I have tried a number of multiband wire antennas at GB2GP over the last year and have never been really happy with the results. The current antenna is a 1/3 2/3 split OCF dipole, which seems to work but still causes me a few problems. The main issue is that there is huge BCB breakthrough from Brookmans Park which is in LOS, so I am using a high pass filter at the transceiver to reduce this to a reasonable level. The filter is designed for 50 ohm impedance and the OCF is no where near that on all bands and even though the radio ATU can tune out any mismatch we toasted one of the filter torroids during JOTA due to the mismatch.

The answer seems to be to use a resonant antenna for each band of interest. One of my neighbors, G0RPM, has had good results with a parallel dipole made by Alpha Delta. I called the UK importer Martin Lynch to enquire about these and was told by an unhelpful person they were out of stock and didn’t know when they would get any more in. As a result I have decided to stop being lazy and build one!

The plan is to have an antenna for the 80-10m contest bands. This means four dipoles, 80m, 40m (which also works on 15m), 20m and 10m which I measured out in my hall from wire I had knocking about in my store.

The next job was to build some spacers for the elements. A search on google suggests the spacing should be wide as possible to make tuning easier. I have a miniVNA which should simplify tuning so I decided to use only 75mm between wires. I picked up a length of PVC pipe from my local hardware shop cut it into pieces then 3mm drilled holes in my workshop (aka the kitchen).

Feeding the wires through the holes was a simple job, but securing the spacers was more difficult. I tried hot melt glue, which was partially successful, but ended up using cable ties to produce my ladder effect. I had a spare commercial 1:1 balun which I put at the feed point and the antenna is ready to go in the air. Hopefully, installation will be an easy job, but I hope that I don‘t get too cold trying to tune the thing as the temperature here is not predicted to rise above freezing for a few days.

I usually use either a fist microphone or a headset when on the air, but my recent experiences at GB2GP have shown me that a desk microphone is useful when operating a special event station as it is easier for visitors to use on the air.

GB2GP has two radios that don’t have microphones at the moment so I looked into building a couple of electret gooseneck desk mics from the ARRL handbook. Once I had costed up some parts that weren’t in my junk box this project felt too expensive until I saw PC desk mics on ebay for only £2 each. At that price I bought a couple and they arrived this morning. The external quality looked just fine - so far so good

Like any good radio amateur, the first thing I did was take one apart to see how I could add a PTT. As expected the quality inside was only worth £2, but the thing that really surprised me was the bag of grit that had been inserted to add weight to the base!

I guess it works, so why not stick with it, but I will be sealing the bag as I spilt half the contents on the floor when I tried to take it out of the microphone!

Next job is to change the flex to some 4 core and add an 8 pin microphone so they can be used with the TS-711 and TS-690S at GB2GP which shouldn’t take long.

Here are a few old photos of the team installing the radio cabinet at GB2GP. FIrst of all te antennas on the mast

Then the LDF5-50 run entering the LID building

30m of LDF 5-50 (for each of three antennas) runs inside the LID store room from the entry point to the celing over the radio cabinet. We installed cable tray to hold the weight of the run

Finally the radio cabinet after fitting with Frank, M0AEU testing things out.