Transmission Lines

Steven Ring M0SVR delivered a technical talk on the theory and practical uses of radio transmission lines. This was followed by a practical session where simple home-made test equipment was used to measure the characteristic impedance (Zo) of several readily available types of cables. The cable test set-up used is illustrated in the picture. This exploits the use of a quarter-wave length of cable to transform the impedance at the right hand end down to 50 Ohms at the left hand end of the cable under test shown in the picture. A 50 Ohm impedance measurement bridge was used to measure the quality of the 50 Ohm match at the left hand end of the cable under test, whilst a 1k-Ohm variable resistive load (R-load) fitted to the right hand end of the cable is adjusted to achieve a good 50 Ohm match as measured on the bridge. The characteristic impedance (Zo) of the cable under test can then be calculated from the formula: Zo = Square-root(50 x R-load).


Reading July 2016

A a very pleasent day spent meandering around Reading Rally. In my humble opinion a better rally this year than Newbury. The first picture below (although not brilliant) tried to show a new tri-band mini beam on test can’t remember who from but claims to be totally portable and with a fantastically light head load.  To be honest I was at the other end of the show so by the time I got to the arena the demonstration was over. I also couldn’t hear the audio from the PA system well either so apologies on that.  In the foreground of the picture there was a model army vechical display which was interesting and I did manage to see some of that. In terms of spend!!! dare I say it I did buy wisely this time and not with either my eyes or heart but head. Some millspec 214 (ex test lab) feeder approx 50m made off neatly with N type £10, ideal for my portable stuff. Galvanised coated base for my antenna mast (perfect inside diameter 65mm) to allow full rotation once slotted together – spot on and some N type connectors and adopters (as you do).  Nearly talked into a NOS IC7000 but resisted.  Very good day indeed. Same time next year  ????


The Icom IC-7300

There is loads of noise about the IC-7300 at the moment in Radcom, QST and other magazines.  So I felt we should do our bit too!  Here are a couple of video reviews of the radio.

The first is by AmateurLogic and chaired by George Thomas of Ham Nation and Ray Novak from Icom America.

Should the club get one of these?  Let me know 😉

The second video is by Bob McCreadie (G0FGX) of TX Factor fame as he talks with Icom UK to give an overview of the radio.


Antenna Horizon

Have you ever wondered what it would be like to sit at your antenna and see what it ‘sees’?  Well, this evening I attached a camera to my antenna and shot the following short video as the mast was raised and rotated.

The video starts with the antenna pointing at 45 degrees.  Once elevated its rotated to the following directions where it stops momentarily: North, West, South, then back around to East, South, back to North then to 45 Degrees before the mst is finally lowered again.

What this little experiment shows is that the horizon looks pretty flat in all directions – no big hills evident.  It also gives a good feel for how well the antenna clears the surrounding houses.


Have you seen these characters????


Following on from Andrew’s post I couldn’t help but add the picture took by Thornbury Carnival staff. Struck me as a cross between the blues brothers (only more of us) and a bunch of people you probably wouldn’t buy a car from… :).  We had fun so who cares!! Great day and looking forward to more of the same.

Mark M6KMJ



Pedestrian Fox Hunt 2016

Wednesday evening (6th July) saw this year’s pedestrian Fox Hunt in and around the Thornbury area. This year it was decided to use 70cm instead of the usual 2m. It was found by the hounds however that it was much more difficult to locate a 70cm signal. After approximately an hour most of the hounds were in the local area of the fox. However the final few hundred yards proved very difficult.

At around 9pm most of the hounds were suffering with fatigue leaving just two in the running.

The fox was eventually found after a number of clues and instructions, by Garry G7NVZ with Peter M6KVA meeting us on the way back.


RSGB Convention

RSGB Convention

The RSGB Convention takes place in Milton Keynes over the weekend of 8th and 9th October.

Not to be confused with a rally, the convention has lots of lectures on topics related to Amateur radio including DXpeditions and a construction competition.

