Booster in HA DX 2024

Booster - Cylinder dipole

The HA DX contest is a contest with much activity. So I decided to work with my indoor Booster Cylinder Dipole. As a low power enthusiast I always work with QRP or QRPp (less than 1 W) when possible. The stonger the received signal, the lower the power can be. The Booster hangs in the Dormer Window.

The table shows the 17 QSO's that I made on 21 MHz.
21 MHz worked more easily than the other bands. Hi.
Further only one QSO on 14 MHz was made.

PA1B in HA DX 2024 with QRP on 21 MHz
Booster Cylinder Dipole - Wingspan 55 cm

Booster
The Booster is a cylinder dipole. The two cylinders, are each made from 6 Energy Booster cans from aluminium, that are cut open and bolted together.
Click for details >>

The Booster in the dormer window (dakkapel) PA1B

Taps on the coil. One turn apart. PA1B

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 >>

Cilinder dipool met koffieblikken

In september 2019 heb de NVRA in Haarlem bezocht voor het geven van een lezing over de cilinder dipool. Tijdens de lezing vertelde ik dat de afmeting van de cilinder dipool evenredig met de golflengte vergroot moet worden, om te werken op een lagere frequentie. Na de lezing heb ik twee voorraad blikken voor koffie meegekregen voor een cilinder dipool voor 7 MHz. Daar heb ik begin dit jaar een cilinder dipool mee samengesteld. De spanwijdte van de dipool is 60 cm. (0.6 meter).

PA1B Cilinder dipool 24" met voorraad bussen (60 cm)

Deze cilinder dipool met forse cilinders is veel groter dan de andere cilinder dipolen zoals de Monster cilinder dipool en is (daarom) geschikt voor 40 meter. Deze cilinder dipool voor 7 MHz heeft een spanwijdte van 60 cm. Dit is slechts 3% van de spanwijdte van een halve golf dipool voor 7 MHz. Echter deze cilinder dipool werkt en past met gemak in mijn dakkapel. Zelfs een cilinder dipool voor 80 meter met de dubbele afmeting zou er nog net in passen. hi.

Ik heb met deze cilinder dipool in de dakkapel QSO's gemaakt met 4 Franse stations tijdens de REF contest op 7 MHz alle 4 met 980 milliwatt.

Op 14 MHz werkt deze antenne ook heel goed. In de HA-DX contest heb ik QSO's gemaakt met slechts 360 milliwatt. 

eQSL van F5KHP in de REF contest
op 7 MHz met 980 mW 

De opbouw van de cilinder dipool is zeer eenvoudig.

De cilinder dipool kan zo'n kleine spanwijdte hebben, door de grote onderlinge capaciteit van de twee cilinders. Een spanwijdte van 3% van die van een halve golf antenne geeft goede resultaten.

Not really a DX QSO with the Booster

In the PACC 2016 I used a new cylinder dipole, that I had build shortly before. I built the Booster to experiment with larger cylinders and a larger coil. To work on 7 MHz and 14 MHz.

Booster in the PACC  2016  

In the PACC contest of 2016 I made a total of 32 QSO's with the Booster.
25 QSO's were made on 40 m with 3 W and 2 QSO's with 150 mW.
On 20 m I made 5 QSO's with 4 W.

I had no intention to make hundreds of QSO's, but on that moment I wanted to know, how the new Booster would work. 

Read more about the Booster Cilinder dipole >>

eQSL of PA0AA

Recently I received an eQSL of the QSO, that I made with PA0AA over a distance of aubout 10 miles. Not a real DX QSO, but still a very nice QSO. 

eQSL of the QSO with the Booster Cilinder Dipole - Wing span 22"

 Thanks to Veron afdeling Centrum A08.

Cilinder dipool met koffieblikken

Bert PA1B tijdens de lezing

Vorig jaar heb de NVRA in Haarlem bezocht voor het geven van een lezing over de cilinder dipool. Ik was uitgenodigd door de voorzitter Arnold Vogelaar.
Voorafgaand was nog even naar Kraantje Lek in Overveen gereden. Daarna ben ik doorgereden naar Haarlem. Omdat ik zeer vroeg was, had ik alle tijd om de antennemast te bewonderen.

