Date   

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


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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


Re: How to decode JT4G #10ghz

Andy G4JNT
 

Go into  files-settings  and tick the box "Enable VHF and Submode Features"



On Mon, 8 Mar 2021 at 07:35, Maarten PA0MHE <maarten.heuvelman@...> wrote:
I'm trying to decode the GB3PKT beacon on 10GHz which I can receive weakly. However my WJST-X only knows JT4G-A.
Is there a difference and if Yes, how to setup decoding ?
--


How to decode JT4G #10ghz

Maarten PA0MHE
 

I'm trying to decode the GB3PKT beacon on 10GHz which I can receive weakly. However my WJST-X only knows JT4G-A.
Is there a difference and if Yes, how to setup decoding ?
--


Re: Phase Centre of WiFi dongle

Murray Niman
 


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: Phase Centre of WiFi dongle

Glyn M0XGT
 

I think it’s always going to be slightly tricky relying on the internal antenna in the dongle – better to either hack the board and connect via the test connector or use a device that has external antenna connectors. 
 
The solution I like is a Ubiquiti Bullet M5, or dual-chain Rocket M5, with external N-type or SMA (after RP-SMA adaptors) connectors and an Ethernet connection to a 24V POE switch or POE injector plus 24V DC-DC converter and LiPo. This lets you put the access point at the top of a mast with data and power run over a long outdoor Ethernet cable, and it leaves you with just a short coax run to the antenna ports. I get the ubiquity kit on eBay, new from Latvia or used from UK/EU.
 
I have a collection of different antennas depending on the task: 6 dBi or 8 dBi omnis for UAV ground-to-air links or general area coverage, a pair of 18 dBi patches for moderate distance, and a pair of 28 dBi dual-polarised dishes for much long point-to-point links. For short range links you can push the data-link channel bandwidth right up (300 Mb/s with 40 MHz channels, dual-chain) or dial it down to increase the range. 
 
Glyn M0XGT  
 


Re: Phase Centre of WiFi dongle

John E. Beech
 

Tnx Glynn,
I did do some tests a few years ago which showed some promise. I used a Sky/Amstrad elliptical dish (
designed for 11 GHz, so reduced gain at 2.45 GHz about 20 dB) at one end with a helical feed antenna and about
10 ft of RG58 with an SMA connector on one end to connect to the Wifi card in a desktop PC. The other end of
the link had a
60 cm diam Grampian outside broadcast microphone dish ( also about 20 dB, which I had previously used on 3 cm
WBFM) with the dongle at/near the focus. It worked over the length of my garden - hardly surprising as the distance
was only 130 feet! The "normal" wifi set-up dropped out at that distance.
I then tried it at a range of about 1 km ie between my QTH & Coventry ARS QTH with mixed results. The
path should be line of sight, across a valley, but it is obstructed. The only place I could detect it was 50 yards up the
drive (inconvenient) from the club house ( church hall). At the time I chose "middle for diddle" as far as dongle/dish
focus went.
However, since then one of the obstructions to wit a 120 ft tall Lombardy Poplar tree at the bottom of my
garden has gone - blown down in a gale and sawn up for firewood. So I thought I might try again, but this time
optimising the system a bit better. And perhaps I might get it to work via a reflectin path as there are a number of
high rise buildings dotted about the area.

de John G8SEQ

-------Original Message-------
From: Glyn M0XGT <glyn.thomas512@gmail.com>
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Phase Centre of WiFi dongle
Sent: Mar 07 '21 17:15

It's usually at the far end opposite the USB connector (along with a
u.fl test connector that you can hack).
What sort of link distance are you aiming for?

