Date   

Re: GB3MCB

SAM JEWELL
 

My preference is towards the W/SW, based in location and windows in the room. 

73 de Sam


Sent tomorrow from my time machine


On 8 Mar 2021, at 15:49, John Fell <john.g0api@...> wrote:


Good to hear that Sam.
If it points out of a window looking SSW , I may be able to hear it again.

73
John
G0API

On Mon, 8 Mar 2021 at 14:26, SAM JEWELL via groups.io <jewell=btinternet.com@groups.io> wrote:
The subject of the GB3MHZ 3cm beacon came up during today’s Martlesham Radio Society AGM (on Zoom, where else?!).
The beacon power level is well down on normal, hence reception can be difficult. Site access is a continuing problem. However, as soon as room access can be arranged a temporary 3cm beacon, running a bit more power, will be installed in one of the tower windows. This will restrict take off direction, but is better than no beacon. Once outside access to the antenna gallery can be arranged, something more permanent can be installed.

73 de Sam, G4DDK


Sent tomorrow from my time machine


> On 8 Mar 2021, at 14:17, Chris Bartram G4DGU <chris@...> wrote:
>
> Was that report of the reception of 'MCB today, Dave? I'm located only about 5km from the beacon, and it is usually audible here, albeit quite weak due to the beacon's location not far up the mast on Hensbarrow Downs and path obstruction caused by the aforementioned lump of granite.
>
> On a near-LOS path, such as that from Hensbarrow to quite a lot of Dartmoor, the path losses can be quite low: as soon as obstructions come into play, they increase quite surprisingly.
>
> I've listened for the signal several times over the last few days, and nothing has been audible. Although I'm only using a low-noise feedhorn as an antenna, that has a waveguide-input HEMT preamp driving a transverter which is well proven, I'm surprised that I've not seen anything. If the output power has crashed significantly, that could explain the problem.
>
> One of the problems with MCB/10GHz is that the group who host it seem to give it a very low priority. I'm not even sure that they have the ability to monitor it properly. I get the impression that they treat it as a bit of a PITA.
>
> 73
>
> Chris G4DGU
>
>
>
>
>







Re: Re GB3MCB

John Fell
 

Hi Dave ,
That signal is a good 579 in EME ears ......
I just looked up my last Spot of MCB and I see it is very close to the frequency you quote today - which makes me happy to know it was not another spurion .It was VERY weak though .Now my Pine tree 'tut West /SW is now 20Ft lower I hope to hear MCB during good RS .If all else may take some kit down to Helston in June hols .

73
John
G0API 

On Mon, 8 Mar 2021 at 13:05, Dave via groups.io <davidnewman55=icloud.com@groups.io> wrote:
I stopped briefly by the roadside at a very elevated spot 
(362 masl)at IO70XM west of Princetown with an excellent low horizon to the Cornish beacon on 10ghz.
The recording is enclosed , and I can convert it to another file type if necessary.
Using a DB6NT transverter mark 3 with GPS control and an FT817 the frequency came out at 10368.96833 MHz.
The report was 569 and with high pressure and only being 58km away I had expected thew beacon to be a bit stronger.
73
Dave G4GLT






Re: GB3MCB

John Fell
 

Good to hear that Sam.
If it points out of a window looking SSW , I may be able to hear it again.

73
John
G0API

On Mon, 8 Mar 2021 at 14:26, SAM JEWELL via groups.io <jewell=btinternet.com@groups.io> wrote:
The subject of the GB3MHZ 3cm beacon came up during today’s Martlesham Radio Society AGM (on Zoom, where else?!).
The beacon power level is well down on normal, hence reception can be difficult. Site access is a continuing problem. However, as soon as room access can be arranged a temporary 3cm beacon, running a bit more power, will be installed in one of the tower windows. This will restrict take off direction, but is better than no beacon. Once outside access to the antenna gallery can be arranged, something more permanent can be installed.

73 de Sam, G4DDK


Sent tomorrow from my time machine


> On 8 Mar 2021, at 14:17, Chris Bartram G4DGU <chris@...> wrote:
>
> Was that report of the reception of 'MCB today, Dave? I'm located only about 5km from the beacon, and it is usually audible here, albeit quite weak due to the beacon's location not far up the mast on Hensbarrow Downs and path obstruction caused by the aforementioned lump of granite.
>
> On a near-LOS path, such as that from Hensbarrow to quite a lot of Dartmoor, the path losses can be quite low: as soon as obstructions come into play, they increase quite surprisingly.
>
> I've listened for the signal several times over the last few days, and nothing has been audible. Although I'm only using a low-noise feedhorn as an antenna, that has a waveguide-input HEMT preamp driving a transverter which is well proven, I'm surprised that I've not seen anything. If the output power has crashed significantly, that could explain the problem.
>
> One of the problems with MCB/10GHz is that the group who host it seem to give it a very low priority. I'm not even sure that they have the ability to monitor it properly. I get the impression that they treat it as a bit of a PITA.
>
> 73
>
> Chris G4DGU
>
>
>
>
>







Re: 'MCB

John Fell
 

Maybe the spurious signal is due to a rusty bolt diode multiplier on the Wind machine ....LOL.