In de lezing staan mijn ervaringen met de cilinder dipool met Monster Energie drank blikken centraal. Met deze cilinder dipool heb ik vele QSO's gemaakt op 21 MHz. En ik niet alleen. Alex SA5BFZ heeft op mijn aanwijzing een zelfde cilinder dipool gemaakt. Wij hebben daar beide zeer mooie QRP en QRPp QSO's gemaakt - met de antenne binnenshuis op de eerste verdieping.
Lees het artikel: Cylinder dipoles on 10 meter

Na het verhaal over deze antenne voor 21 MHz, met een spanwijdte van slechts 35 cm (15 inch), vertelde ik dat je voor een lagere frequentie, grotere cilinders moet gebruiken. Dit om een goed rendement te behouden. Want ook voor de cilinder dipool geldt: Des te groter de afmeting, des te lager de frequentie. Daarbij verwees ik naar een paar grote koffieblikken, eigenlijk voorraad bussen, die ik op de kast bij de bar had zien staan.

PA1B Cilinder dipool 24" met voorraad bussen

Toen de lezing afgelopen was zei Arnold: "Bert we hebben nog een cadeau voor je". En je raadt het al, Ik kreeg twee grote voorraad bussen mee. De bussen hebben een lengte en een diameter van 25 cm. (10 inch). De blikken hebben eerst een tijd in de shack gestaan. Maar een paar uur voor de HA-DX contest besloot ik, om de blikken tot een cilinder dipool om te toveren. Het mooie van onze hobby is dat je onmiddellijk je bouwsel kan uit proberen, door er QSO's mee te maken.
De afmeting van de voorraad bussen is zo veel groter dan de afmeting van de blikjes van de Monster Energie drank, dat deze cilinder dipool uitnodigt om te werken op 14 MHz en op 7 MHz.

PA1B Cilinder dipool 24 " met voorraad bussen

Ik ben begonnen met in elke bus een gat in de bodem te maken. De bussen zijn van blik en daardoor is een waarschuwing wel op zijn plaats. Wat geknipt blik is loei scherp. Ik dacht dat ik er ongeschonden uit zou komen. Maar ja. . . halverwege de bouw zat er toch in eens bloed aan de cilinders. Oeps. Zonder het te merken had ik toch een ijzer splinter in mijn vinger gekregen, die er pas 1 februari uit kwam.

De lezing werd zeer gewaardeerd. En het was heel gezellig.
Ik bedank de NVRA voor de zeer genoeglijke avond en de voorraad bussen.

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

Cylinder dipole in CQ magazine

Cylinder dipole in
CQ Magazine

In the CQ WW WPX CW contest 2016 I used two indoor cylinder dipoles. After I sent in my log for the CQ WPX, Terry N4TZ noticed my soapbox. Terry asked my to send in a picture of my cylinder dipole to include in the write up of CQ Magazine. I thank Terry for the nice and beautiful write up.

Click to read

The CQ WW contests generate a lot of activity.
I use contests to make QSO's with very low power.
And. . it is good opportunity to test your antennas.


Soapbox PA1B in CQ WW WPX CW 2016
X-RADIOS:           FT-817
X-ANTENNAS:    Cylinder dipole
SOAPBOX:            I had great fun with QRP and two cylinder dipoles
SOAPBOX:           On 20m I made 3 QSO's and on 15m 4 QSO's with a 15" cylinder dipole 
SOAPBOX:           On 40m I made 3 QSO's with a 22" cylinder dipole 
SOAPBOX:           The PA1B cylinder dipole consists of two cylinders and a coil
SOAPBOX:           The coil acts as a impedance transformer
SOAPBOX:           The QSB and the good activity, did not make it easy to answer CQ's - hi
SOAPBOX:           Thanks for the activity in the contest

PA1B with cylinder dipole in CQ Magazine

The cylinder dipole shows a large capacity between the cylinders.
Although the coil and the capacity  are tuned to the band of interest, the cylinder dipole can be used as a multi-band antenna. Two taps at the center of the coil provide a low impedance feeding point to connect the twin lead.  Match for a SWR of 1:1 with your symmetrical tuner.

