For this next session of the the UKAC series I decided to use an old site that was the site of my first ever 144MHz VHF contest when I entered the PW QRP contest with Kevin G1VDF. I chose to operate here as I was hoping to get back earlier as getting into bed at 1am on a work night was a bit late. The drive is slightly longer but it is a drive on site so packing away hopefully would be quicker.
Where I decided to set up was a little cramped and awkward to raise the mast on my own so it took longer than it could have. However I did manage to get all set up and on air a little before the kick off although with no real spare time for any photos this time.
I could hear some seriously strong stations giving me some interference so I tracked them down to check they weren’t in the field behind me or something similarly close. They weren’t but they did report I was giving them issues with splatter and sounded like I had far too much compression on my audio. This was the first time out for my new build of the BX-184 CQ caller which I suspected might be set too high in the mic. As I didn’t have the right tools with me to do anything about that I tried to cut down the overdriving by turning down the SSB mic gain down a fair way. This was said to help but not solve the issue completely, though I was receiving the complaining stations so strongly the signal reading never came off the ‘stop’ between their words even. I changed my operating frequency for a further 10KHz away from them to try and help.
Once under way activity was quite good as last time but generally although signals all seemed to be really big I didn’t really get as many more distant stations. I’d hoped to make use of the ON4KST chat like most do for finding multipliers but I was not getting any cell coverage to get online which was a shame. I did manage to find two new GI squares searching and pouncing though again missed some other ones. It’s tough to know how long to spend away from the running frequency searching and pouncing!
My QSO map for this contest:
My QSO count was 2nd highest and my claimed score put me in first place in the low power section. However it was close at the top and adjudication could easily scupper that:
The results came in quite quickly this time and I was pleased to see I was still top out of the 85 entries in AL section! I lost 5 QSOs for errors but luckily others lost some too and I stayed top:
Oh, and I was in bed by 11.45pm, result!
As I have always operated way more as a portable station than a base station I have operated from the car many times and in many ways. Some not as comfortable as others that’s for sure. It gets tiring twisting to one side or hunching over. In the end I came up with a simple solution for me that enables me to easily set up and have space, and be comfortable operating, which is important if you are spending a long time operating like in a contest.
Basically, a plank of wood!
More accurately it is a small sheet of plywood sized and modified for purpose to make a flat table in the car to carry the radio and any ancillary units like batteries, PSUs or amplifiers etc. It’s strong enough to support a 4CX350 based 200W VHF amplifier.
The sheet is sized wide enough to fit in most normal cars and long enough to reach from the top of the dashboard to just past the back of the driver’s seat. There is a slot cut to allow it to slip over the steering wheel:
I keep it in the boot ready to go as it doesn’t really take any space. I just take the head rest out of the driver’s seat and sit the board on the top of the seat. The slot for the steering wheel allows the board to sit on top of the dash and adds a level of security from catching a sleeve on a corner and knocking it off. In my shiny new car I just add a towel over the steering wheel and dash and another on top of the seat to protect them from any markings. The two head rest entry points and top of the curved dash make a tripod style stable platform. And the weight of the radio and batteries keep everything steady.
I use my backpacking batteries because I don’t have a DC feed at 20A to the car battery for the radio and I don’t have to worry about draining the car battery if a pileup comes my way.
I pull the steering wheel all the way forward to drive anyway, but this means the wood extends back enough to sit normally in the back seat without even moving driver’s seat and I can sit with my back against the back seat (rather than hunched forward) comfortably and operate. In fact these days as you see, I have the tablet on my lap. The most comfortable car portable operating I have found, and I have done a lot over the years!
This is about the 4th or 5th car this board has seen action in and it is now into it’s 4th decade (with about a 2 decade break).
I was scrolling down my Facebook feed and spotted a post in I think one of the SOTA Facebook groups mentioning a BX-184 CQ Parrot. It looked interesting at first, then awesome! Within 20 minutes I had it ordered.
This is a modification to the standard MH-31 microphone that comes with the FT-817, FT-857D and FT-879D etc. It will record and playback a message, perfect for calling CQ Contest or CQ SOTA etc, but without the requirement to carry and connect up another gadget as it fits completely inside the microphone body. It was designed by Oliver DH8BQA and he describes it on his website here http://www.dh8bqa.de/bx-184/.
