Author Archives: gdars

PW 144MHz QRP Contest 2024 – Sunday 9th June 2024

Again members of the club will be going up the hill to operate a portable station for the Practical Wireless 144MHz QRP contest on Sunday 9th June 2024. We will be using the callsign GM4YEQ/P.

The contest runs between 0900-1500 UTC (1000-1600 Local/BST). We’ll likely be on-site by 0915 (local) if not earlier for setting up.

We’ll be at the usual “Middle Swire” location between the Yarrow and Ettrick valleys 6 miles west of Selkirk.

All club members are welcome to come and visit and catch up for a few hours, assist with setting up or operating, or operate your own sets on HF away from urban QRM.

Or if not able to come to the site, please give us a shout on 2m simplex FM or SSB if you hear us (144.150-144.397MHz is the SSB range). Someone will likely be scanning simplex channels 145.200-575MHz through the day. The more contacts we get (even local ones) the more points we get multiplied by the number of locator squares. Calling CQ on 145.500 isn’t allowed so don’t just listen for us there (nor on the repeaters)! Individual members may be monitoring repeaters and calling channels though if you want to make contact with someone in the group.

Exchange will be signal report, serial number (if you’re not participating then give 001 for your first contact) and your Maidenhead grid reference (or approximate location if you don’t know it as it still counts as a contact just not a new grid square).

Visitors should bring their own food and drink if they’re staying all day. Bring suitable clothing in case it’s windy or wet and footwear suitable for a grass field (with sheep droppings!). Dogs under strict control.

Location: Yarrow Swire, off summit of C22 road between A708 (Yarrow) and B7009 (Ettrickbridge). Marked as Witchie Knowe on some maps.
Locator: IO85MM
Coordinates: 55.5215N , 2.9984W 360m (1180ft) ASL
NGR: NT370257 (WAB Square NT32) (NT 37058 25768)
Google Maps shortcut: 9C7VG2C2+JJJ
Closest Postcodes: TD7 5ND (Wester Kershope Farm on north side of the hill on the approach from Yarrow valley) or TD7 5JW (Area covering from our site southwards)
What3Words: /// juggles.police.chiefs (Switch to satellite view)

Click image to open full screen.


From Yarrow Valley:

From East on A708 from Selkirk / Philiphaugh turn left just after Yarrow village onto the C22.
From West on A708 from Innerleithen / Gordon Arms / St Mary’s Loch turn right just before Yarrow village onto the C22.
The postcode provided leads to this farm. Do not turn off to this farm but continue on the C22 road to the top of the hill.
At the summit, cross the cattlegrid then immediately turn left up the rough track (on the south side of the dyke).

From Ettrick Valley

From West on the B7009 from Ettrick, turn left on to C22 then follow road to the top of the hill.
From East on the B7009 from Ettrickbridge turn right onto the C22 then follow road to the top of the hill.
At the summit turn right before the cattlegrid onto the rough track up the hill.

Moonbounce – A Science for Everyone

4 yagi antennas pointing at the sky

By John Berry GM8JBJ

On 12th May I bounced signals off the Moon.

OK, I’d been bouncing signals off the Moon ever since I put up the antenna system a fortnight before. Just that I didn’t know there was anyone on the other end to decode my 13-character message. Until, that is, on the 12th Mr Potts, callsign NC1I, replied from Massachusetts, USA.

Successful QSO between GM8JBJ and NC1I shown on WSJT-X screen.

Moonbounce (or Earth-Moon-Earth, EME) communication is a very cool thing to do. Just imagine the cred you’d get when next in a bar and you throw that out there when things go quiet.

And importantly, anyone can do it.


The Moon is about 400,000km away (less at perigee, more at apogee). Hence, the flight time for a signal from Earth to Moon and back is about 2.7 seconds. The corresponding round-trip free-space path loss for a signal is a huge 400dBi – no way anyone can bridge that gap. But whilst the Moon is a poor point reflector with a reflection coefficient of 6.5%, it’s also a 3,500km diameter billboard that reflects from all points across its area. The result is a real total path loss of around 250dBi and that’s (just) low enough for radio amateurs to exploit our natural satellite to communicate almost globally.

Basic Kit

Today, almost everyone uses Joe Taylor (K1JT)’s ultra-narrow-band algorithms to code and send a very short message. The message is pared to the bone – it’s even skinnier than FT8. And using his software, WSJT-X, this is sent repeatedly. So, you need a computer, a sound card, and the application. The setup is the same as for FT8, but you’ll configure to use Q65B with a 60-second period.

Video of a transmission via the Moon using Q65B (specks on waterfall and tones in noise) on 432.093MHz at

The transmission modulates the audio of a rig and uses upper sideband (USB). The simplest bands for moonbounce are 144MHz and 432MHz. 1296MHz is another option, but above 432MHz you’ll need a high stability reference to hold the frequency steady and 23cm kit gets expensive. Of course, you could do it at any GHz frequency amateur band, but I’m assuming no-one starts at 10GHz or the like. So, you need a VHF/UHF SSB rig.

And then there’s the antenna.


There are three options when it comes to antennas: huge, big, and modest. Huge VHF/UHF antennas are for Americans and others with acres of land. They are typically 48 or more stacked and bayed Yagis. Since you must point at the Moon, you can imagine the mechanics and electronics to automatically rotate and elevate 48 Yagis. Radio amateurs with huge antennas are the heavy lifters of the moonbounce world. Without them, novices wouldn’t get off the ground.

