zondag 13 juli 2014

Accurate and fast 5 watt attenuator for QSO's

Fast in QSO's
A simple way to reduce the power of your QRP set to milliwatt level, without modifying the set, is the use of attenuators. The combination of 20 dB, 10 dB, 7 dB and 3 dB is fast to switch, when you want to increase your power in QSO's. In one move, one attenuator section is switched OFF and an other is switched ON, to increase the power with a step of 3 db or 4 dB.

5 watt Accurate and Fast Attenuator for QSO   20 - 10 - 7 - 3 dB
All attenuator sections are designed for an continuous input power of 5 watts. This is 10 watts in CW.
The attenuator sections consist each of 3 compound resistors, which each are formed by a number of resistors in parallel. These resistors are a power resistor of 1 watts and a some resistor of a modest power (1/4 watt). The resistors with a star * can be 1/4 watt. Or you can chose  1 watt resistors for all resistors.
The power resistors, with a lower ohmic value, dissipate most of the power and an other resistor is added in parallel, to arrive accurately on the wanted ohmic value. The power attenuator sections of 20 dB and 10 dB are build with 9 resistors, since they must dissipate much more power than the other sections.

With two or more resistors from the E12-series in parallel, you can accurately make any value you want.
The resistor value of the combination is most of the time within 1% of the theoretical value.
This is why an accurate attenuator section, must always consist of 6 resistors or more.
Checking the value with an ohm meter and picking the resistor, with the higher value by hand, will improve the accuracy of attenuator section to 0.1 dB.
Notice that when you use the attenuator as an accurate attenuator, the accuracy of the attenuator is largely determined by the 20 dB and the 10 dB  sections.

Simple layout
The choice of placing resistors in parallel, leads to a very simple layout of the attenuator sections.
There's NO need for a PCB. hi.

Table for the fast and accurate  20 - 10 - 7 - 3 dB    5 Watt  Power Attenuator

donderdag 10 juli 2014

First place in the YO DX HF contest 2013 for CS8/PA1B

Today I received a beautiful Award of the YO DX HF contest.
Last year I partcipated while on holiday on the beautiful island of Saõ Miguel on the Azores.

During the contest I used an end fed wire on the roof of the hotel.
In the contest I used my FT-817 with 2.5 watts or less and a homemade light weight keyer.

The envelop from Romenia arrived in the rain.
When my wife entered the room with the wet envelop, she said:
"I hope all is OK".
I immediately recognized the envelop of the YO DX contest.
Despite the rain the Award is in good condition, because it is plasticized.

My thanks goes to Ovidiu YO2DFA, the contest manager of the
YO DX HF contest.
CS8/PA1B   First place in YO DX HF - Azores - Single OP - 14 MHz - Mix 

zondag 22 juni 2014

Two eQSLs over more than 2000 Miles

RF9T  2080 miles and 800 mW gives 2600 MPW
In the batch of eQSL cards,
I received a card from from RF9T.

With a distance of more than 2000 Miles to UA9, its easy to make a more than 1000 Miles/Watt QSO, when I reduce the power below 1 Watt.

The eQSL card of RK9UE was received earlier and was made with even less power. hi

RK9UE  3126 miles and 360 mW gives 8684 MPW
1000 Miles per Watt is not as difficult as it seems.
When you hear a station over a distance of  500 miles (800 km), just reduce to 500 milliwatts.

dinsdag 3 juni 2014

PACC 2014

The PACC is the annual contest from the Netherlands.

In other contests I always work with search and pounce with very low power, but in the PACC
I operate by giving CQ myself. Most QSO's were made with the highest power of my FT-817.
Last year the top of my inverted vee broken during a storm. I repaired the antenna temporarily.
One wire lays on the roof. Still I managed to make more than 130 QSO's.

I notice a difference with this antenna but the differences  due to changes in propagation, are larger.
I made more than 130 QSO's with 29 different DXCC's, with less than 5 watts.

Because we had visitors I could not start at 12:00 utc.
I did not wake up early on Sunday.

 De top van de Inverted V hangt slechts een paar meter boven het dak, nadat ik hem weer
provisorisch opgehangen heb, na een storm verleden jaar. Een draad ligt gedeeltelijk op het dak.
Tot mijn verbazing maak ik nog vele QSO's met QRP en zelfs met QRPp.
Dit wijst er op, dat de propagatie belangrijker is dan de antenne.
Ik maakte 138 QSO's met 29 DXCC landen met 500 mW tot 5 W in de contest.
Bedankt voor de activiteit in de PACC.

As a milliwatt and QRPp enthusiast very much like the "DX contests" in which every one works every one.

