Wednesday, 29 December 2010

New Laptop

Bought a new laptop yesterday (well it was the 'January' sales) - an Acer Aspire 4820T.
With a 14" screen, its just a bit more portable than the average laptop, without losing any of the features like a DVD drive. My last laptop had an 11" screen (and still had a DVD drive) and I think the medium sized models are best (11 - 14" screens), being someone who uses their laptop mostly away from home.
Netbooks look nice and easy to carry around but there are many times when I need to burn a CD or DVD away from home, or even just watch a DVD.
I've had an Acer laptop before, a Travelmate 4101 which I had from May 2005 - March 2008.

Also today I got 2 new handheld antennas (Nagoya NA-701 and NA-702) which are SMA-M fitting 2m/70cms. These are about 21 and 28cm long, somewhere between the standard antenna supplied with the handheld and the largest 'Super Gainer' whips. The 40cm long whips are a bit big to use when carrying a radio inside my coat or bag.
The biggest improvement is away from the amateur bands, increasing the length slightly has given a much wider bandwidth because a smaller loading coil is used. I recently got a Watson WSMA-7000 (18cm long) and that was no better than any of the original handheld antennas.
The shorter of the 2 new antennas (NA-701) seems slightly better on UHF.

Wednesday, 22 December 2010

Puxing PX-2R

I recently ordered a Puxing PX-2R handheld and it arrived today.
This covers 400 - 470 MHz, with 2 watts RF power.
The battery is a 3.7v mobile phone type and charging is through a Nokia type 2mm power connector at 5 volts, so it will charge from a USB port (cable supplied) or Nokia phone charger.
It has a female SMA antenna connector (unlike other Chinese handhelds).
The manual has no information about how to store frequencies into the 128 memories or connect to a PC for programming, but there is programming software available on the Puxing website and the 2.5mm speaker/mic socket must be used for the PC connection. There is no mention of 6.25KHz steps either, the menu allows only 12.5 or 25 KHz channel steps, but if you type in a 6.25 KHz offset frequency (e.g. 446006) then it tunes in 12.5 KHz steps from that frequency (446.00625, 446.01875 etc.)
As usual for this type of radio, the S-meter is useless, taking about 2 seconds to respond to any change in signal and showing either full or nothing.
For £28 including postage this is worth the money though.
Forum discussion on this handheld
Instructions on storing memories

Tuesday, 14 December 2010

Old Stuff

Some old radios of mine:
Fidelity CB3000 homebase. 40 UK channels. I don't think I've ever talked to anyone on this, probably got it off someone giving up and left it in a cupboard for the last few years.

AOR AR1500 scanner. 0.5 - 1300 MHz AM/FM/SSB, 1000 memories.
I used to have one of these from 1994 - 1996 (first scanner I owned) but bought another 2nd hand in 2007 just to remember what it was like. It doesn't have a lot of the features you would get on a more modern receiver but at the time it was one of the best. This one is probably in better condition than my old one before I lost it but my old one was an AR1500EX, whatever that meant. I've got the case for this, just took it off to take the picture.

Realistic PRO-50 scanner. 20 memories. 68 - 88, 137 - 174 and 406-512 MHz FM only.
I bought this in November 1996 after my AR1500 was stolen. It was the cheapest scanner at the time and cost about £50. It was an 'American style' scanner, with only 5 KHz steps on VHF. It was enough to last me until January 1998 when I got a 2m/70cm ADI handheld. It looks a mess because it's not grey plastic, it's black plastic painted grey and the paint started coming off soon after I bought it.

Thursday, 9 December 2010

Nokia NetMonitor

I've got an old Nokia 3310 phone which I've had for nearly 8 years. I don't use it as my main mobile any more (not since December 2004), but after I got a new phone I unlocked it and enabled the Network Monitor functions. The unlocking was through a serial port cable which goes to a special connector underneath the battery.

The Network Monitor screens show lots of data about the phone's battery, software and radio transceiver. The best ones are tests 3,4,5,11 and 17. The current channel number and Cell ID are shown, as well as the channel and signal strength of nearby cells. Signal strengths are in dBm, how can a cheap mobile phone display signal strengths in 1dB steps but on the amateur bands we still have to have meters in S-units which may or may not be about 6dB per unit except when we're using FM?

