zondag 7 juni 2015

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

15" Indoor Cylinder dipole PA1B
I had great fun in 56 QSO's in CW with S&P, with 20 DXCC countries with an indoor 15" cylinder dipole. The antenna consist of two 500 ml energy drink cans and a coil of 80 mm with 8 turns.
By making QSO's in a major contest, I could discover the properties of this very short antenna.
On Saturday I worked with the antenna in  the shack, with the antenna 4 meters above the ground. On Sunday morning I placed the antenna in the attic, on a height on 7 meters above the ground.

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. Then I  could make QRPp QSO's with 720 mW, 360 mW and even one with 72 mW. When the S-meter goes up my power goes down.

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 divided to move the antenna 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 antenna 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.
When did you make QRP QSO's with 20 DXCC counties on a indoor antenna?

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

Solar Eclipse WPA of WSPR spots by PE4BAS

Solar Eclipse WSPR Propagation Analysis (WPA) of spots by PE4BAS.
The spots were made on 160 mtr, during daylight hours.
The lower the Lowest Possible Power, the better the propagation.

woensdag 3 juni 2015

10 dB attenuators of Stefano IZ1OQU

On my Blog and website I show information, on how I work with QRP and QRPp and the use of attenuators for more than 1000 Miles per Watt QSO's.

Stefano IZ1OQU built a 10 dB attenuator, that I described in an earlier post. (Click to read) With this attenuator Stefano made QSO's with 50 milliwatt in SSB from his home over more than 2000 kilometers, using vertical antenna's.

With a difference of 13 dB between SSB and CW, the 50 mW in SSB can be compared with 2.5 mW in CW.
Congrats to Stefano, for this great achievement.

Stefano has recenly built a light weight attenuator with two sections of 10 dB. He wants to use the attenuator in SOTA and portable operation.
Here is the interesting e-mail from Stefano with photo's of the light weight attenuator.

Dear Bert,
I'm IZ1OQU Stefano. I wrote to you some months ago for the attenuators on your website.
With the 50 mW of the first attenuator that I built, I had my best Miles per Watt SSB QSO's with Finland, Russia and Georgia, over 2200 kms with the top-score of 2700 kms with Georgia: 
54.000 kilometers per watt.

I'm writing again to show to you the new step attenuator that I've made: with switches and 2x 10 dB steps to reach the 5 mW output with my FT-817.
I attached some images of the new toy, made with pcb enclosure. I left one removable side just to shot some photos. You'll see, It's tiny (about 6x3x3 cms size) and low-weight. With that small space it was hard to solder everything but I did it!

I'll look forward to find ways to reduce again the size wile adding more steps but not before some testing: you know, SSB is not the best way to play MxW with such little power but I am still newbie with CW.

I keep following your blog, I shared it to some friends because they also like MxW, QRP and homebrewing things. The MxW comunity in Italy is slowly growing thanks to the WxM (watt per mile, or mile per watt... anyway we call it, it's the same thing) contest.
Go on with your good job

73 from Italy
Stefano IZ1OQU 

Light weight 2 x 10 dB attenuator IZ1OQU 
Stefano will use the attenuator on SOTA and portable operation. FB.
To read more, visit Stefano's interesting QRZ page by clicking on the link.

zondag 31 mei 2015

Cylinder dipole at 21 MHz

Click on the pictures to enlarge
After the experiment with the Red Bull antenna, I built a second Cylinder Dipole with two energy drink cans of 500 ml. The cans together with the coil resonate at 16 MHz.
The ribbon is connected to the point at the top of the coil with the red and yellow alligator clips (arrow in the top of the picture). The antenna is hanging from the ribbon. I can tune the cylinder dipole for the a SWR of 1;1 with my symmetrical tuner.

Closed cylinders
In this antenna I used the complete can, without removing the top and the bottom of the can, to keep the construction simple.
A week after the construction I saw a program on the construction of large cargo planes on the Discovery channel. They showed that closed cylinders are much stronger than open cylinders.
The same goes for the fuselage of very large cargo airplanes,
I discovered that the closed cylinders of this antenna radiate just as good as the open cylinders of the Red Bull antenna.

500 ml 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 cans is probably better than the Red Bull antenna.
In general the cylinder dipoles are very quite on receive.

