Monster in DARC 10m 2024

PA1B with the Monster Cylinder Dipole 
Wingspan 35 cm - 15 inch

I took part in the DARC 10 meter contest with the Monster Cylinder Dipole. This cylinder dipole is called the Monster, because it is made of two  Mønster  Energy Drink cans and a coil.
The wingspan is 38 cm which is 15 inch.

In the past I used the Monster cylinder dipole on 21 MHz. On 21 MHz the dipole is doing well.
I was curious how the Monster Dipole would do on 28 MHz.

Indoor antenna with a wingspan of 35 cm
The dipole is hanging in the dormer window (Im Dachfenster) and is connected to the tuner with 300 ohm twinlead. The tuner does not tune the antenna, but is adjusting the impedance.

Strong signals
When I started in the DARC 10 meter contest, I noticed that the signals were strong S+.
Strong signals are a good sign. Please notice that the antenne is very small, so the voltage of the received signal will be very low. 

CW QRP S&P
I always work with CW QRP. 
The first station that I worked was LZ55ZF. I answered his CQ with power of 2.7 Watt. I received an immediate correct respons and logged the contact. The distance is 1100 Miles. Not bad for an antenna with a wingspan of 35 cm or 15 inch. Hi.
I was in the contest for 1 hour and 1 minute and made a total of 5 QSO's. 

4 DXCC's
I could easily work stations over a distance of 1000 miles or 1600 km with just 3 watt.

PA1B in DARC 10m contest
3 Watt in Monster Cylinder Dipole 

Local QRM on 10 meter
The local QRM was strong. It was S9. When I switched the MorseMachine off, the local QRM was S8. The MorseMachine is the main source of QRM. Luckely is 10 meter the only band, on which the MorseMachine will give QRM. Switching the MorseMachine off during listening, does not work. Switching off on receive is not fast enough. I tried in a dry run, but that would in a real QSO result in missing the exchange. So I leave the MorseMachine on during the whole QSO.

I am very pleased with this result.

More info on the << Monster Cylinder Dipole >>

Cylinder dipole

The cylinder dipole with two Monster energy drink cans and a coil is easy to build and is working fine on 15 m. With 2.5 % of a wave length, it is very small antenna, that can be easily used indoors.
Building and operating with the cylinder dipole is not as difficult as it seams. There are no critical parts or critical procedures.
I wish you good luck, but most of all to have fun. 

I have writen a description on my website
about the Cylinder dipole (Click to visit)

PA1B Cilinder dipool in de BQC Nieuwsbrief

De cilinder dipool is een interessante antenne, die zelfs binnenshuis gebruikt kan worden. Vooral met de cilinder dipoool met Monster blikken, die bij uitstek geschik is voor 21 MHz, heb ik al veel QSO's gemaakt. 

Ik heb vandaag enthousiaste reacties gehad van BQC leden, op het artikel over de cilinder dipool in Nieuwsbrief 161 van de BQC, tijdens het bezoek aan de Vlooienmarkt in Rosmalen.

In het artikel over de cilinder dipool met Monster blikken wordt verteld, dat de capaciteit tussen de blikjes overgeveer 6 pF is en deze capaciteit een essentiële rol speelt, bij de werking van de cilinder dipool.

Er wordt uitgelegd dat de cilinder dipool zich gedraagd als een parallelkring, de blikjes niet van blik zijn, maar van aluminium en welke voordelen dit biedt.

Verder wordt uitgelegd dat de cilinder dipool via een 300 ohm lintlijn gevoed wordt en daavoor een symmetrische tuner gebruikt wordt.

Veel leesplezier met de BQC Nieuwsbrief.

Cilinder dipool met Monster blikkken - PA1B

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

Cylinder dipole construction

Constructing a cylinder dipole
The cylinder dipole consist of two open aluminium cylinders and a coil. The coil is connected between the cylinders and is hanging below the cylinders. I constructed my first cylinder dipoles from aluminium energy drink cans that I found on the street. To get open cylinders, I remove the top and the bottom of the cans.

Cylinder dipole  -  PA1B

Energy drink cans
The cylinder dipole, that is tuned to 15 m, but also works very good on 10 m, consists of two aluminium energy drink cans of 500 ml. The top and the bottom of the cans were removed. 
The two cylinders form the radiators of the cylinder dipole. The current on the surface of the cylinders, causes the radiation.
The coil has 9 turns and is wound on a PVC tube with a diameter of 80 mm. The taps are one turn apart. 
I have a lot of fun with this cylinder dipole in the shack at the first floor, 4 meter above the ground. This cylinder dipole can also be used on 20 m, with lower efficiency.

