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EME to the Lovell Telescope

Lovell

You can view the BBC TV news report on the event at:

http://www.youtube.com/watch?v=RMJUASMShCw

This year, the University of Manchester's Lovell Telescope is celebrating its 50th anniversary with a number of weekend festivals at the times of significant events in 1957. Over the weekend of June 16th/17th - to celebrate the first move of the telescope - the festival organisers, Tim O'Brien and Teresa Anderson, decided to have a literary theme. Teresa came up with the idea that we might try to send poems to the Moon and back. The Times newspaper held a competition to select a suitable poem and, in addition, Cheshire school children were given the opportunity to write and speak their own poems.

I had been responsible for Jodrell Bank's attempts to receive signals from the Beagle II spacecraft in 2003 and also hold a full UK license, G0 DMU, so it naturally befell to me to bring this about - no real problem they thought, after all, clear voice signals were sent to the Moon and back in 1958 when Bernard Lovell gave the Reith lectures and radio amateurs have been doing EME for years!

However, then the Mk1 telescope (as it was then called) was used for both transmission and reception, but this time it could only be used for reception - the observatory's policy is to be totally radio quiet. It didn't take long for me to realise that voice communications would not be that easy even with a 76m antenna for reception! Significant power and a large antenna would still be needed to transmit a sufficiently strong signal to allow SSB transmissions at a frequency at which the telescope could be easily equipped.

We have a good feed system at 408 MHz which we felt could be tuned up to 432 MHz. As 432 MHz seemed to be quite widely used by EME enthusiasts this seemed the obvious frequency to choose. Although from my home location in Macclesfield, about 8 miles away, the direct signal could easily be picked up through the side lobes, I thought that it would be quite nice to transmit short bursts of CW and allow first, only the direct path signal to be received but then, as we moved the beam of the Lovell Telescope on to the Moon, hopefully the echo of my signal would be heard.

My local radio club, the Macclesfield and District Radio Society, offered to loan me a 432 Mhz rig with which to transmit and also, in the guise of their chairman, David Lucas (who had worked at Jodrell Bank for many years) and vice-chairman, Keith Kelly, G0BIE and G3VKF respectively, operated the receivers at Jodrell Bank during the day and the preceding test periods.

I decided to use a single 19 element Tonna (16.2 dBi gain) for the transmit aerial and our workshop made some brackets so that it could be mounted on a computerised optical telescope mount. This was accurately aligned on the stars during a clear night some while before the event so that, on the day, I could simply command it to track the Moon, invisible above the clouds. The minimum length of RG214 cable was used to transfer the RF from of the rig to the antenna. With the output of a typical UHF rig this still wouldn’t allow my reflected signal to be received by the Lovell telescope even with CW. (Using a very narrow band filter it might have been just possible, but remember that we wanted both the direct and Moon bounced signal to be heard by the participants and the relative motion between Jodrell and the Moon means that they are received on different frequencies.)


19 Element Tonna on computer controlled equatorial tracking mount.

GB50 EME

It didn't take long for me to find that Linear Amp, UK make some 11 dB gain amplifiers for 70cms and so I made a phone call to their managing director, Peter Rodmell, G3ZRS. He was incredibly helpful and immediately put one of his latest 70cm designs into production for me to borrow for the festival. As I collected it, I was able to see the superb internal quality of the amplifiers being built in the workshops at the time.


GB50 EME UHF tranceiver and Linear Amp Discovery 70cm amplifier

GB50 EME

What of our Lovell Telescope receiver? This was set up by Dave Glynn, one of our RF engineers. The feed uses crossed dipoles in a triple cylindrical housing to improve polarization circularity. These feed a hybrid to give two hands of circular polarization the outputs of which were fed to two room temperature lna's. Their measured noise figure is ~0.15 dB and they were specifically designed with very high intercept points for use in the presence of strong signals. In turn, the lna outputs were passed through tuneable cavity filters and fed into mixers using a local oscillator of 461 Mhz thus giving an intermediate frequency of 29 Mhz. This inverts the band and so our receiver was tuned below 29 Mhz to receive above 432 Mhz.


