Nagoya UT-108

Don't buy a Nagoya UT-108 dual band mini magmount antenna. They're available on Ebay from a few places. There are a few other in their range of mini magmount antennas, which are smaller or have different connectors.
On my car roof, it was a lot worse on 70cms than the proper mobile antenna (Watson W-770 copy) which was mounted quite close to the ground on the tailgate. Probably the RG-174 coax being so lossy but it didn't seem to be resonant on any amateur band at all. Even when the car body was in the way, the W-770 was much better.
The mini magmount was OK around 165 MHz, compared to other antennas, but none of the others were meant to work on that frequency anyway.
Other mini magmount antennas are probably the same, but the last one I had (I think it was from Moonraker) fell apart soon after I bought it. Other stuff from Nagoya looks like it's a direct copy of the Diamond/Watson antennas.

Multi Ranger 200

Watson Multi Ranger 200 on the car. I've not tried this at over 30mph but probably won't be driving very far with a HF mobile antenna on.

RG8-Mini

RG8-Mini (or RG-8X) is the 50 ohm coax size which is somewhere between RG58 and RG213, 7mm diameter. You might use it where you need flexible coax but where RG58 isn't good enough. But is it really any better than RG58?
It seems to be sold more as a high power HF cable than for use where low loss matters, and I first saw it being used on CB. There were red and grey versions of this cable.
A few years ago I made up a cable of black RG8-Mini, about 11 metres long with PL259 plugs on and sometimes used it for portable operation. I thought it would probably be better than RG58 so wasn't too worried about the loss. But this week when I was on Muncaster Fell I had a listen around 433 MHz and didn't hear very much. I could hear more on my handheld's own antenna than on the 2m/70cm mobile whip that I had set up on a pole.
When I got home I measured the loss of this 11m of RG8-Mini on 2m and 70cm. With a very short piece of RG58 I was measuring 9 watts on 70cm. Replacing that with my coax cable reduced that to 2 watts! That's about 6.5dB loss or 0.6dB per metre. RG58 is supposed to be better than that on 70cm. At 144 MHz, the loss was about 2dB which is more like RG58 should be.
The official figures for RG-8X are better than this but it doesn't seem as much of a standard as RG58 or RG213. I think I bought mine at a rally and I had some on a 2m/70cm dual bander at home before I put decent coax on it so that might have been the same piece of cable.

70 MHz WSPR

There's some activity on 70 MHz WSPR now, on 70.0286 MHz. I can receive G0MJI from Liverpool, using my Icom IC-7000 and the dual band 2m/70cm colinear on my chimney. On the proper 70 MHz dipole in the loft, there is no improvement in S/N because there is more noise indoors. I've nothing to transmit on 70 MHz SSB though.
Alex G7RNX in Dalton was also on 70 MHz WSPR on Sunday and could be received by G0MJI and G3ZOD (Stockport).

Made a PC to radio interface for an FT-847 before finding out it wouldn't work properly because...
On the Yaesu FT-847 there are separate connectors on the back for FM and SSB data modes. The 6-pin mini DIN socket can only be used to transmit on FM (there seems to be receive audio on SSB through it though). On SSB, transmit and receive audio are through a 3-pole minijack socket. The tip of this jack is for transmit audio and PTT (ground through a resistor to transmit).
The 6-pin socket can be used for the PTT on both FM and SSB.
Connecting a cable directly between the headphone socket on a PC and the FT-847's SSB data socket made the radio stay on transmit. There needs to be a capacitor to block any DC current path which might key it up.
It seems a bit of a strange thing to have 2 data sockets but when the FT-847 was designed, people weren't using a PC sound card for data modes so would have had a standalone packet TNC.

HF Vertical

I'd bought some ferrite rings at the rally last Sunday so decided to have a go at making a transformer for use with a HF vertical antenna.
Wound 9 turns on the ring with a tap at 3 turns for the coax. The wire goes to the other end of the coil. Connected about 7 metres of wire, taped to a 7 metre fishing pole. This had a low SWR at about 28 MHz, and also around 7 MHz (why 7 MHz?).
Went to Kirkby Moor (SOTA G/LD-049) this afternoon and tried it out. On 28 MHz I talked to G6MZX (Thornton In Craven), G6LKB (Ulverston) and G4TUZ (Lancaster). G4BLH and G1KLZ couldn't hear me so it might not have been working very well, I'd expected them to be stronger on that band.

Worked G6LKB and G6CRV (Heysham) on 18 MHz, both were strong signals.
Transmitted some WSPR using the recording stored on my phone, on 7 and 18 and 50 MHz. There was only one report on 7 MHz but on 18 MHz there were a few from the USA. On 50 MHz, I got -28 and -24dB reports from G3ZOD in Stockport, which was about the same as I get from home. As Kirkby Moor is a much better site, the antenna was probably not working that well on 50 MHz either.
Made another 2 QSOs on 145 MHz with other summits (Gummers Howe and Lambrigg Fell) before packing up.

On the way home I parked above Marton and did a test to compare my new vertical with the Watson Multi Ranger 200 on the car. Sent some WSPR on 18 MHz (using the fishing pole) and the reports weren't much different to what other UK stations were getting into the USA.
On 7 MHz I transmitted once from the Watson and then from the fishing pole, 4 minutes later. 2 stations received me both times and there was only 1dB or less difference between the two. A 1.2 metre long mobile antenna isn't going to be very efficient compared to a full size dipole but it was good to know that the home made vertical (which shouldn't work on 7 MHz anyway) worked about as well.
To check the 28 MHz performance against the Watson, I listened to someone in the Liverpool area on 27.800 MHz (CB channel UK21). With the Watson they were S4 but with the fishing pole they were 0.64 wavelengths at 28 MHz).

Another time I'll have to compare my transformer with the red 'long wire balun' and the same length of wire.

Ofcom Frequency Search

Want to know the frequencies and locations of business radio users in your area? Once upon a time you had to buy a scanner frequency book but the nice people at Ofcom now let you search online.
Ofcom Spectrum Information System



Make sure that "Business Radio" and "Technically Assigned" are selected if you want to filter out all the on-site paging and UK General users (otherwise you'll get a list of everyone in the UK who has a UK General licence)

Results for the whole of Cumbria

Antennas at home

I took some photos of the antennas at home last weekend while the weather was nice.

Where the HF wire comes down to the back yard. The wire is tied on to the clothes line hook with some rope and then hangs down to the ground. There is about 10 metres of wire in all, making a half wave on 14 MHz.


The Solarcon A-99 with the transformer for the wire below it. The pole is 8ft 2" diameter steel.





View from the top of my street, looking south. In the background is the south end of Walney Island and Piel Island (on the left). The mast is at the United Utilities depot in Barrow, with antennas for their 139 MHz system on it, as well as some mobile phone networks.


Tried wPrime on a Samsung N130 netbook (on its battery) and the 32M test took 137.4 seconds in Windows XP. That was about the same as I got when trying another laptop which had a 1.4 GHz Pentium M processor (which have been around since 2003).