Friday, 30 September 2011

National Hamfest 2011

Today sees the start of National Hamfest 2011 at the Newark and Nottinghamshire Showground. I went for the first time last year and am attending again this year, going tomorrow with my brother, so will probably end up goading each other in buying lots of expensive toys!

It looks like the weather will be much better than the wash-out it was last year!

 photo from National Hamfest

Wednesday, 28 September 2011

Solar Flares

Not sure what is going on, but both computers I use at work have just borked, one just froze completely and no option to turn it off and on again, the other was reporting one of the drives in the RAID had failed!

Yesterday one of co-workers computers developed an unmountable boot volume BSOD while he was out the office....

I jokingly tweeted about solar flares being the culprit, I know solar activity has been on the increase but little did I know that in fact there have been some severe coronal mass ejections in the past week due to a huge sun spot and there is a resulting geomagnetic storm

AR1302 Alan Friedman via Bad Astronomy

Going to keep an eye on for more data, however like the sun itself I wouldn't recommend looking at it directly without some eye protection!

Tuesday, 27 September 2011

Homebrew ADS-B

One of the most interesting and therefore popular things to monitor on a radio scanner are the airband transmissions. Listening to aircraft communicating with air-traffic control can be quite addictive, especially if you are able to hear transmissions from the tower of a busy airport.

Several years ago the geek factor for would be air-traffic controllers soared with the introduction of virtual radar systems. These units monitor the Automatic dependent surveillance-broadcast (ADS-B) that all modern aircraft now transmit in the 1090MHz band.

My younger brother who lives near Birmingham International brought a system a while ago and has great fun watching the approach of aircraft on 'radar' as they rattle the roof tiles on approach to BHX.

Not being a wealthy as my brother I have been looking for a cheaper alternative... and on Hackaday perhaps I have found one...or maybe not...

A simple decoder made from some salvaged parts from an old satellite receiver!

Until then I will have to make do with more low tech ACARS decoding.

Tuesday, 20 September 2011

Twitterfeed - you are getting on my tits!

Now I am regularly updating my blog I enabled to post to updates to my twitter feed and facebook pages to informed the frankly uninterested masses about my technical perversions.

Well it seems to be broken and unreliable, either doesn't post or misses off the url so no one can follow the link! - I have been in yet again and changed the settings, hopefully this works!

Monday, 19 September 2011


Just spent the evening playing with PSK-31 using Digipan on my PC. I found some informative videos on K7AGE's youtube channel. The video below is just an introduction, there are more dealing with interfacing, setting up etc.

Inspired by it I got the Alinco DJ-X10 in USB mode and tuned into 14.070MHz and sure enough got loads of messages from amateurs with very little effort.

Obviously following on from the SSTV experiments I soon hooked up a couple of  PMR446 handhelds and sent a few messages going across the ether!

Got a few wav files in the MP3 player so I will probably do some field trials tomorrow!

Wednesday, 14 September 2011

SSTV on PMR446

Following on from my experiments in receiving slow-scan television (SSTV) from the ARISSat-1 satellite I was intrigued by the prospect of actually transmitting and receiving some images myself.

Being unlicensed the only legal equipment I can used is PMR446 these are low power (500mW) handheld transceivers with very limited range. I have several some older models kicking about from when I built a eQSO internet PMR446 gateway.

The SSTV image is transmitted by frequency modulation using a varying audio tone to indicate different brightnesses. The software I have been using to decode SSTV is MMSSTV by JE3HHT (Makoto Mori) It can also be used to transmit SSTV images by connecting the audio output of the PC to the transmitter audio in. It allows editing and customisation of the images and the encoding format to use.

Obviously I couldn't carry a PC around so instead I generated some images and recorded the generated sound to a WAV audio file and then used an old cheap MP3 player (which supported WAV files) connected to one of the Audiovox PMRS-838 handsets, configured to operate in VOX mode.


The plan was to drive around to a number of local high spots and with the transceiver on the dashboard of the card output a series of images and see if they could be received and decoded back at base! - Each image taking around 2 minutes to transmit.

