QRP Club

QRP Station => Antennas => Topic started by: sm5mek on June 20, 2015, 09:52:33 UTC

Title: Vertical multi band antenna.
Post by: sm5mek on June 20, 2015, 09:52:33 UTC
Recently i did an vertical antenna with tunable coil with an slider outside the coil. I now have done an English text page about this See here (http://www.sm5mek.se/vertical-antenna-for-portable-use/).  8) :o ;D
Title: Re: Vertical multi band antenna.
Post by: ON6KZ on July 21, 2015, 08:57:41 UTC
Interesting project. What is the performance?
Title: Re: Vertical multi band antenna.
Post by: sm5mek on July 21, 2015, 09:57:56 UTC
It works well, but conds here realy poor, tested via RBN and not at all the same signals i use to have from any of my systems. The coil could be with less turns, maybee 70n to this 3m telescopic rod. Smaller rod vill have more turns on coil. At 40 m i am on the middle of the coil, but it works good. Easy to tune for low  (almost no) SWR with the slider and dont need any tuner. For higher bands, above 20m i have to tune with the telescopic rod first and fine tune vith coil.. ground plane just some meter of one wire if any ground needs at all.
I am now ready with this antenna, see whole description on my homepage (http://www.sm5mek.se/vertikal-antenn-for-portabelbruk/). one bottom tube above is the coil and above coil is the telescopic rod. I can chose between 170 cm rod and 300cm rod. I also use one unun 1:1 and two counterpoises. This give me good values on SWR and also my ref. stn. on 80 m heard me weak but there was nothing in the beginning and conds very bad last week.
Title: Re: Vertical multi band antenna.
Post by: sm5mek on September 13, 2015, 11:11:01 UTC
Dont realy know yet, the conds here make the bands almost impossible. I have done one qrpp qso this month so far. I will report when having anything interesting to say about it.