Glyn M0XGT


Re: Phase Centre of WiFi dongle

John E. Beech
 

Tnx fer that Peter,
Is that white ceramic thing really an antenna for 2.45 GHz. I've never seen one like that &
wouldn't have recognised it as an antenna. Or is it a matching device or phase shifting device for a track on the
other side of the PCB that acts as an antenna. I'm thinking circular / mixed polarization. There is some symmetry to
the board which suggests there may be two antennas at right angles, if you look at the bottom LH corner of the
board.

de John G8SEQ

-------Original Message-------
From: Peter Burgess via groups.io <g4bch=yahoo.com@groups.io>
To: ukmicrowaves@groups.io <ukmicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Phase Centre of WiFi dongle
Sent: Mar 07 '21 18:09

Hi John

A google search for D-link DWL-G122 H/W pcb brought up an image of a
dissasmbled unit.

http://studycasini.dx.am/d-link-dwl-g700ap-drivers-for-mac.html image
near the bottom of the page.

It looks like it uses a small ceramic chip antenna under the Act LED
label.

Peter
G4BCH


Re: Phase Centre of WiFi dongle

Peter Burgess
 

Hi John

A google search for D-link DWL-G122 H/W pcb brought up an image of a dissasmbled unit.
It looks like it uses a small ceramic chip antenna under the Act LED label.

Peter
G4BCH


Re: Phase Centre of WiFi dongle

Glyn M0XGT
 

It's usually at the far end opposite the USB connector (along with a u.fl test connector that you can hack). 
What sort of link distance are you aiming for?

Glyn M0XGT 


Phase Centre of WiFi dongle

John E. Beech
 

Hi All,
Anyone any idea od where the phase centre of the antenna inside a wiFi Dongle might be? Specifically a D-link
DWL-G122 H/W. It is 60 mm high excluding the USB connector.

I'd like to be in or near the ball bark with my mounting, as I don't have much adjustment once it is fitted to my dish f/D
ratio about 0.3. I'm trying to extend the range for a point-to-point connection.

de John G8SEQ


Re: Mast head preamp box wanted

Michael Scott
 

Hi Rich

I think I have a couple which I bought years ago and have never used, and you can have them for the cost of postage if that helps.

73, Mike, G3LYP.

On 06/03/2021 16:42, G8ZHA via groups.io wrote:

I am looking for a suitable box for a mast mounted preamp.

 

One such as the SHF-Electroink  type as shown on the attached picture.

 

I did manage to pick one up from a rally a few years ago – does anyone know who sells them?

 

Rich G8ZHA


Re: GB3KBQ

Adrian G4UVZ
 

Thanks both ...I think thatthe rainey season is on it's way again so that should help propogation!!

A


Re: Contest 7th March

Noel G8GTZ
 

I intend to be on 13 and 9cms from around 12 noon.

73
Noel - G8GTZ


Re: Mast head preamp box wanted

G8ZHA
 

Just what I need. Many thanks. Rich.

 

From: UKMicrowaves@groups.io [mailto:UKMicrowaves@groups.io] On Behalf Of Peter G3SMT via groups.io
Sent: 06 March 2021 16:49
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Mast head preamp box wanted

 

Rich,

Have a look here :-  https://g3nyk.ham-radio-op.net/componen.htm

Alan has the enclosures that you are looking for and is most helpful.

73

Peter  G3SMT

 

On 06/03/2021 16:42, G8ZHA via groups.io wrote:

I am looking for a suitable box for a mast mounted preamp.

 

One such as the SHF-Electroink  type as shown on the attached picture.

 

I did manage to pick one up from a rally a few years ago – does anyone know who sells them?

 

Rich G8ZHA


--
Peter G3SMT


Re: Mast head preamp box wanted

Peter G3SMT
 

Rich,

Have a look here :-  https://g3nyk.ham-radio-op.net/componen.htm

Alan has the enclosures that you are looking for and is most helpful.

73

Peter  G3SMT


On 06/03/2021 16:42, G8ZHA via groups.io wrote:

I am looking for a suitable box for a mast mounted preamp.

 

One such as the SHF-Electroink  type as shown on the attached picture.

 

I did manage to pick one up from a rally a few years ago – does anyone know who sells them?

 

Rich G8ZHA


--
Peter G3SMT

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