G4IRX/P

Overview

HF operation from my home location is challenging due to various urban factors such as high noise levels, a short garden and intereference to and from rogue burglar alarms.

I put together a compact portable setup which can be carried around in the car and rapidly deployed whenever I fancy some outdoor operation.

Radio

I currently use the Icom IC-703. I had considered the Yaesu Ft-817 but it seemed a bit small for my liking and difficult to operate. The IC-703 runs 10 watts on all HF bands and 6 metres, it also has a built-in ATU which will match anything in the range of 20-200 ohms, ideal for dipoles and full-wave loops. There is a also a speech processor (audio compressor) and iambic keyer. My only complaint is the cost of optional crystal filters - 25% pf the cost of a new radio! but I was lucky enough to get an INRAD #122 250Hz filter for mine.

For a power source I managed to obtain a surplus 17AH gel battery. This can be charged from a convenient 13.8v power supply and will run the IC-703 for several hours. The downside is that it is rather large for back-packing so I will have to get a smaller power source if I decide to try any SOTA activities.

Aerials

FiveMegs communication is mainly by NVIS (near vertical incidence skywave) communication. Aerials for this mode should be designed to produce maximum radiation straight up into the sky.

Currently I use a lightweight wire dipole. The centre-piece is terminated with a BNC socket and it is fed with approx 10m of RG174A/U coaxial cable. This is supported on a 6m telescopic fibre-glass fishing pole, obtained from Decathlon (a sports megastore).

In the future I plan to get some more fibre-glass poles so I can set up a full-wave loop configuration.

Ancillary Equipment

I also find it useful to carry a GPS around, a Garmin GPS-II. I can quickly get both the National Grid reference for any temporary location and also the QTH Locator. This allows me to give out an accurate location as required by the Amatuer Licence when operating from the "Temporary Location". As a back-up I carry an Ordnance Survey map too.

Other essential items are drinking water, a torch (it gets dark at night!) and waterproofs (in case it rains!). A mobile phone is also useful.

Most importantly I ensure I follow any safety guidlines. If I'm going to remote locations I ensure somone knows where I'm going and what time to I'll be back.

GM4IRX/P September 2004

I usually spend a week on holiday in north-east Scotland around September time and decided to take some radio gear.

I found this location near Golspie (NGR NC800047) whilst out and about. Unfortunately I had forgotten to bring any antenna supports with me and there are never any "natural" antenna supports just where you want one. A visit to the local hardware store in Dornoch produced some 2-metre bamboo canes and a roll of electrical tape soon had them assembled into a 5 metre portable mast! This was used to support the dipole in an inverted-V configuration, with a single 2m pole to hold each end up.

Once the dipole was connected up to to the IC-703 I hit tune on FE and all appeared well. The site was extremely quiet, receiver noise level not even indicating on the S-meter. Contacts were made as far as the south coast of England and both beacons on FC (GB3RAL and G4JNT) were consistently audible.

Although I started operating with the equipment in the boot I soon moved into the car as the midges have very sharp teeth!

Here are some short MP4 video clips of the outing with commentary:

Unpacking and midges.
Site view 1.
Site View 2.
IC703 with audio from M0STP.
IC703 in dark with audio from M0STP.

A second Evening's activity with the same setup took place from a site north of Dornoch, (NGR NH790937) This time I set the antenna up at a convenient Forestry site entrance. Despite the heavy rain everything worked well and I received a visit from a local amateur, John 2M0BPH.

G4IRX/P 2005

I got some more fibre-glass poles so I now have a set of four.

Here is a picture from one outing showing a full-size horizontal dipole deployed between three of them. Another "feature" of this site is the metal fence that runs underneath the dipole and acts as a reflector to improve the NVIS performance of the system.

GM4IRX/P July 2007

I've made some more updates to the portable station.

Here we are at Longniddry, east of Edinburgh. I've added a 3.5MHz dipole to the mast, at right angles to the 5 MHz dipole, so I can do comparisons between 3.5 and 5 MHz. This summer, the FoF2 (critical frequency) has been just below 5 MHz, making conditions on 7 MHz difficult for inter-UK working. Even though the dipoles are at right angles, due to the high angle of radiation (NVIS) there is very little directivity.

I'm now using a Kenwood TS-480SAT from the car, the Icom IC-703 is now used as a self-contained back-packing radio.

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