Undeterred, I decided to build a DK7ZB 10ele 2m Yagi. I got the Yagi finished quite quickly, but then building the driven element took approximately a year of procrastination. Seeing Bob ZL1RS's DXPed was the impetus to get it finished. I finished the dipole, wound the impedance transformer, boxed it all up, tested it, and wondered what all the fuss had been about.
I then set about working out just how I was going to mount a 6m long Yagi in a townhouse paved back yard that is a shade under 6m long x 2.5m wide. Fortunately, for moon rise in the East, I could point the Yagi out over a council owned paddock next door, albeit over a 6ft Colourbond fence. By careful positioning of the mast on a portable mount, I could track the moon through to transit in the N, but thereafter the house would get in the way. That would mean no European stations at moonset, but it did give me a window for JA and the whole of the USA.
I used the lower portion of my NBS Antennas mast, in a home brew drive-on portable mount, and set about making the various parts to allow the antenna to elevate. A 12V 18" elevation ram was sourced off eBay.
Time for some pictures, which will tell a thousand words:
First, to mount the lower end of the elevation ram on the mast
And then to mount the other end of the elevation ram onto the boom
I did some quick geometry in CAD with circles to work out the likely elevation angles.
The top of the mast elevation hinge was achieved by making a platform that pivoted on an M10 bolt. The holes in the top are tapped M6 again for a similar clamp arrangement to hold the boom as the elevation ram mount on the boom.
So, by the time it was all put together, this was (a portion of!) the antenna at roughly horizontal
As the afternoon went on, waiting for my first ever taste of EME, the clouds rolled in, and by the time darkness came, it was a 100% cloud-out with no moon to be seen. After hurriedly cooking our evening meal, feeding the dog and the rainbow lorikeet, the moon was already up (at least in theory) at around 5deg.
I got onto the EME loggers, and saw Bob KH8/ZL1RS was operating on 144.138MHz. I tuned in, hit the monitor button, and waited. I saw nothing. Minute after minute there was nothing to be seen. Stations on the logger were saying "Strong Sigs Bob" yet I was seeing nothing. An hour went by. Still nothing. I was tempted to knock it on the head as a bad job, but I persisted. Suddenly, I started to see a weak trace. It decoded as 'RO'. Then in the next minute segment, another trace; 'RRR' was decoded. The in the next trace a '73'. It was working! It appears Faraday rotation had been against my polarisation, and it was just starting to come good.
By now the moon was well up at around 40deg. All pointing was done with a Silva sighting compass and an inclinometer app on my smartphone. At one point, the moon was just about visible through cloud, and I found my antenna was pointing a good 10deg off target. I quickly realigned.
By now I was starting to see CQ's from Bob, some quite strong. I also saw other QSO's in action, and a CQ from a JA station who was as strong as -19dB with me. Whether it was my mind playing tricks on me or not, but I am convinced I heard his tones in the noise on the rig speaker!
I put a few calls out back to Bob, and was very aware my IC910H backplate was getting extremely hot. I grabbed a small 5" desk fan of my XYL's, and aimed that at the back of the radio to assist in cooling during Tx cycles. It certainly helped.
Bob kept calling CQ, so wasn't hearing me. Bad Faraday effects at his end? But then one cycle I didn't decode his CQ, but decoded 'VK2GOM F6BEE JN06'. So, someone was calling me, BUT - it was certainly not a French station as their moon was not up. I am guessing Bob was trying to call back, but the WSJT deep search got it wrong.
After that, signals faded again, and nothing more was seen. I got to bed around 1am after packing up.
So, after 27yrs dabbling in ham radio, I finally get to receive signals off the moon. What a thrill!
Moreso with my extremely limited QTH and the challenges of fitting an antenna into my back yard.Future upgrades I can think of right now will be to mount the mast mount up on some sort of platform. Even an extra 12" in height would give the Yagi reflector more ground clearance. Also, some sort of friction brake on the azimuth axis, so I can hopefully run my lower loss 5m length of LDF4-50. The LMR400 has a calculated loss of 0.35dB over 7m, and the LDF4-50 only 0.13dB over 5m. However, wIth that stuff, IT decides where your radio goes, it's that stiff. Also, I have a feeling a lower noise preamp would assist. The MiniKits amp specs 'Noise Figure <1.5dB' I believe. Something down near 0.4dB would of course help greatly. Every fraction of a dB helps.
The next part of the challenge is of course to complete a QSO, but I feel I got off to a decent start given the QTH limitations here.
For all you guys with a garden, you have it easy. There is simply no excuse not to get started in 2m EME
See you on the moon sometime.
73 - Rob VK2GOM / GW0MOH
Security board camera on boom and crosshairs taped on monitor perhaps?!
