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Re: Monday Night Activity

g4bao
 

I'm QRV Now 2300, 2320, 10GHz 24GHz currently CQ 2320.200 to NW

73

John G4BAO JO02cg


Re: RAL 2015 14th June

Mike Willis
 

Hi Andy,

Yes though the joke is 20 years too late as previously its been a Harwell Round Table.

Mike


Monday Night Activity

g4bao
 

I'll be QRV from around 1930 on 2300.200, 2320.200 10368.200 and 24048.200 MHz. Nice and rainy with all my local beacons showing RS. Beaconing / CQing on CW in various directions. but not all at the same time:)  Looking for AS/RS skeds SSB/CW/JT
 
I'll listen 144.175 but you'll have to be >S6 due to my noise floor on 144

I'll be on KST
 
73
John 


Re: 10GHz World Record

John Fell
 

I agree with Chris - it is a very FB effort !

Somewhere near to Port William - IO74RR does indeed just scrape past EI to make the seapath down to the Canaries , so it would be interesting .

If that goes there is a slightly longer sea path that I found between Goular on North Uist , IO67FO to Cabedelo in Paraiba HI23OA08 - that would be a GM/SA first on 10GHz at a mere 7599.6km.
Now, how to erect a pair of EME size stations launching into the super refractive duct , would make for some thought......

HNY/V 73
John
G0API

Well its been a wet old day so making helical antennas for 10GHz and listening to GB3SCX from inside this warm shack.

On 12 January 2015 at 10:09, Christopher Bartram cbartram@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

I'd like to add my congratulations to VK7MO and VK6DZ to those of Roger.
It's interesting that their QSO was made using JT4 ...

It's worth noting that there seems to be an unobstructed oversea
great-circle path from Southerness, on the Solway, to the northern end
of Tenerife. Several years ago, I was trying to generate interest in EA8
for tests on 10GHz, but at that time, despite some interest, EAs weren't
licenced for the band, and, understandably, nobody wanted to try. Now
there is both interest and activity on the Canaries, the potential
exists for a GM-EA8 world record ...

Vy 73

Chris
GW4DGU
--



10GHz World Record

Christopher Bartram <cbartram@...>
 

I'd like to add my congratulations to VK7MO and VK6DZ to those of Roger. It's interesting that their QSO was made using JT4 ...

It's worth noting that there seems to be an unobstructed oversea great-circle path from Southerness, on the Solway, to the northern end of Tenerife. Several years ago, I was trying to generate interest in EA8 for tests on 10GHz, but at that time, despite some interest, EAs weren't licenced for the band, and, understandably, nobody wanted to try. Now there is both interest and activity on the Canaries, the potential exists for a GM-EA8 world record ...

Vy 73

Chris
GW4DGU
--


Re: RAL 2015 14th June

Mike Willis
 

Yes,  sorry but we have Newbury the following week and can't do the previous week as it's NFD.

Mike


Re: RAL 2015 14th June

John Fell
 

Seem to think you can get patches for that Andy..........LOL....

My mast is luffed too Mike - because we can.... tiz blowin from the West - again .

73 de John , playing 10GHz synths in the shack
G0API


Re: RAL 2015 14th June

g4bao
 

Hi Mike, you've picked the same weekend as the East Suffolk Rally again, where the ukug usually have a stand.

I'd like to come to RAL this year so I'll be looking for a volunteer from Eastern England to set up and run the Rally stand this year or it won't happen.

73

John

On 11 Jan 2015 12:24, "willis.mj@... [ukmicrowaves]" <ukmicrowaves@...> wrote:
 

Or I should say, nearly RAL as we have had to move venue.

As most of you know, I am not at RAL any more and that has been making things increasingly difficult.  The event this year is being sponsored by Harwell Amateur Radio Society (HARS) and we have made a booking for 14th June which will be held at a nice yet affordable venue, the village hall in East Hagbourne. Hall - Hagbourne Village | East Hagbourne Parish Council in Oxfordshire

Hall - Hagbourne Village | East Hagbourne Parish Council...
Hall - Hagbourne Village | The website of East Hagbourne Parish Council in Oxfordshire
Preview by Yahoo

 

There is plenty of parking and two large halls. I will be looking for some offers of talks. I think it would be quite nice to hear about innovative new experiments going on in the new allocations in the lower bands, e.g. 146MHz and 2300MHz.