It is available for sale on the German Funk Amateur site here Funk Amateur BX-184. However they also do another kit that includes an MH-31 microphone body if you don’t want to disturb your original mic and that is the option that I took Funk Amateur BX-184M. The website is all in German so if like me you don’t speak German Google Translate will help a lot! There is also now a USA vendor here http://www.box73.com/product/2
It came pretty quickly and this is what you get in the box:
A complete kit with all you need. The PCB is part SMT (surface mount technology) and part through hole components. You just need to fit the through hole components.
The double sided PTH PCB is very nicely built.
Top:
Bottom:
Before it arrived I did some research and found some mods made by DG2IAQ on eHam which sounded worthwhile:
Mod 1:
“I do always replace C8 (4,7µF) by a nonpolarised SMD 1,0µF to fasten up the AGC. With this Change the internal AGC works more as a mic compressor than as a (slightly delayed) mic Level limiter.”
Mod 2:
“And for the first time I changed R4 (82k) into 56k to bring the sample rate from 8kHz up to 12kHz (by a shortened play time of 40s instead of 60s, but that’s still more than enough for my needs). This change gives even more punch for the replayed calls as the sound is a little more high-pitched afterwards. You simply can solder a 100k SMD in parallel to R4 instead of completely replacing it.”
I emailed Oliver DH8BQA for his thoughts on these mods and he confirmed they should be worthwhile.
So I decided an 0805 ceramic chip 1µF capacitor would fit best across the pads for the 4.7µF electrolytic it was replacing:
I should have fitted this first as the 15µF cap next to it made it awkward to get a good solder joint on the GND side of the capacitor due to the ground plane wicking the heat away. Got there in the end though:
R4 is an 82K 1206 sized resistor located on the rear of the PCB (this is easy to locate as the kit comes with build instructions in German with a good circuit and layout supplied. English instructions can be downloaded here, page 5 onwards English Build Guide):
And with a 100K 1206 fitted in parallel (on top of the fitted resistor) as suggested above:
With all parts now fitted (including a 1206 capacitor fitted across the supplied electret insert terminals) all that is left to do is mount the electret insert into the microphone body and solder that to the PCB.
Opening up the supplied microphone and removing the PCB revealed these 2 slabs of steel in the body. The only function of these I could see was to add weight to make it feel more substantial. So I got rid of those. No point in carrying dead weight:
Next I hot melt glued the electret insert into the mic and filled up the void as the instructions said. Actually I filled more than the picture in the build instructions showed by mistake. Then solder the screened cable to the PCB and fit the IC and it’s ready to be assembled:
As the replacement PCB does not have the two position slide switch, there is the unused hole in the back of the mic. For this I just used some good quality sticky label material I have to hand.
One piece inside:
And one on the outside.(not pretty but functional):
Once assembled I compared the standard supplied Yaesu MH-31 mic for weight against the BX-184 CQ parrot. A 40% saving in weight, I’ll take that:
I soon connected it up to the radio ready to go but there was no outgoing audio! What!? With several projects on the go I could do without time spent fault finding. What if I have cooked the electret soldering the capacitor on now it’s well and truly hot glued into place. Hmmm. Hold on, what was that pot trimmer for? I remembered when building it I couldn’t see any mention of it. A check of the circuit confirmed the obvious answer. It’s on the mic output to the radio. A quick check with the meter confirmed it was currently set to ground the mic line going to the radio. A quick tweak and we are back in business.
In fact the worst part was setting up to monitor myself. Eventually I had a reasonable system, FT-857D on 5Watts into a dummy load near the FT-897D with a 4mm banana plus as an antenna feeding into the sound card on the PC, with Audacity dealing with the recording. The recordings are not broadcast quality but are good enough for a comparison.
Here is a CQ call using the standard MH-31 mic:
Here is same CQ call live using the BX-184:
And the replayed recorded CQ call from the BX-184:
I might need some on air radio reports for final setting but it doesn’t seem to be clipping at all though does have a little more punch.
Can’t wait to try this out in a contest or SOTA activation. All in a great little kit well thought out and went together very well. The only small point is no actual mention of the trimmer function or setting which would be good as a reminder if nothing else. I know this kit is aimed at radio amateurs who should be able to look at the circuit and deduce why the pot is there so this is a very minor point in a great kit.
