The cylinder dipole can be used as an indoor HF antenna, with VHF/UHF dimensions. Our test showed that the cylinder dipole constructed from aluminium energy drink cans can be used as a multi-band antenna on 10 m to 15 m.
In the weekend of the
ARRL 10 meter contest, Alex
SA5BFZ and I (
PA1B) made
CW QSO's on 10 meter both with our indoor cylinder dipoles.
Alex
|
Cylinder dipole of Alex SA5BFZ |
Alex operated on Sunday, outside of the contest. He made 2 excellent QSO's from Sweden with
Spain on 10 meter and a QSO with Russia on 17 m. Alex used the cylinder dipole that consists of two 500 ml
energy drink cans and a coil of 80 mm with 8 or 9 turns. The photo shows the cylinder dipole of Alex.
Bert
I participated on Saturday and Sunday for two very short periods in the
ARRL 10 meter contest. I was curious what my
Red Bull antenna would do on 10 meters. I never had the opportunity, to use it before on 10 m, due to the lack of propagation on 10 meters.
|
Coil and cans. PA1B
The Cylinder Dipole principle is not yet in the text book |
I worked 2 stations on both days, within 8 minutes and within 5 minutes. With only 10 meter to operate, I was fully depending on the propagation on this band. My cylinder dipole with Red Bull cans is doing fine.
The signals must be
S8 or stronger, then it is
easy to make a QSO. In 3 QSO's I used 2.7 W. In the QSO with
RU6AV I used just 0.8 W.
I used a cylinder dipole with two
Red Bull cans and a coil of 40 mm with 14 turns.
Results
Both cylinder dipoles of Alex and me are doing fine on
10 meters. We made QSO's over large distances within Europe, with low power. The table below shows both call signs of our QRP stations and the stations that we worked, the distance in Miles and the used power in watt.
Lowest possible power
We both operated with the
lowest possible power. We reduce our power according the reading of the S-meter
before we answer a CQ. To use the lowest possible power we must use
S&P.
How to compare
Because we both used the lowest possible power, it is possible to
compare the QSO's.
The QSO's can be compared by calculating the value of the Miles/quare root of the power or by calculating the Electrical field strength at the receive antenna.
deciBel
In the last column I compare the QSO's in
dB. The higher the value in dB, the stronger the signal.
I choose my QSO with
RN3GQ to be 0 dB. The other QSO's on 10 m are made under better conditions.
The value in
dB shows the influences of the
propagation and the antenna of the other station.
|
The higher the value in dB, the stronger the signal. |
I say
Thanks to
URQRP.org for the link from their interesting site to this Blog entry.
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Miles per WHAT?
The calculation of Miles per Watt can not be used to compare QSO's. To double the distance we need more power. The power must be increased 4x to get the same signal strength.
The value
Miles/SQRT(watt) is calculated from the distance in miles divide by the square root of the power in watt. This value is very easy to calculate and is an
excellent propagation indicator.
The
higher this value, the
better the propagation. (The value is NOT accurate over a short distance.)
Electrical field strength in V/m
.
E = electrical field strength in V/m
P = used power in watt.
R = distance between the radio stations in meter.
An other way to compare is to calculate the Electrical field strength E.
The
lower the Field strength the less power is needed to cover the distance, the
better is the
propagation.