zondag 12 maart 2017

G4EFE WSPR with 5 mW on 40 m

Martin G4EFE is an enthusiast milliwatt WSPRer.
I curiously follow the WSPR adventures of Martin in which he uses very low power.
Here I show new analysis of the spots that Martin made with a power of 5 milliwatt on 40 m with a full-size 40 m square loop.

The table shows the number of spots over a three day period, from day to day and hour to hour.
From the used power of 5 mW (in all spots) and the SNR, I calculated the lowest possible power.
A spot with a SNR of -28 dB is a "solid copy" in WSPR. So when, for instance, the SNR is -18 dB, the signal is 10 dB stronger and could have been 10 dB lower and still give a solid copy, with a SNR of -28 dB.
The better the SNR, the stronger the signal and the
lower the calculated lowest possible power will be.

In the spots that were received by F6EHP, you can see the development of the propagation from hour  to hour. You can see that the signal peaks at 9 UTC at 3-2-2017. The strongest spot could be made with a power of 0.1 milliwatt. This is also the strongest spot in this table.

Martin uses his IC703 and an attenuator to make a power of 5 milliwatt. His antenna is a full-size 40 m square loop. As I saw on WSPRnet.

zaterdag 11 maart 2017

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

woensdag 8 maart 2017

UBA DX CW 2017

I was looking forward to participate in the UBA DX CW contest with QRPp. This is a very nice contest with a lot of activity. I found out that my End fed antenna is working fine. This time I also made a few QSO's on 7 MHz. I discovered that I had to use a longer twin lead on 7 MHz than I use on 14 MHz. I made most QSO's on 14 MHz using QRPp. Click to see my End Fed with a twin lead feeder.

I came back home late, so I made 1 QSO on 14 MHz and 3 QSO's on 7 MHz on Saturday.
On Sunday I made 23 QSO's with 360 mW and 7 QSO with 800 mW to 3.6 Watt.

UBA DX CW contest 2017 - PA1B
Numbers in red are more than 1000 Miles per Watt
I am very pleased that I could make that many more than 1000 Miles/Watt QSO's.
I ran the FT-817 without the attenuator.
The lowest power of my FT-817 is 360 mW, after a serious mismatch.
But as you can see, this low power is still working fine most of the time. Hi.
20 m UBA DX CW contest 2017 - PA1B
Numbers in red are more than 1000 Miles per Watt
All QSO's were made with Search & Pounce (S&P).
I only increase my power when I am sure that my low power signal is not heard.
40m UBA DX CW contest 2017 - PA1B
Using low power not that difficult and is great fun.

woensdag 1 maart 2017

ARRL int DX CW 2017

I was hoping to make QRPp QSO's in the ARRL international DX CW contest 2017. I did not make many QSO's, because I had very limited time on both days. But I did enjoy the contest very much.
A week ago I made an End fed antenna to work in the PACC. The antenna is sloping down to the east, so I was curious how the End fed would do to the west. I am not disappointed.

Because I was away for most of the day, I started late on Saturday on 14 MHz.
In the first 3 QSO's I had to use 3.6 W and 1.8 W. After that I could reduce to 800 mW.
When the band closed on Saturday evening, I had made 11 QSO's all with Search and Pounce (S&P). The signal of K1ZZ was very strong, so I reduced to 360 mW before answering his CQ.
The response was immediately correct.

When I started on Sunday I could hear European stations. On 14 MHz I could only hear stations that I had worked before on Saturday, so I went to 21 MHz. On this band I could work 6 stations all with just 800 mW, as you can see in the table below. I could work with W3LPL with 360 mW. His response was also immediately correct. hi.

ARRL int DX CW contest 2017 PA1B
Numbers in red are "more than
1000 miles per watt QSO's"
599 001      001?
Working with QRP and QRPp is great fun.
In the ARRL DX CW contest the DX stations like myself give their power in the report.
When I reduce to less than 1 watt, I will give the report 599 001.
This report can create some confusion. When I use 3.6 W I will give 599 004.
I will give 599 001, when I use a power of 800 mW, but also with 360 mW.
One operator was quiet for one full second after receiving my 599 001, before he realized that my power was about 1 W.  Hi.

Excellent ears
When I met K5ZD and N1TA, their  signals were not that strong and the QRM was increasing. I was really surprised that they could hear my 800 mW at all. But we could complete the QSO with no trouble at all. FB. Probably they had less QRM than that I had.