  Energy  Booster  cans or not, a cylinder dipole will radiate better than a wire dipole of the same length.

Thank you, Terry for the very nice write up. 

Cylinder dipoles in the UBA CW 2016

In this UBA DX contest I experimented with  the new built Booster cylinder dipole.

Wingspan 55 cm
The Booster antenna is called Booster, because each cylinder is made out of 6 Energy Booster cans, that are cut open and bolted together. The length of the cylinders is 22 cm (9") and the wingspan of the antenna is 55 cm (22")
The booster is hanging in the dormer window at the second floor. The coil is wound on a 110 mm PVC tube and has 15 turns. The Booster resonates on 10 MHz.

The Booster - One cylinder is made of 4 cut open cans - PA1B

It took my a long time to discover the right setting of the tuner for the Booster on 20 m. At first I could not get a good matching at all on 20 m. The SWR was too high. At the end of the contest, I discovered the right setting for the tuner to get a SWR of 1:1  This is the setting that I always use on 10 m, with the inverted Vee. hi.

The Booster - Wing span 22" - PA1B

The table below shows the QSO's in chronological order.

Booster on 20 m 
The table shows that in the first 5 QSO's, I used the Booster on 20 m. The Booster is longer than the Monster, so I expected much of the Booster on 20 m. But I could not get a SWR of 1:1.

Taps at the center  - ONE turn apart - Click to enlarge

Monster (35 cm) on 20 m
After 5 QSO's, I was a bit disappointed. Just to make some QSO's, I decided to switch the shorter Monster energy can antenna, which is located in the the shack, also on 20 m . This antenna is easy to match. I could easily make two QSO's with UA.

Booster on 40 m

On Sunday morning I went to 40 m. I started with the twin lead two turns apart. I ended up with the twin lead connectors ONE turn apart to get a SWR of 1:1 

Monster on 15 m

The monster is doing fine on 15 m. A total of 8 QSO's were made on 15 m. The signals in QSO number 14 were very strong so I reduced to 800 mW.
QSO number 16 was with R0AA over a distance of 5200 km and was very easy to do.
<<  Read the details of the  QSO with R0AA >>  Click

Booster again on 20 m

My experimenting payed off. I found out by desperately playing around with the tuner, that I had to use a very strange setting of the tuner to get a SWR of 1:1   - Finally I got the Booster working on 20 m. With this setting the last two QSO's were easily made. hi.

UBA CW - Booster - Monster - PA1B

Wat een gein

De blikjes komen van de straat. Ik drink het niet zelf.

 Energy Booster  is verkrijgbaar bij Trekpleister voor 39 Eurocent.

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 dipole in PACC

Booster - Cylinder dipole 22"

In the PACC I used a new cylinder dipole, that I have build recently.
I built the Booster to experiment with larger cylinders and a larger coil. To go below 15 m.

The  Booster  has two cylinders, that each are made
of 4  Energy Booster  cans of aluminium, that are cut open and bolted together. The length of each cylinder is 22 cm. The wing span of the dipole is 22 inches. The coil former has a diameter of 110 mm and the coil has 15 turns. The taps are two turns apart. The Booster resonates at 10 MHz.

The cylinder of 4 cans PA1B

On Friday I made the coil and just before the contest I made the taps on the coil. During the contest I used the taps that are two turns apart. The Booster could not be MATCHED with the taps 4 turns apart. I suspect that the impedance on the end of the twin lead in the shack is too low, or too high, for my symmetrical tuner. So I switched to the taps that are 2 turns apart. I later realized that I did not try taps that are one turn apart.

I started with checking the MATCHING of the Booster on 15 m, 20 m and 40 m. Matching on 15 m and 40 m is very easy. Matching on 20 m is difficult.

Before the PACC, I made the first QSO with the   Booster   on 40 m, with 7S6WRD from Sweden. My RST was 339. hi. Not a very strong signal, but it works.

PA1B in the PACC 2016 

PACC    

I made a total of 32 QSO's with the Booster. 25 QSO's were made on 40 m with 3 W and 2 QSO's with 150 mW. On 20 m I made 5 QSO's with 4 W.

