During the build of the Band Pass Filters it has become obvious that my little miniVNA is just not up to the job. Because of this (after some advice from Bob 5B4AGN) i will be embarking on building one of these
Author - M0YOM
Construction of the band pass filters continued today, progress has been slow recently as i needed some more parts (M3 10mm bolts and some M3 nuts), I also had the problem of finding some appropriate coax to use for the internal connections. As luck would have it i have a couple of barely working Wifi antennas that have some nice long leads of very thin coax, it turns out that the coax is RG-174, perfect for my short internal connections on the BPF’s.
My large 7 segment displays have arrived, these are 2.24″ tall and will be eventually be used in couple of large band readouts for the M0XXT contest station.
They are yellow and of the common anode variety. Should look pretty nice once the project is finished. If anyone knows of a suitable enclosure to hold 3 of these plus associated circuitry please let me know.
For CQ WPX this year i built two sets of high power coax stub filters to allow the M0XXT team to enter as Multi-Single.
These stubs performed reasonably, although there are some improvements i plan on making for the final design to be used in conjunction with the Band Pass Filters already under construction.
Expect a full article on the coax filters soon.
(P.S. Fitting over 80 PL-259’s is not fun)
I started construction of the first of two automatic band pass filters tonight. These will be used in the M0XXT contest station in conjunction with high power stub filters to allow us to run a proper Multi-Single or Multi-Two station.
These are similar to the Dunestar 600 devices, however they use the W3NQN filter design so the performance is superior to the Dunestar’s. They were designed by Bob Henderson 5B4AGN, who had some professional boards and cases made up.
They employ a very clever motherboard system, so the filters can be removed/replaced easily.
The photo is of the first, nearly complete motherboard
My thanks to Lee (G0MTN) James (M3YOM) Terry (G4MKP) and Aidan (M6TTT, Scout) for getting our new station on the air for a first-time-out on WPX.
We also roped in Chris and Dan, two new foundation student contest Scouts for the spotting on the Mult Station. Barry M0DGQ also gets a big thank you for supplying hundreds of meters of 75 ohm coax for James’s stub-filter project and Charles at Moonraker for sponsoring the large number of required PL259 and T pieces.
We ran a pair of very old Yaesu FT1000MPs (non-Inrad versions) which were completely swamped by QRM to a number of interesting antennas including our new super all-band Mega-Loop (horizontal delta loop at 85 feet) delivering about 12dbi on 20m to US at 10 degrees elevation (more on higher bands). However, it also delivers 10dbi to EU and most of Russia at a very low angle, hence QRM flooding. James’s stub filter project worked but still needs some tweaking. Thanks to K1TTT for helping James get his head around this. Next time, James will have finished Bob Henderson’s filters as well which should sort out any final interference between bands. Poor James soldered nearly 100 PL259s last week. Don’t worry James, fingers should re-grow by CQWW!
Progress on the band pass filters is progressing nicely, the second motherboard is almost complete and winding of the coils for the first set of filters has begun. Hopefully I should be starting on tuning the filters shortly.
Here is a quick pic of the L1 winding for 40m
107 in the log. I’ve no idea what my score was since I used N1MM’s DX Serial Contest template to do the logging and the miscellaneous field for logging random text did a hopeless job of being able to edit long club names efficiently.
The last time I entered this contest, my log was called into question when the adjudicator asked me to clarify what I meant by the club station “Reading”. It transpired that there was only one radio club in Reading anyway. I vowed not to do this again but I’m back.
This year, I had the added luck of G3WZT CQing 1.7kHz up from my run frequency of 1.903 MHz on the off at 8:00pm. Yes, I had been talking to James for about an hour prior to the off and yes, of course he would have noticed me there – but his deep concern for our predicament was (to use his words) ”tough luck”. John, thanks a lot, 1967 RAE passes were obviously excellent vintages. I’ll endeavour to remember you next time and offer you my run frequency quicker than you can say, “I’m a G3 and I certainly act like one”. I wonder if you behaved like that in 1967 when you had a fresh RAE pass in your pocket and a 12wpm ticket?
Luckily for me, the scout hut was warmish during the event so I wasn’t doing my normal teeth chattering. I took a 20 minute phone at 10:00pm from Wendy which gave me a break but I missed a few because of it and then S&P’d for a while. I notice that there were actually very few clubs playing which was strange. I would have thought this would be more popular. EI and DL stations were playing too, giving Non Member reports bar one DL who gave his full radio club, bless. I wrote Non Member in my log but didn’t tell him so not to cause any upset!
Absolutely nothing wrong with the antenna; 174 metre equilateral triangle at 85 feet fed with 4:1 balun and coax in one corner. It had good ears. Only three stations I gave up with and two of them were in mainland EU; a PA and a DL. M3s (and M6s) were heard well on their 10w. I notice last year’s top score made 130 Qs which was a reasonable benchmark so I’m fairly pleased with 107 bearing in mind the proximity to “John the G3″ and that I had to take Wendy’s important call at 10:00pm. I could only make more if I was either slightly more lucky with the G3s – or played more seriously with SO2V.
Will I do this contest again? Well, I’m not used to a) the quality of operating (come on, it was a bit geriatric) and b) I’m not that keen on the rules. Even just logging the Town would do justice to copying something interesting and different, but logging ”Wensleydale Cheesmakers Transmitting and Electronics Amateur Radio Society” is a bit of a mouthfull. In light of the fact that this contest is apparently a route to getting newbies interested in contesting, forget it. Committee, do yourself a favour and get into my head. I have M3s that want to operate. Give them something they can do and build their copying (and confidence) skills, not drown them with difficult reports under heavy QRM.
Anyway, Sunday’s Remembrance Parade was fabulous. I was back to Front Rank Drummer again after all these years. Great!
73
Callum.
2008 will go down as a wet year. Both VHF NFD and SSB FD was a soaking experience. Luckily, as with most close knit teams, we laughed it off and worked through it, however a tough act all the same. I didn’t take too many photos due to the extreme wet weather however I managed to get a few in the can for the memory box. I uploaded them here:
Arriving at the site on Lunchtime Friday, I got the tent up in a complete hurricane. Stripped to my shorts and a T-shirt in the driving wind and rain and all on my own, at one point I just burst out laughing at my predicament. The only thing that kept me sane was the knowledge that some other crazy people in other parts of Europe were also following my example and getting their stations worked up.
Finally at about 15:30hrs, I had a tent up – and all the tent pegs used up, a sure sign that I had screwed the thing hard into the ground. Sporadic rain continued as Terry and James arrived to part assemble the A3S.
Massive success this year with the new antenna, generating huge pile-ups world-wide. We shall never go near 80m again for JOTA. 20m is the band that synchronises extremely well with passing Scouting messages around the world, particularly if you have a technically proficient station and crew.
I notice Tim (M0URX) has done a little write up of this event here:
Needless to say, if having ones Cub pack sending their greetings message to the Father in Law to the Crown Prince of Brunei isn’t one-upmanship, I don’t know what is 🙂
It is just for me to say thanks to Tim, James and Terry for helping me put on such a sterling event. The QSL cards have started arriving already! Fabulous.
73
Callum.