Parallel resonance
The cylinders show a large self capacity. This capacity is much larger than the capacity of a wire of the same length as the cans. The capacity of the cylinders and the induction of the coil form a parallel LC resonant circuit. The impedance of this LC circuit is high at resonance. 
Please notice, that this parallel resonance, is what makes the difference between the cylinder dipole and a dipole with very short wires.

Tuning
The cylinder dipole is tuned by choosing the number of turns of the coil.

Feed point
I made taps, at the center of the coil. The connection on the taps of the coil, form a feed point with low impedance, to which the 300 ohm twin lead is connected. The lower the number of turns between the taps, the lower the impedance will be. I had good results with the taps just ONE turn apart. 
Please notice, that because the taps are placed at center the coil, the ribbon will not radiate it self.

Matching
The cylinder dipole is matched (not tuned) by the symmetrical tuner in the shack. The tuner is adjusted to the lowest SWR. 

Multi band antenna
The cylinder dipole can be used as a multi band antenna, simply by matching the antenna to a SWR of 1:1 on the band that you want to use. That's all. 

Build - Work - Analyse 
I am curious about your results.

Quite a distance

The 15" cylinder dipole amazes me time and time again.

Today I was surprised by the cylinder dipole that is made of two  Monster  energy  cans  and a coil that hangs inside the shack, on the first floor. This antenna with a length of 15 inches, has proven before, that it is doing fine on 21 MHz. After a number of QSOs's with Russia and the Ukrain, I made a QSO deep in to Russia.

An hour before the end of the UBA DX contest, I met Alexander R0AA from Atsjinsk. (Ачинск) My paper notes states that the QSO was easy. (makkelijk). This was QSO number 16 in the contest.

Later I realized that R0 must be deep in to Russia. On the map I saw that Atsjinsk lays east of Kazakhstan and north of Mongolia. hi. The distance is 5223 km or 3245 Miles. WOW.

R0AA - PA1B - 5223 km  - Cylinder dipole 15" - 4 watts 

One coil and Two Monster cans
Really amazing. HI.

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.

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.

-------------------------------------------

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.

Tuning the cylinder dipole

Cylinder dipole PA1B

In the photo you see the cylinder dipole with open Monster cans. The cans are connected to the coil. I made radial cuts in the top and the bottom of the cans and I bent the points inwards. Later I pushed the white tube, which has a diameter of 40 mm, through the holes. The coil is hanging below the cans and the tube.
This coil has 9 turns on a PVC tube with a diameter of 80 mm. The distance between the cans is equal to the diameter of the cans and is 65 mm. The distance between the cans is not fixed, but can be made smaller by shifting the cans.

Measurement
On both sides of the coil I have attached a single turn, coupling loop. The loops are lightly coupled to the coil. One loop is connected with the RF generator. The other is connected to the oscilloscope.
It's very simple to measure the resonance frequency of the cylinder dipole. By adjusting the frequency, I just peak the signal on the oscilloscope to determine the resonance frequency.

Open cans

In this cylinder dipole I use open cans, because they show less capacity between the closed tops of the cans. This capacity does not contribute to the current on the surface of the cylinders.
The cylinder dipole with the open Monster cans and the 80 mm coil with 9 turn, resonates at 18.9 MHz. This is a higher frequency of the closed monster cans, which resonates at 16 MHz. The capacity of the open can is lower than the capacity of the closed cans and also because the cylinders are further apart.

I use the Cylinder Dipole on 21 MHz and 14 MHz as an indoor antenna in CW contests.

CQ WW WPX CW contest 2015 with an indoor 15" Cylinder dipole

Monster Cylinder Dipole PA1B

I had great fun in 56 QSO's with my
 Mønster  Cylinder Dipole in the CQ WW WPX 2015.  (Click on the picture to enlarge)

The monster antenna consist of  two
 Mønster Energy Drink Cans  
and a coil of 80 mm with 8 turns.
I determined the number of turns of the coil by experimenting.

This very short antenna has a wingspan of 15" or 38cm. "Indoor" results are best if you place the antenna as high as possible.

By making QSO's in a major contest, I could discover the properties of this very short antenna. All QSO's are made with CW and with S&P (Search and Pounce). As a low power enthusiast, I will reduce my power when the received signals get stronger.

On Saturday I worked with the Monster Dipole in  the shack, on a height of 4 meters above the ground. On Sunday morning I placed the antenna in the dormer window in the attic, on a height of 7 meters above the ground. 

