Mobile Antenna for 20
This is the story and build log of
this antenna project.
One winters day I was out with my field day setup , a 100W Yaesu
feeding into a ground mounted 1/4 wave vertical.
This usually works quite well despite its simplicity.
Now I hear another local ham about 20kms away calling CQ - It was Niko
We chatted for a while and he told me that he was running a fully
mobile station with a multiband helical whip of only 1.75 Meters in
length on his Ford Ka.
Niko's antenna is small , and I considered it to be a bit of a joke,
but I was about to be 'learned a serious lesson'.
We heard a VK3 station , that was quite strong having many good
contacts with Europe.
I was listening to the replies and most were from countries a bit south
of my location , so the DX path wasn't ideal for us here in Finland.
With my superior and bigger antenna I was located in a car park of a
sporting complex near my house about 10km from the ocean on the
southern side of Finland.
My ground was not the best , my horizon was a couple of hundred meters
away as I was in a dip surrounded by buildings and trees
, but I did get some good contacts during the day , so I felt that I
had a good chance of catching this VK3 contact.
Now Niko was in his Ka about 25km away from me , but he was located
exactly at the sea shore where he had a conductive ground with a long
horizon view to the the south toward VK land.
So Niko was putting out calls , and I was calling too.
The sad end of the story is that Niko got the contact and I didn't. :-(
*** You cant judge a
DX'er by the size of his stick ***
Yes , even with his inefficient helical stick antenna he still got a
good contact BECAUSE
of his location.
Here in Helsinki city there are pretty well no public open spaces
suitable for setting up an antenna like what I use and operating at
home is likewise impossible for me due to highly restrictive tenant
A portable station is my only choice , and while I don't mind braving
the minus 15 degrees in winter in order to DX , it is not too good when
your setup isn't as good as it could be.
What the Niko experience taught me is that a good location is worth
more DX miles than the efficiency of your antenna.
I don't intend to retire the full size 1/4 wave vertical just yet , on
good soils near the ocean that things screams out well , so my plan is
make a car mounted antenna that I can more easily take with me and use
in more suitable TX sites.
One option is just buying a short stick like Niko's , but the fact
remains , that short helical whips are poor radiators.
This article will detail the build of a vertical for
stationary mobile use that will not compromise efficiency.