1.3.10

Why is the home installation not as good as the vehicle installation

As a follow up to the previous post on grounding the hatchback lid the performance improvement is so great that it is making me look at the home HF installation which I have to admit has always been a compromise and has been thrown in to get me back on HF when wires has snapped etc. So weather permiting I will be looking how I can impove the grounding om my HF vertical this weekend.

My current antenna consists to a 10m fishing pole with a helical winding around the pole with 1 inch (approx) spacing between windings. At the base I have a CG3000 Auto ATU (Chinese origin) the ground or earth is four random length earth wires connected to the cold side of the CG3000.

As you will see from the logbook, the antenna does get out but most of my real DX has been via PSK31 and not via SSB and to be honest I do prefer to talk. 

So I think the the first job will be to make a radial plate out of some aluminium angle stock that I have in the shed, then use some braid left over from the previous project to connect this to the CG3000. Then lay in some more radials. I also have some 2m electrical earth rods and may sink them in strategic positions, then link them all in together. with the copper braid I have. Also was wondering about making a fixed 20m dipole (Beaming east west) for the second input on the 756 Pro II.

Mobile Antenna Efficiency (Grounding Issues)

Each day I have a 45 minute journey from home into work and spend a lot of time scanning around the 20m band, I have never been very happy with the initial installation, but had more pressing matters to deal with (such as the kitchen refit) so had settled on just listening to stations.

I had a number of problems when I tried to use the radio:
  • RF in the radio head unit, causing the display to
  • Intermitant high SWR depending on if it is raining or not (Better SWR when wet)
  • Intermitant rebooting of the radio.
 Whilst I had some free time this weekend I decided to have a go at providing a better ground for the antenna to work against. The car is a 56 plate Renault Megane hatchback with a Comet fixed 20m antenna on a Maldol adjustable mount. I suspected that the electrical contact in two obvious places was a little less that what was needed. So I stripped the outer cover from some RG213 I had stored in the shed and then proceeded to remove the outer braid from the remaining cable (This was much easier than I had anticipated).
I then proceed to cut 4 x 1ft lengths of the braiding, put two pieces together and krimped a ring connector to end one.

FIX 1: I then connected this to the Maldol adjustable mount and drilled a hole in the tailgate (Inside & out of view) crimped another Ring connector and screwed it to hatch lid.

FIX2: Same double strap of RG213 Braid across the hatch back lid hinge, making a solid RF contact between the main car body and the hatch back lid.

Results: 95% of the RF issues have disappeared, I still need to put some ferites on the cable between the head and the transciever. On air results have been much more impressive. Talked to a number of stations whilst out and about over the weekend and cannot believe the difference on received signal reports, whilst talking to a UT5 station this morning I got a 5.9+20db and he almost accused me of not being mobile at all. The main thing I am pleased about is home much more I can hear. Now mobile operating is a pleasure and I will endeavour to take some pictures later today and post them to hopefully make my description above clearer.