Cylinder dipoles on 10 meter

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.

The cylinder dipole of Alex SA5BFZ

Alex SA5BFZ built his version of the cylinder dipole with 500 ml monster cans. Before building this antenna, Alex asked by email  information on several details of the cylinder dipole. With the information Alex was able to build the antenna and operated with good results on 10 m and 17 m.

The cylinder dipole with open cans in detail.   Alex SA5BFZ

In the photo you can see that the dipole is attached to the curtain. The cylinder dipole consists of two cans and a coil. I advised Alex use open cans. So he removed the top and the bottom of the cans.

Hej Bert,

Thanks for the info. I removed the top and bottom of the cans as you suggested.

I did some playing around with the antenna this evening. It tunes beautifully 30 - 10 m. 

I will try it more seriously in the weekend, when I have some daylight available.

If I make one single QSO with the antenna, I will keep it as a trophy. Hi hi.
73, Alex

Cylinder dipole of Alex SA5BFZ 

The dipole is connected to the tuner with a ribbon. Last Sunday Alex had some time to test the dipole.

Hallo Bert,

First tests with cylinder dipole done. On 10 m I made QSO with EF5Y using 2.5 W and EF7X using 0.5 W, both with CW. It was very quiet on 10 m, so I went to 17 m and made a 599 QSO with UE25R using 1 W. This really shows that propagation is everything. A good antenna on the other end helps as well. Hi hi. I include a couple of pictures of my operating spot and the antenna. Very simple setup but a lot of fun!  73 Alex

Hallo Bert,

Yes very fun indeed! I still can't understand how they could hear me. Hi hi.

I will try to send the picture again. If you want to use the pictures and info please go ahead. I'm glad that I can be of help. :)  73 Alex

Beautiful results

Alex managed to make  two QSO's over a large distance to Spain with QRP with the cylinder dipole. The first contact with EF5Y was made over a distance of 1688 miles or 2717 km.

The QSO with EF7X was made with a power of 500 mW over a distance of 1848 Miles and is good for 3696 Miles per Watt.

The QSO with UE25R on 17 m was made over a distance of 785 Miles. This QSO on 17 m shows the cylinder dipole, can be used as a multi band antenna. The band is changed, simply by adjusting the tuner on the band of interest.

It looks like the indoor cylinder dipole, can be useful in situations with antenna restrictions.

Thank you Alex for testing the cylinder dipole, sharing the results and the beautiful pictures.