Thursday, September 29, 2011

EchoLink or D-Star?

Over the last few days I have been running my EchoLink node #3098 connected into the IRELAND conference server. As I've been feeling a bit tired and lethargic recently it has been a way to pass the time listening to QSOs and making the occasional contact.

Apart from IRELAND there seems to be nowhere else on the EchoLink network where there is enough activity that you can guarantee something to listen to or that someone will reply if you call CQ. I know this is like talking of selling your soul to the Devil but would D-Star, which I have never experienced but which I gather has something called "reflectors", be any better from the point of view of making contacts with hams around the globe using a handheld?

Tuesday, September 27, 2011

Yet another fake Diamond antenna

I ordered a Nagoya NA-771 antenna on eBay. I was impressed with the shorter NA-701 and wanted something with a bit more gain that was not poke-you-in-the-eye long. The NA-771 had mostly good reviews on eHam.

I ordered from an eBay seller that shipped from the UK. The price was £4.99. When it arrived, I found the packaging and the antenna itself claimed to be a Diamond RH-771 not a Nagoya NA-771.

But this is clearly another fake Diamond. The lettering is white whereas the real Diamond product is lettered in blue. The lettering also contains nonsense. It claims "144/430 MHz & VDE BAND HECEMNG COVERAGE JAPAN." Eh??? Perhaps it was supposed to say wide band general coverage? And the antenna is only 36cm long whereas the real RH-771 (and the NA-771) are supposed to be 39-40cm long.

None of this would matter if the antenna was any use, but in fact its resonant frequency is just below 120MHz. At 145MHz the SWR is more than 4 to 1 and it radiates a poorer signal than the shorter Nagoya NA-701 antenna.

Anyone want an air band antenna? Yours for a fiver. And can anyone recommend a seller that has the genuine Nagoya NA-771?

Tuesday, September 20, 2011

Waste of money

Yesterday I received a personally addressed letter from our cash-strapped radio society, the RSGB. What had motivated them to write to me? Apparently it was to tell me the annual subscription is to rise to £47 a year - the first increase since 2006 - and to ask if I would donate to the Spectrum Defence Fund - which I already have, once, and a lot of good that did - or the Radio Communications Foundation.

Why could this letter not have been put in the same mailer as RadCom, the monthly magazine that all members receive, or even published in the magazine itself? Why did this even merit a letter, rather than a page of the magazine, in the first place?

A few months ago I read that the RSGB was to use a bequest from a silent key member to employ a professional fund raiser. This, presumably, is the result. What a waste of money.

Sunday, September 18, 2011

UV-3R programming software

A new programming software has been released for the Baofeng UV-3R. At the moment you can download it here. I used BitZipper to open the rar file.

This software is claimed to be for the UV-3R MkII with the dual frequency display but it works with my MkI as well. I took the precaution of reading from the radio before modifying and writing anything: some people who didn't do that with the old program experienced problems.

The new program is easy to use. Interestingly, it has two options for frequency range, one of which limits the range to the ham bands 144-146MHz and 430-440MHz. I assume that is to get approval in some countries that don't allow radios that can transmit out of band. There is also a column called Name for each channel, though I couldn't type anything in there. Perhaps a newer model will allow you to have channel names as well.

I discovered a bug with setting the priority channel, though it's kind of hard to explain. You choose the priority channel from a drop-down list of channels that have been used. If you haven't used all the channels between channel 1 and the priority channel then the radio will check the channel corresponding to the position in the list of the one you selected instead of that actual channel number. I wanted to make channel 20 the priority channel but the radio started checking channel 14 because 20 was the 14th filled channel in
the list! To use channel 20 as the priority channel I had to select channel 26, which was the 20th one in the list.

I don't know what would have happened if the channel I'd picked was one that didn't have a frequency programmed into it - and I'm not going to risk finding out!

I ought to mention that the cross-platform multi-radio supporting memory management software CHIRP supports the UV-3R as well. Not sure about the UV-3R MkII though.

Tuesday, September 13, 2011

VK5 with V4

Looking for something to pique my interest enough to overcome my lethargy I decided to have another look at the V4 Chat digital mode. I tried it first at the end of last year and made one contact with it, but the alpha software was a bit flaky, then the developer Rick KN6KB had a bereavement and nothing happened for a while so I forgot all about it.

What attracted my interest was discovering that the ARQ mode had now been implemented. V4 Chat supports two conversation modes: Forward Error Correction (FEC) in which the data is sent with a lot of checks and redundancy so many receiving errors can be corrected but you have one chance of getting it correctly, and Automatic Repeat reQuest (ARQ) in which the receiver can request a repeat if a transmission is received with errors. Using ARQ a receiver can repeatedly request a repeat (up to a limit) so even if conditions are marginal a QSO is possible as long as propagation is adequate for short periods of time. Under the same conditions conventional (non ARQ) digital modes would print so much garbage that a contact would not be possible. People who own expensive SCS modems like to boast about how Pactor gets through under difficult conditions but V4 ARQ offers the same kind of performance and requires only your PC and a bit of open source donationware.

I re-subscribed to the V4Protocol Yahoo Group (which is where you can get the software from), downloaded and installed the latest version. Then I set my K3 to 14.073MHz (which is the 20m "calling frequency" for experimental narrow data modes) and waited. After a while I heard the sound of V4 ARQ bursts, and found that VK5PO was in QSO. I saw him disconnect from the other station and sent a CQ. He then connected with me and we had (just about) a QSO.

Signals were marginal both ways and I had to crank the K3 up to 50W to help John copy me but over about 10 minutes names and signal reports were exchanged. One of the nice things about the ARQ mode is that when the text prints up you know the other station has received it error free.

OK, it wasn't much of a chat, but ignoring WSPR spots I have only ever made one contact with Australia before and that was using JT65A which is not a keyboard chat mode. I was pretty chuffed to exchange words with a ham 16,000km away using my stealth radio station!

I think I'll be spending a lot more time trying out V4 Chat digital mode and I hope you will too because the more people use it the more contacts we can all make. The V4 signal is 200Hz wide so if 14.073 (or 21.073) is busy move up in 250Hz increments to avoid QRMing someone else's QSO.

Sunday, September 11, 2011


Everyone remembers what they were doing when they found out about the 9/11 attacks. I remember it because I had a bad migraine that day, rather like the one that turned out to be a harbinger of my brain tumour. I switched off the computer, drew the curtains in the bedroom, lay down on the bed and switched on the radio. Instead of the expected classical music there were voices talking about a plane that had crashed into the World Trade Centre. For a few minutes I lay there thinking I was listening to some "mockumentary" radio play like the famous Orson Welles "aliens have handed" spoof. But something told me that wasn't right, so I went downstairs, turned on the TV and saw that this was all too real.

Today I hope against hope that we get through this anniversary day without another terrorist attack attempt. I just don't understand why anyone would want to give up their life, and end the lives of other innocent people, for any "cause". One thing being diagnosed with an incurable brain tumour has made me realize is that life is too short to waste getting angry about things you don't agree with.. Wouldn't the world be a better place if we could all banish negative thoughts, focus on enjoying life as best we can with those we love, and make peace even with our enemies?

Tuesday, September 06, 2011

Two new 2m repeater channels

According to the UK repeaters website, two new 2m repeater channels have been internationally agreed:
  • 144.9750MHz input / 145.5750MHz output (RV46)
  • 144.9875MHz input / 145.5875MHz output (RV47)
Though these channels are not available for use in the UK yet, the wording of the announcement suggests that they eventually will be.

Looks like we dinosaurs who still insist on calling the calling channel S20 are going to have to give up QSYing to S23!