Edit:
I have since used this ‘in anger’ in 144MHz contests. The first contest I got some complaints about over driving and being wide (complainant was also wide to me for that matter!!). But I turned SSB mic gain down in the FT-817 and back at home I did turn down the audio output level on the microphone itself and did some tests between it and the standard MH-31. Subsequent contests have resulted in zero complaints but some good audio reports.
After hoping to enter the previous two sessions of the RSGB 144MHz UK Activity Contest series but for various reasons failing to get on the air this time I finally succeeded. It’s 18 years since my last VHF contest. This time I could try out my newly finished and as yet untested on air 9 element DK7ZB yagi and lightweight portable mast.
I checked the past year’s results to see if my old (from back in early 1980s) site was being used in the UKAC series. As it didn’t seem to be I chose to try there for this contest.
The original plan was Paul G1YFC would also come up for the contest (we won our last contest in 1998) but he couldn’t make it so I slogged up the hill with all the gear on my own to the trig point on Graig Syfyrddin which is at a height of 423m which a clear take off though has the 400m higher black Mountains West of it:
Literally every radio item I would be using for this contest was new to me since the last contests I did. It was a pretty calm evening so setting up was fairly straightforward and I soon had the mast and tent up:
Once I had the Yaesu FT-817 connected up and the tablet fired up I worked a few stations before the contest getting good reports from my QRP station which was good to hear. I did learn it’s much wiser to operate from a hill you can pronounce the name of though. One quick check outside before the contest starts revealed a nice sunset:
Once the contest started activity was pretty good. For the first hour or so I was exceeding 1 QSO per minute and getting great reports. Things did slow down a bit and QSOs came in little bursts of activity. I made use of the 2nd VFO for some search and pounce but was mostly running. Logging was done on my Surface Pro 3 using Minos by G0GJV. What I should have done I think was also try the ON4KST chat that everyone uses. It actually never occurred to me on the night. This was a great shame as I missed a couple of leading big gun stations somehow that would have given me some valuable new multiplier squares. Anyway I got 120 QSO in total which seemed respectable.
Here is my QSO map:
Packing up as quickly as I could by headtorch I headed down the hill almost running at some points. Even rushing it was midnight when I reached the car and 1am by the time I got to bed.
My claimed score (before adjudication) put me in 3rd place in my section. 4 multipliers (2 UK new squares) would have put me top! Missing those big station multipliers was very costly indeed!
Overall I am very pleased with the first go out this century. It was meant really as a practice run for the forthcoming 144MHz Backpacking series of contests and also the PW QRP Contest which I have always been a big fan of. The equipment all seemed to work well apart from one small temporary issue with the keyboard on the Surface Pro 3 failing to respond which was very inconvenient. I did get it going but without know how or why it stopped working.
In order to facilitate the building of my backpacking lightweight 144MHz 9 element DK7ZB yagi with a friend I came up with this reinforced plastic element mounting plate.
The primary idea behind it was that it would make it easy to accurately position elements in the right position along the boom and also ensure the elements were mounted nicely perpendicular to the boom. This was the sought after benefit for my build, ensuring all elements were nicely parallel to each other and in the same H plane. Also it would allow easy use of specific element mounting methods particular to my variation of a DK7ZB 144MHz long yagi beam design. The mounting plate is specifically designed to work with 20mm square section boom.
Here is the 3D design of the element mounting plate: And a dimensional drawing for suitability to other yagi build applications:
For my beam (linked at top) I was able to use this to mount both parasitic elements and the custom driven element:
The element mount plate has location ridges underneath to align perpendicular with the 20mm square boom and has a small central sighting hole to align with a marked up boom for element centreline positions:
Two fixing holes are provided to fix the element mounting plate to the boom. They are sized for 3.2mm pop rivets but can be easily drilled out for other sized bolts or rivets. The element mounting clip holes provided can also be easily enlarged. They are supplied undersize for M3 deliberately so that an M3 bolt has to be screwed into them thus providing a precision centre aligning of the bolt and hence element clip mount.