Mike



Re: RAL 2015 14th June

Andy G4JNT
 

Does mean  we now have the Hagbourne RoundTable, or  HRT   :-)

'jnt



On 11 January 2015 at 12:24, willis.mj@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Or I should say, nearly RAL as we have had to move venue.

As most of you know, I am not at RAL any more and that has been making things increasingly difficult.  The event this year is being sponsored by Harwell Amateur Radio Society (HARS) and we have made a booking for 14th June which will be held at a nice yet affordable venue, the village hall in East Hagbourne. Hall - Hagbourne Village | East Hagbourne Parish Council in Oxfordshire

Hall - Hagbourne Village | East Hagbourne Parish Council...
Hall - Hagbourne Village | The website of East Hagbourne Parish Council in Oxfordshire
Preview by Yahoo

 

There is plenty of parking and two large halls. I will be looking for some offers of talks. I think it would be quite nice to hear about innovative new experiments going on in the new allocations in the lower bands, e.g. 146MHz and 2300MHz.


Mike




Re: QRV 2300, 2320 10GHz and 24GHz this morning

g4bao
 

No probe Mike. It's been remarkably calm here apart from a bit of a blow yesterday evening as the front passed over.
Being surrounded on 3 sides by hills has to have SOME advantages for a microwaver!

73
John

On Jan 11, 2015 12:07 PM, "willis.mj@... [ukmicrowaves]" <ukmicrowaves@...> wrote:
 

Sorry - my microwave mast is luffed over due to the effect of the high winds on my dishes - these storms are forecast to return so I'm leaving it that way and doing AMSAT / DATV stuff instead with my VHF/UHF mast. Even had a QSO via AO-73.

Mike


RAL 2015 14th June

Mike Willis
 

Or I should say, nearly RAL as we have had to move venue.

As most of you know, I am not at RAL any more and that has been making things increasingly difficult.  The event this year is being sponsored by Harwell Amateur Radio Society (HARS) and we have made a booking for 14th June which will be held at a nice yet affordable venue, the village hall in East Hagbourne. Hall - Hagbourne Village | East Hagbourne Parish Council in Oxfordshire

 

There is plenty of parking and two large halls. I will be looking for some offers of talks. I think it would be quite nice to hear about innovative new experiments going on in the new allocations in the lower bands, e.g. 146MHz and 2300MHz.


Mike



Re: QRV 2300, 2320 10GHz and 24GHz this morning

Mike Willis
 

Sorry - my microwave mast is luffed over due to the effect of the high winds on my dishes - these storms are forecast to return so I'm leaving it that way and doing AMSAT / DATV stuff instead with my VHF/UHF mast. Even had a QSO via AO-73.

Mike


QRV 2300, 2320 10GHz and 24GHz this morning

g4bao
 

Anyone for a test? SSB/CW/Digimodes,  WHU?

Otherwise I'll have to go play on HF

73
John G4BAO  


Re: WG20 Round flange

Christopher Bartram <cbartram@...>
 

Hello John

The answer is that _if_ you can calibrate the length of transmission-line as an attenuator, eg. by using a stable, well matched source and a VSWR indicator like the HP415, and confirm that it's well matched, then it would make a perfectly usable, albeit frequency-dependent, attenuator. The phase response might be also be a problem in some applications ...

If you were starting from scratch, measuring the return-loss might be difficult problem to solve, as good coaxial components such as directional couplers at frequencies above 18GHz (where conventional SMA connectors run out of steam), are difficult or expensive to buy. Waveguide components are much easier to find, and work better than coaxial/planar ones at 24GHz and up.

Transmission-lines, such as a waveguide operating below its cut-off frequency, have been, and I think still are, used as attenuation standards, as it's possible to directly relate the physical dimensions to attenuation.



Vy 73

Chris
GW4DGU

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Christopher Bartram RF Design
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Re: WG20 Round flange

Mark GM4ISM
 

John,
Quite possibly, good enough for amateur purposes anyway.
I had not considered this. I have certainly measured moderate losses at 24GHz with such cable assemblies.
 
a few caveats
You will probably have to get the cable you use checked out on good testgear.  microwave round tables are good for this, (or a visit to my shack.. not too convenient from GW i guess)
I suspect the attenuation and match may be affected by bending the cable so once measured it should be left well alone.
Avoid Elbow connectors!
I am not sure if the impedance of such cables is always  50Ohms to a reasonable accuracy.  If you are buying new coax for this purpose you can choose cable and connectors to the appropriate spec.
 