I think the Cornish Beacon Group do a good job of keeping beacons across the bands going and they are to be congratulated on providing space for a10GHz beacon .

My understanding is John G8ACE and Brian G4NNS provide the beacon and logistical support - from over 200 miles away .....

If MCB is to be heard it will probably be by RS and looking at forecast could occur quite soon .

Even LEX was below noise earlier today .

Have you had decodes from KBQ Neil ?

73
John
G0API


On Mon, 8 Mar 2021 at 14:59, Neil Smith G4DBN <neil@...> wrote:
Thanks Dave and Chris, what I was seeing is very very close to that
frequency, but I was definitely not seeing any FSK, so that nails the
factr that I was seeing something that is probably an artefact from a
strong out of band signal in the same direction. I can't see ANYTHING
that is in that direction though, so perhaps it is something on a
sidelobe, but I can't find it now.  Has to be on an X band or higher
frequency as the signal traverses 80cm of WR90.  There is nothing at all
in terms of human habitation or anothing other than fields for almost 15
miles, and then it is only a couple of villages.  There is a wind
tuirbine exactly on that path, so it is possible that I'm seeing a
reflection of a harmonic of something, but it is remarkably stable.

Anyway, definitely NOT GB3MCB. It would be great to see it again, I used
to see it coming through quite regularly.

Neil G4DBN


On 08/03/2021 14:46, Chris Bartram G4DGU wrote:
> Armed with Dave's measurement of frequency, I had another look for
> MCB, this time using a reputedly 20dBi patch array antenna. It is
> there, but just too weak to copy the FSK aurally. As an estimate, the
> level here is of the order of 25dB below that I which was seeing when
> I last looked - but that was about 18months ago.
>
> I almost agree with the frequency Dave quotes. Also using a GPS
> referenced system, I made the frequency (at about 14.00)
> 10368.896832MHz. As the beacon isn't frequency locked that's pretty
> close ...
>
> 73







Re: Multiband loop dish feed

David Law
 

I think that's a fair idea. I'd be interested to see how that goes. 


Re: 'MCB

Neil Smith G4DBN
 

Thanks Dave and Chris, what I was seeing is very very close to that frequency, but I was definitely not seeing any FSK, so that nails the factr that I was seeing something that is probably an artefact from a strong out of band signal in the same direction. I can't see ANYTHING that is in that direction though, so perhaps it is something on a sidelobe, but I can't find it now.  Has to be on an X band or higher frequency as the signal traverses 80cm of WR90.  There is nothing at all in terms of human habitation or anothing other than fields for almost 15 miles, and then it is only a couple of villages.  There is a wind tuirbine exactly on that path, so it is possible that I'm seeing a reflection of a harmonic of something, but it is remarkably stable.

Anyway, definitely NOT GB3MCB. It would be great to see it again, I used to see it coming through quite regularly.

Neil G4DBN

On 08/03/2021 14:46, Chris Bartram G4DGU wrote:
Armed with Dave's measurement of frequency, I had another look for MCB, this time using a reputedly 20dBi patch array antenna. It is there, but just too weak to copy the FSK aurally. As an estimate, the level here is of the order of 25dB below that I which was seeing when I last looked - but that was about 18months ago.

I almost agree with the frequency Dave quotes. Also using a GPS referenced system, I made the frequency (at about 14.00) 10368.896832MHz. As the beacon isn't frequency locked that's pretty close ...

73


Multiband loop dish feed

Barry VE4MA <ve4ma@...>
 

Hi John,

I have  not played with the loops, but with the dual dipoles over the ground plane, there is a dimiinishing return on the size of the groiund plane. A perfect ground plane gives you optimum gain for a reflector and does not keep giving additonal gain as a shaped reflector ( corner or parabolic ) would.

I suspect that the performance reduction on the highest band is probably due to the effect of the other loops on the pattern.    If you want to experiment, why not try a new feed with just the highest band loop by itself?

