vrijdag 3 oktober 2014

What is QRPpp

QRPpp is the (not official) term that I use for a power of less than 100 milliwatt.
Here is a nice diagram on QRPpp, QRPp and QRP.

How is it possible to use QRPpp?
Read the post QRPp How is it possible

zondag 28 september 2014

PI4AA is terug

Dankzij een enthousiast team van medewerkers,
is de Veron afdeling 't Gooi er in geslaagd,
de uitzending van PI4AA voort te zetten.

De uitzending is op elke eerste vrijdag van de maand 
om 21:00 uur op:
80-meter: 3605 kHz in LSB
2-meterband: 145,325 MHz in FM

Voor nieuws over PI4AA kijk je op de website: http://www.pi4aa.nl

vrijdag 26 september 2014

WSPR Propagation Analysis - G3XBM 28 MHz

Many WSPR operators jump from one band to the next, when band conditions changes.
Roger G3XBM ran his WSPR signal for several days on 28 MHz.
This provides interesting information on propagation on 28 MHz.
I collected data from the WSPR database, to make this diagram.
In this diagram, I choose to show the spots of Roger received by DK6UG over 600 kilometer and LB9YE over 1500 km.
The diagram shows the number of spots for a day and from hour to hour.
The stronger the signal, the lower the calculated lowest possible power.

DK6UG over 600 km
It's interesting to see that the propagation to DK6UG changes from day to day.
On the 13th there are two peaks in the propagation, with no propagation in between.
On the 14th there is only a spot on 18 UTC.
This is at the same time of the peak of the day before.
On the 15th there are 3 peaks at 11, 14 and 19 UTC
The 17th is the most interesting day.
The day starts with reception on 11 till 12:58 UTC.
The 17th shows one very strong spot at 14:10 UTC with a calculated lowest possible power of 10 mW. The next spot with a CLPP of 1000 mW was on 14:54 UTC. Notice that in this spot the signal strenght is 20 dB lower.
Please notice that there is no reception from 13:00 till 13:58 UTC on all days,except for the 19th.


LB9YE over 1500 km versus DK6UG over 600 km
Most interesting are 13th and 14th
At the 13th the propagation is good to DK6UG, but not to LB9YE.
At the 14th it's the other way around.

vrijdag 19 september 2014

DL1DN - HF SSB QRPP QSO´s down to19mW

David DL1DN has send me a link for his very interesting video.

David made a video in which he reduces his SSB signal from 2.5 W to 19 mW, during a QSO
He reduces his power using an attenuator of 3 dB and 3 attenuators of 6 dB.

An attenuator of 3 dB reduces the power to 1/2.
An attenuator of 6 dB reduces the power to 1/4.

David starts with 2.5 watt (0 dB) and uses a homebrew multiband dipole at 1.9 m above the ground.

The next steps are:
Time          Attenuation         Pwr                Signal
0:15               0 dB                 2.5 W
1:30             -3 dB                 1.25 W             S6
1:42             -9 dB                 300 mW           S5
2:00            -15 dB                80 mW                         Video says:  -18 dB, but it is -15 dB.
2:14            -21 dB                19 mW             S4 or S3  

Please notice that every step of 6 dB is 1 S-point.
The receiving OM has an calibrated S-meter, which is excellent for this experiment.

The video shows what happens when the power is reduced.
David transmits but also receives through the attenuator.
Every time that David  reduces the power, also the signal of the received station is reduced, so you can hear for yourself what each step of 6 dB does.
As you can hear, listening though the attenuator is absolutely NO problem.

Click here: https://www.youtube.com/watch?v=rvpxyoacrec

Enjoy this very interesting video

For non German speakers:
Wahnsin  = madnes
Hintergrundpegel = back ground level

dinsdag 16 september 2014

Reparatie van de Numark NDX800

De NDX800 is een hoogwaardige controller voor de DJ met meerdere muziekbronnen. U kunt alles mixen met de NDX800. 
Het maakt niet uit of de muziek op uw computer, USB stick of CD staat! 
Dit digitale deck heeft het 'gevoel' en de indeling die u gewend bent. Natuurlijk wel met een beetje Numark-innovatie!