End fed
I am very pleased with my End fed. It works fine to the east and to the west.

vrijdag 24 februari 2017

PACC 2017

In the PACC 2017 I made 51 QSO's. In most QSO's I used 800 mW by giving CQ or by using S&P.  The 20 m was good for most of the QSO's.
Friday before the PACC I made an End fed antenna with about 20 meters of wire. Just as my holiday antenna's the wire is feeded via a twin lead that acts as counter pose and impedance transformer. I applied linear loading to make the wire fit in my garden. This antenna is a great success.

Inside Europe I could make QSO's with QRPp running with just 800 mW. With 800 mW all QSO's over a distance of more than 800 miles (1280 km) are good for more than  1000 miles per watt. After the contest I counted 38 QSO's with more than 1000 miles per watt in my log.
The power of 800 mW was not enough in every QSO. I had to increase my power to 3.6 W, to work K6ND and P3YA and a few other stations.

The antenna is a great success.  I could run with QRPp with a power of 800 mW.

As a milliwatt enthusiast I often use the lowest possible power from QSO to QSO in other contests. Then I use Search and Pounce. (S&P) But when I give CQ, it is more difficult to copy the call than when I use Search and Pounce. Most of the time I must hear the call twice to copy the call. 
I enjoyed meeting operators that were patient. FB.

woensdag 15 februari 2017

Auxiliary antenna for the PACC

At first I did not think about contesting at all, because my inverted V is damaged. In the summer I had great fun with my cylinder dipole with Monster cans on 15 m with a power of 3 watts.

When I was on the Veron club meeting, I heard that the avid contesters were preparing for our annual contest from the Netherlands, the PACC. So I also got inspired to participate.
But with what kind of antenna?

I did not want to use the indoor cylinder dipole with Monster cans. Because of it's low height of 4 meter above ground level, a power of 3 or 4 W would be needed. And with winter propagation, it is not even sure, whether the 15 m band will be  open.
But most of all I wanted to participate with QRPp on 20 m.

End fed wire
So I begun thinking about an outdoor antenna. With more height I can use less power. To limit the activities on the roof, I came up with an end fed. I had a wire that was too long. But I decided to put it up and see. So on Friday afternoon before the PACC I ended up with this end fed.
End fed with twin lead feeder. PA1B
To get the power into the wire, without radiation in the shack, I use 300 ohm twin lead. The  twin lead also acts as an impedance transformer. I always use a tuner with my antennas. So whatever the impedance at the end of the wire may be, as long I can adjust the SWR to 1:1 it's fine with me. The twin lead has to be long enough to tune. A twin lead of 4 meters works fine on 14 MHz.
I use this type of feeding by twin lead for all my end fed holiday antenna's since 2001.

donderdag 9 februari 2017

G4EFE WSPR with 5 mW on 40 m

WSPR is a beacon system that is designed for low power. How low can you go?
Martin G4EFE ran WSPR with very low power.

Martin G4EFE wrote after experimenting with 1 mW, using his attenuator of and 20 dB:
So I've had a little time for some experimentation, and the results - I think - are spectacular. Attenuating the output to just 1mW netted me several spots from neighboring countries. 
Best DX was GM* at 711km, who reports me at -18b dB SNR, suggesting I can go even lower.
So today I'm running just 100 MICROWATTS. I can't believe anyone will spot me, but I'm the optimistic kind! Thanks again, Bert, for this easy and fun station accessory. 

The map, the tabel for 1mW and the picture of the beautiful attenuator can be found here: https://www.flickr.com/photos/71155570@N00/albums/72157679958156316
OK Martin, thank you for sharing this fine info.

5 mW down to 1 mW
Martin started with 5 milliwatt for three days, as you can see in both tables. On the 5th the power was reduced to 2 milliwatt. On the 6th Martin had great fun in 21 spots with just 1 milliwatt.
To make a power of 1 milliwatt Martin uses his IC703, at it's lowest setting with 100 mW and an attenuator of 20 dB. His antenna is a full-size 40 m square loop. As I saw on WSPRnet.