The base receiver was my Alinco DJ-X3 connected to the loft based discone. I had to use the DJ-X3 because it supports to 6.25kHz narrow band channel step required by the PMR446 channel allocations.


Well the first set of results today have been pretty good, I went to three sites to transmit from and using the terrain profiler on I could calculated any obstacles in the line of site..The base is on the left hand side, the transmission point on the right of the diagrams below.

Site 1, was 0.9 miles from home  This site is just across on the other side of the Trent Valley with no significant buildings in the transmission path.

as you can see the five images all came across very well, just a slight sync error on one.






Site 2, was 1.2 miles from home and is one of the local high spots. Unfortunately there is a housing estate on the top of the hill. It is possible to go by foot on some footpaths to get into some fields with a clear vantage point across the town and down the Trent Valley towards Nottingham. However today these were from the car parked up near to the edge of the estate. I just sent two images - and they are a lot nosier.




Site 3, was 3.2 miles from home and is on a slight high spot across on the other side of the Trent Valley. I parked up in a layby and transmitted three images and really wasn't expecting much. So was very pleasantly surprised by the high quality of the received images, as you can see there isn't any geographical obstruction but there is a very big new power station at Staythorpe in the line of transmission which I expected to cause some issues. Some of the lines of noise on the images I suspect were caused when large lorries and vans were passing by on the road momentarily blocking the transmission path as it is quite a busy road.




From these encouraging results definitely some more experiments to be done on this, and some tests further afield!

My final images from ARISSat-1

It has been a fun month tracking and attempting to catch images from the ARISSat-1 satellite. I have succeeded in catching some decent images from the on board cameras (which I have previously posted) I was just missing the second elusive ident image, well yesterday my unattended station managed a noisy capture (as well as yet another of the other ident!)

13th September 2011 - 10:03 (BST) 09:03 (UTC)

13th September 2011 - 14:57 (BST) 13:57 (UTC)

I will not be attempting to capture anymore, instead I am starting some experiments myself with SSTV using some PMR446 equipment, I will keep you posted.

Monday, 12 September 2011

Digital8 - Digital Obsolescence

I suspect like many people I have numerous boxes of camcorder video tapes acquired over the years, some are the older 8mm video format and the later ones being Digital 8mm. Many of the videos are recordings of me running my dogs in agility competitions and others are the normal holiday type, obviously they all have a strong sentimental value.

A few years back I had made a start in archiving tapes onto DVD but didn't get too far because of time and other commitments.

I was already acutely aware that the Digital 8 format had almost gone the way of Betamax with Sony not producing any new cameras and was aware should my trusty used and much abused Sony camcorder fail I would unable to view them. However the bewildering range of current equipment and the move to hard drive base equipment filled me with dread and I'd kept put off making a decision on a replacement and continued to use the camera as normal.

Well the enviable happened a few week back and the camcorder started exhibiting playback issues, lots of coloured mosaic banding.

Thankfully eBay came to the rescue and I've finally managed to get a good condition used replacement camera at a sensible price. It is obvious I am not alone in this predicament given the frankly amazing prices some other auctions finally went for.

Now I can transfer them to DVD, but there are still worries that these might not last, so I will probably transfer them to some large hard drives, but how do I format them.... it's never ending...

Friday, 9 September 2011

ARISSat-1 Images for 8th September 2011

Two images, first pass at 13:27 BST - Another one of the ident

second at 15:04 BST, shame about the noise as it was almost a full frame view of the earth below!

Thursday, 8 September 2011

ARRISAT-1 featured on Ham Nation video podcast

Checking the ARISSat-1 website this morning and saw that Steve Bible (N7HPR) one of the technical team was being interviewed by TWiT.TV for the Ham Nation video podcast. Very interesting, starts about 25 minutes in.

ARRISat-1 Continues to broadcast

The 4th September marked the first month of operation of the ARISSat-1/Kedr spacecraft and despite some early worries has continued to broadcast.

Following the installation of my new antenna I have had some successful SSTV captures of images from the onboard cameras, including two from the same pass.