OP1A  in the PACC  2011

zaterdag 24 mei 2014


Here are some eQSLs' from the last batch.
The QSO's are all made QRPpp using the Lowest Possible Power.
QRPpp is the (not official) term, that I use for a power of less than 100 milliwatts.
Also known as two digit milliwatting.

Making QSO's with very  low power is not that difficult.
It´s all a matter of propagation.
The changes in propagation can be hugh.
So when the S-meter goes 20 dB up, the power can be reduced with 20 dB.

Look for a CQ of a station with an earsplitting S++ signal.
Answer with low power, with the excellent timing that you always use.
Don´t suspect anything, but be prepared after you give your call.
Most of the time, other stations are answered.
But than suddenly, the frequency is clear and you will be heard.
It´s possible that you are surprised, that you hear your call, being send immediately correct.
And before you know it, you also get an exchange. What was that? What number did he gave? hi.

9H1XT    1205 Miles   3.6 mW   334841 Miles per Watt

IV3ZXQ   550 Miles   22 mW   25002 MPW

SM5QU   740 Miles   36 mW   20549 Miles per Watt

SV1ENG   1318 Miles   98 mW   13453 Miles per Watt

S56M   588 Miles   80 mW   7349 Miles per Watt

OE2008S   445 Miles   98 mW   4698 Miles per Watt
See me smile from ear to ear after such a QSO.  

woensdag 21 mei 2014

Notes from the SP DX contest

I never use a fixed power, but adjust my power from QSO to QSO.
Before I answer the CQ, I adjust my power to:  500 mW,  1 W, 2.5 watts or 5 watts.
If the signal is very strong, I use the S-meter to determine the power that I wil use.
For example: a signal of:  S+ + 10 dB, I can answer with 50 mW,
using an attenuator of 10 dB.

To enter or write down  the call and to set the power, at the same time, is impossible,
So I am always too late for the first opportunity to answer.
And sometimes, I even switch to the wrong setting, which can be to low or to high. hi

Using the lowest possible power is great fun, but can also be a nerve wracking enterprise.

Interesting Experiences      Wow's and Woo's from my handwritten notes, made during the SP DX 2014
* In the QSO with SP8HW I realized that listening is very important.
    When I started to answer a CQ, I heard an other station answering, in the background.
    When he stopped, I gave my call twice, in the clear and made the QSO with 500 mW.
* I worked 3Z50AYP in a hurry. I was so excited, that I used 500 mW instead of a lower power.
    After the QSO it was quiet on the frequency. But a dupe will be impossible. ;-(
* SP6EIY can not hear me with 500 mW and 1 W. Maybe later.
* I seized the opportunity to switch back to 500 mW, while waiting  for a very loud station.
    It's important to immediately adjust to 500 mW, after a QSO with 1 W or 5 W.
* I had to push to make a QSO with SP2GJV with just 50 mW, which is quite remarkable.
    There was a lot of QRM in the background.
* Station after station, visited SP3FYX.
    I had to have a lot of patience, not to increase the power to 5 watts.
    And finaly, to use just 500 mW.
* I love chirpping stations. I work SP7.... with 5W.
* Worked SP9YFF with 500 mW, before I got the call complete.
    I realized that . . . FF was a new one.
* After the QSO with SN8N, I realize that I should have used 50 mW instead of 500 mW.
    The signal was earsplitting loud. S++
* One station after the other goes in to the log. It 's a mix of 500 mW and 5 W.
* It's very busy. I have to look for stations that are calling CQ with no takers.
* SP6ZDA At the last moment, I decide to switch in the 10 dB attenuator.
    Resulting in a QSO in the clear, with just 50 mW.
* Now I recognize new stations by the last letters of the call.
* 3Z8Z fades. I need 5 W.
* The numbers of my computer program and the Morse Machine differ.
    I correct the Morse Machine.
* SP9MZS Earsplitting signal. But the setting is wrong, so 500 mW instead of 50 mW.
    Next time better.

    I could make all these fine QSO's, thanks to all the fine operators in the from Poland.

maandag 12 mei 2014

eQSL avalanche

Last week the number of eQSLs in my eQSL inbox had risen to more than 100.
Between these QSLs were many 1000 Miles per Watt QSL's.
For these QSL's, I determine the distance and calculate the Miles/Watt.
I mention these numbers in the comment field of the individual eQSL.

Last week I replied many eQSL's.
  F6KDF  435 Miles and 8.5 mW gives 51128 Miles/Watt
It took me a few days, to reply manually,
on the eQSL site.
So I was glad, that I had reduced that number
to about 10 remaining eQSLs.

But when opened my eQSL inbox a few days later, it knocked my socks off.
There were 208 eQSL's in my inbox.
This number is very large to reply manually.