Best 73
Barry VE4MA


Re: GB3MCB

Dave
 

Yes, GB3MCB was received this morning about 1100z. When I can listen properly I shall have to see if it can get a better signal level as it ought to be stronger I would have thought.
Dave G4GLT.

On 8 Mar 2021, at 14:26, SAM JEWELL via groups.io <jewell=btinternet.com@groups.io> wrote:

The subject of the GB3MHZ 3cm beacon came up during today’s Martlesham Radio Society AGM (on Zoom, where else?!).
The beacon power level is well down on normal, hence reception can be difficult. Site access is a continuing problem. However, as soon as room access can be arranged a temporary 3cm beacon, running a bit more power, will be installed in one of the tower windows. This will restrict take off direction, but is better than no beacon. Once outside access to the antenna gallery can be arranged, something more permanent can be installed.

73 de Sam, G4DDK


Sent tomorrow from my time machine


On 8 Mar 2021, at 14:17, Chris Bartram G4DGU <chris@chris-bartram.co.uk> wrote:

Was that report of the reception of 'MCB today, Dave? I'm located only about 5km from the beacon, and it is usually audible here, albeit quite weak due to the beacon's location not far up the mast on Hensbarrow Downs and path obstruction caused by the aforementioned lump of granite.

On a near-LOS path, such as that from Hensbarrow to quite a lot of Dartmoor, the path losses can be quite low: as soon as obstructions come into play, they increase quite surprisingly.

I've listened for the signal several times over the last few days, and nothing has been audible. Although I'm only using a low-noise feedhorn as an antenna, that has a waveguide-input HEMT preamp driving a transverter which is well proven, I'm surprised that I've not seen anything. If the output power has crashed significantly, that could explain the problem.

One of the problems with MCB/10GHz is that the group who host it seem to give it a very low priority. I'm not even sure that they have the ability to monitor it properly. I get the impression that they treat it as a bit of a PITA.

73

Chris G4DGU









'MCB

Chris Bartram G4DGU
 

Armed with Dave's measurement of frequency, I had another look for MCB, this time using a reputedly 20dBi patch array antenna. It is there, but just too weak to copy the FSK aurally. As an estimate, the level here is of the order of 25dB below that I which was seeing when I last looked - but that was about 18months ago.

I almost agree with the frequency Dave quotes. Also using a GPS referenced system, I made the frequency (at about 14.00) 10368.896832MHz. As the beacon isn't frequency locked that's pretty close ...

73

Chris G4DGU


Re: GB3MCB

SAM JEWELL
 

The subject of the GB3MHZ 3cm beacon came up during today’s Martlesham Radio Society AGM (on Zoom, where else?!).
The beacon power level is well down on normal, hence reception can be difficult. Site access is a continuing problem. However, as soon as room access can be arranged a temporary 3cm beacon, running a bit more power, will be installed in one of the tower windows. This will restrict take off direction, but is better than no beacon. Once outside access to the antenna gallery can be arranged, something more permanent can be installed.

73 de Sam, G4DDK


Sent tomorrow from my time machine

On 8 Mar 2021, at 14:17, Chris Bartram G4DGU <chris@chris-bartram.co.uk> wrote:

Was that report of the reception of 'MCB today, Dave? I'm located only about 5km from the beacon, and it is usually audible here, albeit quite weak due to the beacon's location not far up the mast on Hensbarrow Downs and path obstruction caused by the aforementioned lump of granite.

On a near-LOS path, such as that from Hensbarrow to quite a lot of Dartmoor, the path losses can be quite low: as soon as obstructions come into play, they increase quite surprisingly.

I've listened for the signal several times over the last few days, and nothing has been audible. Although I'm only using a low-noise feedhorn as an antenna, that has a waveguide-input HEMT preamp driving a transverter which is well proven, I'm surprised that I've not seen anything. If the output power has crashed significantly, that could explain the problem.

One of the problems with MCB/10GHz is that the group who host it seem to give it a very low priority. I'm not even sure that they have the ability to monitor it properly. I get the impression that they treat it as a bit of a PITA.

73

Chris G4DGU





Re: GB3MCB

Chris Bartram G4DGU
 

Was that report of the reception of 'MCB today, Dave? I'm located only about 5km from the beacon, and it is usually audible here, albeit quite weak due to the beacon's location not far up the mast on Hensbarrow Downs and path obstruction caused by the aforementioned lump of granite.

On a near-LOS path, such as that from Hensbarrow to quite a lot of Dartmoor, the path losses can be quite low: as soon as obstructions come into play, they increase quite surprisingly.