Crossed Yagi Feed on the Lovell Telescope

432 Mhz Feed

The festival organisers wanted voice communications - my station was unlikely to be able to achieve this - so again I turned for help which was, this time, gladly given by Rod Wilkinson of Ofcom. He was able to tell me the names of some eme stations in the UK who had special permits to run high power - I was sure that this would be need to achieve clear voice communications. He also encouraged me to apply for a special event call for my lowly 432 MHz station and, within days, I received a notice of variation giving me the callsign GB50 EME for the 17th June.

The UK EME community immediately rallied to my aid, some were involved in contests at other frequencies on the 17th, but Dave Dibley, G4RGK and Paul Higginson, GW8IZR offered all the help they could. Dave's was the stronger station and also much further away so eliminating the direct path so we asked him if we could send (via skype) voice signals from Jodrell for him to transmit to the Moon. We cleared this slightly unusual mode of operation with Rod Wilkinson and Dave was given the special call GB50 EMJ (Earth-Moon-Jodrell) for the day.

It occurred to me that other stations around the world might like the opportunity to be received by the Lovell Telescope and so I alerted the international EME community and skeds were arranged. It happened that, by chance, the Moon was ideally placed in its orbit on the 17th June allowing the possibility of a path from Australia (as the Moon was setting) to Jodrell (where it was rising) with, later, paths open from Japan and the USA.

On the Thursday prior to the event the 432 MHz feed and receiver were mounted on the Lovell Telescope. We were able to monitor eme transmissions from Europe to Hawaii and decode the CW from OZ4MM which was really encouraging. Later, I returned home to make my first eme transmission as G0DMU. Over a phone line I could hear the direct path signal and then the echoes of my stations calls as received by the telescope. As the Moon was then setting, Jodrell was moving away from the Moon due to the Earth's rotation. This would result in the returned echo having a lower frequency than the direct path but, as our band was inverted, I heard (over an open phone line) my echo at a significantly higher pitch.  I found that the rig - a Yeasu FT-857D which had never been used on UHF before - only produced 20 Watts, but I suspect that Peter's amplifier might well have had higher than 11dB gain at low power levels so I may well have been transmitting with ~ 300 watts and with a very short length of coax and a superb match on the single Tonna most of this may well have been transmitted.

On the 16th, the day prior to the festival, we organised test transmissions from Paul, Dave and myself. Late in the day we were able to set up a skype link from the marquee where the event was to be held direct to Dave and were able to successfully test out the loop path Jodrell - G4RGK - Moon - Jodrell. There was much jubilation here when it worked! A highlight of the day was a scheduled test transmission from Martin, KC3RE, as the Moon was just rising in Virginia, USA. More of this later.

I was at Jodrell early on the 17th June to receive the call from Doug McArthur (VK3UM), who is celebrating his 50th year as a radio amateur, located 10km north of Glenburn, Victoria, Australia. I believe that the Moon as seen from there was only 3 or so degrees above the horizon. Doug was using a 8.3m Dish with 1500 Watts TX power so it was not surprising that his CW was strong and I had no difficulty in resolving his SSB signals when his Australian accent became obvious! He sent messages of congratulations several times - not all identical but this is a meld of them:

cq cq GB50EME, Lovell Telescope Manchester, de VK3 UM ,Victoria Australia This is Australia calling.

Congratulations on the 50th anniversary of the Lovell Telescope. We wish you many more years of further operation. 73's Doug VK3UM


Doug McArthur's dish!

VK3 UM

This was a great start to the day - thanks Doug!