De NDX800 is echt een prachtig apparaat.
Maar zoals op internet te lezen is, gaan de schakelaars nog wel eens stuk
Zo ook bij beide apparaten van Sebastiaan, DJ SeppieJ.
Pijl bij de defecte START schakelaar,   Demontage,   STARTschakelaar verwijderd  en   Wachten op de nieuwe schakelaars.
Chef monteur Wendy heeft de apparaten open geschroefd, nadat ze op internet een video voor het vervangen van de schakelaars had gevonden en pa(1B) heeft de schakelaars vervangen.
Niets is zo erg als een haperende schakelaar.
Ik heb sinds lange tijd de soldeerbout weer eens opgestookt.
En een zeer tevreden Sebas, mixt weer als vanouds. hi.

zondag 14 september 2014

Fast and accurate 40dB Power Attenuators for QSO's on the PA1B QRPp page

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.


Last week the PA1B QRPp page was updated:

Click to read more about the interesting
PA1B Fast and accurate 40 dB Power Attenuators for QSO's.
Specially designed to use in QSO's with very low power.


vrijdag 12 september 2014

PC4T with 5 watts on 14 MHz with WSPR

In addition to the update of the post of 2014-09-08, I made a new analysis of the spots between made over a distance 1500 km to 2200 km.
The spots were made during the morning.


Leersumse veld

Bij het meertje Leersumse veld
Gisteren hebben mijn vrouw en ik eerst geklust.
Daarna zijn we doorgereden naar het Leersumse veld.
Vanaf een bankje hebben we de schaapsherder en zijn kudde gadegeslagen.
Het was heerlijk zonnig weer.

We zijn doorgelopen tot het meer en hebben daar heerlijk in de zon gezeten. Ik heb genoten van de mooie kleuren groen van de bomen.
Dit is een van mijn favoriete plekken.
Toen we terug liepen kwamen we nog drie koeien tegen, die ons luid loeiend begroetten.

Ter afsluiting hebben we een heerlijk kopje koffie genomen bij La Place in Maarsbergen.
We hebben genoten van deze mooie nazomerdag.

Mijn vrouw heeft nog twee foto's van de schaapskudde gemaakt.
Schaapskudde Leersumse veld

maandag 8 september 2014

PC4T with 5 watts on 14 MHz with WSPR

Here is a WSPR Propagation Analysis of spots of Paul PC4T on 14 MHz.
The lower the Calculated lowest possible power, the better the propagation.
Nearly all spots over 1100 to 2200 kilometer could have been made with 20 milliwatts.


Update 2014-09-10
I made an extra analysis of the spots in the red fields.
The spots were made from 19:12 till 19:40 UTC
The lower the Calculated Lowest Possible Power, the better is the propagation.

LA9JO at 2000 km
The signal strength increases with 6 dB (in power 4x as strong) from 19:12 till 19:40 utc.

SV8QG
The last spot is 14 dB weaker than the first.

VK5MR
The last spot is slightly stornger than the other two.

donderdag 14 augustus 2014

Schematic and building info of the 6 watt Power Attenuator


PA1B 40 dB Power Attenuator
PA1B Fast and accurate 40 dB Power Attenuator for QSO's

This Power attenuator is  fast in CW QSO's, because
7 dB and 3 dB can be switched instandly..
The attenuator is also very accurate.

Power Attenuator
All attenuator sections are designed for an continuous input power of 6 watts.
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 7 resistors, since they must dissipate much more power than the other sections.
The large resistors are resistors of 2 watts. The resistors with 2 stars (**) are resistor of 1/2 watt and the resistors with 1 star (*) are resistors of 1/4 watt.
I built my attenuator with metal film resistors of 2 watts, 600 mW (*) and 400 mW (*)

Asymmetrical attenuator
To reduce the number of resistors, I chose for asymmetrical sections in the attenuator. 
Input and output can not be exchanged.


Schematic
PA1B Fast and accurate 40 dB Power Attenuator for QSO's.
Power 6 watts built with resistors of 2 watts, 1/2 watt and 1/4 watt
Click to enlarge


The switches on the front.      20 - 10 - 7 - 3 dB        
Reversed order
The schematic goes from left to right.
Please notice that the layout on the switches, inside the box goes from right to left.
So you will find the the resistors of 150 ohm and 330 omh to the right.
Notice the reverse order with respect to the schematic
R2 and R5 are also placed

Naar Blijdorp met Eneco


Als trouwe klant van Eneco, kregen een aanbieding om met Eneco gratis naar Blijdorp (Rotterdam Zoo) te kunnen gaan.
Dus besloten we al snel om met onze kleindochters te gaan.