I have no idea as to the absolute stability of this sort of cable over time, or over a temperature range but given the large numbers of these cables in use in microwave gear, I don't expect you will see much change when in use. Kept away from dampness, in the shack at a relatively constant temperature I would imagine this would be OK 
You should be able to dissipate a reasonable amount of power in these cables. With 50W of 10GHz into a length of  141 semi-rigid, the losses are sufficient that the cable runs quite warm (I estimate I am easily dissipating a 2-5 watts in the short cable between the TWT output and the waveguide transition in my PA
If the cable gets really hot the coax insulation expands and soldered SMA connectors fall off.  I have seen this several times.
 
I have just done a few measurements on some pre-made lengths I have around. The longest has 12 dB attenuation but is showing a ripple  ( 0.75dB peak to trough) on the sweep indicative of a slight mismatch in the measurement system. Measuring its match terminated in a precision load showed why, it had only 15dB return loss.
Shorter cables tested had return losses ranging from 15 to 22dB  (For what its worth the measurement set is calibrated and has a quoted 38dB directivity)
 
all told a good well terminated length of semi-rigid , calibrated using the average loss measured over the approx freq range you would not have a huge error. If you were using such a cable to drop the output to a level suitable for a power meter, the added uncertainty may well be acceptable, it is probably no worse than a surplus directional coupler or surplus attenuator. You should be able to make reasonably repeatable measurements, which with amateur equipment is about as good as you can hope for.  Even measuring the loss to a reasonable accuracy will require access to good test equipment in the first place.
 
Lastly, you simply cannot assume the cables and coaxial components you happily use at 10GHz will be good at 24GHz  Get everything checked and use only components you know work up that high.
 
 
 
 
  Regards
Mark
GM4ISM
 
 
 
 

Sent: Saturday, January 10, 2015 5:17 PM
Subject: [ukmicrowaves] Re: WG20 Round flange
 
 

Mark

Not a solution but a question for my own education:-

Would a length of suitable semi rigid cable make a useable dissipative attenuator at 24 GHz that could be reliably calibrated? I see that some of the smaller types are quoted with very high figures  of attenuation per 100ft (300-500 dB) and are rated well beyond 24G.

John

MW1FGQ

 

 

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Re: WG20 Round flange

mw1fgq
 

Mark

Not a solution but a question for my own education:-

Would a length of suitable semi rigid cable make a useable dissipative attenuator at 24 GHz that could be reliably calibrated? I see that some of the smaller types are quoted with very high figures  of attenuation per 100ft (300-500 dB) and are rated well beyond 24G.

John

MW1FGQ




2300.35MHz Test Transmission

Andy G4JNT
 

2300.35MHz
Will be going all weekend running ISCAT-A
 (SSB Ref 2300.349MHz tuning point)

Currently pointing north from IO90IV58, RH circular polarised.  Beamwidth about 20 deg , and can be changed oN request.

Reports to beaconspot.eu pse.   It will recognise 2300MHz spots

Andy
G4JNT


Re: 10GHz World Record

Mansueto Grech <mansueto.grech@...>
 

OOOPs sorry Thanks for the info Roger
73's
Mans. 9H1GB

On 10 January 2015 at 10:16, Mansueto Grech <mansueto.grech@...> wrote:
Congrats to VK7MO and VK6DZ on their achievement.
Well done guys and keep it up
Mans. 9H1GB



On 10 January 2015 at 09:01, g8cub@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Congratulations to Rex VK7MO and Derek VK6DZ for their 2732km 10GHz contact - a new world record.

Well done!!


New World Record Claimed on 10 GHz


  Roger

G8CUB






Re: 10GHz World Record

Mansueto Grech <mansueto.grech@...>
 

Congrats to VK7MO and VK6DZ on their achievement.
Well done guys and keep it up
Mans. 9H1GB



On 10 January 2015 at 09:01, g8cub@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Congratulations to Rex VK7MO and Derek VK6DZ for their 2732km 10GHz contact - a new world record.

Well done!!


New World Record Claimed on 10 GHz


  Roger

G8CUB





10GHz World Record

Roger Ray
 

Congratulations to Rex VK7MO and Derek VK6DZ for their 2732km 10GHz contact - a new world record.

Well done!!

New World Record Claimed on 10 GHz


  Roger

G8CUB