Thursday 15 September 2011

Windows 8

Installed the Developer Preview of Windows 8 tonight. Apart from the screen resolution being limited to non-widescreen settings of 800x600, 1024x768, 1152x864 and 1280x1024 (none of which will scale up to the full size of my monitor, which is 1920x1080), everything so far has worked the same as in Windows 7.

I've tried installing some of my regularly used software and it has all worked. One program needed .NET but Windows downloaded it automatically.
The usual desktop and Windows Explorer are there behind the new tiled UI, and work mostly the same.

At the moment I'm running WSPR 2.0 and it's definitely transmitting and receiving somewhere so the sound card and serial port are working.
But will Windows ever have PDF support or have single-click turned on by default (it's only been available for 14 years)?

Holmfirth on 21MHz WSPR tonight (IO93CN, 111Km).

Wednesday 27 April 2011

SRC 9:1 UnUn

SWR plot of Snowdonia Radio Company 9:1 UnUn, with about 7.5m of wire on a 5m fishing pole. The wire was coiled loosely round the bottom half of the pole to fit the extra length.
Fed with about 5m of RG58 coax, and no earth (except for grounding through radio power cable to car body).

Compare that to my own end fed half wave for 14 MHz which I have at home, using a similar transformer:

The basic SWR curve looks the same but there are some other resonant frequencies below 14 MHz where the SWR is not so bad. This might be because the wire is going across the back yard, close to buildings and telephone wires (also radiation from the coax). I shouldn't really be able to operate on 3.5 and 7 MHz with it but it works OK with a tuner.
Do "magic" short antennas like transformer fed wires/verticals just couple into other wiring when used at home?

Rooted my HTC Hero Android phone (Universal Androot) so the time can be synchronised with an NTP server. It's now accurate enough to be used as a WSPR beacon. Set up an alarm clock to play a recording of the correct WSPR tones at a certain time. Even if I'm away from network coverage, the time stays within a second as long as I've synced it in the last day.
Better than my new Samsung N150 netbook, which always says the clock is 5 seconds off when synchronising over NTP, but then sets the clock with a 5 second error.

Sunday 10 April 2011

Icom CAT/data modes cable

I bought a data cable for Icom HF transceivers from the Blackpool rally today. It's something like the Icom IC-Cable-8 (cable 8 on this page).
The cable I made myself used the 6-pin mini-DIN socket on the IC-7000 but this one uses the 13-pin accessory socket and the 3.5mm jack (CAT interface). This replaces separate CAT and PTT/audio cables, freeing up a serial port.
PTT is possible via both CAT and serial port (RTS line). When using the 6-pin socket, there was no transmitted audio if CAT was used to key the radio (so there is no need for the hardware PTT circuit anyway). This doesn't happen with the 13-pin socket but there is one problem, the microphone sockets aren't disconnected. So when operating data modes using this cable, the mic gain needs to be turned to 0. If there is someone keying up with no modulation then it's probably me forgotten to turn the mic gain back up for voice.
The level of the PC Line Out also needed to be turned up from 10 (using my 6-pin cable), to 25 (using the 13-pin cable) to get the same output power.
I also got a Snowdonia Radio Company 9:1 Unun

Saturday 5 March 2011

New Car

Some photos of the new mobile set up in Vauxhall Meriva VXR. I've not put the APRS tracker in yet but that should be able to go back on its sticky mat.
Yaesu FT-8900 main unit on passenger side. CRT extension speaker.

FT-8900 front panel fixed to air vent using some old air fresheners and clothes pegs. The CD player will play MP3 discs.

Nagoya NL-77B 2m/70cm mobile antenna on magmount