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Monday 19 November 2012

RDS Spy v0.99


Today I moved up to RDS Spy v0.99. This latest version is compatible with most modern sound cards and is designed to work at 16 bit, 44100 kHz. This means I can take VAC out of the equation as all the conversions are done in the new RDS Spy software.

True to form, I installed the software and it didn't work. After performing a System Restore (Windows 7/64), reinstalling the soundcard software and removing Perseus from my laptop, which never worked either but I suspect was part of the conflict, I still had to struggle to make my soundcard find the RDS data and clock signals from my Kenwood KT6040. The problem was not RDS Spy, but my soundcard which had defaulted to use all manner of pointless digital effects which included noise reduction, audio compression and all kinds of other things I didn't need. Realising (eventually) that by switching off all these features, RDS Spy would spring to life.

So, what's v0.99 like? In terms of sensitivity, it seems exactly the same as all the previous versions I have used, but maybe slightly more so. Previous versions I have used include 0.95. 0.97 and 0.98. Initial trials of RDS Spy 0.99 were a little strange though. The first time I ran it I could not get a bitrate error on local Belmont BBC Radio 2 on 88.8 (strong local signal) of less than 20%. This was unusual as all Belmont frequencies produced a 0% error rate on previous versions, yet v0.99 seemed to be slightly more sensitive, producing RDS, with weak signals. I feed the RDS data and clock directly from the demodulator on my Kenwood KT6040 which in turn goes to a Conrad RDS Manager. From this, I tap the clock and data again and run it directly into the microphone input into my laptop. Previous versions of RDS Spy would typically produce PI codes and partial PS names with a signal registering two to three lights on the KT6040's display. This is when using the widest IF filter position and I check this using semi-local stations on which I can vary the signl levels with my rotatable Triax FM5 antenna. With v0.99 I seem to get PI and partial PS with only two lights on the KT6040, virtually without fail. This is impressive.

About an hour later, Windows prompted me to perform some important updates and so it went through the motions and I re-started my laptop accordingly. I don't know if the updates were responsible but something changed after this and I found I could then get a 0% BER on signals from the Belmont transmitter. I did not notice any further improvements in RDS decoding on weaker signals though. It's one of those strange quirks which come along from time to time. Perhaps the re-starting of the laptop made some adjustments to the sound card. Anyway, it all seems to be working well again. Just one odd thing with RDS Spy v0.99 however, when running on an empty channel, it likes to produce a false PI code of "0100" within seconds. I wonder if anybody else experiences this.

RDS Spy can be downloaded freely from www.rdsspy.com  It looks like a full, non-beta version may be on the cards shortly too. I would not hesitate to recommend this software, though configuring it can be tricky, depending on the complexities of individual sound cards and audio levels.

UPDATE 25-11-08
After using version 0.99 for a few days I have to say that this is the most sensitive edition of the software to date! I have a had a few instances of PI and even PS names forming. This is quite unusual as meteor scatter has not been productive since February of this year when I had to lower my FM5s from the mast at the bottom of the garden. One of the FM5s was then transferred to the roof of our bungalow.

My garden FM5s had to be removed due to issues with one of the neighbours and I first thought that the new rooftop location was the reason my continental 'scatter' reception, i.e. meteor scatter, aircraft scatter and troposcatter, had suddenly taken a dive. It's taken almost a year to realise that this was purely coincidence and it was conditions in general which were to blame. This can be readily backed up by comparisons with known DX locations in the Lincolnshire Wolds which also suffered. DXers across the UK also niticed the sudden drop in general scatter conditions around the beginning of the year.

My FM5 is still in free space on the roof and is roughly at the same height as when it was on the mast at the bottom of the garden. A small degree of noise now extends across band 2 as the FM5 is receiving general mains type interference, thankfully not all the time and it is very weak. Most of it emanates from the neighbours who initially made the complaints about my FM5s.

How do I know v0.99 is more sensitive? With the possibility of receiving some meteor scatter from the Leonids I decided to fire up the KT6040 and RDS Spy again and I did this several days in advance see if it would decode a few pings. Quite simply it didn't! I had been using v0.98 but decided to upgrade to v0.99 on the 19th. Suddenly I was able to see several decodes of meteor pings and troposcatter. This has to be down to increased sensitivity from v0.99.

Unfortunately, there is now much more in the way of random PI code generation and this backs up my observations about the increase in sensitivity. Providing you know how to interpret the random PI codes you should be OK though. The random codes tend to be repetitious and the following appear very regularly: 0100 F880 FCE0 and FFE5. There are others but they are quite obviously incorrect. So far though, genuine PI codes show "PTY History".

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