From hour to hour
In the table below you can see the number of spots in each hour.
The days go from the bottom to the top.
The number of spots vary from day to day. this is not only propagation.
Martin is constantly transmitting, but the listeners can be jumping from band to band.
G4EFE WSPR with 5 mW down to 1 mW - From hour to hour
The best DX from GM*with a SNR of -18 dB, that Martin refers to, gives a calculated lowest possible power of 0.1 milliwatt. This spot could be made with 0.1 mW and still be a solid copy with a SNR of -28 dB. See the spot in the red circle in the table below.

G4EFE WSPR with 5 mW to 1 mW, using an attenuator
The better the propagation, the better the SNR will be and the lower the Calculated lowest possible power. The Calculated lowest possible power is calculated from the power and the SNR.

donderdag 19 januari 2017

Attenuator for the FT-817 by G4EFE

On my Blog post about the Power attenuator for the FT-817, that I published in SPRAT, I got a very nice comment from Martin G4EFE.

Martin writes:
Hi Bert - I just built this into a tiny 25x25x50mm metal enclosure. Of course, it works great.
Looking forward to some QRPp WSPR from the IC703.

Attenuator built by Martin - G4EFE
As you can see, the attenuator is built in a beautiful, small enclosure.

The maximum power of the attenuator is about 1.5 W. With a derating of 33% the nominal power of the attenuator is 500 mW. I advice to use the lowest power setting of the transceiver. For my FT-817 this is  500 mW.
Martin will use a IC703. This transceiver can make 100 mW at it lowest setting.

Thank you Martin for sharing the info and good luck in QRPp.

vrijdag 6 januari 2017

Jan Weissenbruch 1822-1880

Van de week heb ik een bezoek gebracht aan de prachtige tentoonstelling van schilderijen van Jan Weissenbruch die te zien was in het Teylersmuseum te Haarlem.

De site van het Teylersmuseum vermeldt:
Jan Weissenbruch is een van de meest eigenzinnige Nederlandse kunstenaars van de 19de eeuw. Met felblauwe luchten en heldere lijnen bracht hij de oude poorten, stadsmuren en huizen in beeld die in rap tempo werden afgebroken om plaats te maken voor de moderne tijd. Met een romantische liefde voor het verleden legde Weissenbruch het verdwijnende oude Nederland vast, maar hij deed dat met een fotografische scherpte en een realisme die ultramodern waren.

Zelf vind ik het fantastische kleurgebruik, het durven afsnijden van de onderwepen door het kader en het oog voor detail bijzonder mooi. 

Oplettende lezertjes herkennen in dit schilderij de linker foto in de derde fotocollage uit mijn Blog verhaal: Kanoën naar IJsselstein
De IJsselpoort is in 1852 afgebroken maar het water, de brug en het brandspuithuisje rechts zijn er nog steeds.
Weissenbruch maakte schetsen, waarop soms details ontbraken, die hij later uitwerkte in een prachtig schilderij. Dit verklaar mogelijk het verschil tussen het brandspuithuisje in het schilderij ten opzichte van de foto. Tel de treden van de trapgevel maar en kijk naar de ramen. Hi.
Maar het blijft een prachtig schilderij.
Een trekschuit vaaart langs de IJsselpoort in IJsselstein 1852  -  Jan Weissenbruch
Brandspuithuisje uit 1622
gezien van uit de kano
De tentoonstelling toont prachtige schilderijen, is mooi ingericht en is zeker de moeite waard om te bezoeken.

zaterdag 31 december 2016

Best wishes for 2017

Best wishes for 2017

Best wishes for 2017

Blik over het weiland naast de oprijlaan naar Rhijnauwen. 
Door de mist heeft landschap een sprookjesachtige aanblik gekregen.
De dooi had al ingezet, waardoor het onder de bomen zeer licht leek te sneeuwen.
De bomen zelf waren nog steeds prachtig wit.

Weiland bij Amelisweerd
Koetshuis Rhijnauwen

vrijdag 25 november 2016

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. 

vrijdag 18 november 2016

36dB Attenuator for 20 W by PH2LB

This beautiful attenuator is designed and built by Lex PH2LB.
0...36 dB attenuator built by PH2LB  -  Click to enlarge the pictures
The attenuator can handle a maximum power of 20 watt and is used to reduce the power of a 5 watt transceiver.
At first I did not realized why Lex designed the attenuator for 20 W. Like many HAMs I thought, that 20 W is QRO. But please notice that 20 W is the Maximum power.  The chosen maximum power of 20 watts for the attenuator is an excellent choice. The attenuator can easily handle a power of 5 watts, without getting hot.