Here is a video of the element mounting plates in action:
As I was planning to resume 144MHz contesting but this time full backpacking style I wanted a decent beam that was suited for repeatedly assembling and disassembling. I have a Cushcraft Boomer and also a pair of homebrew DJ9BV yagis but neither are really ideal for the job. After nearly two decades away from radio yagis have moved on and researched showed the DK7ZB yagis were very popular. His designs seemed ideal for my purpose.
I settled on the 9 element long yagi as it is not too long but with decent gain and also has a good flat SWR curve. The RSGB Backpackers section we wanted to participate in only allows one antenna so stacking shorter yagis was out.
The dimensions are available on Martin DK7ZB’s site:
I went for the 10mm elements as a compromise between size and weight and best performance. I was also able to find 10mm clips to suit my intended design.
You can buy some of the DK7ZB yagis ready made and also in kit form, but I didn’t really think the parasitic element mounting methods were ideal for repeated building especially in cold weather. Also the driven element was a problem as it’s not ideal at all for disassembly. There was one example of a driven element designed for taking apart on DK7ZB’s site but I couldn’t find any parts like they were using. I was already building my own lightweight portable mast so I decided I may as well design the yagi from scratch too. So I modelled the full antenna down to every nut and bolt in 3D CAD software. This enables me to know exactly what materials I need and also predict pretty accurately the weight, bearing in mind I plan to backpack this up hills:
To source the main raw materials I found that it was cheaper to buy from https://shop.nuxcom.de/ in Germany than anywhere I could find in the UK! I went for the 20mm square boom and 10mm elements. My 3D CAD model told me I wanted two sections of boom 1.72m long and one section 1.62m long. (After ordering I noticed that is the same lengths Attila uses in his 9 element kits!) I didn’t go for a kit as there were several parts in the kit I didn’t need and I wanted to order a few spares of the elements just in case I cocked up some of the cutting. Nuxcom sell the boom in 1.5m and 2.0m lengths but the 2.0m lengths cost more than double the shipping, so I asked Attila if it was possible to buy 2.0m lengths but have them shipped in two pieces, 1.72m and 28 cm lengths. He did this for me at no extra cost which is good service. The offcuts would be useful for doing tests later.
First building task was to cut the parasitic elements to size. Although I’m pretty good with a wood saw I’m a bit rubbish with a hacksaw and I didn’t want to use a pipe cutter as certainly for the driven element I needed no deformed ends to the tube, so I managed to borrow a mini circular disk cutter like so:
With this I was able to make nice square cuts. To measure them I used a metre ruler (tape measure for the reflector-checked against the metre rule first) butting both up against a stop to get an accurate measurement. I checked that the first mm was a true mm before starting as some rulers have a dubious first mm:
And checking D2 (ever so slightly short if anything by a fraction of a mm):
After cutting the parasitic set I fitted end plugs from Nuxcom for a nice finish. (Elements in bottom box, spare elements and boom sections in top):
Next to assemble the boom. I bought the Nuxcom boom joiners and I must say they are very well recommended. The fit onto the 20mm boom sections is a snug push fit and the extrusion is thick enough to be strong yet still light. I got them with the M4 bolt and wing nuts. The one thing I didn’t like so much was the massive hole for M4 which was 6.5mm diameter. However, once I modelled up the joiners and dropped them into the antenna assembly I could see that a 4mm hole at the top of the 6.5mm hole would be pretty much bang on centre of the boom, and mean the boom could not move up in the joiner. I also added a vertical bolt on each side of the joiner too as shown below. That meant the boom section was forced into the joiner tightly ready to drill the holes. I drilled from each side, using the 6.5mm hole as a stop for the 4.0mm drill bit:
The above picture is showing the boom joiner fitted to the centre section. Both joiners are fitted to the centre section and will stay there permanently so I have used socket cap heads and nylocs, all stainless steel, bolts cut to minimum length. (The four supplied wing nut bolts will be used to attach the end sections on the hill top). With both joiners fitted, the centre section then is pretty much the same length as the outer sections (by design). I also bought the square boom end caps from Nuxcom to finish them off nicely:
The boom was then assembled in my hallway and the centrelines of the element positions scribed on. I used a tape measure masking taped to the boom to ensure it never moved and starting at the 100mm mark on the tape measure to eradicate any errors from the tape measure hook end.