Video’s of lectures, talks and events from previous years can mainly be found on Youtube or on the RSGB (Members only section) website where there  is a Navassa Island video.

Hope to see you there,


Thornbury Carnival 2016

Jane talking outside the TSGARC tent

The 2nd of July was the date of the Thornbury Carnival and what a glorious day it was.  Hot and sunny.  Thanks to those who helped with the organisation, who provided equipment, who got equipment to/from the site and to those that manned our tent through the long day.

We where allocated a prominent position slightly down the hill from the entrance/exit so there were lots of people passing and quite a few stopped by to see us.  Although the pitch was in a good position for passing traffic, it was in a very noisy position, not far from a music stage and had a children’s inflatable play ‘thing’ next door.  The latter had an acoustically noisy generator running the whole day which, at times, made hearing the radio’s hard.

Mark and DerekAll-in tho, it was a good day.  We handed-out many flyer’s advertising the club and had at least one person promise to come to the club.  Jane and Sue did an excellent job at arresting our local Police, telling them about Amateur radio and getting a promise of a lecture….

The real test of success will be how many potential members come and see us over the next few weeks.  But even if its none, I believe it a worthwhile exercise as it helped communicate Amateur radio to the general public, raise our profile within the community and has most likely secured us a talk.

Garry, G7NVZLashing a pole to an in-situ climbing frame and another to my truck we managed to get a dipole for 20m operational and made several contacts across Europe. We also had a short ‘white stick’ antenna for 2m and 70cms which allowed us to communicate with members not attending the site during the day.  Peter assembled 10 x SDR radio kits to sell to interested visitors and sold 5, including 1 to Mark ;-).

Thanks again folks,


Friedrichshafen visit

Below is ongoing detail. I will add more to this post as the trip unfolds.

Click any of the photos in this post for bigger versions.

Day 1 – 22nd June 2016

Graham and myself are on a European adventure to Friedrichshafen (link). We embarked on our journey at 11am UK time on Wednesday 22nd. An easy journey to Dover was followed by an earlier than planned crossing (at 3:15pm) to Calais via DFDS.

Waiting to board at Dover

The ferry couild have been named the Marie Celeste as we were 2 of 4 people using the aft lounge.


On investigation we realised that the majority of the travellers were truckers, filling their lounge to capacity. We arrived in Calais at 5:50pm local time and proceeded through Calais passing the Bleriot memorial on our way to the Formule 1 motel. Following check in an evening meal was had at Flunch a short walk away and a browse through the Auchen Hypermarket. The night was pucntuated with Thunder, Lightning and HEAVY Rains.

 Day 2

We awoke at 7am and were on the road by 9am proceeding to Dunkerque followed by Steenvoorde where an uneventful crossing into Belgium was undertaken. Then on to Epres, Kortrijk, Tournai, Mons, Charleroi and Namur with a stop just after Liege for Lunch and the first part of this post. On the way we drove through many storms some with the biggest hailstones ever, passing out into glorious skies and 30+ degrees Centigrade.

Continuing after lunch saw us past Aachen to Bad Neuenahr-Ahrweiler on the river Ahr. after settling in at a spenldid, clean, tidy and welcoming youth hostel (Below) we joined approximately 150 schoolchildren and their handlers for an evening meal.

Bad Neuenahr UHA

After dinner of three courses we took a stroll into Ahrweiler along the river. The town of Ahrweiler has a restored wall and cobbled streets as below where a pleasant evening was enjoyed.


Day 3

started as day 2 at 7am for ablutions and a continental breakfast, once again with the cast of Oliver Twist. It is to be remembered however that we were in their territory as neither of us could be considered to be youths!

Travelling saw Koblenz with stunning views at a stop of the Moselle Valley (below) then Stuttgart followed by loads of scenery.

Mosel ViaductMosel Valley

Lake Constance then came into stunning view followed by a drive down the eastern side arriving at Friedrichshafen YHA at approximately 4pm. We have found that we are 2 of 212 people staying here. Everyone of which appears to be an amateur or XYL.