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 cylinder dipole with two 500 ml cans works better on 21 MHz than on 14 MHz.
The antenna is "detuned" to 21 MHz 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. I estimate that the lower efficiency at 7 MHz reduces the signals with 10 dB.
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 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 log, in which I write down the power in each QSO.
List of QSO's with the cylinder dipole, with cans of 500 ml PA1B
The QSO's in red are more than 1000 Miles per Watt QSO's.
DXCC's per band and per power category PA1B

woensdag 20 mei 2015

Red Bull Test Antenna

When I putted the Red Bull test 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.
I was curious, whether I could use the antenna on 14 MHz, although it was tuned at 26 MHz in stead of 14 MHz.
Further I was curious, whether I could use a symmetrical tuner to get a SWR of 1:1

I clamped the PVC tube of the antenna between the books and the bookshelf and connected a 300 ohm ribbon 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
The tuning runs smoothly. It's 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 even better 28 MHz.. 

Does it work? Yes.
I convinced myself. Not with a power of 360 watts, but with 360 milliwatt. with the antenna indoor, at a height of 4 meter above the ground.  Isn't it 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 special station of the DX Club Tortoreto 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 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 second 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 dipole or inverted V and short antenna's. 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 test antenna to test the properties of symmetrical feeding, a few months before.
The test showed that when the cable is connected at the middle of the coil,
there is no hand effect on the cable.  The antenna lay around in the shack.

Was it properly tuned to the operating frequency? NO. I advice you to tune the antenna to the frequency of the band you want to operate on, to get a good efficiency.

Red Bull test antenna - May 2015  PA1B
Connecting the ribbon. One turn apart 

**  I don not intent to upset other HAM's, with this amazing 12 inch antenna, made from wast, ran with QRPp at a height of 4 meters and by doing so, also breaching the 1000 Miles per Watt boundary. **

zaterdag 2 mei 2015

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.

Please notice that the Cylinder dipole is NOT a joke, but a very short, attic friendly antenna.

Red Bull gives you wings 
This a a catchy one liner, I could NOT resist, LOL (But here it is a joke -  LPR and CER)

Test antenna
A few months ago I built an experimental cylinder dipole with Red Bull cans and a coil that works as an autotransformer to test an better way of feeding, in which the cable doesn't radiate and the cable has no hand effect.

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

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  They repeated my call immediately, but my exchange 001 never made it to Italy. Even when I increased my power to 3.6 W, the cracking ribbon spoiled the fun.

Indoor Cylinder dipole
Then I decided to try to use this test antenna and clamped it between the books on my book shelf.
I connected a 300 ohm ribbon between the coil of the antenna and the symmetrical tuner.
I tuned 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 test antenna could be tuned 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 and 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 Cylinder Dipole, with a power of 360 mW to 3,6 watts in the rest of the ARI DX contest.

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

Cylinder dipole 4 m above ground @PA1B's shack
The magic in the Cylinder Dipole lays in the large capacity between the two cylinders.

The capacity closes the circuit, 
is a better one liner. hi.

Auto transformer
The coil acts as autotransformer. The 300 ohm ribbon is connected to 2 point on the coil that are 1 turn apart. The coil it self has 14 turns. The voltage between the cans is 14 times higher than the voltage on the single turn in the middle of the coil.

Symmetrical feeder
The ribbon 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 reduce the hand effect of the ribbon. 

Connections, one turn apart

The Cylinder dipole

6 m WSPR analysis for Roger G3XBM

In his informative Blog, Roger G3XBM wrote about aircraft scattering of signals on 6 m.
I had the pleasure of making an analysis of the WSPR spots reported by Roger.

In WSPR the drift is measured over a period of 1 minute, so the drift is given in Hz per minute.
Recently I included Drift in my Excel spread sheet that I use to make an analysis.


  • The value in the table, such as  -4, is a spot with a drift of -4 Hz per minute.
    Positive drift means that the radio path is getting shorter and negative is longer.
  • The signals of M0MVB show spots with a drift of -2 and   3 Hz per minute.
    It is possible, that there is a flight paths involved in the spots with -2 and an other path with the spots of   3 Hz per minute.
  • The scattered signals with drift, sent by M0YOU are very strong, with a lowest possible power of 1 mW. The spot with no drift (0 Hz per minute) has a lowest possible power of 50 mW, thus is 17 dB weaker.
  • The signals of M0EMM show no drift. So it's possible that there is no airplane scatter here, but an other form of propagation, such as difraction. Notice that all these spots are made within one hour.
Thanks to Roger. FB.

A few day ago I wrote to Roger: See article
Hello Roger, 
This evening I took some time to make an analysis of a number of spots on 6 meter.
I took the most interesting spots for airplane scatter.
I hope you like it and can place it in your blog.
I left in M0EMM to show the difference. hi
Positive drift means the path is becoming shorter.

