I haven't done much portable operation except for Field Day, and when I
do I have access to tall trees for some pretty good wire antennas ...
including wire yagis.
But I did make a portable vertical antenna that I can set up anywhere.
It uses four 4' long 1/2 inch diameter aluminum tubes that fit together
end to end, sitting on top of another 4' long 1/2 inch diameter graphite
rod as a base. Four radial wires act as guys for the top of the
graphite rod, and four thin nylon lines act as guys about 2/3 of the way
up the vertical. The radials and the nylon guys lead to the same four
stakes (or rocks, as the case may be). I've timed myself and I can put
it up by myself in about ten minutes, and everything fits in a backpack
except for the five 4' lengths that I can easily carry as a bundle with
one hand as I walk. It feeds very easily with the tuner in my KX2. It
was of course designed for 20m, but I've also been able to get a good
match with the tuner on 40m and 15m.
I couldn't care less about pedestrian mobile, and it's no more hassle
for me to carry that antenna to set up somewhere than it would be to
carry a hiking stick. The heaviest antenna item in the backpack are the
stakes.
I once set the antenna up on my deck and monitored PSK Reporter for FT8
signals on 20m over the course of 24 hours. I got hundreds of hits
across the entire U.S., of course, but also dozens in Europe, dozens in
southeast Asia, a couple in Africa, and 8 or so in central Asia. I can
send you the screenshot if you'd like.
Maybe some day I'll make a YouTube video of setting it up and making
contacts to see how far I can get with it.
Dave AB7E
On 9/23/2022 11:10 PM, Dan Presley wrote:
I wanted to revisit this discussion to add a perspective that I think needs to
be considered. First,as far as modeling short verticals I believe it’s possible
to use something like the ‘poor man’s’ AX1 that Doug Hendricks developed at
Pacificon in 2019. A group of us from Oregon went and participated in the
build,and subsequently Doug posted the plans and parts list in the QRP
quarterly. So if you don’t want to obtain or borrow an AX1 for testing here’s
an inexpensive alternative. Build it and give us your results.
Second-I want to hear from Dave AB7E in particular what antenna(s) you use when
you’re operating in the field,and specifically when you can’t set up a wire;
maybe no trees or a bare summit, or as Thomas K4SWL talks about-when you really
don’t or can’t throw up a wire (check out his blog on recent operations in
Canada). Or pedestrian mobile. So far I’ve seen nothing that is as
compact,lightweight and easily packable as the AX1 or 2, and that’s important
to me when I’m hiking. Each part is no more than 6” in length or less. Oh-and
by the way I just completed another’S2S’ (summit to summit) contact on 30M
using the 40/30 add on coil with the AX1 with KR7RK from Oregon to AZ both at
5W.
Personally I always prefer a wire antenna if possible-either an end fed or as
is spelled out in the manuals for the KX3 and KX2, a length of wire about 25-28
feet with a counterpoise. But sometimes it’s not an option. Share with us..I’m
always wanting to hear what others do or build. How do you solve this?? Thanks.
Dan Presley 503-701-3871
danpresley@me. com
n7...@arrl.net
On Sep 22, 2022, at 10:09, Wayne Burdick <n...@elecraft.com> wrote:
On Sep 22, 2022, at 9:47 AM, Jim Clymer <ws6x....@gmail.com> wrote:
On Thu, Sep 22, 2022, 11:28 AM Wayne Burdick <n...@elecraft.com> wrote:
Yes indeed.
This is why you need an ATU when using such antennas. The ATU can correct for
terrain, counterpoise length and deployment, body capacitance, conductors
associated with other connected devices, etc.
Wayne
So that would lead me to believe that matching requirements for bicycle mobile
with a trailing counterpoise would be a moving target.
I haven't tried that myself but yeah, probably.
However, radios like the KX2 and KX3 are tolerant of dynamic SWR variations.
For example if you hit the ATU button at some point and the SWR goes to 1:1,
then walk (or bike) over varied terrain that causes the SWR To vary from 1:1 to
2:1, the radio won't complain. Only if the SWR gets really high will power
rollback occur.
Without the ATU, and using an electrically short/narrowband antenna, you might
see SWR vary from 1:1 to 10:1.
Wayne
N6KR
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to n7...@arrl.net
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
