ELSTAR Oy,Ltd Radio & IT Communications
DX toimintaa tukeva sivumme
DX Spring 2006
Looks like we finally move into Low Band conditions. 10,12 and 15m seems to be closed. There was some openings during Peter 1, but they did not have real DX antennas on high bands.
So the best idea is to concentrate to Low Band DX operation.
How to do well:
Most of us, who lives in town or near town has limited space for antennas like me / editor. During contest, some of us are able to move onto country side. But also in small garden some antennas works OK.
I got my 3Y-Peter1 on 160 with very simple bended two element wire antenna. Antenna takes only small area of garden, about 1 x 44m and tower is just between. Over my DX beam, there is support boom, which does carry ends of wires. Same boom ends are mounting points to my 2 element delta loop. Loop is in use on mainly on 12,17,30 and 40m , nut works also on 15, 20 and 160m.
If there is any people, who likes to know more, I could add information into this page in April-06.
I wish to get experience of you Low Band DX antennas. Please write to me and I will publish all here.
Here are some of my experience and ideas:
80m Rotating polarization is interesting and gives very nice QSOs on 59/599 signal reports but usually "also heavy deep QSB".
There is antenna, which works always well: 12 - 18 m high 50 x 3 tube + C-cap wires + 80m high quality trap + 2m fiber + 6m aluminium . Most of fiber tube length is covered by PTFE-Silver 0.8 - 1.2 mm wire 150-200 turn and highest 38mm tube high end has 2nd c-cap wires to 4 direction. This antenna can be calculated exactly to coaxial feed, but a bit difficult and not necessary. If you are not able to get very good hard 50 x 3 tube, you must go to 60 or 75mm size.
Best idea is to have Feed point tuner. Then you do not need amplifier. 100W is good for all DX. But in contest 2KW feed point tuner is great and amplifier. Other way is Elstarīs special 100 ohm ultra low loss feed line or 300 ohm foam line. In case you use RG8Foam coaxial or Rg213/RG8, best way is to measure length to 33m on RG8foam, its full wave length on 40m. This helps to tune 40m as 180 deg. line shows same reactance on both ends of transfer line. I have used this and I got real nice long path pile up on 7mHz SSB to W6,W5,W7 etc area.
Most simple good DX antenna is two dipoles. As we all know, 80m beam works well as soon we get it over 27-28 m of ground. On 20 m itīs like one element dipole. But if you get 2 dipoles to 20m height and you draw them S - N and you feed on 180deg. phase them, you will get broad E/W low angle gain. Only problem is, that you must have antenna tuner. Best is Outdoor Feed point tuner. On sharp portion of DX band, you can use 0,3 e / m satellite coaxial and 1/4 Q-sections to get 50 ohm. Antennas should be 27m of each others.
I wish some of you will write to me / OH3LX. I do some wireless antenna switch box work now to use 4 element simple antenna during coming Low Band top time. Also I will try to use 12m or 18m high vertical on very long 4 x C-cap wires and long coil in each. C-cap wires may be even 40m long or more each.
73; Mark OH3LX.