Tuesday 25 November 2008

Thursday 13 November 2008

Ham Radio Software






A few years ago I started looking for some radio software that provided all of the facilities that I wanted and that had a user friendly interface when I stumbled on Ham Radio Deluxe.



In those early day Simon Brown and Peter Halpin (Now SK) had just started the development and over the years the program has changed dramatically and now includes the following features.


Full rig control - Supports most radios
Logbook
DX Cluster
Built in web browsers
Winkeyer support
Rotator Support
Most of the data modes including SSTV, PSK, RTTY, Olivia, Throb etc
Satellite tracking with Doppler tracking and AZ/EL rotator control
Plus many other features to numerous to mention


HRD is in my opinion the best Ham software available today and it is completely free, although some of its 50,000 users do donate via PayPal to help Simon defray his costs.


Download it at
http://www.ham-radio-deluxe.com/

Terry - G4POP

Monday 3 November 2008

Congratulations to Lewis Hamilton





Lewis Hamilton became the youngest ever F1 World Champion and the first British World Champion since Graham Hill yesterday so hearty congratulations to him.



Terry Genes

New Soldersmoke Podcast

A new Soldersmoke podcast was released yesterday, to listen to it visit http://www.soldersmoke.com/

Terry

Saturday 1 November 2008

Letter sent to the Ham Radio Media

Times they are-a Changing!

During my first 30 plus years as a SWL followed by over 28 years as a licensed amateur I like to believe that I have changed and adjusted to the many new developments and challenges presented by this great hobby.

As an example, I no longer build my projects using an alloy chassis and valve bases nor do I keep a paper log having moved with the times to transistors, IC?s and computers etc. all of which are great improvements and enhance my enjoyment of this hobby.

However of late there are many changes that I find hard to accept particularly in the area of operating practices, for example:

I fail to understand why operators find it necessary to tune up on air. Have they not heard of analysers etc for monitoring the VSWR while matching to their aerial? and why not use a dummy load for tuning the PA or linear? Neither of these cause live transmissions and interference to other operators.

Some of the vocabulary (or lack of it) that is creeping into QSO's beggars? belief and some of it is bordering on gibberish e.g.:

“The personal is” - I understand this translates to “My name is”!

“The rig, personal or location would be....” - I wonder why it ‘would be’ is it an imaginary rig/name/QTH?

For as long as I can remember the order of call / hand over has been ‘Your call’ de ‘My call’ why now is it being changed to:

‘My call’ sending it right back to ‘You call’ or something similarly stupid? Whilst on this subject what is wrong with the long established ‘Over’?

These are just a few examples of what I, and I am sure many others, consider to be the current declining operating standards in our hobby.

Perhaps this decline is caused by most new amateur’s relatively short introduction to being a radio operator without the proper foundations? In the past these foundations were laid by a much longer association with the air waves and experienced radio operators before being allowed on the bands.

With due respect to Bob Dylan's original protest song I don't consider that operating practices are "a-changing" for the better. Perhaps experienced amateurs should correct these bad practices whenever they hear them on the air but one wonders what reaction this would solicit from the offending parties?

Terry - G4POP

The result of the general dumbing down of standards.

John - GI0HWO

Wednesday 29 October 2008

Doublet Antennas and Balun's
My friend John (GI0HWO) and I carried out a lot of research and testing on feeding a doublet antenna and in the process learnt a lot about balun's, mainly due to a great article by Tom W8JI.

The document below was written by W8JI and both John and I can confirm that what Tom suggests is 100% correct and as a result our doublets' are now performing better than ever, so with credit to Tom we re-produce an extract from his article below:

I would just add that this article blows out of the water all the common thoughts on baluns.
Like most people I thought that a 4:1 was the way to do it.
A lot of people think that what Terry & I are doing is not far short of herecy but the proof of the pudding as they say. Try it, but you need a good balun (or a big pile of inferior ones HI HI)


John - GI0HWO

"Multi-band Dipoles (Doublet's)
A Multi-band Dipole antenna is cut for a specific frequency, but plans call for it to be used on any of the frequencies above that..

The correct construction technique is based on making the antenna element a half-wavelength on the lowest frequency on which the antenna will be used based on the 468/F formula. The parallel conductor, air-dielectric feedline is led away from the antenna at right angles.

Lower impedance feedlines result in less extreme impedance changes from band-to-band. For instance, 600-ohm feedlines tend to present wider load impedance excursions to the tuner in multi-band applications than 300-ohm feedlines.

Coax has a still lower impedance, but the non-air dielectric causes great loss within the feedline with high SWR. For instance, at 10:1 SWR you lose half of your power for each 100 feet of coax, parallel feedlines with air dielectric have much less loss at the same SWR.


Why you don't want to use coax when the SWR is high?
For each 100 feet of coax, you lose half your power at an SWR of 10:1 and at frequencies higher than 14MHz, it's worse. For higher loss coax like RG-58 or RG-8X it is worse, too.

Feedline length is critical to antenna performance. Always choose a feedline (connects the antenna to the balun, in this instance) that is 1/8th wavelength or some odd-multiple of 1/8th wavelength long on the lowest band.

Balun's
Often, a 4:1 balun is suggested for Multi-band Dipoles; however, the best balun to use for this application is a 1:1 ratio. The impedance at the end of the feedline is going to vary greatly from very high to very low. Tuners have an easier time with high impedance than a low one. A balun with a ratio of 4:1 or more will transform already low impedance to an even lower one that will make the antenna hard to tune. The 1:1 ratio balun will just pass the low impedance through.

The parallel conductor feedline should be led to the balun located at a convenient location. The balun should be located such that the coax between it and the tuner is as short as possible BUT do not route the parallel line so close to the tuner or the rest of the station equipment that RF feedback occurs. This will manifest itself by making the tuning of the antenna very difficult and the controls will be very “touchy”. There may also be RF present on the microphone, key, etc.
Even when properly done, this arrangement will subject the coaxial line between the tuner and balun to very high standing waves and high voltage and/or current. You should use good low-loss coaxial line and keep the coaxial line length as short as possible, RG8X and smaller will not do a proper job. Belden RG-213 or equivalent is the minimum."

Comment
As Tom states there will be 'high voltages and /or currents' on the feeder so please make sure that you select a high power balun, John and I both use the excellent DX engineering 10 KW baluns, at full UK legal power limit these baluns dont even get warm!

Saturday 25 October 2008

Photos from space





I received these images from the International Space Station last week on 2 meters FM using a Kenwood TS 2000 that was being controlled by Ham Radio Deluxe and the pictures were decoded with DM780
Have a look at my Netvibes page at: http://www.netvibes.com/G4pop#News

Hello

OK this is my new Blog which I will develop over a period of time to include things that I find interesting mainly related to Ham Radio but also to include anything else I think is interesting.