AO-07 on a Sunday evening

Posted 09 Jan 2012 — by Alex
Category Radio

After a hour or so of the JT-65 used frequencies (note – not allocated but generally used frequencies) being covered in RTTY I decided not to bother trying to have a QSO using that mode. It also helped that the JT-65 programme kept crashing on my struggling net top.

I thought I’d try and listen out for the ISS if it was passing me by and using HamSatDroid on my trusty phone I was presented with a big fat ‘not today you won’t’.  I remembered that I hadn’t updated the Keplerian data before checking the passes so I did and the programme defaults to the first on the list. AO-07. It showed that it was due to make a pass in about an hour. Taken from HamSatDroid Website (http://sites.google.com/site/hamsatdroid/home)With this opportunity I assembled my Sotabeams SB270 and checked to see if the pass was easily visible from my house, i.e. from about SW to roughly NNE and luckily it was so I thought this would be an opportunity to taken.

Bearing in mind it was dark at this time and my decking needs a good coat of ‘taking down and rebuilding thanks to Story homes’ I pointed the antenna skyward and was met with a crackly warbly of ‘CQ satellite’ from a German station. he called CQ for the complete pass and I didn’t hear a single response to his calling. At this point I wish I had a duplexer connected to the antenna and a steady tripod as well as a handy lightweight rotator to help with the pass as this was too good an opportunity to miss. Alas I had none of the above and the station went unanswered. A 2m / 70cm duplexer is now on the shopping list as the chance of me being able to spend some time making a rotator is fairly small. Perhaps a larger one will come available at a Hamfest or eBay.

VHF is by no means easy at my QTH but there seem to be opportunities and its probably about time I explored a few of them

RTTY QSO’s everywhere

Posted 08 Jan 2012 — by Alex
Category Radio

It must be the weekend, the bands are just packed with RTTY noises. RTTY is just one of those modes that refuses to go away and thankfully my rig is handy at muting out the warbles so it doesn’t drive you insane.

RTTY

Contests are really not my thing but they do give you opportunities that might not be available at other times in the calendar. For me it was a new one VP9 or Bermuda in English and a welcome break from revision for my MSc exams

The screenshot above is just a taste of what was taking over the lower portion of the 20m band. I did actually fancy a few PSK-31 QSO’s but glad I ended up giving RTTY a go. probably not the most conversational of the data modes where you actually type in real time but still nice to get the VP9 in the log.

Cobwebb modelling

Posted 06 Jan 2012 — by Alex
Category Antennas

I’ve enjoyed building the Cobwebb antenna and thought I’d do a little bit of modelling to investigate the design in a little more detail. After downloading a copy on MMANA-GAL I started to get to grips with it. Well I say get to grips with it, it was more like a wrestling match where the result was pretty much pre-determined. Guess who won?

Modelling the Cobwebb antenna is a little more complicated than you may imagine. The construction is based around twin cables and basically the effect of having 2 wires close together gives MMANA-GAL a bit of a headache.

MMANA-GAL

I had to laugh as even I can get the SWR a little lower than that!

Seriously though the modelling package is similar to the EZNEC flavour which I have had a play with in the past and its something I would like to get my hands a bit more dirty with in the future. My Sotabeams MFD is looking a little tatty after some heavy use last year and I’d quite like to make up a rucksack antenna that fits my pack and that doesn’t get blown over in the strong winds we get here on the fell tops in Cumbria.

What is good about all these mistakes and mishaps is that they are free in terms of money, they only cost a bit of time and without this learning I doubt I would still be that interested in ham radio. There are of course frustrations but these are far outweighed by the successes. I can’t thank the dedicated and talented individuals enough who put out the various pieces of software that allow us to tinker effectively for nothing.

Good start for WOTA

Posted 03 Jan 2012 — by Alex
Category Radio

2012 has barely started and I hope those of you who read the clap trap I spout have had a lovely new year and the bad weather we’re currently having hasn’t affected your radio play time.

As regular readers will know I’ve a soft spot for WOTA. Getting out and about on the fells has really added another dimension to my radio activities. I decided a long time ago that spending a fortunate on expensive rigs and antennas was not going to give me much more pleasure and that being outdoors is just as enjoyable and in a lot of ways more rewarding. A hike up to a summit may not suit everyone and add to that carrying gear up there as well the numbers will be diminishing. Still. it works for me and I’ve met some great people on the way as well.

This year I plan to keep on going up the fells and activating summits either as Wainwright and / or SOTA summits. I finished off the back end of the year by activating Lord’s Seat (LDW-147 / G/LD-033) and Whinlatter (LDW-160) but the weather and the friends and family who came with me had seen enough of the snow and rain that followed us from the start. That brought my total activated summits up to 25 since March 2011.

The new year ushered in some slightly better weather and my first 2 contacts as a chaser for the year with G6DAT and M1DCU both on Muncaster fell. Not quite from the home QTH as I had to drive up to the top of the hill to get any signal out but nice to work some fellow WOTA-ists from nearer my QTH.

As I sit in my office I can see Dent (LDO-059 / G/LD-045) and even though its fairly windy I know I’d rather be up there that in here.

Santa’s been

Posted 26 Dec 2011 — by Alex
Category Radio

Santa very kindly left me with a new addition to the radio set up yesterday. A 5 element LFA antenna from InnovAntenna’s. I must admit I gave him a little steer in the right direction but even so it was delivered on time.

Its figures suggest its a good yagi for my QTH for use with the local net and SOTA / WOTA on FM and into the NI repeater GB3NI at a push.It’ll also be useful for any back packer work as well as club special event stations if needed. The website throws the usual information and as always it should be read in conjunction with your own experience of your site. Never less the numbers are:

Gain: 11.16dBi @ 145MHz

F/B: 19.59dB @ 145MHz

Peak Gain: 11.18dBi

Gain 10m above ground: 16.93dBi

Peak F/B: 20.32dB

Power Rating: 5kw

SWR: Below 1.4.1 from 144MHz to 146MHz

Boom Length: 1.789m

The antenna came in a large cardboard tube but with nothing else in it, no clues as to assembly, which is odd as you get pages of helpful advice from people like Sotabeams who sell cheap out and about antennas. It also states that the elements are solid 1/4 inch (6.35mm). Although mine were not and the use of high quality insulating blocks is let down by the choice of threaded inserts. Which in my case spun one the box section holes that were drilled and made the insulators sit slightly proud of the section and hence area point which over time will allow fretting. One of the elements isn’t quite as secure as it could be and when I looked inside the box to see the type of insert used I was met by quite a few bits of swarf. Nice!

Still, the new toy is up in the loft (until I can sort out the wobbling elements. Each block needs a deeper countersink in order to make sure the raised insert sits fully inside the insulator and not on the taper of the countersink, if you follow that. The spinning insert will be dealt with by a bit of Loctite 603 or other bearing retainer before the holes get too big.

Whilst I am cheesed off that the manufacturing IMAG0173quality is a bit below par for my liking I’m sure once I’ve fixed the issues it will be a very useful antenna. Here is is in the loft aiming at GB3NI and getting in (just) and you can just about see a bit of the non perpedicularity / wonkiness of the loose elements. Once the go ahead for an exterior installation has been approved by  the in house planning department I’ll be fixing it outside to make the most of the beam. Until that occurs I’ll be manually rotating it by going up into the loft and moving it about, There’s plenty of room up there so there is no problem and means that it’ll give me the kick I need to board out the rest of the central part of the loft.