The 432MHz array – Frank Potts, NC1I. At

Then there’s big. ‘Big’ describes folk like me who put up four or more Yagis. That’s easily done. It’s all standard kit. My antennas are on a five-metre scaffold pole. Yaesu and others make az/el rotators, and at VHF/UHF the feeder doesn’t cost a mortgage. Automatic Moon tracking can be done on an Arduino or the like. And many folk in this bracket run 500W.

4-Yagi array at GM8JBJ at

Finally, there’s modest. There’s a whole movement of folk who use single Yagis and a barefoot rig. And many of those use a lightweight long Yagi mounted on a homebrew tripod. The advantage of this is that you can also avoid spending on a rotator, or on a low noise pre-amp (since you’ll be close to the Yagi feed point). These simple systems are often used /P from some piece of open high ground.

Single antenna portable EME operation at

Personal Qualities

There are two. Belief (that you can do it). And patience.

It also helps if you do a lot of research to optimise your kit.


The software does everything for you. But you must do the research to know when is best to try.


The truth is that Moonbounce is not that easy. There are several propagation mechanisms that will thwart your attempts.

First, there’s Faraday rotation. The polarisation of the transmitted wave is sometimes distorted along the path. And there’s nothing you can do about it – save use rotatable antennas, and that’s hugely complex.

Then there’s libration fading. The Moon wobbles. And sometimes the reflected waves received back on Earth create an interference pattern in time with deep fades. There’s nothing you can do but wait till the effect stops.

And of course, it’s stupid to try when the Moon and Sun are both within your antenna’s beam. The Sun adds noise to a sensitive system. But you can just wait till the Moon is on its own.

And then there’s the little issue of few folk listening at any point in time. But you can always arrange a sked on a chat room.

None of these issues diminish its street cred. They even enhance it because they make it complicated.

But here’s the secret. Given the simplicity of the kit, anyone can do it.


More detail from John Berry GM8JBJ
John Berry QRZ page
NC1I QRZ page EME on a Budget
WSJT-X Digimode Software

2024 Rally and Open Day – Sunday 27th October 2024

This year’s Galashiels Rally and Open Day will take place on Sunday 27th October 2024.

This is the last weekend of October so the morning of the clocks changing back an hour.

Venue as usual is the Volunteer Hall, St John Street, Galashiels TD1 3JX.

Read more »

2023 Rally and Open Day – Sunday 22nd October 2023

Lost and Found: Found a pair of glasses with grey translucent frames left at the Canny Components stall. GDARS club has them, contact us by email if they’re yours.

NOTE (21/10/2023): Rally still on! Not badly affected by Storm Babet, just a little soggy and windswept. All weather and flood warnings finished on Saturday.

This year’s Galashiels Rally and Open Day will take place on Sunday 22nd October 2023. Venue is the Volunteer Hall, St John Street, Galashiels TD1 3JX.

Note that this is NOT the weekend of changing the clocks as previous years but is the weekend before to avoid the CQWW SSB contest weekend.

Doors open for general admission at front doors at 11:00 BST.

Disabled/accessible entry and early book-in of Bring and Buy items only at 10:45 BST at rear door.
(Table traders entry at rear door from 08:00.)

Admission will be £2.50 per person, with free entry for under 16s accompanied by an adult.

CASH ONLY at the door. Change will be given but we appreciate having correct change for faster entry.

A sticker will be provided for exit and re-entry.

Confirmed traders (as of 18th October):
Bob McClements GM4CID (Club Stall, Used equipment)
Alan Clegg (valves etc)
Mirfield Electronics
Canny Components
Mick Hunter (Batteries, Memory cards etc)
Tony Kruszelnicki from TK Electronics in Lincoln
Perth Repeater Group
Pete Bates GM4BYF
RSGB (Books, Memberships)
Ken Elliott GM4NTX
Dave Bagshaw
Michael Wills
Gavin Chalmers GM0ALW
Fraser MM0HCD
DX Maps (Michael Whitehead)
John 2M0YTN
Paul GM0EDJ (Elderslie ARS, SK equipment)

Bring & Buy Stall (50p Book-in charge, 10% Commission up to £10 maximum)
Catering with hot and cold refreshments.

Any trader queries or traders not already booked but wanting to check table availability please email Jim Keddie GM7LUN (

The Volunteer Hall
St John Street
Scottish Borders
(Google Plus Code 9C7VJ57R+WV )

Access to Galashiels by road from A7, A72 or A68 (via A6091), by bus ( or by train (

Railways On The Air 2023- Whitrope Sat 23rd/Sun 24th September 2023 – GB0WRH

Club members will be taking part in this year’s Railways On The Air event, with a station being set up at the usual place of Whitrope Heritage Centre near Hawick on the weekend of 23/24 September.

The callsign used will be GB0WRH (Waverley Route Heritage) operating on HF bands. Dave MM0HTL will be arriving around 9am on Saturday and setting up, and then along with other members will be operating through the day and evenings until late Sunday afternoon.

All club members and visitors are welcome to come along and see the stations (radio and railway) and help with operating or just come along to chat with us.

The Whitrope Heritage Centre is run by the Waverley Route Heritage Association who have restored a length of track and sidings on the old Waverley line (1849-1969) between Hawick and Carlisle. Further details here:

Whitrope Heritage Centre, Whitrope, Hawick, Roxburghshire TD9 9TY
Location: 11 miles south of Hawick on B6399 (Hawick to Newcastleton road).

Maidenhead Locator: IO85PH 00co
55.294320, -2.748944 (55°17’39.6″N 2°44’56.2″W) 1034ft (315m) asl
NGR: NT 52540 00279
Google: 9C7V77V2+MC

Satellite image showing location of Whitrope Heritage Centre carpark