Friedrichshafen YHA

Bicycles have now been rented for tomorrows short ride into the Messe for the 2nd day of the rally.

Our evening meal was taken at a restaurant over the road and co-located with a campsite on the shore of Lake Constance. Some discussion of the menu contents was discussed until an English menu was provided. A brief walk along the shoreline was completed before bed.

Day 4

Day 4 started at the usual time with the usual routine. We then took a short ride on the bikes (missing the queues and parking) to the Messe. Shown is Hall A1 and A2 in the distance.

Messe Friedrichshafen

The rally is split into four halls/hangers as follows;

  • Hall A1 is for Manuafacturers, Associations and non-flea market traders with a huge DARC stand
  • Hall A2 is for the talks and association meetings
  • Hall A3 is the first flea market hall (14 rows by 40 odd tables)
  • Hall A4 is the second fleamarket hall with test equipment auction (14 rows by 30 odd tables) Where can you get 1,000 tables?
  • Hall A5 is an added bonus of the Bodensee Maker faire.
  • Other areas included a stage for talks and presentations, QSL wall and special interest groups including an ARDF contest

Full details of the halls and traders can be obtained at the link above.

We then spent the whole day having our first look around and trying to ensure we walked every gangway. It did take us all day to view A1, A3, A4, and A5 just once. Halls A1 (where we signed in with the RSGB) and A3 were completed before lunch with A4 and A5 after lunch. Many purchases were made with some return to stalls previously dismissed.

We then returned via bicycle to the YHA to rest and recuperate after a day on the hoof.

Our evening meal was taken at a local Italian fish restaurant along the river from the YHA. We then returned to the YHA for coffee and discussion with other HAMS (the place being full of them) and then to bed.

Day 5

Day 5 started at the usual time with the usual routine.

Travel to the Messe was by car today to allow for antenna purchase. Parking was a mere 4€ (£3.20) and then into the halls for another walk through to see everything missed yesterday. Those who have been to rallies with me will know that I’m not fast, except for when in the car. More purchases were made with some bargaining as it is the last day.

Major manufacturers were there including;

  • Yaesu (who were very free with their freebies)
  • Kenwood
  • ICOM
  • Hillberling
  • Lusso
  • Hytera
  • FlexRadio Systems


There was a wide range of items to be purchased including;

  • New and second hand transceivers (at least 4 large stalls selling new Transceivers)
  • Lots of Valves and restored/un-restored equipment
  • lots of Microwave bits
  • loads and loads of components
  • Vacuum capacitors
  • some tool stalls
  • some computer stalls
  • Cable and rope
  • Antennas (at least 6 stalls in A1 plus stalls in the flea market)
  • 3D printers and supplies
  • The obligatory XYL gift stalls (only 4 I think)

Our evening meal is planned for the local Italian fish restaurant (Fischerstuble €20-25 per head) along the river.

Day 6

Day 6 started as usual at 7am. We then began travelling towards Bad Neuenahr-Ahrweiler however we had agreed an initial detour to avoid some of the 5 Autobahn and then agreed an additional detour through the Rhine valley with some stunning scenery.

Day 7

Day 7 will see a return to Dunkirk for the ferry crossing with arrival home late on Tuesday night.

Other Items

Some prices at the rally were more than you would normally pay. For example a PL259 was 80 pence (£1:€1.25) compared to the best rally bargin in the UK of 65 pence. But you don’t go to Friedrichshafen for the prices.

Many photos and videos are available from me in addition to those within this post.

The youth hostel nights cost on average €35 and included a breakfast with optional packed lunch. An evening meal can also be purchased where it is available. Breakfasts consisted of cereals, fruit, yogurt, meats and cheeses with breads. Accommodation was either on or off-suite depending upon the hostel and availability.

The route taken was fairly painless with good continental roads and knowledge of where the hold-ups may be.

Entry into the Rally was either €9 per day or €18 for all three days in advance.

The third day did however see some stalls leaving early including the RSGB packing up at 9am!