Contest QSO's with the cylinder dipole

Is it really THAT simple?

The cylinder dipole has proven to be a indoor HF-antenna with the size of a VHF/UHF-antenna.  The cylinder dipole with Monster energy cans is working fine on 15 m.

Build  - Work  -  Analyse

This table gives an inside on the number of CW contest QSO's that I made with cylinder dipoles per band and per contest. In the table, QSO means a single QSO outside a contest. All QSO's were made with 4 W or less.

Most of the QSO's were made with the cylinder dipole with two Monster cans.
I noticed that there is NO sharp boundary, but the the Monster seem to work better on 21 MHz than on 14 MHz.
It is not easy to compare antennas on different bands or in different contests, because the propagation has much more influence than the used frequency.

Number of QSO's per band with Cylinder Dipoles  -  PA1B

Easy to build indoor antenna

The Monster cylinder dipole, made of two Monster energy cans of 500 ml is a good, easy to build indoor antenna for 15 m, but also works on 10 m and 20 m. If you want to get acquaint with the indoor cylinder dipole, I suggest to build the cylinder dipole with Monster cans and a coil with 9 turns on a coil former of 80 mm. The cylinder dipole is fed on two taps at the center of the coil that are ONE turn apart.

More construction info here Click

140 QSO's with the cylinder dipole

Since the ARI contest in May 2015, I made 140 QSO's with 3 types of cylinder dipoles. The table shows the 3 different cylinder dipoles that I used, in several contest in 2015 and 2016.

Build  - Work - Analyse

I made this table to show the number of QSO's, that were made, with each of the three types of cylinder dipoles that I have build.

Number of QSO's with different Cylinder Dipoles - PA1B

I used the Red Bull antenna in the ARI contest on 20 m and 40 m. At that moment 15 m and 10 m showed no activity. But the propagation on 20 m and 40 m  was excellent.
The 6 QSO's on 10 m were made in two different 10 m contests.

The Monster antenna, made of two Monster cans of 500 ml is an excellent, easy to build indoor antenna for 15 m, but also works on 20 m. The table show that it works better on 15 m that on 20 m.

The Booster with it's wingspan of 55 cm (22") is build for 20 m and 30 m and is until now, only used in the PACC.
In the PACC I made 27 QSO's on 40 m. The Booster works on 40 m and 20 m. In the PACC there was more activity on 40 m than on 20 m. But I suspect that the booster works best on 20 m,

The used the cylinder dipoles indoor from the shack or from a dormer window at the second floor, with a power of 4 W or less.

UN3M on the Red Bull antenna

When I putted the Red Bull antenna into use in the ARI contest, I made 9 QSO's on 14 MHz and even 1 QSO on 7 MHz. At that moment I did not know that the conditions were extremely good. The Red Bull antenna with the coil of 14 turns on a tube of 40 mm, resonates on 26 MHz.

So now I was curious, how the Red Bull antenna would do on 28 MHz. 

I decided to participate in the DARC 10 meter contest, to make QSO's with the Red Bull antenna. A contest for 10 meter is a good opportunity to make contacts on that band, because it creates activity. The DARC 10 meter contest is a very short contest, that runs from 9:00 till 10:59 utc. I have been on the band for 90 minutes. During the whole contest, I did not hear any German stations, because of the very short distance to Germany.

After a few minutes I could make a QSO with LY2NK with 3 watts. Then the band was empty, but I had to stay on.
Much later I could make a QSO with UN3M. Nickolay is in the western part of Kazakstan. The distance is about 1950 miles. FB.

QSO with the  Red Bull antenna  on 10 mtr with 3 watts

Red Bull Test Antenna

When I putted the  Red Bull  antenna into use, during the ARI DX 2015, I was aware of the controversial nature of short antennas. But I had absolutely NO doubt about this short antenna, with it's "wingspan" of just 12 inch.
I was convinced that I could make QSO's with QRP or even QRPp from the shack.

Why?
I was curious, whether the  Red Bull  antenna  could be used on 14 MHz, although it was tuned at 26 MHz, in stead of 14 MHz.

Further I was curious, whether the symmetrical tuner could be used to get a SWR of 1:1

I clamped the PVC tube of the antenna between  the bookshelf and connected a 300 ohm twin-lead between the symmetrical tuner and the coil of the antenna. 

The coil had 14 turns on a 40 mm coil former. I did not bother to change the coil to lower the operating frequency, which was 26 MHz and thus much higher than 14 MHz, on which I would operate. The 300 ohm ribbon is is equipped with two alligator clips, which are connected to two connection points on the coil one turn apart.

Red Bull test antenna May 2015 PA1B

SWR.

The tuning runs smoothly. It's very easy to get a accurate SWR of 1:1 So I could transmit with the antenna. I only tried 14 MHz, because that was, where the action was and I wanted to make QSO's immediately. I did not try 21 MHz or 28 MHz.. 

Does it work? Yes.
I convinced myself with 360 milliwatt, with the antenna indoor, at a height of 4 meter above the ground.  Is it not amazing.