The spots of M0MVB shows spots where the path is becoming shorter (+3Hz per minute)
and spots where the path is becoming longer.   (-2 Hz per minute)
I just saw that the spots of M0YOU with scatter, are much stronger than the spot without scatter. 
The lower the lowest possible power, the stronger the signal.  
A lowest possible power of 1 mW is 17 dB stronger than 50 mW. hi.
I left in the spots of M0EMM, to show that there is no Doppler and the signals are not that strong.

Good luck in further analysis,
73, Bert PA1B

donderdag 30 april 2015

Opening van het zwembad Lobeke in Lopik

Gisteren werd het zwembad Lobeke in Lopik spectaculair geopend.
De opening geschiedde met medewerking van wethouder Johan van Everdingen.

Wethouder Johan van Everdingen
 Na het praatje van wethouder Johan, werd de taart voor de grootste groep van de aanwezige scholen uitgereikt.
Wethouder Johan, Wendy, badmeester Ben en Kees (mic)
De Zomergaard kreeg de taart voor aanwezigheid met de grootste groep.
Na het uitreiken van de taart aan moeder Wendy, was het tijd om de badeenden te beoordelen.

Er werden 25 prijzen voor de leukste of mooiste badeendjes uitgereikt.
Dit naar beoordeling van wethouder Johan.

De wethouder ging gekleed in eendenpak als eerste van de duikplank te water, gevolgd door de kinderen. Bekijk het artikel op de gemeente site. Click.

Opa en Zoe in het water
We hebben genoten.
Het evenement was goed georganiseerd en de presentatie was erg leuk.

zondag 5 april 2015

Lowest possible power

In WSPR analyses I use the lowest possible power to compare the signal strength of WSPR spots.
The lowest possible power is calculated from the transmitted power and the SNR of the receiving station. The lowest possible power is an excellent propagation indicator.

Click on the Tab: WSPR propagation analysis at the top of the Blog for a new explanation on the lowest possible power and a easy to use beatiful table.

Lowest possible power  -  Click to enlarge PA1B
I am proud at the beautiful table. hi.

zaterdag 28 maart 2015

K5MQ WSPR 100mW on 40 Meters (2)

Dave K5MQ has been running WSPR for 4 days at 100 mW output on 40 meters.

To show the behavior of the propagation from day to day, I made a overview for four days.
This analysis uses the same data as Blog entry of yesterday, but also shows the relative signal strength of the received signal.

Horizontally you find the time in UTC in blocks of 1 hour.
Each rectangular black block indicates an hour, in which one or more spots occurred and the calculated lowest possible power of that spot(s).
Vertically you find the lowest possible power, which is a good indication of the signal strength.

The lowest possible power is calculated from the power of the sending station and the SNR of the receiving station. The higher the SNR, the better the propagation and the lower  the lowest possible power.
The lower the lowest possible power, the better the propagation.        

Please notice, that not all patterns in this propagation diagram,
can be easily recognized and can be easily explained. hi.
Propagation diagram. K5MQ WSPR on 40 m with 100 mW.
Propagation to WB5WPA over 500 km
Dave 's signal was received by WB5WPA over a distance of 500 km at 13 utc on the 24th with a calculated lowest possible power of 1 milliwatt.
From 13 utc on the signal becomes weaker. At 18 utc the signal is 10 dB weaker.
From18 utc to 1 utc on the next day, the process is reversed.
At 1 utc the signal has the same signal strength as at 12 utc of the previous day.

For the distance of 500 km we can see, that when the signal is reflected
in the ionosphere, the propagation is immediately at it's best. 
From that moment, the signal will be weaker, until the process is reversed. 

Propagation to N8SDR over 1100 km
On the 24th we see the same pattern in the propagation, but this time throughout the night, between 3 utc and 10 utc. At 3 utc the signal suddenly appears and is immediately very strong . Than rapidly becomes weaker (16 dB) and than gradually becomes stronger again, to reach the highest value at 10 utc.

Electrical field strength
Dave noticed that K9AN at a distance of 1003 km copied his 100 mW throughout the daylight hours, many times.  And that he must have a great receiver there.
To compare the signals of the different stations I made an analysis of the received signals by the Electrical field strength in micro Volt per meter.
The analysis below shows that K9AN, N8SDR and KE7TYT received Dave's signal with the same field strength. hi. The difference between each of the columns is 5 dB.

A calculated lowest possible power of 1 milliwatt means that a signal of 1 mW,
could be received with a SNR of -29 dB.

vrijdag 27 maart 2015

K5MQ WSPR 100mW on 40 Meters

Dave K5MQ reports on his blog, that he has been running WSPR for 4 days at 100 mW output on 40 meters.  He wanted to try lower power on 40 meters, than he did on 160 m.