The element clips I needed to find something that was quick to mount the elements and remove them again. The typical single bolt through the centre of the elements I didn’t fancy as it was a bit fiddly especially with cold hands on a windy hill top. My friend found these 10mm pipe clips that were ideal. Snap in and lock, and easy to open again to remove the elements. They will have a finite life but my test piece has had dozens of cycles and they come in a bag of 100 for under £6: Another plus point of this is the element centre is a reasonable distance off the mounting surface which means I had good scope for getting the driven element to be on the same plane as the parasitic elements. I just need some suitable plates to mount these on nice and squarely on the boom. My friend offered to injection mould me some rather than my trying to accurately drill out several plates exactly. So I modelled up a mounting plate to be made from glass fibre reinforced nylon which is extremely strong and stiff for its weight. The image shows the underside. The two ridges are to locate on the square boom:
Soon in the post came a parcel of element mounting plates. We decided riveting them on was a secure and lightweight fixing method. The two location ridges on the bottom had a slight amount of play when offered to the 20mm boom which of course would be amplified by the approx 100cm elements so I fitted two tiny strips of masking tape which made the plates a perfect fit. Once the rivets were in it doesn’t matter if the masking tape decomposes away:
The small hole in the very centre of the element plate is a sighting hole to align the element in it’s correct position on the boom. This was used to line up to clamp the plate on for the drill of the first rivet hole:
Once the first rivet was fixed, the clamp was no longer needed and the 2nd hole drilled and riveted:
Then a simple case of fitting the 10mm pipe clips and snapping in the elements in the right place centred on the boom. In order to easily locate the element centrally on the boom with out any time consuming I fitted to each element a piece of adhesive lined heatshrink to be positioned between the clamps. I also added some marking numbers for the 8 parasitic elements, numbered 1 to 8 from from to reflector:
Now the easy bits are done, time for the driven element. This was the biggest head scratcher on how to make it suitable for repeatedly taking apart and assembling. I needed to come up with a method that both left the electrical connections to the driven element halves but also enabled me to remove them for transportation. This meant a split in each half of the driven, but how to attach it?
I decided to come up with a system of employing a ferrule in the driven to join the two halves. With some custom made parts it would also be mounted on the same element mounting plate as the parasitic elements and is the reason the element plate is larger than a typical one, although that was also good for rigidity and build accuracy.
When I ordered my 10mm element tubing from Nuxcom I also ordered 1 metre of 8mm tubing to do this. But there were two issues with this. The first was this was the only piece of tubing that arrived with a bend in it. If I had planned to use it as an element I would have had to reject it. As it was I could cut out straight parts to use but the 10mm diameter 1mm wall thickness elements have a bore of about 7.92mm and the 8mm tube an outer diameter of about 8.10mm. No chance of a fit. Out with the calculator and it soon transpired 5/16″ should be a perfect size. I bought some T6 grade aluminium from eBay and it was a perfect fit. Sliding with no slop at all.
To cut slits in the 10mm tube to compress it with clamps to grip the ferrules I used two 10mm element clamps to mark a dot each end and each side of the clamp and joined them up to make cut lines to follow:
I’m not fantastic with a hacksaw to be honest but using the element clamps above to hold the tube in the vice I was able to cut (from both sides) fairly neat slits with a junior hacksaw (I wanted thin slits):
Then it was a case of fitting the ferrules into the outer halves of the driven elements and adding a screw to maintain a good mechanical and electrical grip:
Next to feed that driven element. I decided to straighten out the feed match to take the feed point a little closer to the centre of the yagi. I’m using WF100 75ohm coax which is fairly low loss for its size, and is not too big or heavy. Its claimed velocity factor is 0.85 so I worked out the length as so:
300/144.300 = 2.079m full wavelength
2079/4 = 519.75mm for quarter wave
519.75 x 0.85 = 442mm
DK7ZB gives a length of 440mm for this velocity factor, but I notice all his lengths are in multiples of 5mm so I wondered if he did some rounding down? I hope so!