5th September 2011 - 1348 UTC

5th September 2011 - 1350 UTC

7th September 2011 - 1502 UTC

Monday, 5 September 2011

Weekend update

Well it was busy weekend and managed to achieve some of what I hoped to.

On Saturday morning I had a trip up to Lincoln to visit the Lincoln Short Wave Club I have for some time been considering taking the plunge to get an Amateur Radio Licence and I'd inquired about any foundation courses and exams they were holding. The secretary contacted me as there is the chance of course in the near future so I popped along to have a chat. It wasn't the best weekend as they were preparing for the RSGB SSB Field Day Contest but I had chance to make contact. I would have loved to stay around watching/helping them set but I was visiting my family in the afternoon.

During the visit I got chatting to my brother, who has inherited some of interest in radio, and convinced him to lend me his currently disused discone antenna, more on that later.

I also retrieved my old Binatone Worldstar radio which I got one Christmas as a child and got me well and truly hooked on the hobby. It doesn't quite look at pristine as this one as it was heavily used and abused during my childhood. It lost it's distinctive world map timezone cover, the handle, antennas and earphone socket were broken and clumsy repaired and it has spent nearly two decades in my late fathers shed/workshop. To say it is looking a little bit worse for wear is an understatement but I hope to restore it, it will never be back to it's former glory but it would be nice to honour those childhood memories.

On Sunday I did have a good clean up in the workshop, things are packed away in boxes and stored on shelves now, at least I can now get into the workshop without clambering over junk and can find tools now!

During the afternoon I left the scanner and pc monitoring the ARISSat-1 frequency and got this image on the late afternoon pass.
At the time of the pass I was actually up in the loft dimantling the majority of my 'antenna farm' (some of them are deaf and not worth the coax) and installing the discone (it is as high as it can go in the loft space). I haven't been up the loft for a while but was shocked by the amount of stuff up there. I did some rearranging but I really need to have a good clear out.

Well I can report the discone was worthwhile and while I have only used it for a few hours it certainly has improved my reception. I am now hearing the lower power mobile transmissions as well as the more powerful base transmissions from a number of more distant sites. The 70cm/2m amateur bands were also much more active last night and the RAF Waddington Radar is coming through much more cleanly.  

The discone is a Sirio SD 1300 U and I feel my tinkering in the future will be a bit more productive.

Friday, 2 September 2011

Looking forward to the weekend

The last few weeks have been dreadful, for quite a long time I have been suffering pain in my left side and other issues. Various visits to the doctors later I was referred to a hospital consultant with suspected diverticulitis.

In the meantime I was away on holiday in the caravan near Barnard Castle last month when I was stuck down with really acute pain, so bad I collapsed and was taken off to Darlington Memorial Hospital for a four day stay. The provisional diagnosis is diverticulitis following a CT scan. I was discharged with antibiotics and told to take it easy. Well of course due to work pressures I couldn't and have not really recovered and I have had some more complications which good taste prevents me from detailing. Thankfully I am now on a new course of treatment and hopefully I will improve.

If I feel well enough this weekend I will finally make a start kitting out my new workshop/shack. We have had a complete makeover in the garden this year with new drainage, patios, lawn and some serious landscaping around the pond. Our somewhat battered summerhouse has been restored, painted and furnished and new electrics fitted.

A key part of this makeover was to replace a shed with a big (16' x 10') workshop, it has been divided into two sections one 6' x 10' which is the shed replacement and the other 10' x 10' which I was going to turn into my workshop/den/shack - all my 'junk', tools, radio stuff and computers would be housed in there giving me a refuge.

Unfortunately due to other demands I have made no progress getting it fitted out, but hopefully this week I will get the chance to make a start. If nothing else I will get hopefully give it a much needed coat of preservative as 8 months of sunshine has bleached it somewhat.

Thursday, 1 September 2011

Nice ARISSAT-1 Capture

Left the scanner on and the PC running MMSSTV hoping to catch a ARISSAT-1 pass this evening, but as it was it caught one as it passed over at 14:38(UTC)


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