We hebben genoten.

Apen met roze konten leidde tot grote hilariteit.

Neushoorn, Giraffen en een opa's lieveling, de otter


  Eneco, bedankt voor het fijne bezoek.

dinsdag 12 augustus 2014

PA1B 20 - 10 - 7 - 3 dB power attenuator measured

We measured the new built 6 watt PA1B  Power Attenuator, in the shack of Mischa PA1OKZ.
The attenuator is built with metal film resistors of 2 watts, 600 mW and 400 mW, from the E12-series.
I was curious how well the metal film would do HF.       Click for schematic

Conclusions
* The 20 - 10 - 7 - 3 dB  sections are very accurate
* The 20 and 10 dB  sections show an accuracy of 0.1 dB to 0.2 dB at 30 MHz
* When all sections are switched OFF, the attenautor has a attenuation of
    0.13 dB at 1 MHz  to 0.61 dB at 30 MHz.
    This "extra" attenuation is frequency dependent.

Relative attenuation
The purpose of an attenuator is to attenuate the signal with the value 
of the sections, that are switched "ON".
In this table the attenuation with all section switched OFF is 0 dB.
The table shows the "extra" attenuation of this section, when a section is switched "ON ".
Relative attenuation of the PA1B  20 - 10 - 7 - 3 dB power attenuator    
At 10 MHz all sections are very accurate.
The 10 dB and 20 dB sections are more frequency dependent.
The section of 3 dB is the most accurate section. The section of 7 dB has an accuracy of 0.1 dB.
The section of 10 dB and 20 dB show an accuracy of 0.15 dB at 30 MHz.

I am very content with these values, considered that the resistors are resistors of 5% from
the E12-series. The measured values of all resistors in this attenuator, show that the accuracy of the resistors is about 2 %.

Absolute attenuation
This "extra" attenuation is caused by the fact, that the circuit formed by switches is not 50 ohm.
The value of 0.13 to 0.61 dB is typical for the switches that are used and the distance between the switches.
We measured about the same values in another attenuator with two section of 20 dB and one of 10 dB, that is built in the same way.
Absolute attenuation of the PA1B  20 - 10 - 7 - 3 dB power attenuator     
Inside of the box of the attenuator with simplified schematic


woensdag 30 juli 2014

Building a 6 watt power attenuator

I am building an attenuator with metal film resistor of 2 watts, 600 mW and 400 mW.
Sorting out the resistors
Click to enlarge
The store had no resistors of 1 watt, so I bought the power resistors
of 2 W and made a redesign of the attenuator.
All the resistors are metal film resistors.

The attenuator is designed to for a continuous power of  6 watts.

To the right you see the blue  box with the resistors that are needed.
The 3 dB and 7 dB sections both consist of 6 resistors each.
The 10 dB and 20 dB sections dissipate more power.
They consist of 7 resistors each.

     Outside of the box with the 20 dB section to the left.                         Inside of the box. 20 dB section to the right.                     Switches set to 17 dB                                                                             Switched mounted               
Next step soldering the resistors. 

zondag 13 juli 2014

Accurate and fast 5 watt attenuator for QSO's

Please visit the PA1B QRPp page for more info on Power Attenuators.

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.

PA1B Fast and Accuarate 40 dB Power Attenuator for QSO's
PA1B Fast and accurate 40 dB Power Attenuator for QSO's
Asymmetrical attenuator
I choose to design this attenuator asymmetrically, to reduce the number of resistors.
Please notice that the resistor on the input of each attenuator section, R1, R4 and R7, consist of 5, 4,and 3 resistors.

Power
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.

Accuracy
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, always consists of 6 resistors or more.

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 PA1B Fast and accurate  40 dB  Power Attenuator
Click here for

PA1B Fast and accurate 40 dB Power Attenuators for QSO's

for a symmetrical attenuator built with resistors of 2 watts

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