New HF antenna

The last month I worked on a new HF antenna, there is no space for anything fancy in our garden, but one thing I could improve is the height of the antenna at the side of the house. For this I installed a mast right of the bathroom window for which I needed to put mounting brackets in the wall. It looks like this and it required me to drill 12 mm holes for 5 expansion bolts for which you need an SDS+ drill (the older drills only go to 10 mm diameter):

IMG_0555

Next is to install the mast, it consists of glass fiber army mast parts that you secure together with aluminum tubes and hose clamps. Four mast parts are put on top of an aluminum part that is clamped in the antenna mounts:

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The new mast
IMG_0582
The antenna is a G5RV junior, I could not fully span it so there is one arm going sideways to the roof of the garage block.
IMG_0584
Looking up under the mast, the matchbox is a 1:4 current balun, the coax-cable goes back over the roof under the roofing tiles to the shack.

What comes out of the antenna is 450 Ohm twin line that goes in the 1:4 guanella balun. For this antenna you need a tuner, and since I didn’t have anything free for this I used the T-match tuner that I built last month.

IMG_0593

The noise floor of this long wire antenna is substantially better than the CG3000 long wire running to the aluminum support mast at the end of the garden.

Tuner settings for this antenna

Freq         L     C1     C2
3603   16,25     +5    -45
3777   10,10   +90    -10
7080     3,50   +45    -20
7130     3,30     +0    -30
7160     3,25     45    -45
14195     1,50   +20    -45
14255     1,50   +20    -45
14310     1,60   +45    -45
14305     1,60   +45    -45
18130     1,50    -45   +45
28300     1,33   +80     +0

So the conclusion is, you can practically use this antenna for 40 to 10 meter, for 80 meter you have to be careful with the inductor, but it can be done, NVIS on 80m was fine up to 200 km away with my set-up. But probably the inductor will dissipate most of the power on the eighty meter band. Another thing is, tuners need to be in a closed case because the capacitors should not spark because of dust etc. What it also proves is that my two ring guanella 1:4 balun does work fine between 3 and 30 MHz for a power up to 100W. For higher powers I probably need to look at a larger ferrite ring.

Last update: 9-jun-2017

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