A doubling in a couple of days.
And what if that number doubles again?

donderdag 8 mei 2014

G4ILO Whispering with 20 mW and 1 mW

This is an other analysis of the data collected from the
WSPR database for spots of Julian G4ILO.
Julian transmitted with a power of 1 mW and 20 mW.

The table shows, that the spots that were made with 1 mW, 
were about 10 dB weaker than the spots made with 20 mW

The table shows a selection stations that received spots made with both 20 mW and 1 mW
To compare spots over different distances, I use the 
Calculated electrical field strength, E, in microVolt per meter.
For details see the WSPR Propagation Analysis page of this Blog.

The lower the electrical field strength the better the propagation.

A power ratio of 10 means 10 dB
Please notice the the value for E is given in Volt/m, so a Voltage ratio of 10 means 20 dB
Which is indicated at the top of the table.
A Voltage ratio of 10 is a ratio of 100 in power.

The table shows stations that received the signals, that were transmitted with 1 mW and 20 mW.
Notice the difference in field strength in spots made with 1 mW or 20 mW.
The difference in field strength between the spots of 1 mW and 20 mW is about two steps in this table.
This is about 10 dB.
This is no surprise because, the difference in power between 1 mW and 20 mW 
is  10 log (20 / 1) = 13 dB.

The differences in propagation are huge
The field strength of the spots made with 20 mW, received by ON7KO over 600 km, 
show a value of 0,3 microV/m to 0,03 microVolt/m. 
The ratio in voltage is 10 and the ratio in power is 100, which is 20 dB. Wow

maandag 5 mei 2014

SP DX contest

Poland - Voivodeships
My objectives
As a milliwatt enthusiast I tried:
* to make as many QSO's with the
   lowest possible power
* to make as many 1000 Miles per Watt QSO's as
* to work as many different prefixes as possible for the
   BQC- Marathon.

1000 MPW
The distance to many of Voivodeships is more than
500 miles  from my QTH in JO22na.
Only the distance to the Voivodeships Z, B, D and
a part of W, is less than 500 miles.
With a power of 500 mW, and a distance of more than 500 miles,
these QSO's will be, more than 1000 Miles per Watt QSO's.

Crippled antenna
This year I did not expect much of my Inverted Vee.
Last year the top broke and I fixed the antenna temporarily.
The top is now just 2 meters above the roof.
And recently I found out, that the 300 ohm ribbon is damaged, so only one wire is still connected
But the antenna worked better than I expected.
Click here to read about the state of the antenna.

1000 Miles per Watt
The number in red, show the QSO's with more than 1000 Miles per Watt.

zaterdag 3 mei 2014


General Vladimir Zaimov
I just started in the ARI DX contest.
This is an interesting contest for a low power enthusiast like me,
because this is a DX contest, so I can work any station, so many stations can be worked with low power.
For the first QSO, I selected the very strong signal of OM5WW and worked him with just 50 mW.

The second station was LZ69VZ.
I like stations with special calls, so I gave him a call.
After exchanging the numbers, something very remarkable happened.
I got a question. At first I though that I had to repeat my call.
And repeated my call. But the question was . . . .
So the question was: what power do you use?
I immediately thought, this must an operator, that had met me many time before and knows from my QSL cards that I often use low power. And indeed, the operator is Gosho LZ1ZF, who I meet in many contests.
I gave: 500 mW. hi

Thank you Gosho. My 1000 Miles per Watt QSL for LZ69VZ will be on his way in a few weeks.
If you hear Gosho, give him a call.

dinsdag 29 april 2014

Congratulations! Your log was accepted!

I just sent in the Cabrillo log for the SP DX contest and the CQMM DX contest.
Just in time, because I had almost forgot.
Often I leave the shack after the contest, when the contest ends in the afternoon.
Sometime I spent some time on the log in the same evening.
But often I forget the contest at all, until the next weekend.

After the contests I had little time to send in the Cabrillo files.
But today I luckily remembered.

The most important part of the Cabrillo file is the Category.
Wrong category, no award.

I always spent much time on the Soapbox comments.
It's great fun to mention in the Soapbox, a single QSO made with very low power,
for example 10 milliwatts, using an attenuator.
Or the number of QSO's made with more than 1000 Miles per Watt.
Or a QSO that I made with South America, during the CQMM DX with just 2.5 W
But this can take quite some time to calculate and write about it.

75 Characters
The Cabrillo file of the SP DX was immediately accepted.
The Cabrillo file for the CQMM DX was rejected at first.
The Soapbox line which are restricted to 75 characters in a line, so they were tooo long. hi.

Notes on paper
In the SP DX contests I made notes on paper during the contest.
I had great fun with QRP and QRPp in both contests.
So I wanted to catch these special moments, that I experienced,
while using the lowest possible power in these contest QSO's.      (Click to See the Notes)

zondag 27 april 2014

Armando in Oud Amelisweerd

Detail - Chinees behang
In 2012 bezocht ik een tijdelijke tentoonstelling van Armado in Landhuis Oud Amelisweerd. Het Chinees behang op de beletage is een van de bezienswaardigheden van het huis.
Nadien is het landhuis is prachtig gerestaureerd en als museum in gericht.