We then had two scheduled contacts with Toyoshige Kamei, JA3SGR who was operating with 400W through 2 x 25 element yagis - put together during the preceding days especially for the contacts. Not surprisingly, his signals were not a strong as Doug's, but could be copied quite easily by Keith who had arrived at Jodrell to help with the signal reception. His message was:

CONG to celebrate the 50th anniversary of the Lovell Telescope de JA3SGR 73

It was really pleasing to make these contacts from across the world!


Toyoshige's 2 x 25 element Yagis

JA3SGR

We had made test contacts with Paul, GW8IZR in Anglesey who came through with an excellent signal. We were able to copy the direct tropospheric as well, with both the direct and moonbounced signals being roughly the same signal strength.


Paul's antenna array

GW8IZR


Following a test transmission, both CW and SSB, from Dave, who was now GB50 EMJ, he organised a sked with Peter Sundberg, SM2CEW. His station, with a 28ft dish and similar power to Doug's station in Australia is close to the Artic Circle in the north of Sweden. A summary of his voice signal to us is:

cq cq GB50EME de SM2CEW Greetings and congratulations to the Lovell Telescope from close to the artic Circle. 73's Peter.


Peter's dish!

SM2CEW

The main event of the day started at 14:00 BST. Following some final tests I returned home and made test transmissions with my station, now GB50 EME. A voice and video link was set up with a large display in the marquee. Around 90 participants were there along with a TV crew. My colleague, Tim O'Brien opened the proceedings and then passed over to me seen over the video link when I demonstrated the direct and then the echo from the Moon as we swung the Lovell Telescope to its position high in the South. In the marquee the participants watched a chart of the heavens with cross wires showing the position of the beam. As it closed on the Moon, my echos appeared on cue. Though not as strong as those from Doug or Dave, those receiving were pleasantly surprised with the strength of my signal. I was then able to send a CW message in 2.5 second bursts - hearing my echo over the skype link made this quite easy. I was using a "Swedish Key" bought just before my morse exam many years before and had been practicing for several weeks to get up to speed. My CW message at ~ 13 wpm was copied at Jodrell:

CQ Moon CQ Moon de GBO EME The staff of Jodrell Bank Observatory congratulate Sir Bernard Lovell on the 50th anniversary of his great telescope.


Ian operating GB50 EME

GB50 EME

I was then able to return to Jodrell Bank to join in the proceedings whilst they listened out for Martin, KC3RE, to call from Virgina. He was running ~150 watts in to a single 25 element yagi mounted horizontally on his Range Rover. He can thus only work the Moon at Moonrise or Moonset. We really wanted him to call during the event when the Moon was getting a little high in Virginia, so Martin went out to Walmart and bought a pair of wheel ramps to give him a few degrees additional elevation. Fantastic! Though not strong, Keith had no problem copying Martin whose message was:

"GB50EME de KC3RE FM18dp Casanova, VA, USA GB50EME de KC3RE FM18dp Casanova, VA, USA please accept my congratulations to the Lovell Telescope on its 50th anniversary." 73 Martin


Martin's Range Rover on wheel ramps to gain elevation!

KC3RE

Sadly, we then had the only setback of the event. I was returning to Jodrell so was out of action. Tim O'Brien expected Paul, GW8IZR, who had given us a cracking signal during tests, to call at 14:35, but Paul was expecting to be prompted by a skype message. Partly due to the TV crew who demanded that Tim gave them an interview at precisely the wrong time. Tim forgot this and Paul was afraid to call in case his signal came over Martin's. Sorry Paul - a real gentleman.

Then it was the turn of Dave, GB50 EMJ, first to be copied by CW to test the signal path and then to use SSB. As the round trip loop was made with our Director, Professor Phil Diamond making the first voice transmission, interference came over the signal and we temporarily moved frequency. At this point the audio output (probably the jack contacts) of the receiver failed, but happily a second receiver was on standby at the correct frequency and amazingly, as we switched the audio across, Dave could be immediately heard.


