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Sunday June 25th 2023 Multi-Tx DF Location The start was by the Play area on the corner of East End Lane, East Bergholt, Suffolk. CO7 6XL. Map with zoom If using a mobile phone, you may need to rotate to give landscape view. |
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 Philip had been exploring and found us a new site, this picture must have been taken in a drought, the fields had plenty of grass! |
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 It was a cosy 30 C, thanks to Philip for thoughtfully providing chairs and plenty of water.
Doctors' notes were inspected: 1 shoulder problem, 1 recovering from broken foot bone, 2 with knee problems, 1 awaiting heart bypass surgery. No problem then, all pronounced fit to Multi-DF, bottles in pockets, off we go ...... |
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Tx
locations  It looks so easy NOW!
Using the path running N-S was the key but bearings from low down
M were warped by the topology, tempting any 'have a go heroes' to
follow the 20 contour, making a
semi-circular path out to the East, thinking Txs were located North of
the stream and nettles! Did anyone attempt to go
through? Most were wise but there is
always one !!!!
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Results (Points mean prizes)
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 Multi-Star of the day goes to Chris |
 George 2nd |
Times (For info only)
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| So
over to our winner Chris, we have Rxs for people to borrow but for
some, experimenting is a key reason to get into RDF: I last won a DF competition around 1990 when Ipswich Radio Club used to run a single Tx on 2m- that was fun but had long since stopped. I was aware from RadCom that radio orienteering competitions took place nationally and internationally but these look like they are for serious athletes- I’m not an athlete – the only race I ever won was the wheelbarrow race at infant school and I was doing the easy bit. Fortunately thanks to Roy G4JAC attending Suffolk RED I discovered that, Goldilocks style, there was an RDF activity just right for me, a way to make a walk in the countryside interesting. I now also had reason to build my own receiver. I wanted it to be as simple as possible but perform well enough to use in competition. I did some research and experimented with some prototypes. https://g6pde.wordpress.com/2020/10/30/ardf-background/ |
 I settled on a design using the SA602 Gilbert cell mixer IC and used dual gate mosfets for aerial and IF amp and a filter using cheap microprocessor crystals. https://g6pde.wordpress.com/top-band-ardf-receiver-using-dual-gate-mosfets/ I repurposed an antenna analyser I’d built based on an arduino and an Si5351a frequency synthesiser to provide the VFO and BFO. |
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| My
preparation for this multi Tx was mostly focused on coping with the
heat, 30 C and sunny was forecast so I packed three bottles of
water and two frozen cartons of fruit juice and applied factor 50 sun
block before George picked me up. On arrival at the site I was relieved to note a cooling breeze as I tested my radio and put my walking boots on. I thought the boots might be too hot so I selected the soft wool socks my daughter had knitted for me as I thought they would be cooler than boot socks. Start time came and I tried to position myself away from metal fences but still in the shade. I had no trouble plotting bearings for all three green Txs but I was surprised that all sounded a long distance away. I later put that down to the dry ground. My joker (A) was due north and I was already standing on a convenient footpath heading in the right direction. I set of at steady pace keeping to the left to let Tim and Gary jog pass. The signal got stronger as I approached a row of trees – the Tx appeared to be to the right but I couldn’t see anyway in, Tim and Gary had disappeared. I went back to the path where Tim and Gary had reappeared I looked around and saw a dark hole in the clump of trees where I presumed they had emerged from. I ducked in and as my eyes accustomed to the shade I saw the triffid. I was pleased to have found my joker quickly but slightly disappointed to be the third to find it. Quickly changing to the yellow frequency I heard B and headed east along the tree line, the next cycle came up as I was passing and Tim popped out from the other side of the trees. |
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I
soon found the triffid and listened for C but it sounded a long way off
and I remembered a discussion with Roy that leaving the difficult one
for when I returned to my joker at the end was a sensible strategy so I
listened for K which I knew from my initial bearings was nearer than F.
Again there was a convenient path going in the right direction and soon
I found myself out on a road and remembered Philip’s briefing about no
need to cross any roads so I searched this side of the road and found
the triffid. Onward to L again along a path- no getting stuck in the middle of a wood this time. Again the path led to M and crossed the foot bridge reassuring me that I actually knew where I was on the map. After another cycle I suspected I was on the wrong side of the stream, not wanting to risk drowning I went back over the bridge noticing a likely way in to a place to hide a Tx. The very strong signal confirmed I was in the right place and I found M – a red Tx, I was definitely doing better than last time when I only found 4 Txs and came last. Now to listen for F – I could hear it but it was weak and direction wasn’t quite where I was expecting based on my first bearing from the start. I set off in the direction of F but this time there was no convenient path and I found my way blocked by a stream banked by nettles. I now had no idea where I was on the map. I followed the edge of the field looking for a gap in the nettles but found none. |
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contemplated trying to make my way through the nettles- after all I was
wearing long trousers and a long sleeved shirt but I hadn’t seen
another human being for at least 30 minutes and if I fell in these
nettles I might never be found so I made my way back the way I’d came. I listened for G on the way just to make sure it was also the other side of the stream – it was. Eventually I came to a path and gap in the hedge and somehow I was the other side of the stream on a path, after about 45 minutes of fruitless walking I was back in the game. I had a good idea where G and F were from bearings I taken on the long walk so as I headed towards them I listened for H, a strong signal , “I’ll get that on the way back”, I thought. After another long walk up hill I closed in on F inside a hedge, there was no easy way into it and I had to get on my hands and knees and crawl in. Back towards G which I found at the side of the path. The path looked different coming back and I must have walked straight past H as the next thing I saw was George sitting on chair. Confusion turned to relief as I realised I was back at the start and knew I could find my way quickly back to A, my joker. |
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Philip
kindly offered me a bottle of water but I had another one in my little
rucksack. I had 35 mins to search for C and get back to A. C was a strong signal and paths trodden through the grass were extra clues. I found C and still had 30 mins to get to A , I considered going back for H but decided not to risk it. I got back to A sat in the shade and finished my water while I waited for the machine gun. As we sat down to dinner in the cool breeze of the pub garden I was very surprised to discover that I was the winner, mostly due the generous handicap system and maybe Philip not being so tricky hiding the triffids and just possibly the lucky socks. Thanks to Philip for arranging a fun competition and Roy for the prep work he does every time. |
Hero gains and discards for
this event
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| Thanks to Philip for hiding the Txs,
providing chairs, water, finding a pub, booking all the meals and
taking the pictures - great job. And thanks to those who travelled long distances to be with us, particularly those from Kent who were stuck in a traffic jam (30C) on the A12 for over an hour, making it just in time for 'the off'. Next event is on July 16th, watch the noticeboard for information. |