Tag Archive: eme

A35JT 6m EME Activity Report

EME Trial Number 1 – Corny Point in VK5

A35JT’s journey to running 6m EME from Tonga has been a long one. It began at the end of 2018 with an email from Lance W7GJ encouraging us to give it a go. Little did we know what that would trigger!

Over the following 12 months, we conducted two trials of the EME gear in VK before the final activation in Tonga in September 2019. The first trial was in February 2019 where we successfully contacted 6 stations over a moon rise and a moon set from the Yorke Peninsula in South Australia. The second was in July where we contacted one station from Lake Alexandrina before suffering gear failure.

Finally, in September 2019 we shipped the gear out to Tonga. The result has been to work 25 stations via the moon from “A3”, and receive calls from a further 28 stations. For a group of 6m EME newcomers, we couldn’t be happier with this result.

The team must thank everyone in the 6m EME community who supported us in getting the EME gear to Tonga. Without your help and encouragement, this part of the DXpedition project would never have happened. Thanks definitely goes to Lance for giving us the nudge to try and give this a go!

6m EME in Tonga:  a Bumpy Road

The first trial from Yorke Peninsula was made from Corny Point on the tip of Yorke Peninsula approximately 3.5hours drive from Adelaide. We worked 6 stations across Europe, Japan and the USA that night, which lit the fire to give EME a serious try during the A35JT DXpedition. Everything ran surprisingly smoothly and set the scene for what we hoped would be a successful project.

Choosing a site in Tonga

The heart of any remote activation is getting a licence and choosing a site. Things had been progressing in this area, however not everything went to plan.  Our original site on Tonga became unavailable just as we were about to book it. That prompted a scramble to find an alternative. We finally settled on Teukava Beach Oasis  on the far North West tip of the island of Tongatapu. The owners were very accommodating of our strange requests to set up a radio station across their resort. We also took the step of renting the entire 3 cabin complex so we could control our noise environment as well.

As it was about as far out as you could get from the centre of the island even that presented us with logistics challenges to solve just transporting gear from the freight depot and the airport out to the resort. Fortunately we were introduced to Christian, A35CS, who was a great help in solving our logistics problems.So that solved our location and part of the transport story.

Trials and Tribulations: regulatory hurdles and gear failure during testing in VK

For a time it seemed that road blocks kept being laid down as fast as we could clear them. Just getting regulatory approval to run high power 6m EME in VK was an ordeal that took 4 months with the ACMA. Operating EME portable is something the regulator struggled to comprehend it seems. It is clear more work needs to be done to improve this process in the future.

Finally at the start of July, with our ACMA approvals in hand, we set out for Nanda Farm, a farm-stay house located on the shores of Lake Alexandrina about 90 minutes SE of Adelaide. By now we had solved our antenna and mast mounting problems. SpiderBeam helped us out greatly with one of their 10m aluminum retractable masts. There, we erected the station and began our trials.

Just as we completed the first EME contact of the test, catastrophe struck. We were using an SPE 1.5-kfa linear amplifier running 1kW to run the tests. Much to our dismay, the amplifier failed after 3 hours of operation. The precious blue smoke escaped with a pop, and that was the end of the EME testing from VK. It actually put the entire project in jeopardy when it became clear several weeks later that the amp was not coming back from repairs in time for our departure for Tonga in September. So, we started looking for options.

Thanks to Bjorn SM7SJR’s impeccable timing, (he was selling a suitable replacement amp just when we needed one) we bought his M6-1k2 1kW amplifier in early August, thus restoring plans for EME from Tonga. We must give many thanks to Peter VK5PJ who donated a 50V power supply to run the amplifier and to Bjorn who helped cover some of the freight costs of getting the amplifier shipped to Australia from Sweden..

Shipping the Gear – Customs Worries

The final hurdle was simply getting the equipment to Tonga. The original plan of taking it as excess baggage was set aside after warnings from Air New Zealand that the risk of it being offloaded due to weight in Auckland and being delayed was real. So instead we resorted to airfreight. This cut our preparation time but allowed us to have the time for the air freight network to fit our shipment into their manifests.

The donations received helped cover the extra freight costs of getting the 6m antenna equipment out to Tonga from Australia and back. The total weight for the 6m antenna system and feedline came to ~40kg.

It also was the first time I had tried using international airfreight. This was a learning experience indeed (next time I will send the keys in advance to the destination to help with customs inspections). It took a lot of phone calls to put everything in place to satisfy the customs department in Tonga and have them clear the shipment. It actually came down to the final 3 days before we arrived before the freight was released, but finally everything was done – setting the rest of the expedition up for success!

