Monday, October 23, 2023

Inverted-L with autotuner

 Last year I had no 160m antenna when participating in the CQWW SSB contest. Next weekend there will be the big contest again, I wanted to be shure I could use 160m without tuning a alternative antenna this time. So I got the advice to try a inverted-L. Then I thought why not an inverted-L fed with an autotuner?


The CG3000 autotuner just needs a random (long enough) wire, not close to a half wave on any band. So I made a wire of about 25m long (1/2 wave on a non amateurradio band). As counterpoise I have four radials about 10-15m long, one of them is connected to my neighbours fence. I placed some ferrites on the coax and the 12V supply to prevent possible RFI on RTX.

Since I have no good experiences with verticals I expected a lot of noise on all bands. I was actually surprised I had less noise on 60m, considerable less noise from my neighbours solar system. On 160m I had some hum noise exact on 1840KHz, not shure it was from my neighbourhood or elsewere. 



Besides that this antenna performed very well on 12m surprisingly, although the noise level is higher as on my multiband halo. Difference between the halo and vertical on DX (outside Europe) was about 1-2 S-units. Inside Europe the halo wins. On 80m I tried to receive the 10mW PA0RYL beacon on 3555,555 CW. It was well received on my inverted-V but not audible on the inverted-L. Logical because the inverted-L is not suitable for NVIS. But the main reason I build this antenna is 160m. I had reasonable results. At the greyline I received A71XX, but no QSO, I made a QSO with RV9CX in Asiatic Russia a distance of about 3400km, not bad. Later in the evening I received ZS1J from South Africa, no QSO unfortunatly. I think the inverted-L does well enough for the contest next weekend.




I will test the inverted-L this week when time allows. I will be primarely on 160m FT8 I guess.

2 comments:

VE9KK said...

Good morning Bas, looking forward to reading your post after the contest next weekend. I hope the 160m antenna works well for you and adds even more contacts.
73,
Mike
VE9KK

PE4BAS, Bas said...

Hello Mike, tnx for the comment. I really hope this antenna will work well. In previous years I used a 160m sloper antenna on which I worked Canada with only 5W. I hope this antenna is capable of doing the same. I will make a contest review for shure. 73, Bas