I've listened for the signal several times over the last few days, and nothing has been audible. Although I'm only using a low-noise feedhorn as an antenna, that has a waveguide-input HEMT preamp driving a transverter which is well proven, I'm surprised that I've not seen anything. If the output power has crashed significantly, that could explain the problem.

One of the problems with MCB/10GHz is that the group who host it seem to give it a very low priority. I'm not even sure that they have the ability to monitor it properly. I get the impression that they treat it as a bit of a PITA.

73

Chris G4DGU


Re: How to decode JT4G #10ghz

Maarten PA0MHE
 

Found, thanks all


Re: How to decode JT4G #10ghz

Andy G4JNT
 

Use the up/down arrows on the Submode box.   Slightly bottom right of the centre


On Mon, 8 Mar 2021 at 10:44, Maarten PA0MHE <maarten.heuvelman@...> wrote:
Thanks Andy,

Sorry for my ignorance, but then my questions should be: How to select a "Submode"


Re: How to decode JT4G #10ghz

Tom GM8MJV
 

Maarten

Down by the ’Submode A’ field  there are two up/down arrows - click them.

This will list all the sub-mode - select G


Tom
GM8MJV

On 8 Mar 2021, at 10:44, Maarten PA0MHE <maarten.heuvelman@...> wrote:

Thanks Andy,

Sorry for my ignorance, but then my questions should be: How to select a "Submode"


Re: How to decode JT4G #10ghz

Maarten PA0MHE
 

Thanks Andy,

Sorry for my ignorance, but then my questions should be: How to select a "Submode"


Re: Phase Centre of WiFi dongle

John E. Beech
 

Very interesting Murray. Shows how much I'm out of touch with modern electronics. However, after googling how they
work, it seems the associated ground plane is doing a lot of the radiating & in a dongle the g-plane is probably acting
more like a patch antenna.
I might buy a few and try them as a dish feed.

de John G8SEQ

-------Original Message-------
From: Murray Niman <g6jyb@microwavers.org>
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Phase Centre of WiFi dongle
Sent: Mar 08 '21 06:50

Plenty of small ceramic antennas around...
Look on here and you will see similar:-

https://uk.farnell.com/c/passive-components/antennas-single-band-chip

Their physical size vs freespace wavelength may not be uber-efficient
though, but for short range WiFi or bluetooth it doesnt matter much

Murray


Re: How to decode JT4G #10ghz

Andy G4JNT
 

I don't know what you mean by "JT4G A" indication

The mode is JT4, submodes A - G  
so you have JT4A, JT4B...JT4G.    The microwave beacons use JT4G

So just select G in the pulldown menu.

image.png


On Mon, 8 Mar 2021 at 09:07, Maarten PA0MHE <maarten.heuvelman@...> wrote:
The tick setting "Enable VHF and Submode Features" was already done. So does this mean WJST-X v2.4.0-rc1 now already can decode JT4G despite the JT4G A indication ?


Multiband loop dish feed

John Lemay
 

'Morning all

I have a question, and a proposal, about multiband loop dish feeds:

I'm using a home-made dish feed for 23/13/9cms, which is similar to the RF
HamDesign series, with a full wave circular loop for each band in front of a
140mm diameter solid reflector. Each band has a separate connector.

My gut feeling is that on 9cms, performance is down a few dB. I've measured
sun noise, which I found quite tricky, and there's a deficit of about 1.5dB
in the Y factor between sun and cold sky.

In terms of wavelengths, the reflector is a different size for each band.
Therefore on 9cms it is a relatively large reflector which leads to a
narrower beam from the feed, with consequent under illumination of the dish.
That's my thinking - and I'm happy to be corrected here !

Based on that thinking, my proposal is to use a solid reflector of about a
wavelength diameter on 9cms, surrounded by a mesh ring reflector of a
wavelength diameter on 23cms. For example, a 20mm mesh is almost transparent
at 9cms, but reflective on 23cms. This leaves a mid-way effectiveness on
13cms - not sure about this.

Is this proposal a totally whacky idea - or well worth trying ??

TIA

John G4ZTR


--
This email has been checked for viruses by AVG.
https://www.avg.com


Re: How to decode JT4G #10ghz

Maarten PA0MHE
 

The tick setting "Enable VHF and Submode Features" was already done. So does this mean WJST-X v2.4.0-rc1 now already can decode JT4G despite the JT4G A indication ?


Re: How to decode JT4G #10ghz

Maarten PA0MHE
 

Thanks Andy
73's Maarten

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