The analysis shows the stations, that spotted Dave for 3 days or more.
Under UTC you find the number of spots from hour to hour.
E.g. K9AN was spotted 3 times on 2015-03-22 between 23:00 and 23:59 UTC

Futher, I also chose to show two stations with the largest distance.
KL7L from Alaska and EA/LA3JJ from Spain.

WSPR spots of Dave K5MQ on 40 m with 100 mW

donderdag 19 maart 2015

Peters QSO's with 5 milliwatt

Are you curious how Peter DL3PB made these amazing QSO's, with an 
All diode transceiver with just 5 milliwatts on 15 meter, then read this
informative e-mail from Peter.

Hello Bert,
Glad to hear from you and thank you very much for posting my latest milliwatt results on your blog and the kind comment - I like especially the stamp-sized logos for each entry – nice work.

The original version, as posted in February 2012 ( was 2 mW / 20m band ) allowed some minor DX
e.g. EA8 or 5B4, but within three years,  I could not make a single contact beyond the usual one-hop distance.

Finally I came to understand, how the efficiency of the parametric VXO could be improved:
all I had to do, was to insert two small inductors in series with the varactors
once you got it, it’s all so easy...with now 5 mW on 15m band some real DX leaped into view.

Not sure, whether it’s about the somehow higher power now or the different band,
The more or less first serious attempt in the Black Sea contest was rewarded with a
first transatlantic QSO with Randy/N1KWF and the ARRL-DX contest two weeks later,
was good for another one into NJ with John/W2ID at 6050 km.
John had lot of fun with my exchange ( 599 001 ) and replied with something like 
hi ur pwr 1W fb” –
I didn’t dare to tell him the truth, because of the heavy QSB.
These two OMs must have excellent ears and actually they did most of the work.

I’ve attached a schematic (Click) with a better resolution ( .bmp ) than that on QRZ.com,
but of course it’s up to you, whether or not you want to post that, which will require to edit the text a bit.

Will make some more photos, when I got it into an enclosure, but that will take some time, the TRX
is still under construction and I want to maintain its multiband capability, so far I’ve tested 17m and 15m, but 12m should work as well, but that requires careful planning.

Again, many thanks, Bert – keep your great blog going.

Tot ziens!


zaterdag 14 maart 2015

Pi Day

Pi = 355 /113

As a teacher in electronics I use this accurate fraction for Pi,
when I use a calculator without a key for Pi.
I have been looking for a fraction with one or two prime numbers.
I came up with 113 as divisor, which is a prime number.

The numbers are easy to remember.
The accuracy is better than one millionth. 10-6.

maandag 2 maart 2015

5 mW All diode TRCV crosses the pond

This winter Peter DL3PB built a new version of an
"All Diode" transceiver, the Paraski.
The new transceiver works on 15 meter and has an output of 4...5 mW

For Peter a dream comes true, by crossing the pond with milliwatts.
Peter  made a few QSO's with 5 mW, into an EFHW vertical on 15 m.

Peters rig has only diodes in the amplifiers and oscillators.
It's amazing, even for a milliwatter as myself. WOW.

Please visit the QRZ page of Peter (Click) to look at the schematic and a photograph 
of the Parasaki for 15 meter.

Data on the drawing:
PWR OUT 4...5 mW

See the post of the 8th of February 2012 in this Blog,
for the 20 meter, 2...3 mW, Parasaki, all diode transceiver built in the winter of 2011 by Peter.

zondag 1 maart 2015

UBA DX contest 2015

This weekend I participated in the UBA DX contest.
The conditions were not very good , but I still made 27 QSO's with S&P in CW.
I could make 1 QSO with less than 100 mW, 3 QSO's with 800 mW.
The rest of the QSO's was made with 3 or 4 watts.

Rigth at the start, I heard YT1A.
Vladans signal was very strong, so I reduced my power.
With the FT-817 set to 800 mW and with the "PA1B 40 dB step attenuator" set to 10 dB,
the power to the antenna is reduced to 80 mW.
With a distance of more than 900 miles, this results in more than 11000 Miles/Watt.
This was the only QSO with less than 100 mW in this contest.

After that I made QSO's with 800 mW to 4 watts.
The FT-817 here gives less than 5 watt with full power, after a serious mismatch.
This is less than 4 watts on 14 MHz or less than 3 watts on 21 and 28 MHz.

The ribbon of the Inverted V is not yet repaired.
As long as there is no wind, all is OK . See the post on the PACC 2015 Click.
But with a wind force of 6 on the scale of Beaufort , it was not always easy. hi.