One of niced things from our hobby is experimenting. And when I am on my /A adres I can experiment all the way. So as you saw on my portable equipment its easy to take my set with me. I want to make an antenna thats easy to build, to place and to take with me. I want to make an vertical antenna wich I tune with te build in tuner from the transceiver. The materials I used coming from de DIY store and are used to connect wooden poles. The metal sheet meassures 60x300mm and is 2.5mm thick.
The fishingrod is about 5 meters long. Thats the longest rod I have. I wil feed the antenna via a 1:9 unun
The antenna excists of 8m wire wich I wound as a spiral around the fisingrod. As a counterpois I used a single wire with a length of 9m. This is not based on theory, but its the space I have.
the Trueth

Lets see what happens when I gonna test this project. The table below gives the SWR on the different bands with and without a tuner.
One thing is sure without a tuner its nt pssible to operate this antenna. But I did not expact that. Wht I use the MAC200 from SGC sees My FT857 on the bands fro 10-0m 50 Ohms. Now lets listen on the bands and compare the vertical with the half G5RV. The half G5RV and the tuner wil work on 80m but its not designed for that band so I wont use this band to compare. The band 10 and 15m are during tis period (may 2008) almost closed so I leave them also outside the test.
Band
SWR
Without tuner
SWR
With tuner
80m
>50
1.5
40m
3.7
1
30m
3.5
1
20m
>50
1
17m
>50
1
15m
>50
1
12m
>50
1
10m
>50
1
First of all I want to mention that its a compromis antenna. All designs of an antanne used for multiband use is a comprimis when they use traps, inductors or capacitors. We wil lose somthing on one band and maybe win on the other. If you dont want that, than there is only one alternitive. Use for each band an single antenna.But there ar situations that its not possible to place more antennas or you will hhave te reduce the size because ther is not enough room. The table below shows the difference in signal strenght of the vertical compared to the G5RV (half size)
Band
Local (in Europe)
DX
(outside Europe)
80m
2 S-points lees
than the G5RV
the same as the
G5RV
40m
1-2 S-points less
than the G5RV
1 S-point stronger
than the G5RV
30m
1 S-point stronger
than the G5RV
the same as the
G5RV
20m
1-2 S-points less
than the G5RV
1-2 S-point stronger
than the G5RV
OK lets see, when dows the vertcal the its work locally? Well thats only on 30m. On the other bands the sigals are 1 to 2 S-points weaker copared to the G5RV. Its certain that if we are on holliday in Europe and want to make contact with home its not the right antenne. But we have to remind that the use of only one radial has an impact onthe radiation of the antene. The favorite direction of the antenna is the direction of the radial. When I changed the direction of the radial over 180 degrees give for som station a 6dB (1 S-points) signal increase. Maybe its wise to ad another radial. For local contact on 40 and 80m I would prefer the dipole over the vertical.

Lets see how it acts for DX. As a fanatic DIGI mode operator is it my sport to work as far as possible with QRP. According to the low radiation angle of the vertical is DX with the vertical always better than the dipole. During the tests I asked seriously my contact to look at the S-meter when I switched from vertical to G5RV and in 80% the vertical was stronger.

On my /A location I changed the position of the antenna a bit. The feedpoint is now about 3m above the ground. This has no influence on the results, only on the radio. There is no BCI anymore.
Download VF-Antenna as pdf: VF-Antenna.pdf