So how many times have we wanted to get a rope over a tall tree? American amateurs have a great solution but unfortunately, I suspect, its not possible for us here in the UK. 🙁
The solution is in episode 263 of Ham Nation (21 mins into the show) and is entitled ‘Coax and how To Get it 200 Feet into the Air!’. Whilst Ham Nation is always worth watching I’ve also put the manufacturers video below too.
Any dog owners know if something like this is available in the UK?
Andrew
G0RVM
This month, the RSGB have published their strategy for the next five years. The outline provides a short summary of their Purpose, Values, Goals and Priorities but they have also made available a five page document that provides more details.
Andrew
G0RVM
Browsing the website of the Weston super Mare club (G4WSM), I found the video below. As its rather fun, I’m posting it here too 🙂 Whilst we’ve just had our field weekend wouldn’t it have been good to make a video like this? Unfortunately, the sound is a bit corrupted with funny ‘dit and dah’ noises. Only kidding 😉
Andrew
G0RVM
There a few club members who know Morse code and would like to improve their skills in one way or another. Speaking with members, I’ve heard mention of FISTS but never of CWOPS. I know an amateur who has spent the last year with the CWOPS Academy program and who has greatly increased their speed and accuracy of receiving and sending.
Not to be forgotten is also the slow Morse transmissions by amateurs here in the UK on behalf of the RSGB. This is how I originally learnt the code.
So, for those who may be interested, I’ve posted the links below:
Andrew
G0RVM
Using the excellent Radio Mobile program by Roger VE2DBE, I’ve produced a 144.3MHz coverage map for our current setup at the club-house. For info about the antenna, losses, power etc see the first page.
The report is here.
Andrew
G0RVM
So, most members should be aware by now that the old 40m dipole has been removed and replaced with a new 40m dipole! The feedpoint 1:1 balun was also changed for good measure and sealed thoroughly for the winter.
But this is not the end of the work on the HF antenna, that was just task 1 😉 Task 2 consists of two activities and is planned for Spring 2017 once it dries and warms a little 🙂
Activity 1 will add elements for 30m and 20m expanding the 40m dipole into three parallel dipoles. This will result in a tri-band antenna that is resonant on 40m, 30m and 20m giving us a very useful antenna.
Activity 2 will replace the coaxial feeder between the radio room and the antenna feedpoint.
Today we have approximately 2.3dB of loss at 7.1MHz between the radio room and the antenna feedpoint. Assuming the coax is in the very best condition (which its not) and it’s RG-58C (Its an RG58 of some sort) this equates to about 54m of coax. That’s a 40% power loss on Tx and Rx. Replacing this with RG-213 reduces the loss to 0.9dB or a 19% power loss. An improvement of 1.4dB or 20% doesn’t sound much and its not but consider the situation at 14MHz. With RG-58C there is 3.2dB / 53% loss but using RG213 the loss is 1.3dB or 26%.
| Frequency | RG-58C | RG-213/U | Ultraflex-10 |
| 7.1MHz | 2.2dB | 0.9dB | 0.5dB |
| 10MHz | 2.7dB | 1.1dB | 0.6dB |
| 14.2MHz | 3.2dB | 1.3dB | 0.8dB |
Coax loss per 54m
To put this differently. The transmitter places 100W max into the feeder at 7MHz, 10MHz and 14MHz. With RG-58 the antenna receives: 60W, 54W & 47W respectively. Replacing with RG-213 results in: 81W, 77W & 74W. Using a better coax and one that does not cost much more than RG-213 the situation can be improved further. The overall difference of using something like Ultraflex-10 over RG-58 is definitely worth having and that is why activity 2 is so important.
The completed parallel dipole antenna will remain in its current location supported by the trees at either end. But supporting the end of the antenna elements will require two attachment points instead of the one we have today. Investigation has showed this is not a significant obstacle.
Thanks to Peter, G3LDO for the above diagram taken from his excellent book Backyard Antennas.
Myself G0RVM and Peter 2E0UAR attended the RSGB Convention in Milton Keynes this year. We left Bristol around 15:30hrs but got stuck in jam after jam. Towards the end of the journey ‘here comes another set of blue lights’ was becoming a bit of a joke! Fortunately we did arrive before the buffet dinner finished. It was a close thing tho as there where only a few slices of pudding pie left 😉
This was my first Convention and I must congratulate the RSGB for such a great event. The accommodation was good, the food and conference facilities excellent. It was educational to hear talks on a variety of subjects from speakers deeply knowledgeable in their subject. Access was free to those under 21yrs too – a great way of incentivising attendance by younger radio amateurs. Thank you RSGB.
In addition to the rooms hosting five parallel lecture streams there was a room with stands by Icom, Kenwood, the RSGB and of course, Martin Lynch who were the prime sponsor. Outside this room was a rather large trailer tower with HF antennas providing live signals for the exhibitors.
Proudly parked outside the front of the conference centre was Flossie, the mobile radio van of Camb-hams. Protruding through its roof was a Clark pneumatic mast with rotary HF dipole. The van looked excellent and a great way to get a portable setup to a distant location, setup and on-air with minimum fuss. As I have a pneumatic mast also it was good to swap experiences, finding we shared some of the challenges associated to these masts.
Some of my favourite talks over the weekend were:
I was really looking forward to “Best practice for VHF UHF DX” by Ian White GM3SEK but unfortunately Ian had to cancel. Maybe next year.
From the first talk identified above I learnt that we as radio amateurs are soon to have a ‘bend-pipe’ transponder in geostationary Earth orbit. Wow that is an amazing feat and I can’t wait till its operational. Amazing. The talk by Prof. Cathryn Mitchell was excellent being delivered superbly and hugely informative. It was interesting to hear how in 2015 space weather was identified in the UK National Risk Register with an impact of the same scoring as emerging infectious diseases, inland flooding, effusive volcanic eruptions, major industrial accidents etc. In fact, in 2015 the likelihood of a major space weather event occurring in the next five years was in the second from highest category.
I can thoroughly recommend attending the Convention and I know I will be booking my 2017 ticket as soon as they become available next year.
Andrew
G0RVM
Members who attended tonight had a talk about the types of propagation commonly used at VHF by radio amateurs.
The slideware from the talk, along with material from other talks, may be found in the Lecture notes section of the TSGARC website.