Hi Folks
It has been a fantastic year for Top Band, great activity and good long
distance QSO?s. During the year I had several different scenarios to test
the HWF, high local noise power line noise until Dec 24th and very quiet
local noise January and February, and also a long raining season.
Testing this great antenna for one year gave me a good picture what we can
expect from the Horizontal WF
Here the most important observations pros and cons the HWF; all notes are
for 160m where is not specific mentioned the band.
Pros
1- The HWF is very quiet because the vertical polarization is attenuated 20
to 30 db below the horizontal gain, It means no power line noise, most of
man made noise arrives vertical due the propagation near surface act as
filter allowing only vertical polarization, most of them are filtered out
by the vertical pattern of the HWF
.
2- The HWF is very efficient on high power line noise, I was able to work 14
new countries where the copy on the Vertical WF was none, including a 160m
long pass QSO with 9M2AX some others good QSO?s were TO7RJ, FR5DN, JD1/m,
C21, YJ0, 7P8.
3- The HWF to perform well on 160m needs to be above 100ft high (30m). Based
on the fantastic performance on 80m and 40m, I think he HWF can perform even
better close to ½ wave or above 140 ft high.
4- The size of 24 ft x 14 ft ( ~ 8m x 4m ) for the loop is big enough for
quiet locations and performs well on 160m, even in a single horizontal loop
configuration.
5- I can not see my station without the HWF, this is my main antenna. During
the winter and without power line noise; the signals on the Vertical WF was
always 5 to 15 db strong then the HWF, most of the time with better copy,
but the HWF always with a comfortable quiet RX. My two antennas are almost
the same size and with low man made noise they performance on 160m are
almost the same.
6- During low man made noise month, some times the DX was out of noise on
the HWF and some times on the VWF, diversity reception always helped a lot,
the QSB is easy to identify the signal changing polarization from one
antenna to another. The big issue with the power line noise is that you can
control when it will be back, but you know the power noise can and will be
back any time.
7- A Single Horizontal loop become a ?miracle antenna? for several friends
living down town with high power line noise, and this is for all bands, 160
? 20m, PY1RO is back on Ham radio only because he can hear very well with a
single 5m by 5m single HWF at 8m high, noise is zero and before with Rolf
vertical it was s9+, Rolf already worked over 200 countries on 40m, and
before the HWF he was planning to go QRT. You can hear some WAV file on his
blog and use Google to translate his blog. He called a ?new cure for power
line noises? . PY2XB also built a single HWF and are enjoying a very good
performance on all bands mainly on 30m and 80m. Fred has a 2 elements yagi
for 40m and the HWF is not far behind it on 40m
http://riodxgroup.dxwatch.com/node/301
At the end you can open the WAV file, and it speaks for it self. Don?t miss
that!
Cons
1- The tower reradiates into the HWF and needs to be very well detuned.
Initially I assumed the difference in polarization was enough to avoid
detuning the tower but it is not the case. Any thing goes wrong with the
detuning increase the noise floor on the HWF.
2- The HWF is very quiet and has low gain; you can use 2 or 3 Norton
preamps, 22 to 33 db of gain means you need to control common mode noise
very well, good shield, chokes, ground, low SWR between the preamps.
The noise measured by my SRD receiver, the QS1R during a quiet day around
noon (mid-day). (500 Hz BW) No power line noise in a suburban location
EL96ub in South Florida
No preamps
RX open, no antenna - 124 dBm
50 ohms load - 124 dBm
RX plus 3 Norton preamps
RX + 2 Norton, no antenna -119 dBm
50 ohms load -115 dBm
HWF connected -113 dBm
VWF connected -110 dBm
When you connect the HWF using preamps with 33dB gain, the increase of back
ground noise over no antenna is 6 db, but it is only 2 db above the 50 ohm
load. When the HWF is working properly there is almost no increase on the
background noise when you connect the antenna at the preamp input. For a
dual flag HWF if the noise increase > 10 db or more something is wrong, if
its increase > 20 db mean one loop is open or very big common node noise
problems
It is important to notice the kind of noise, the HWF noise is normally band
noise, QRN at the distance, but it is no thermo noise limited at my place.
WHATCH COMMOM MODE NOISEWHEN USE A HWF
3- The resistor must support 3W or more power, we had several failures and
now I?m using 16 resistors (series/parallel) off a 3W non flammable metal
film resistor from NTE, they are good up to 30 MHz, and usable on 50MHz.
4- Use twisted pair as much as possible; avoid coax cable and ground loops
5- In my case the HWF boom is part of my TX antenna, it is the top hat, and
there is high voltage all over the place, the trafo and the resistors must
be well isolated at KV levels.
6- During the equinox the lack of horizontal signal made the WHF so quite I
tough it was broken. Some times there are no horizontal signals or high
angle signals at all.
7- The main lobe elevation is around 40 degree and the best gains is from 60
to 30 degree, this mean QRN rejection is bad, the vertical WF has peaks at
20 degree and rejects a lot of QRN, not the case of the horizontal antenna
that likes a QRN .
The performance of the HWF on 80m is out of scale to miracle or
unbelievable, may be the HWF really needs to be at ½ wave above the ground
or 80m here has a lot of horizontal signals. Remember that the man made
noise on 80m is at least 20 db bellow 160m and the HWF is ½ wave above the
ground on 80m in comparison ¼ wave on 160m a my place.
The overall conclusion is that a HWF is a high performance antenna that adds
value at any top band station. The main made noise is growing fast
everywhere, in 10 year the situation could be unbearable, and the HWF is one
great solution to kill man made noise.
I hope these observation motivate more developments, my next step is build a
large HWF all fiberglass and see what performance it brings, as they say, it
is still up its not big enough!
Regards
Jose Carlos
N4IS
.
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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