Saturday
On Saturday I started on 14 MHz. Between QSO #3 and #4 we went to a fair. After working 6 stations all on 14 MHz, I went to 21 MHz.
The 15 meter band was open, so I made all QSO's on this band from 12 UTC until 19 UTC. From time to time I went back to 14 MHz, but with NO success.  After 19 UTC I could make just one QSO on 20 mtrs. After this QSO an other 16 QSO's were made on 15 m.
After 19 UTC the signal were stronger, so I could reduce my power. I  could make QRPp QSO's with 720 mW, 360 mW and even one QSO with 72 mW.

Miles per Watt
As a low power enthusiast, I reduce my power before answering a CQ, when the S-meter goes up.
It was great fun to make a QSO with 72 mW with YT6A, over a distance of 851 miles.
This QSO is good for 11820 Miles per Watt.

Thanks to Ranko with his sensitive station with Excellent Ears. FB.

Sunday
On Sunday morning I had time until 10 UTC. The first QSO was made with the Island of Man on 7 MHz. To work on 7 MHz I tune the SWR for 1:1. After breakfast I decided to move the Monster Cylinder Dipole to the attic, just to test whether I could make more QSO's on 14 MHz.The test is not conclusive, because I made the same number of QSO's at the same time as on Saturday.
Between 10 and 18 UTC we visited two birthdays. after 18 UTC I made a few QSO's.

Does it work?
The Cylinder Dipole definitely works.
Because I had limited time on Sunday afternoon, I can not tell whether the antenna works better on the attic on 14 MHz. But I can tell you that it works.

In the interesting table below I show the QSO's from hour to hour.
Please notice the peak in the propagation on Saterday from 19-21 UTC.
I worked 7 stations with  360 mW. But that was not all.

The QSO with 72 mW is years later, still the QSO with the lowest power on the Monster Dipole. Hi.

I am very pleased with results of the Monster Dipole.

CQ WPX CW 2015 with an indoor 15" Cylinder dipole PA1B

When did you make QRP QSO's with 20 DXCC counties on a indoor antenna with a wingspan of 38 cm or 15 inch? Hi.

Worked DXCC's in the CQ WPX CW 2015 with an indoor 15" Cylinder dipole PA1B

Cylinder dipole at 21 MHz

Monster Cylinder Dipole
Click on the pictures to enlarge

Monster Cylinder Dipole
 After the experiment with the Red Bull antenna, I built a second Cylinder Dipole with two Monster energy drink cans of 500 ml. The cans together with the coil resonate at 16 MHz.
The Monster Cylinder Dipole has a wingspan of 15" or 35 cm. Hi.

The 300 ohm ribbon is connected to the point at the top of the coil (in the picture) with the red and yellow alligator clips (See the white arrow in the top of the picture). The antenna is hanging from the ribbon. I can adjust the SWR 1:1 with my symmetrical tuner.


Cylinder dipole

PA1B Cylinder Dipole.  The current at the surface of the cylinder generates the field.

Closed Monster Cans  
In this antenna I use the complete can, without removing the top and the bottom of the can, to keep the construction simple and the cylinders strong. Closed cylinders are much stronger than open cylinders.

Monster cans
Although it is not easy to compare two antenna's, that were used in two different contests a week apart, the cylinder dipole with the 500 ml Monster cans is probably better than the Red Bull antenna.
In general the cylinder dipoles are very quite on receive, because of the small length of the antenna.

On the air
In the H.M. King of Spain contest I made QSO's on 7 MHz, 14 MHz and 21 MHz.
Most QSO's were made on 21 MHz with a power of 3.6 W to 360 mW all over Europe.
This Monster cylinder dipole with two 500 ml cans works better on 21 MHz than on 14 MHz.
The SWR of the antenna is adjusted with the symmetrical tuner.
On 7 MHz it was very difficult to make a QSO. The QSO's on 7 MHz were made over a short distance. NVIS. The low relative heigh at 7 MHz reduces the signal.

The table below shows the DXCC countries per band and per power category.

Across the Atlantic
I very much enjoyed the QSO with N1KWF in New Hampshire over a distance of 3490 Miles, with a power of 3.6 Watts.

Please notice that that the Monster cylinder dipole with 500 ml cans:
 * has a length of 15" (38 cm)
 * is placed in the shack,
 * at a height of 4 meter above the ground.

Click on the table below, to read the hand written notes.
In this way, I record the power that I use in each QSO, on paper .
The QSO data is logged in SD of EI5DI.

 

List of QSO's with the Monster cylinder dipolePA1B

The QSO's in red are more than 1000 Miles per Watt QSO's.

 

DXCC's per band and per power category PA1B