The first QSO that I made with this 12 inch antenna, was a more than 1000 Miles per Watt QSO.

On the air
After adjusting the SWR, I heard the station II6T. 

I could easily make a QSO, using a power of just 360 milliwatt. I tried to work them, earlier in the contest, on the damaged inverted V. But they could not copy my RST on the cracking inverted V.

I am very pleased, with this first QSO on the  Red Bull  antenna. Later I realized that this QSO is a more than 1000 Miles per Watt QSO.

I made QSO's with EA, YU, SM, YL and LZ with 3.6 W

With 800 mW I managed to make a QSO with HA and a QSO with UR.

Further I made a QSO with 360 mW with an other station from Italy.
IK0YVV copied my call immediately, when I answered his CQ. His signal was strong, it was over S9.

On receive

There a large difference between wire antennas, like the half wave dipole or inverted V and the short Cylinder dipole. The signals that are received on this short antenna, are much weaker. But also the short antenna picks up less noise. I noticed that it takes some time to got used to the weaker signals. 

ARI DX contest 2015  -  Red Bull test antenna  - May 2015  -  PA1B

Improvements and Next steps

• The next step is building the same antenna with larger cans and a larger coil former, so the antenna will resonate at 14 MHz and therefor has a good efficiency.
• Test the antenna on 28 MHz. This frequency is near the actual resonance frequency.

From one moment to the other
I decided to put up this antenna this antenna in the ARI DX contest 2015, when my inverted V let my down. I constructed the  Red Bull  antenna to test the properties of symmetrical feeding, a few months before. The test showed that the cable, which is connected at the middle of the coil,
has no hand effect on the cable.  The antenna lay around in the shack.

Tuning and SWR are not critical
Was it properly tuned to the operating frequency? NO.
But I am very happy with the fact that the cylinder dipole is NOT critical in tuning and that the SWR is easily to adjust.

Red Bull antenna - May 2015  PA1B

Connecting the twin-lead.

One turn apart 

Cylinder dipole

I thank Franck F4HFQ for the link from Radioamateur.org to this Blog entry.  Franck writes:

Bert, PA1B, a fabriqué un dipôle cylindrique en remplacement de son antenne défectueuse pour achever un contact QRPp rendu difficile par cette dernière. Résultat ? 1000miles par Watt au premier QSO.

 Red Bull  gives you wings 
This a a catchy one liner, I could NOT resist, LOL.
Please notice that the Cylinder dipole is NOT a joke, but a very short, but working antenna.

Test antenna
A few months ago I built an experimental cylinder dipole with two  Red Bull  cans and a coil, that works as an impedance transformer, to test the properties of symmetrical feeding.
By using symmetrical feeding, the cable doesn't radiate and the cable has no hand effect.

Damaged inverted V
The ribbon of my inverted V is damaged by the wind.  I wanted to make a few nice QSO's in the ARI DX contest, but I was very disappointed by the inverted V. The SWR is constantly changing, even with the slightest bit of wind. The inverted V cracks when the ribbon moves, both on receive and transmit.

I tried to make a QSO with II6T with 360 mW on the damaged inverted. The operator repeated my call immediately correct, but because of the cracking twin lead, my exchange 001 was not received in Italy. Even when I increased my power to 3.6 W, the cracking twin lead spoiled the fun.

Indoor Cylinder dipole

Then I decided to try to use the  Red Bull  antenna. I clamped it between my book shelf.

I connected a 300 ohm twin lead between the coil of the antenna and the symmetrical tuner.
I matched the antenna with the symmetrical tuner for the lowest SWR.
The resonance frequency of the cans and the coil lays between 21 to 28 MHz, but the  Red Bull  antenna could be matched easily to 14 MHz, using a symmetrical tuner.

Into the ARI CW contest

After a while I heard II6T again, but now on the cylinder dipole, I answered their CQ with 360 mW. I got an immediate response and the QSO was easily made. WOW.
In total I made about 10 QSO's on the  Red Bull  antenne, with a power of 360 mW to 3,6 watts in the rest of the ARI DX contest.

Please read the interesting details on this amazing 12 inch long  Red Bull  test antenna,
that I used in the ARI DX contest 2015  (Click)

1000 Miles per Watt

Later I realized, that the first QSO with the cylinder dipole is good for 1000 Miles per Watt. hi.

Capacity

Cylinder dipole 4 m above ground @PA1B's shack

The magic of the Cylinder Dipole lays in the large capacity of the the two cylinders.
The coil and the capacity of the cans determine the resonance frequency of the antenna.

Auto transformer

The coil acts as impedance transformer. The 300 ohm ribbon is connected to 2 points on the coil that are 1 turn apart. The coil it self has 14 turns. 

Symmetrical feeder

The twin lead is connected to two connectors one turn apart, at the middle of the coil, to feed the dipole symmetrically. 

I chose for the symmetrical construction to avoid  hand effect of the ribbon. 

Connections, one turn apart

The Cylinder dipole