I had no intention to make hundreds of QSO's, but I wanted to know, how the Booster would work. 

Saturday

On 15 m and 20 m there was no activity, So I started on 7 MHz. The first 3 QSO's were made with 2 Dutch stations (PA) and with F5IN, all with S&P. Then I stopped to visit some friend.

Around 17:00 utc, I started again on 40 m. I decided to give CQ. To my surprise, I was visited by stations from DL, HA, OE, OK (4), SM and UA (3). I was pleasantly surprise by the stations from Russia that answered my CQ, over a distance of more than 1300 miles.

Sunday

Sunday morning on 40 m gave a mix of stations from PA and DL. When the propagation peaked, I could QSO with PI4CC and with DL5JQ using just 150 mW. WOW. But in the next QSO's I needed a power of 3 watt. hi.

At about 11 utc I went to 20 m and made 5 QSO's with 5 DXCC countries, all QSO's with 4 W.

During the contest I frequently went to 20 m and 15 m. Most activity was on 40 m, as you can see in the table.

The Booster is doing fine on 40 m and 20 m. I worked 10 DXCC countries from the dormer window with the Booster at a height of 7 meters above the ground.

Cylinder Dipole by PA1B  -  Taps two turns apart
Click to enlarge

Cutting the cans  -  Mooi schaartje hè.

Click on the pictures to enlarge.

QRPp QSO with the Booster

In the PACC I tested a new cylinder dipole - The Booster. I tested on 7 MHz and 14 MHz with 3 or 4 watts. I use my cylinder dipoles as indoor antennas. I placed the Booster in the dormer window.(dakkapel).

As a milliwatt enthusiast, I enjoyed to make 2 QSO's with QRPp, which is less than 1 W.
When the propagation peaked on Sunday morning, I heard PI4CC, with a very loud signal. S9⁺⁺.  I reduced to 150 mW, before answering their CQ and made the QSO. In the next QSO with Erhard DL5JQ, I also used 150 mW. His signal was also very strong, S9⁺⁺. In the next QSO I first tried 150 mW, but I needed the full power of 3 watts to be heard. hi.

Yesterday I answered the eQSL of this very special QSO, with Erhard DL5JQ. After answering the eQSL,  I have sent Erhard an email via eQSL to inform him of my power and my antenna.

Hallo Erhard,
Fabelhaft!! Dein Signal war sehr stark. S9⁺⁺. Ich habe in unserem QSO, einer Leistung von 150 mW verwendet. QRPp. Ich bin ein begeisterter Milliwatter. Wenn die S-Meter nach oben geht, geht meine Leistung nach unten.

In diese PACC habe Ich einen Zylinder Dipol versucht. Meine Antenne ist eine zylindrische Dipol in der Dachgaube. Die Flügelspannweite beträgt 55 cm. Informationen über die Antenne:
http://pa1b-qrp.blogspot.nl/2016/02/the-booster.html
Aber schauen Sie sich auch, das Etikett Cylinder dipole an.

Dank für das nette QSO. Ich hoffe du nächstes Mal zu treffen, mit niedriger Leistung. hi.
Mit freundlichen Grüßen,
Bert PA1B

DL5JQ  - 40 meter  - 150 mW  -  Booster

OK dear Erhard, thanks for the nice QSO and eQSL.

The Booster

First light for the Booster (hi)

The Booster is a cylinder dipole. The two cylinders, are each made from 6 Energy Booster cans from aluminium, that are cut open and bolted together.

Cutting the Energy Booster cans. Click to enlarge

I built the Booster to experiment with larger cylinders and a larger coil to work on 14 MHz and 7 MHz.

The Booster has twice the size of the Red Bull antenna.

The length of each cylinders is 22 cm. The wing span of the dipole is 22 inches. The coil former has a diameter of 110 mm and the coil has 15 turns. The taps are two turns apart.

The Booster resonates just above 10 MHz.

Giving CQ on 40 m with just less than 3 W on the Booster, resulted in contest QSO's with  DL (1), HA (1), OE (1), OK (4), SM (1) and UA (3)

The Booster in the dormer window (dakkapel) PA1B

Taps two turns apart. PA1B

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

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

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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.