This is the length of the braid. I hate stripping and cabling up coax so did all I could to avoid twisting bits of braid about. I cut the braid and dielectric off square and about 5mm or so of the outer jacket to reveal the braid. With a very large tipped iron of unknown wattage I was able to tin the braid nicely with no apparent melting of the foam dielectric. I then made a small tinned copper plate to bolt to the N-type socket and solder to the braids making a good earth. For good measure I added a loop of braid from some RG223 soldered all round. Then made the inners as short as I could and soldered to the N-type:
To tame the annoying curling coax I found yet another good use for the short boom offcuts I asked Attila to include. I taped the coax out straight to measure the 442mm finished length:
You can see I am using red adhesive lined heatshrink to keep the coaxes tidy and together. In the picture above the tiny box for the driven element connections is threaded on ready for the stripping and fitting of connections. I used a similar method as on the feed end with some copper sheet to join the braids and solder tags to connect to the element halves. This was a very fiddly job but hopefully worth it keeping the connections as short as I could manage:
To support and space the feed off the boom as recommended by DK7ZB (although this is going to be used for QRP almost exclusively) I got some ABS spacers 3D printed which I placed in position and then wrapped tightly with insulation tape. The idea is to keep the coax off the boom (which it is miles away from) but also as far away as possible from the element plate rivets but also as far from the element the coax passes under:
The driven element box is supported solely by the driven element inner pieces themselves, but I added a very small 3D printed pillar to make everything secure:
Here is the feed match finished:
As I plan to use this on a lightweight mast section only 20mm in diameter I didn’t think the usual U-bolt clamps would be able to create enough friction to stop the beam spinning on the mast without being so tight to possibly crush or weaken the 20mm ali mast. I bought some plastic 20mm clamps for large yagi elements from Nuxcom to try but they do not have enough friction. So I drew up some half round clamps to be made out of aluminium:
I used a small 3mm aluminium plate in usual manner and bought some 20mm square U-bolts for the 20mm boom itself. As the 20mm boom again is quite small for a long yagi I was again concerned about over tightening the U bolts and creating a weak and potential failure point so I added some small 3mm aluminium plates to allow it to be tightened up nice and tight without any fear of crushing the boom. Here is the finished boom to mast mount. (The two unused holes visible are there to use with the lower 20mm boom mounting holes for a 25mm boom yagi I have):
I used a similar arrangement for the boom support to mast fixings, the aluminium clamps and a slightly smaller aluminium plate. Just a simple M4 bolt per half of the boom support and another plate to help strengthen it all up. The intention is that the boom supports will also help offer a little sideways strength against the wind as well.
To bend up the boom supports I first tried to bend some 20mm square section (same as the boom) in my workbench jaws (seen above in the first picture after cutting the elements). They were not strong enough to bend it! Note this is not a proper vice as such, more of a drilling and cutting bench with jaws. I then thought I might use a bottle jack to apply the force but couldn’t think of anything solid I could jack onto. Then I remembered we have a small 3000lb lever press at work used for punching small holes in sheet metal. I soon made up a jig using a 10 inch square of ¼” steel with some small aluminium blocks and I used the spare offcuts (yet again) to work out the right amount of packers below the centre to give me the bend angle I needed:
I used 10mm MDF to spread the load from the press and protect the 20mm square tube and a strip of bare FR4 as a bearing and protection to the underside. Once tests were done I quickly and easily put the bends in the actual supports:
Checking the bends are matched:
Then just a case of offering them up, drilling holes in the right places and fitting. Finished!
Now for the moment of truth, how does it measure on the antenna analyser? Well to me it looks to be best match at 144.660MHz but is showing SWR of 1.1:1 and 51Ω at 144.300MHz so I’ll take that thanks:
Here is a real time video showing how long it takes to assemble the elements (I have not shown the boom assembly as nothing unusual or new about the boom assembly):
Only job left now is to take this up a mountain top and do some contesting!
Edit: I have done my first contests with this now and it seems to work really well and I got good reports all round. Even with a low loss feeder the radio was not indicating any SWR reading at all on transit. I have come 2nd and 1st in the low power section of the first two UKAC contests I have entered so I am really pleased with the way this yagi performs. It ‘feels’ even as good or better than our 2x 19 element MET yagi array.
Due to construction projects I have had on the go for a while I haven’t been out to do much actual radio lately. But I recently purchased a Baofeng UV-82HP 144/432MHz handheld as I am driving up to the top of two 14,000feet+ SOTA summits in Colorado later in the year and thought it would be rude not to activate them. I got the handheld as the trip is with non radio friends and is for sight seeing so I wanted something small and quick to deploy. So when myself and YL found somewhere new to go for our weekend jaunt up the mountains I quickly checked if it was a SOTA summit and turned out it was, so I grabbed the 82HP and took it! I have not used it as yet so at least I could check it worked!