China aan de Kromme Rijn, de restauratie van het Chinees behang in Oud-Amelisweerd - Klik voor bekijken van de video (28min)

Sinds kort is wordt in Oud Amelisweerd werk van de veelzijdig kunstenaar Armando geëxposeerd.
Armando in het woud is de openingstentoonstelling van MOA | Museum Oud Amelisweerd
Het mooi ingerichte, ruim opgezette museum, is geopend door prinses Beatrix.

Schilderij                Twee litho's 
De verdieping
De verdieping, die zich op de zolder bevindt geeft informatie over Oud Amelisweerd en biedt de mogelijkheid om het geschreven werk van Armando in te zien.
Klik op de foto, om te zien wat ik lees.
Het tijdelijke onderkomen van de Veldkeuken
In achtertuin van het Landhuis is een gezellig, 
tijdelijk onderkomen, voor de Veldkeuken ingericht.
Zoals je ziet is het gezellig druk. 
Ik heb genoten van het museum en de Veldkeuken. 

Klik op de foto's om deze te vergroten.

Achter het groene onderkomen is het begin van de Beeldlaan zichtbaar. 

donderdag 24 april 2014

South America in the CQMM DX with my crippeled Inverted Vee

I was looking forward to the CQMM DX contest.
It is a very fine contest with a lot of activity from South America.
I know from earlier contests, that I could still make QSO's with  Europe, Asia and North America with low power, with my crippled antenna.
On Saturday I made 9 QSO's with Europe with a power of 5 watts down to 100 mW.

But I was wondering if I could make a QSO's with South America.

On Sunday afternoon, after I switched to 28 MHz, I heard a station from South America.
At that time, I did not know whether the distance would be more than 5000 miles,
so I decided to use 2.5 W.
I use 2.5 watts and I used a lot of patience to make a QSO with PW2D.
The frequency had to be absolutely clear, so I had to stay cool. hi

With a distance of far more than 2500 miles, this QSO is a more than 1000 Miles per Watt QSO.
Later I heard other stations from South America, but they could not hear me, even with 5 watts. hi
The changes in propagation, are more important than the antenna.
So I say thanks to the fine operators of PW2D.

woensdag 23 april 2014

Lekke antilekband

Het kan dus wel
Het was toch mis
Er klonk een zacht gesis

(Een vingerhoed vol emotie. Maar t'is geen "HighKoe" of 俳句 )

Eerste paasdag
Nieuwsgierig veulentje.
Na het paasontbijt met paasstol met spijs en warme, volkoren  bolletjes, zijn we met de eFiets, even naar plas Middelwaard gefiets.
De hooglanders en de paarden stonden op het toegankelijke deel,
zodat we makkelijk foto's kon maken.
Mijn vrouw schoot dit mooie plaatje van het nieuwsgierige veulen.

Slechts honderd meter op de terugweg, hoorde ik een tikkend geluid, bij het voorwiel. Toen ik stopte zag ik een takje met doorntjes op de band zitten.

Hooglander met de hoeven in het water.
De doorntjes op het loopvlak waren plat en hadden geen schade aangericht.
Maar . . . één van de doorntjes prikte naast het loopvlak,
langs de zijkant, in de zijkant, van de band.
Dit doorntje zat behoorlijk vast en liet zich moezaam verwijderen.
Het was toch mis, er klonk een zacht gesis.
Toen we thuis aankwamen, was de band wel zacht,
maar nog niet leeg.

Daarna ben ik verder gegaan in de CQMM DX contest, tot 1 uur 's nachts. hi

donderdag 17 april 2014

CQMM DX coming up this weekend

Starts: 1200 UTC Saturday
Ends: 2359 UTC Sunday
This weekend there will be much activity
from South America, so join the fun
in the CQMM DX in which you can work every station.

In 2011,  2012  and 2013,
I had great fun with QRP in the CQMM DX contest.
Look at the:  
Blog entry of 2011.    Blog entry 2012     Blog entry 2013

In the CQMM DX contest of 2011, I was suprised by the excellent propagation, which made it possible to work with stations in South America and North America with just 1 W or 2.5 W.

In the CQMM DX contest a QRP station is recognized by it's exchange.
My exchange will be EUQ meaning continent Europe and QRP.
So as a QRP station, I immediately known that the QSO
is a 2 way QRP QSO when you receive such an exchange.

CQMM DX coming up, this weekend.

Rules 2014
Click for    Rules 2014   or the CQMM DX website