Dave's stacked yagis

GB50 EMJ

Then Erica Wagner, the Literary Editor of the Times newspaper took the stage and introduced the competition and the winner, Joanna Clark, who read her beautiful poem in short phrases so that we could all hear her echo. This was followed by great applause. Then it was the children's turn. Their voices were clearly heard and some of their poems were of an amazingly high standard. This really was the highlight of the weekend!


The competition winner,Joanna Clark, reading her poem.

winner!


Erica with one of the school children

another poem

We finished our Moonbounce experiments with the whole audience calling "Hello Moon" (for reasons that will become apparent). I am not too sure if the licence regulations allow many (~90) speakers to transmit at once, but I hope Ofcom will not mind too much - they were, at least, under the supervision of six licensed amateurs.

Tim rounded off the afternoon by playing a recording of the signals sent and received in 1958 "Hello Moon ... can you hear me ... this is Jodrell Bank Calling."

The event turned out to be a marvellous success: both the Times representatives and (even more important for us) those from our funding council (who had provided the marquee) were really pleased with the outcome.

For my part, as must be totally obvious from the text, the success is totally down to all those mentioned above who helped both with the equipment both to set up the stations at my home and at Jodrell and gave unstintingly of their time over the weekend. (Incidently, Dave is really one of us, having taken a Jodrell Bank radio astronomy course written by Tim O'Brien and myself.) It just shows what a great group of people radio amateurs are! Having got my morse sending up to scratch I will now work on my limited morse receiving abilities. So perhaps you might just hear me QRP on HF and 2m again. (I have 4 x 9 element tonnas for 2m and used to enjoy working QRP from the hills near my home!)

My grateful thanks to everyone who took part.

Ian Morison, G0 DMU

Find out more about the Lovell telescope with this link: The Lovell Telescope

Below is the schedule for the day, showing how we tried to communicate back by updating our webpage in real time.



On June 17th in the afternoon poetry will be sent to the Moon to be received by the 76m Lovell Telescope whilst in the morning we would like eme stations to contact us.   On this page we will post schedules showing the times that stations will transmit.   Each station will be sent an e-mail to confirm their own time slot so this page will enable others to see who is transmitting when. We will attempt to update this webpage in real time to provide confirmation of received signal.  E-mails will follow later.  (It could be a bit hectic here!)
At this time the schedules are being added to.

ALL Times UT

Transmission Frequency 432.065

Saturday 16th June

12:00     KC3RE Virginia USA

***** Copied - just above noise - but could read you: nice CW ***** 12:30     G4RGK UK SSB tests.

13:00     GW8IZR UK CW tests.

Sunday 17th June

**********************************************

Please do not call from 13:00 to 15:00 UT . We will be receiving transmissions related to the festival from:

GB50 EMJ - SSB.

At 13:30 KC3RE from Virginia USA

GW8IZR - Medium power CW

GB50 EME - Low power CW (Almost certainly not audible except with Lovell Telescope - but if anyone else does hear me I would love to know: im@jb.man.ac.uk

***********************************************

Morning Receiving Schedule

07:30 VK3UM     Glenburn, Victoria, Australia

08:04 - nice signal and a bit closer to my reading speed - I am very out of practice! Iwill listen on SSB 08:07 Got you on SSB - copied you very well to GB50 EME Lovell Telescope manchester from VK3UM North of Melbourn. 08:15 Another station JA? also in the band. 08:00 VK3UM     Glenburn, Victoria, Australia

08:30 VK3UM     Glenburn, Victoria, Australia

Well copied on CW and voice - thanks Doug!! 09:00 JA3SGR     Japan

09:06 Weak. but largly copied - a colleague from our radio club has arrived and is far better than I. Thank you for the congratulations Toyoshige, we will listen again at 11:00 UT. 11:00 JA3SGR     Japan

11:06 As above, 13:30 KC3RE     Virginia USA. ( In festival EME demonstrations)