92 heavy rain and icing is not serious and is no problem to an SSPA in the 1296MHz part of the band. Those in IO74 and similar squares might need a shrouded yagi design. I have some of these for professional apps., but they are heavy beasts and prices are far from amateur.

Regards,

Alwyn G8DOH
_____________________________________________________

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
_____________________________________________________


Re: 23 cm Yagi Design

Barry VE4MA
 

I can also recommend the DL6WU Yagi designs as they are quite tolerant of wet weather and construction variations.  Only problem is supporting elements on longer booms

73
Barry VE4MA/ K7


From: "ve4ma" <ve4ma@...>
To: "UKMicrowaves" <UKMicrowaves@groups.io>
Sent: Tuesday, January 21, 2020 7:47:15 PM
Subject: 23 cm Yagi Design

A corner reflector is a good but low gain option.   Loop yagis of all sizes are the antennas of choice in North America.  Good all weather performance ( yagis are problematic in wet weather).

Element kits are available from Directive Systems in the US at reasonable prices

73
Barry VE4MA/ K7


Re: 23 cm Yagi Design

Peter
 

Personally, I have had success using the DL6WU Yagi designs at 23 cm.

Simply use the VK5DJ Yagi Calculator, available for download to install in a Windows PC. Carefully consider your material sizes, and simply plug the material sizes into the calculator. Then measure, drill and cut with care. I have a short Yagi built according to the calculator using 4 mm rod for elements and a 20 mm PVC pipe as the boom. It works well for SOTA. Longer Yagis work well if carefully built.

Cheers,

Peter VK3PF


23 cm Yagi Design

Barry VE4MA
 

A corner reflector is a good but low gain option.   Loop yagis of all sizes are the antennas of choice in North America.  Good all weather performance ( yagis are problematic in wet weather).

Element kits are available from Directive Systems in the US at reasonable prices

73
Barry VE4MA/ K7


Re: 23 cm yagi design

Alan Beard
 

Hi guys,

Would we do better at 23cm building a corner reflector?

I built a truncated corner reflector out of a 600 x 900 mesh sheet,
1mm gal wire 20mm mesh. I used two end fed dipoles (or 5/8s)
fed from a trombone match. It seemed to work about as well as
a 12el phased array.
Obviously it's much more 3D than a "flat" yagi. But I recognized
I couldn't build a yagi to the tolerances needed.
Very poor test gear here, a PocketVNA.

Alan VK2ZIW



On Tue, 21 Jan 2020 23:29:56 +0000, Chris Bartram G4DGU wrote
Hello Ben,

Is there any advantage to making the reflector either multi-element,
several elements above and below the boom, either at 90deg to the boom
or in a V shape pointing along the boom?
Essentially no! Yagies for the low microwave bands are very
difficult to get to work very well. I speak from experience :-) My
last design for 1296 which looked good in simulation took a lot of
work to get working properly, as shown by Sun and cold-sky/ground measurements.

Having used both yagies and dishes on 23 over time, I won't be
building a new yagi system for any band above above 432MHz.

73

Chris G4DGU - who you last worked as GW4DGU on 5MHz AM! There's an
admission!


---------------------------------------------------
Alan Beard

OpenWebMail 2.53


Re: 23 cm yagi design

Chris Bartram G4DGU
 

Hello Ben,

Is there any advantage to making the reflector either multi-element, several elements above and below the boom, either at 90deg to the boom or in a V shape pointing along the boom?
Essentially no! Yagies for the low microwave bands are very difficult to get to work very well. I speak from experience :-) My last design for 1296 which looked good in simulation took a lot of work to get working properly, as shown by Sun and cold-sky/ground measurements.

Having used both yagies and dishes on 23 over time, I won't be building a new yagi system for any band above above 432MHz.

73

Chris G4DGU - who you last worked as GW4DGU on 5MHz AM! There's an admission!


Re: 23 cm yagi design

KENT BRITAIN
 




If the other elements are optimized ...... NO.

Kent


Needed the plural form





On Tuesday, January 21, 2020, 4:35:43 PM CST, militaryoperator via Groups.Io <military1944@...> wrote:



Regarding 23cm yagi's. 

Is there any advantage to making the reflector either multi-element, several elements above and below the boom, either at 90deg to the boom or in a V shape pointing along the boom?

Ben


Re: 23 cm yagi design

KENT BRITAIN
 

If the other element are optimized ...... NO.

Kent

On Tuesday, January 21, 2020, 4:35:43 PM CST, militaryoperator via Groups.Io <military1944@...> wrote:



Regarding 23cm yagi's. 

Is there any advantage to making the reflector either multi-element, several elements above and below the boom, either at 90deg to the boom or in a V shape pointing along the boom?

Ben


Re: 23 cm yagi design

militaryoperator
 


Regarding 23cm yagi's. 

Is there any advantage to making the reflector either multi-element, several elements above and below the boom, either at 90deg to the boom or in a V shape pointing along the boom?

Ben


Spectrum Analyser conundrum

Andy G4JNT
 

Openly Pondering ...

My Ailtech / Eaton 757   22GHz spectrum analyser has died.   Now, I could just dig inside and repair it - looks like the main PSU has failed somewhere, so probably is repairable, and I hate repairing stuff, especially old tech.   ANd then there's all the niggly faults which appeared over time, probably dried out capacitors to be  replaced.   The thing weighs over 30kg has already hurt my back in days gone by and is too long in the tooth and irritating to drive

I'd buy a half- decent SA but many popular ones only go to a few GHz and 22GHz ones are not cheap. I already have a modern digital radio test set that has a quite good narrow band SA function that goes to 6GHz  with span up to a GHz, so spending a fair bit of money on an SA that doesn't go much beyond this seems totally pointless.

NOW ...

I have two old YIG filters that tune 4 - 18GHz.  The Ailtech will have another one inside it, as well as a harmonic mixer so thoughts are turning to an external converter.    YIG filter, harmonic mixer and integer-N synth LO with some basic drive electronics.   Simple enough.   Could butcher the old SA for it's harmonic mixer, or make one using a uWave DBM with subharmonic LO.  It also has the switchable attenuator going to 20GHz + and possibly other uWave bits that may prove useful

So the decision to repair (tedious and not exciting) or rip apart for bits to make an external converter has to be made,

Has anyone done this - an external SA convertger?   Might generate a bit of interest in building RF stuff again here !

 


Re: 13cms operation

Ed G3VPF
 

Thanks for the replies, e-mail duly sent to Ofcom. Perhaps the RSGB bandplans could include the link to the Ofcom document.

Waiting for 13cms PA to arrive from SG-Labs but should be on for the coming contest season.

Ed G3VPF IO80RQ


From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of Neil Smith G4DBN <neil@...>
Sent: 21 January 2020 13:40
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] 13cms operation
 

Thanks for the reminder that the 2300 MHz NoVs need renewing after 3 years.  Mine was due to run out, so I renewed it.  You just need your licence reference number and details of any /P locations you intend to use.

Neil G4DBN

On 21/01/2020 13:13, Murray Niman wrote:

Hi Stuart

>"The UK Amateur Licence Schedules have a number of designated zones where restrictions apply"
Please read Schedule-2 of your Licence - the map is what that table is when you plot it!

More uptodate mapping guidance is on
https://rsgb.org/main/operating/licensing-novs-visitors/uk-licensing/guidance-resources/

 Murray G6JYB
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>