During the 2006-7 winter I have had the opportunity to put on my roof this famous GP antenna.
Here I will report some experiences with it.
The HF2 works on 40-80 meter bands and on 160 with an add-on kit.
It is mounted on my roof , near the sea at about 50mt above the sea level. I have installed also the Capacitance Hat (CH) with 4 copper wires with the specified lenght +-3.5mt for 40-80 , and also four guy wires as I was not sure that the antenna could remain up on strong winds.
Sometime later, leaving the same CH on the GP, it has been tuned to work also on 160mt with a kit produced by IT9ZMX Vittorio.
The tuning of the HF2 is an easy task. Of course the tuning procedure is simplified if one has also an antenna analyzer as the MFJ259 or a Mini_VNA.
I have used 4 radials per band .
The bandwidths on each band are as per specs .
I have done the comparisons with the HyGain DX88 GP, a 40mt full size loop, and 80-160 full size(FS) dipoles.
Very weak stations have been listened and in any band condition .
My impressions of this antenna after a full winter of contests and swl_ing are positive.
On 40mt the FS loop is little better.
On 80mt it is better than the DX88 but is almost "au_pair" with the FS dipole.
On 160mt I have had some reports better for the FS dipole .
The reports showed that a qso held at noise levels (S0 = 59 ;-)) in contest) priviledged the dipole.
Anyway I suppose such reports are dependent mostly on the location of my qth, a small hollow near the sea and high mountain toward my south to north-west directions.
As all GPs also the HF2 is prone to pick-up the noise, specially on 160meters.
During rainy days the dipoles were more "silent" than the HF2 .
But the 40mt FS loop let me work the contests even during heavy rain.
Here are the pics of the tuned antenna data :
The next winter I will do more tests with different ground and radials configurations.
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Spring 2008
One Year has passed and more experiences have been carried on the HF2V + 160meters kit antenna.
The following pictures show the definitive setup of the 160 meters kit.
link to larger pic
The 160mt kit has worked "at once" . Only two small bugs : the holding brakets of the BIG capacitor and the loading coil material.
The brakets are not so strong , so I had to reinforce them otherway under windy blasts the Cap moved itself varying the band tuning.
Having no teflon or plastic of such dimension I have used a wine cork to make steadier the Capacitor .
The loading coil is made from a smaller diameter wire and is more flexible, so I have fastened with a rope.
The two smal bugs have been cured and the antenna works very fine.
Last : the ground choke must be put in a definite position to keep the SWR low by stretching or compressing it, so the use of antenna analyzer is a must.
I hope to see you on the Top Band the next winter.
Dic.'09, 160 meter kit strengthening.
As the Top Band kit was too weak, look at the above left pic, during winter 2009 I have changed the tiny straps with ticker aluminium
and steel washers\screws.
At the same time as the HF2V has been on the roof for almost 3 years and the sea oxidation was already evident all the joining points
have been cleaned, NOALOX paste has been put in the contacts and the original screws between the uper antenna tubes have been replaced
with steel clamps.
The original clamp for the coil tap has been redone by bending a new aluminium piece on a 5mm drill point.
- here are the 160mt kit dimensions:
- a) the capacitor is a 500pf \ 35KV, letting full power also on 160mt. Can be also 400pf.
- b) the coil support tube is 46cm long x 28mm diameter, can be shorter.
- c) the coil is 25 turns with an outside diameter of 9cm, the wire is 4mm tick, the original wire is 5mm.My tap is at 21st turns.
- d) upper plastic spreader is about 20cm long x 15mm diameter, protruding about 12cm.
- e) the coil distance from the bottom is about 17cm lower, but can be less.
Again, as the coil wire is not so strong in respect to the original, I have put a piece of rope to keep it steadier.
No problems even on heavy rain. The 160mt coil-tap is shown with an alligator as I was studying a switching system to move
the resonating point on 160.
I will continue the work in the next fall.
Nov'10, Frequency shifting.
As the HF2 tuned window is rather tight and having the need to move over a wider spectrum ,without the use of an antenna tuner,
I have added a simple 2 relais switching unit with the use of steel clamps, which permit to further move the usable RF window.
link to larger picture
The steel clamps are very strong, either the coil joints and the clamps have been covered with the NOALOX compound.
The tests of this frequency shifting arrangement during the last 160 meters contest haven proven to be a good solution.
So the time will show if such solution would last an entire winter or longer.