Category: Ham Radio

IKA Logic ScanStudio Software on MacOS

Playing around with various digital circuits I was pleased to discover the IKALogic ScanaLogic logic analyser for not a lot of money, largely because your PC gets to do the heavy lifting.

However, I did run into some problems running the Scanstudio software under Parallels Desktop 8 on my Mac.  It turns out that the problem is with the DirectX support in parallels.    The problem is that if you import one of the example waveforms, or   try to show a decoded capture, it doesn’t display properly, as shown.

Screenshot 29 12 2012 18 18

 

The workaround is to shut down the VM, open the Parallels hardware settings, and disable 3D Acceleration.

 

Screenshot 29 12 2012 18 20

One that’s done, the traces appear properly:

 

Screenshot 29 12 2012 18 23

APRS Presentation

November 2011, and there’s been a bit of a gap in updates on this site. Actually, it’s been completely neglected. But, I’ve had fit of technical upgrades here, and have now got all my websites in the process of being converted to a single WordPress platform so I can write and update more easily, and I’m intending to try to keep things up to date.

Most recent news on the radio front is that I did a talk in November for the Bracknell ARC, about my efforts to work the Interrnational Space Station using APRS. It was an interesting challenge, and part 2 is still to come.

UKAC 70cms

A very encouraging result for G4BRA/P in the 70cms UKAC contest in January.  Operated by myself, G4AUC and G4DDN, we came a respectable 16th out of 67 in the AR section for January.

Stealth Antennas

I’ve been pondering for a while what to do for a casual HF antenna for home use.  Putting up a portable doublet when I need it doesn’t really lend itself to a quick scan around the bands when I’ve got half an hour to kill, and the MFJ mag loop is pretty poor on 40m and doesn’t cover 80m at all. 

I don’t want a lot of overhead wires, and while there are trees around they are in neighbouring gardens, so it’s a bit of a cheek to start suspending wires from them.  So I started thinking about a loop antenna around the garden fence…. 

After trying M3XPR’s W3EDP design, I’d been wondering about sneaking that up into one of the trees, but couldn’t figure out how to do it.. then I started pondering a bit more… 

I started thinking a bit more… what if I took the measurements of the W3EDP, and laid it along the fence.  It would get the feedpoint away from the house a bit, be pretty much invisible, and would be a good NVIS antenna if nothing else for local contacts.

Well I set it up via my MFJ Z-11 Pro tuner, and after a couple of periods of casual operating I’m encouraged by the results.  The wire runs through bushes and under a big tree, and is rarely more than 5 feet off the ground.  But I worked GM4SSA in Shetland on 40m SSB with about 75 Watts and got a 5/8 report, and was really surprised to hear a W3 station last night – though I didn’t even try breaking the pileup of 1.5kW Italian stations to see if I could work him.  I’ve also heard a reasonable number of stations on 80m but haven’t tried working any of them yet.

The next step is to move the tuner closer to the feedpoint of the antenna, which will require some remote power – probably sticking it with an SLA gel battery in a waterproof box in the garden, and to see if 80m will tune better with the counterpoise disconnected (and if it does, find some way of remotely switching it).  But if initial reports are anything to go by, the real next step will be to weatherproof all the connections as it’s likely to be there for a while!

And the lesson learned is that any wire you can leave out is going to make more contacts than something efficient that takes time to put up when needed.  

Update 1 

Looking at the antenna with my Mini-VNA analyser showed it had a very odd resistance pattern with a very poor VSWR match at 80m.  Since then I’ve moved the tuner into a plastic box in the garden to minimise line loss,  and added a nice hefty earth stake.  The earth stake has not only brought the noise on 80m down to a manageable S3, but means the match is better than 3:1 on top band, 80m and about 8:1 on 40m and 20m.  Contacts on 80, 40, and 20 prove the antenna is working, including 59+30 from M3AFF in Devon with a nice high dipole. 

I still need to make the coax run a bit more permanent rather than hanging out the window, and possibly upgrade it to RG-213 instead of RG-58, and hide the wire a bit better, but I have a workable solution for the lower HF bands.

 

New FT-847 in the shack

After missing a previous sale while figuring out it’s capabilities, I now have a Yaesu FT-847 in the shack.   This has necessitated something of a changearound.

The IC-7000 has been re-designated as the portable station, and my FT-857D is now for sale.  

The FT-847 has a strong VHF-UHF section and is competent HF radio too.  This matches my interests perfectly and gives me a decent home station – almost in a single rig, but I will be keeping the FT-7800 FM rig as well.  

The intention is to augment the loft with a trio of Quadrifilar helical antennas for 2m, 70cms, and the 137MHz weather band, and play with some satellites as well as the “/P at home” on HF.  I’m going to start by copying Julian G4ILO’s 137MHz QFH, and then scale it up to 2m and down to 70cms, using this excellent QFH calculator.  

 

GG100SGS

20th and 21st Feb 2010 was the 25th anniversary of Thinking Day on the Air, and since 2010 is the 100th anniversary of Girl Guiding in the UK, Ofcom had allocated a special GG100 prefix for stations related to guiding in the UK.  When Bracknell ARC was approached with a fairly last minute request to help with a station for a local group, I stuck my hand up, hastily filled in an application for the NoV, and disappeared on holiday for two weeks.