This was an eye-opener for me. hi.
0...36 dB attenuator by PH2LB
with 2 W resistors 
A resistor that  dissipates its maximum power will get very hot.
So it is good practice to choose the maximum power 4 times higher then the continuous power.
Lex choose for  a maximum power of 20 watts, to reduce a power of 5 watts.
The resistors have a maximum power of 2 watts. With a power of 1/4 of the maximum power, the resistors will dissipate about 500 mW each and they will not get hot.

The 20 dB section
Visit the article on the 36 dB attenuator on the web site of Lex PH2LB.

PA1B Power Attenuator Calculator
Lex used the PA1B Power Attenuator Calculator to design his 36 dB attenuator for 20 watts.
This unique spreadsheet in Excel calculates the number of resistors and the values of the resistors from the E12-series for an attenuator section.

In the picture below I show the input values for the section of 20 dB, for a maximum power of 20 watts, that is built with resistors of 2 watts.
PA1B Power Attenuator Calculator - Input values for the 20 dB section
Just download the PA1B Power Attenuator Calculator and play with the values. The calculator has no restriction on the power.

zondag 13 november 2016

Meeting Lex PH2LB

Lex - PH2LB
Last week I visited the HAM convention 2016 - Dag voor de Radioamateur 2016 in Apeldoorn.
I was very pleased to meet Lex PH2LH.
Lex has designed a 0 - 36 dB attenuator for 20 watts, using the
PA1B Power attenuator calculator.

When I approached the stall of Lex, I immediately recognized the 0 - 36 dB Attenuator that Lex has designed and build. Further Lex showed the beautiful build OZ2CPU digital RF mW / dBm / mV meter.
OZ2CPU digital RF mW / dBm / mV meter
   and the  0 - 36 dB attenuator

donderdag 29 september 2016

40 dB attenuator built by DK5LH

40 dB attenuator built by DK5LH
Click to enlarge  
I received a very interesting email from Hartmut DK5LH, in which he informed me that he successfully built the
PA1B  40 dB attenuator.    Click for schematic
He is very pleased with the excellent accuracy of the attenuator, that makes this attenuator suitable for measuring purposes.

Hartmut uses the attenuator to measure the power of his transmitter (2 watts) with a power meter for -80 dBm to -10 dBm
The attenuator is used to reduce the output power of the set to a value that is less than 0.1 milliwatt. (-10 dBm)

40 dB attenuator with metal film resistors of  2 watt and 600 mW  -  DK5LH  
Hartmut has used resistors, that he ordered at the firm Reichelt.   Resistors 2 watts.
In his email Hartmut writes:
Ich habe diese widerstände nicht ausgemessen, sondern einfach so genommen. 
Offensichtlich sind dieses sehr genau
which means:
I did not measure the resistors, but just used them. 
Obviously  they are very accurate.

The attenuator is built with good available metal film resistors from the E12-series, with an accuracy of  5%. It shows an  excellent accuracy, because in practice the resistors show a accuracy of 1.5 %, or better.
The picture below shows the excellent accuracy of each of the four attenuator sections.

Hartmut is very pleased with the excellent accuracy of his 40 dB attenuator. His attenuator shows an attenuation of 40,5 dB, with the maximum attenuation, with all sections switched to ON. He has calculated the attenuation with the method of measuring DC voltages.

Thank you, dear Hartmut for emailing the beautiful pictures and additional info.
It's my pleasure to show your beautifully built attenuator.

woensdag 28 september 2016

Aboriginal Art Museum

Klik om te vergroten
Al weer een week geleden zijn Tjeerd PA3GNZ en ik naar het Aboriginal Art Museum in Utrecht geweest. Het museum toont hedendaagse Aboriginal kunst uit Australië. Naast de permanente tentoonstelling zagen wij ook de tentoonstelling Remember Me Stories in print, die liep tot 21september.

In de moderne Aboriginal kunst worden geen afbeeldingen gemaakt van de mythische verhalen, maar hebben kleur, vorm en compositie een belangruike rol.

Kruis arcering
Er zijn natuurlijk vele details te zien in de kunstwerken.
Maar één bijzonder detail is het gebruik van de kruis arcering.
Hier door ontstaat een krachtig beeld.

Twee voorbeelden van kruis arcering
Door termieten
uitgeholde grafpalen
De moderne grafpalen worden uitgehold met een lange boor.