Saturday, 14 September 2013
They are the old standard of 14 Mbit/s, so aren't compatible with anything available now, but fast enough for downloading some on-demand TV shows (or are they?).
As a responsible radio amateur I should have never have allowed any evil power line network equipment into my home, but I had to give them a try.
I connected a laptop in place of the Sky box and transferred a large file from a network share, through the pair of devices. They were recognised as being 10Mbit Ethernet, so there was no way the 14Mbit/s was going to be reached. In fact the file transfer speed was around 540KB/s (4.5MBit/s), which is what you would get from 802.11b WiFi (11Mbit). Both devices were on the same ring main and upstairs, in different rooms. One was located in the same room as the radio equipment and the PC that was running PowerSDR.
This is lower than the internet connection speed (9Mbit, with a top download speed of about 7.5Mbit/s). But it's fast enough to watch TV through and download on-demand shows.
I picked an empty frequency to check for the noise level, at 10.544 MHz. Using AM in a 6.6KHz bandwidth, the background noise with the devices unplugged from the mains was -97dBm on the wire antenna (no ATU).
When the HomePlug adaptors were plugged into the mains, there were a few short bursts of noise which were hard to get a meter reading from, and then there was a 'click' every second, which was hardly moving the average s-meter reading. Inside the amateur bands the clicks could not be heard over the background noise, there are notches in the amateur bands.
When the file transfer started, the noise on 10.544 increased by 14dB to -83dBm. It was just as if the noise level had increased, no peaks in the spectrum could be seen. Inside the 7 and 14MHz amateur bands there was no increase in the background noise, other noise sources were large enough to hide anything coming from the HomePlugs.
When transmitting a 5 watt carrier in the 7, 10 and 14 MHz bands, it looked like there was a slight drop in transfer speed for a few seconds (to maybe 450KB/s) but then it went back up to the same as before. Probably going into error correction before adjusting the carrier frequencies used.
If you are thinking of buying a set of new HomePlug adaptors then you might get totally different results because of the wider bandwidth used, and they will ruin any shortwave broadcast reception but these have made so little difference to the amateur bands that I've kept using them.
Monday, 2 September 2013
Worked G7RNX/P tonight while he was on Snaefell (SOTA GD/GD-001), on 70MHz FM. I was using my Wouxun handheld and Garex flexi whip antenna near the sea shore on Walney.
Had a problem with the sound on my old laptop (Samsung N150 netbook) yesterday, I was setting it up to use with the FT-817 and instead of a proper data cable, I thought I'd keep it simple by using VOX through a 3.5mm jack - RJ45 cable (with some resistors to drop the level). That worked OK, once the loudspeaker volume was set to the right level (around 20%).
For receive I used a 3.5mm cable from the 817's headphone socket to the laptop's mic socket. I got the level right but then after a few seconds the meter dropped right down on the laptop. I thought there must be a bad connection somewhere. But monitoring the input through the laptop's speaker proved the signal was getting from the radio into the computer without any breaks.
If I unplugged the cable from the laptop and plugged it back in, it would work for a few seconds again and then stop.
I noticed that a message popped up on the laptop every time I plugged in the cable, telling me I'd plugged something in. I've used PCs before which have tried to auto-detect which socket has a microphone plugged in and which one has a speaker plugged in, and failed to detect it properly.
So I tried uninstalling the Realtek application which was installed when I got the laptop, is there any need for a separate application to control the sound? Probably not, unless you really must have some fake surround sound effect.
Uninstalling disabled the sound device until I rebooted, but then Windows 7 recognised it and installed the standard driver for the Realtek audio. No more auto-detecting of plugs, and it worked without cutting out.
The only thing that had changed was the levels, the output from the speaker jack was slightly higher for the same % on the slider.
Sunday, 11 August 2013
After reading these instructions I tried changing the baud rate in Windows Device Manager to 57600 and it connected first time using a USB-serial cable (in Windows 8).
I still got the odd error when reading/writing a large number of memories at once but this may be the radio at fault and not the software, see this page about some alternative programming software.
I didn't think any applications still used the Windows serial port settings, usually it is set somewhere else and the Device Manager page was not something you would ever have to change.
I find it easier to export the Alinco's memory data to a CSV file and edit it in Excel, that way the memories can be programmed in on the go, uploaded and then sorted by frequency etc.
Today I tried connecting my Icom IC-2800 to the PC. I had the CS-2800 programming software but never had any success in getting it to connect. The Icom OPC-478 cable is the same wiring as the USB cable I used to program the Alinco DJ-G7 (a single data line on the ring of a 3.5mm jack plug), so I tried that cable.
I have 2 of these cables which should be compatible with the OPC-478. The first one did not work, I thought it might be something to do with running the old Icom software in Windows 8 or the baud rate (I'd got suspicious about the Windows baud rate settings after getting the Alinco to work) but then I read this message where the writer tried several cables and only one worked. I tried my other OPC-478 type cable and once the COM port was changed to COM2 (the CS-2800 software only allows COM1 to COM4), it worked perfectly. I even tried the Windows baud rate at both 4800 and 9600 and it made no difference.
What is the difference between the 2 cables? The only thing I can think of is that Cable 2 had the ring of the jack plug at 2.78V when not connected to any radio, and the non-working Cable 1 had this at 3.3V.
Saturday, 10 August 2013
The true summit is not the part with the masts on, it is to the west, across a bit of boggy ground that is below the 25m limit of the activation area.
This ship was just off Ayr
The radio mast at the top of the hill is known as Riddings Hill.
Tuesday, 6 August 2013
"Downgraded" from Pro to Unlimited broadband today, still have my static IP address after restarting the router.
Getting a sync speed of nearly 10Mbit now, improved since I got rid of the "filter" that was really just a splitter (I must have had it left over from an old dial up modem). Thought it was normal (about 5-8 Mbit) until the new Sky box got plugged in and speed dropped to 3Mbit.
Now there's no limit, I can get the Sky boxes networked for iPlayer etc. I've got a couple of old HomePlug adaptors (14Mbit) to try, see how badly they wipe out HF!
Monday, 5 August 2013
O2 have moved all their 900 MHz GSM cells into the 955-960 MHz band (channel 101 - 124).
This clears channels 37 - 59, probably for 3G or 4G.
Now in this area:
Salthouse Road, Barrow
Howard Street, Barrow
Dalton TV mast
Morecambe Bay (BBC FM mast)