When I got back, the NoV for GG100SGS was in the post, and after some fairly quick planning we decided to have a go on 80m, 20m and 2m.   Of course, things never quite go to plan, both logistically and technically.

Logistics went to pot when the guide event that we were supporting got cancelled, so visitors were pretty sparse, but I wasn’t worried about that as the whole day was a good excuse to mess around with radios and get people interested in the hobby.  Guest operator Phil G1LKJ did a great stint on 2m working a load of local GG100 stations.

2m surprised us with lots of local activity and was easily “Band of the Day”.  Trying the other bands meant stringing up my doublet, and then solving the problems with the tuner!   Then it turned out that 80m was a complete washout with S9+ noise across the entire band.  40m had it’s own surprises with very short intra-G skip and we worked Chippenham and Northampton on 40m, and 10m was reputed to be open but we were getting EMC issues with the sound system in the hall we were using so that didn’t get a go either!

Conditions on 20m were good with S7/S9 signals from across the pond in the afternoon, but by then the lack of visitors meant we were getting rather bored – Helen as VE1YL in Nova Scotia was working a huge pileup very slowly, and we ran out of patience waiting to get her in the log. 

All in all, a good effort, and a fun day out.  With more preparation next year this had the makings of a nice little regular event station, though we’ll have to think of a new prefix for next year as GG100SGS won’t be an option!

 

GB3RD Snow Net

About 3:45 yesterday I started chatting to 2E0ZIP/M in Reading via the GB3RD 2m repeater in Reading, while I was stuck in traffic in Bracknell.  The snow had just started to accumulate, and traffic was bad as people left early.  We had no idea just how bad.

The net kept on going until midnight, when we’d had 29 different callsigns on the net, with Jonathan M3VJO, an active RAYNET member doing sterling service as Net Controller assisted by Mike M1ELK and Dave G0TKV.

I think we had as good a traffic information service going as the commercial radio stations, as well as providing advice, updates from traffic web sites, and generally making people feel better about the whole thing.  There was even a suggestion of giving out our frequency on BBC Berkshire at one point for anyone who was interested in listening, but I don’t know if it was acted on.

It was really gratifying to see people pull together like this to mutual benefit.  Well done to all who assisted those of us who were trying to get somewhere!

The Foundation Exam

At Bracknell ARC, we cover the course material in a single day – generally a Saturday, and the following week will be devoted to a revision session, the practical assessments, and the exam. 
 
The concepts are:
  • Introduction to Amateur Radio
  • Licence conditions 
  • Technical basics
  • Transmitters and Receivers
  • Antennas and Feeders
  • Propagation
  • Electromagnetic Compatibility (avoiding interference)
  • Operating Practices and Procedures
  • Safety
The practical assessment covers the following exercises:
  • A familiarisation exercise on Morse Code.  You don’t need to learn morse code, just be able to recognise the pattern of dits and dahs.
  • Connecting up a modern transceiver and making a contact with another station on VHF.
  • Making a contact with another station on HF.
  • Adjusting a dipole antenna for minimum SWR.
 
Finally, the exam is 25 multiple choice questions, which you have 45 minutes to complete.  The exam is marked immediately and you will be given your results straight away.  
 
We recommend that you register with Ofcom before sitting the exam.  Within a few days of the exam, you will be able to return to their website and get your foundation callsign and be on the air.  
 

How to get licensed

Unlike many hobbies, Amateur Radio requires that you pass formal examinations to participate.  In fact, the only other hobby I can think of that has mandatory examinations is being a private pilot.  

Unlicensed people can listen in with a general coverage receiver, or operate under supervision under certain limited circumstances, but otherwise the operation of a transmitter is limited to those who have passed the exams.

In the UK, there are three levels of licence: Foundation, Intermediate and Full.   Each of these has a corresponding examination.  The exams must be taken in order, but there’s no requirement to take all three, or to do them in a set amount of time. 

 

  • The foundation examination requires basic knowledge of electrical circuits, what a radio is and how it works, various transmission modes, propagation effects and licence conditions.  Before sitting the 45 minutes multiple choice exam, you will also need to pass a practical assessment.  With this licence you can operate on all the bands from 160m to 70cms, plus the 10GHz microwave band subject to a 10 watt power limit.
  • The intermediate examination builds on this to develop a greater level of understanding of all the concepts, plus a practical assessment that requires building a simple kit and other electronic exercise.  The intermediate licence adds the privilege of building and designing your own transceivers, and 50 watts of power across all the bands.
  • The advanced examination (which leads to the full licence) gets into much more detail of the electronics, mechanisms behind propagation effects, and EMC.  There is no practical component at this level.
All the exams are multiple choice.
 
The first step is to get a copy of the Foundation Licence Now Book from the RSGB bookshop, or your local club.  The next is to contact a local club who are running a foundation course and exam.  You don’t have to do the course, but it usually only takes a day and is a good way to get to know other people learning at the same time.