Other phones often have some kind of Network Monitor screen (there's an Android app which can show the Cell ID but not the channel number, at least on my HTC Hero). On my Sony Ericcson K750 I could get Cell ID and channel numbers on a built in test screen.

The most interesting test of all is number 17, BTS Test. This locks the phone to a single radio channel, so it can't look for the nearest base station. The channel number is selected by storing it as a phone number at address book position 33 on the SIM card.
You can go up a hill and get a base station far away (over 50km), as long as there is nothing local on that channel. At home in an upstairs room I can get the Vodafone base station at Lancaster (the same site as the GB3LD repeater), which is on channel 77 (950.4 MHz).

The base stations are identified by the country code, network number, LAC and CID. LAC is the region of the country where the station is. This helps give a rough idea of where an unknown base station might be if there are none nearby.
For Vodafone, the LAC in this local area is 170.
The CID is the Cell ID. It could be used more than once in the UK, but with a different LAC. Different networks have different CID numbering systems. O2 has the most meaningful.
For O2, the CID is usually a 5 digit number.
The first digit is the sector (the direction of the base station antenna, where there are usually 3 different antennas on separate frequencies, spaced at 120 degrees round the mast). The sector number is 1, 2 or 3.
If the CID is less than 5 digits for an O2 site, an omnidirectional antenna is being used or only a single panel. This might be because it's an old site which has been around from the analogue days or it only has to cover a small area like inside a tunnel.
Sector numbers usually go clockwise starting with 1 as the most northerly pointing antenna. So a CID of 15432 would be base station 5432, beaming north. 30439 would be base station 439, probably beaming towards the south-west. If this was simply CID 439, it would probably be an old site with a single omnidirectional antenna.
If the last 4 digits are 0001 to 01499 then there's a good chance the site had been used for the analogue cellular system, but not always, some newer sites use numbers in that range.

Some older Vodafone cells use a similar numbering system but with the sector number at the end. If the last digit is zero then it is omnidirectional. Newer sites don't follow this system and the numbers mean nothing.
The Lancaster Langthwaite site I get at home has a CID of 1643. This is an old site, which was in use for analogue phones. On the Sitefinder website, this is shows as being site number 164. I'm roughly west of Lancaster, so sector number 3 will be mostly directed towards Barrow.
At the railway station in Barrow there is a Vodafone site with 2 omnidirectional antennas. This is site 3753 on Sitefinder and the CID is 37530.

Channel numbers on the 900 MHz band (O2, Vodafone) are 0.2 MHz offsets from 935 MHz. So channel 75 is 950 MHz.
O2 normally use 37 - 59 and 101 - 124.
Vodafone normally use 65 - 99
On the UK networks, only the odd channel numbers are widely used, except for channels 123 and 124 (for some reason channel 123 is missed out and 124 used instead).

At 1800 MHz, T-Mobile are using the channel 575 - 715 range and Orange in the 750 - 870 range, but that might change now it's the same company.

Some local sites:
Morecambe Bay
CID 10439, channel 109 (North)
CID 20439, channel 101 (towards Ulverston)
CID 30439, channel 57 (towards Barrow)

Lancaster TV mast
CID 10210, channel 53
CID 20210, channel 55
CID 30210, channel 124

Morecambe Bay
CID 2930, channel 91

CID 1643, channel 77
2 other sectors unknown channel numbers

Dalton TV mast
CID 8334, channel 65 (Dalton town centre)
CID 8335, channel 93 (south-west)
CID 8336, channel 97 (north)

All except Dalton TV mast used to be analogue sites.
Old analogue control data channels:
Morecambe Bay Vodafone = 935.8375 (omni)
Morecambe Bay Cellnet = 943.5125 (omni)
Langthwaite Vodafone = 935.6875 (sector 1), 935.8625 (sector 2), 936.0375 (sector 3)
Lancaster TV mast Vodafone = 935.7375 (omni)
Lancaster TV mast Cellnet = 943.0875 (omni)

2m Activity Contest

I had a go at the 2m UK Activity Contest on Tuesday night. I'm not quite last in the claimed scores. Best DX was 129km. This was from home using 50w SSB to a vertical.
If only someone else in IO84 was on, then I would have more than doubled my points because all 6 QSOs were in IO83.