We parked at the start of the very well defined track leading us most of the way to the summit:
The day started cloudy but dry but turned out beautiful later. This picture was actually taken on the way back but is on the early stages of the track. That is Fan Gyhirych on the right in the distance:
I had 3G coverage on Three network along the track which was handy as I could revise my rather hopeful estimation of arrival time on my SOTA alert! The view whilst updating my alert:
Once on the summit I was able to spot myself and my call on 145.500MHz was quickly answered. Moving down to 145.475MHz to carry on. First QSO I was a bit weak with the other station but after a call for QRZ when we closed I had a good strong station return. The wind was quite keen on our bare hands, my YL was logging for me as we were stood up. With 4 QSOs in the bag to qualify as an activation my further QRZ calls went unanswered so it was time to move on.
Heading back down the views from the summit ridge were great today:
All in all quite pleased with the little UV-82HP as people could hear me pretty well on its supplied rubber duck antenna. I did have an issue where it seemed to be slow in opening receive after transmit and as a result I often missed first couple letters of a returning call but I found some squelch tail delay settings to turn off which will hopefully correct this.
When I made my lightweight aluminium portable contest mast I designed up a very lightweight guy ring to use that was both strong and light. I designed it for my friend to injection mould in a fibreglass reinforced plastic that is really strong. The material is so strong I could not damage a 1.5mm thick long credit card size sample by hand even across the edge of a table. All I did was hurt my hands.
So with one eye on weight and one on strength this is the design I came up with. The design criteria was that these rings would hold up a mast carrying a decent sized 144MHz long yagi with at least a 5m boom on an exposed mountain summit in winds at least as strong as the tent will take but also be nice and light and small. They are very similar to many others you will see (there’s only so many ways a guy ring can be designed), but this is only 61.5mm outer diameter and 14.2 grams in weight:
I went for the simple 4 holes rather than extra holes for 3 point guying that some rings offer as it’s easy enough to just use 3 of the holes. Rope holes are 5.8mm which is plenty big enough for 550lb paracord or other ropes you would use with a lighter weight mast system. The centre hole is 20.5mm sized to fit the top section of my mast. For the lower thicker section it’s easy to open the centre hole with a step drill, in my case 26mm. 30mm is about as big as I would open it too though to retain full strength.
When the rings arrived in the post the first job was to test it for strength. I figured I would make a good test load. Just needed something to hang off and give it some welly. I am a good 170lbs, probably more with boots and big coat on. The rucksack is full of 2 litre bottles of water, probably a good 30lbs more easy. So about 200lbs bouncing weight on the guy ring. This is on a very short length of paracord. A longer length will absorb more shock like a climbing rope does:
Once I was happy with them fitted to the mast and the guy ropes tied on:
And in action:
These rings will also be very useful for SOTA activations where the very ultralight commercially available rings may be a little brittle without adding a noticeable weight penalty. Used for a fishing pole mast the mast will break long before these rings will!
I mentioned that these could be ideal for other radio hams doing SOTA activations and other portable operations wanting a very strong but lightweight guy ring he has made these available (pretty much any quantity) on his website: https://dura-id.store/product/lightweight-mast-guy-ring
Having just finished making a lightweight aluminium portable antenna mast for backpacking VHF contesting I wasn’t really happy with the initial way we were tying down the guy ropes.
Typically I have tied off guys that don’t have tensioners with several half hitches. These are quick and easy but they are hard to tie tensioned properly and I have lost two 19 element MET yagis, a Yaesu rotator and an aluminium scaffold pole when one guy worked loose on a windy day. I didn’t want to use tensioners on this setup as they can work loose and we are going to be operating from a tent and won’t see any loose guys until too late most likely. Also I’m using for this mast lightweight paracord which is meant to be good to 550lbs breaking strain, but I am wrapping that around fairly sharp edged aluminium angle guy stakes which might create a weak point on the paracord. The mast is not massive and I have 2 sets of main load bearing guys but I want this to stay up on exposed windy Welsh mountain tops.
