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 http://www.solarham.com/ for more data, however like the sun itself I wouldn’t recommend looking at it directly without some eye protection!

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!

http://hackaday.com/2011/09/22/tracking-commercial-aircraft-with-salvaged-electronics/
http://www.lll.lu/~edward/edward/adsb/VerySimpleADSBreceiver.html

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

PSK-31

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!

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.

Photobucket

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.

Photobucket

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 HeyWhatsThat.com 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.

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

Photobucket

Photobucket

Photobucket

Photobucket

Photobucket

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.

Photobucket

Photobucket

Photobucket

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.

Photobucket

Photobucket

Photobucket

Photobucket
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.

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…