A huge thanks to the Mary and the team at Pacific Forum Line Freight handlers in Tonga for helping get this over the line!

The Station we took

The final station we took to Tonga comprised an InnovAntennas LFA2 6 element yagi, (giving us 12.5dBi gain). With the Spiderbeam 10m aluminium collapsible tower we set up the array next to the radio shack in Tonga and waited for the moon to rise.

The rest of the equipment included an Elecraft K3S transceiver, Elecraft W2 watt meter, M2 Systems M6-1k2 linear and 30m of Messi & Paoloni Hyperflex 13 feedline (sponsored in part by RF Solutions in Brisbane) which was supposed to be equivalent or better to LMR600 but with less weight. The system power supplies were a Codan 3020 12V 30A unit for the driver and an Eltec 2kW rectifier module for the 50V supply. The software was WSJT-X v 2.1.0 running on a Windows 10 instance within a Macbook Pro laptop.

 

Finally Ready to go on the air

Once we got to site things finally started to go our way. The beam was unpacked and assembly and erection went smoothly.  We were able to locate the antenna relatively close to the radio hut which made for fairly easy beam steering manipulations as we manually tracked the moon.

It seemed however that Mr Murphy would not leave us alone. He wanted one last game with us, as just as we were about to start, a noise source appeared that took the noise floor up to S5-6 on 6m. It wasn’t there when we set the station up, and given the work around the site to remove other noise sources we had control over (LED lights being a principle source) we were suddenly panicking that everything to this point was about to come to naught. After a scramble to turn off anything we could find, we tracked this last problem down to one of our laptop power supplies which had failed during the evening, radiating spurious everywhere as a result. Fortunately we quickly tracked it down and were back in business, although it did give us a scare just as the moon was coming up over the horizon the first night.

The final problem was the HF station activity. We found we couldn’t run EME and most HF bands concurrently (we had suspected this might be the case). So, we had to curtail HF operations during the EME windows (which wasn’t popular with the rest of the crew after 4-5 days). That problem solved, we were then set.

First Contact

First contact was made shortly after moon-rise on Wednesday 25th at ~3am local Tonga time. We made 6 contacts the first night of operation elevating the station to ~35deg in the process (thanks to a tilt bracket built by Peter VK5PJ following a design by Lance W7GJ).

The later days saw fewer stations worked each pass, most likely due to the sporadic E and TEP propagation around on the Thursday and Friday. We also came to the conclusion that we didn’t have the antenna gain needed for successful elevated contacts.

For the last few passes we just worked the 0-20deg horizon band with greater success. To the east we found we needed about 5deg moon elevation before we were working stations. To the west (which was a clear shot over the ocean) we could hear people down to ~1deg elevation. The best signal we heard was from G8BCG who we copied at -18. Most signals were between -26 and -30dB with a small number in the -22—25 range.

The Results – Who did we work and who did we hear?

The end result: we worked the following stations over moon rise/moon set between Wednesday 25th and Sunday 29th of September.

OH6MIK, G8BCG, KG7H, GM3POI, G4BWP, W7JW, K2ZD, K4PI, K5NA, W6UC, OH2BC, UR0MC, OH7KM, ON4GG, S57RR, ON4IQ, JA7QVI, N8RR, K5DU, SP4MPB, I4YRW, ES6RQ, NJ6P, N7IP, ZS4TX

We also heard the following stations but were unable to make contact with:

NN7J, VE1JF, HA0DU, *****, WA1MEK, ******, UT7QF, I2RV, GD0TEP, PA5Y, N3XX, W5ADD, N8JX, W0VTT, KA9CFD, OZ4VV, G8VR, EA8DBM, OE3MPL, LY2WR, S51DI, I4EAT, YL2AO, IW5DHN, JG2BRI, SP7VC, ZS6NK, SP3RNZ

Thanks everyone who took an interest in our EME activity and attempts. I know Andy VK5AKH and I in particular learned a lot about it and have a lot of ideas now for how we might improve it in the future. You never know, I may now consider it next time I pick a Pacific Island for an expedition. How many need 6m EME from VK9N (Norfolk) or ZL7 I wonder?

Congratulations to those we did manage to work or hear via the moon. Next time, I will see that we can take more elements so we can hear and be heard better.

6m EME Amplifier Test Successful!

Good News! We finally had a chance to test the new 1kW 6m amp for the EME station! It works a treat and marks the final confirmation that we can still take 6m EME with us to Tonga (after the mishap with the original amplifier back in July).

A huge thank you to Peter VK5PJ who has donated a 50v 40a power supply to us for the expedition! Thanks also to Bjorn SM7SJR who sold us the amplifier and helped with part of the shipping costs getting it from Sweden to Australia.