So I thought a round bar would be a better shape to tie the guys to and a clove hitch would be a good start knot as it can be tightened up. For the round bar I thought I would use some of my old climbing karabiners. And to attach those to the guy pegs I would use some small sized climbing rope about 6 or 7mm and use a clove hitch to quickly attach those to the pegs.
Here are the karabiners and rope loops. The rope loops were made from about 1m of rope each and a double fisherman knot used to make the loop:
Once the karabiner was fitted to the guy peg it was very quick and easy to make a clove hitch and slip it on, tension, then lock off with a couple of half hitches:
This adds an extra 381grams to carry but I think it will be worth it in the long run. I could probably cut that down with newer smaller and more lightweight climbing karabiners (I’m not going to risk the cheapie ebay style mini ones) and probably a smaller rope would be OK to use:
This is one way of many options, I’d love to hear your methods and tip and tricks!
(email explained on welcome page)
My portable HF 3 band linked dipole for SOTA activations I like to pack the wire away on a spool rather than a kite style wire winder. I find the figure of eight loops put kinks into the wire and I just prefer the wire to lie straight.
Since I made the dipole I have been winding both halves of the dipole onto one shared spool like so (picture is an older dipole but the spool is the same one I now use on the portable dipole):
I use this spool as it’s the smallest I have to hand and has the capacity for both wires including their integral guy strings each end. This is OK in that it keeps the wires lovely and kink free but it takes a while to wind them onto the spool, and bringing one half of the dipole to the other invariably involves unhooking it off every tiny thistle or twig on the ground. Also the two halves love to tangle together.
My dipole (described here) is for 20m, 30m and 40m with small bullet connectors for the links and is made from insulated 16/0·2mm wire with 3metres of 3mm nylon guy line attached at the end of each half.
So I decided to model a smaller dedicated single wire spool to separate the wires and make deployment and packing away easier and faster. This would be 3D printed by my friend Paul so the design needed to be suitable for that, ideally with no time consuming support structures needed during the printing. It would be in ABS so a two part (identical halves) design was used which would be cemented together. The cement works like a weld essentially melting the two parts together. Loading on this part is very minimal anyway.
This is the design I came up with:
The design features were to be:
Lightweight. I wanted the two spools to be equal or less weight than the existing single grey spool. I am always aware of ‘feature creep’ upping the carry weight. A large central drum and shallower cheeks keeps weight down, as do the weight reducing holes.
Function. Obviously I need it to take all the wire without overflowing but not have so much capacity I was carrying dead weight.
Usability. I wanted to make it easier and faster to use. The larger internal drum size means more wire wound per revolution and the cross members in the sides are sized to allow a gloved finger from each hand to fit in quadrants 180° from each other to make a simple hand winding action. Additionally the larger weight saving holes were sized to allow the plastic guy locking buckle to pass through to make starting the winding up of the guy very easy.
Bonus features. I realised when adding the weight saving holes that a good airy pattern of holes would greatly help with natural airing and drying out when packed away wet. I also added some internal locating lugs that would self centre each half during the cementing together process (a request from Paul after the prototype build).
The 2nd version soon arrived and was tested with the dipole. It was definitely much easier and faster to wind up the single dipole half which fitted nicely in the spool capacity (that’s an open 20m to 30m link sticking out):
Deployment is extremely fast as the spool is small enough still to use a thumb and finger of one hand as an ‘axle’ on the centre hole each side (sized to take a pen or pencil for when it’s too cold for dexterous hands) and as I can now deploy each half where I need it immediately with no tangles I’d say deployment is between 2 to 4 times faster which is appreciated when the wind and rain is biting.
Paul has made a small improvement to the design for printing purposes. My location lugs had such a small surface area they did not have time to cool down before layers so he has extended them lengthways but removed the vertical part of the lug to keep the volume (and thus weight) the same:
Here are a final pair to make one spool fresh off the 3D printer:
The final weight for the pair of finished 2 part cemented up spools is 44grams. 2 grams over budget but I can live with that for the much better overall system:
SOTA HF dipole ready to roll, literally:
Quick demo showing deployment and packing away:
If anyone with their own 3D printer is interested is making use of this design Paul has made it available on Thingiverse and Youmagine.
(Obviously your wire diameter and lengths will dictate suitability)