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.

zaterdag 28 februari 2015

K5MQ WSPRs on 1.8 MHz with 1 W

I received a fine comment from Dave K5MQ on my previous post:
Dave further mentioned that he was using WSPR with a power of 1 W om 160 m.

Dave wrote:
 I usually run WSPR with 1 watt here. 
Have been on 160 meter WSPR the last few days. 
Have received a 3 stations from the UK, two at 5w and one at 20w. 
The furthest my 1 watt has been heard is VE6 at 2994km from my QTH in Lousiana. 
Using a full size dipole for 160m.
73, Dave K5MQ

Here is a table with spots from Daves 1W WSPR signal from the 16th to the 28th of February 2015.
The lower the Calculated Lowest possible power, the better the propagation.
How to read the table:
K9AN at a distance of 1000 kilometer, received Daves signal 143 times.
45 Of these spots were received with a SNR of about -9 dB.
So the Calculated Lowest possible power is 10 mW
The lower the Calculated Lowest possible power, the better the propagation.

Thanks to  Dave K5MQ.
It's my pleasure to make the WPA (WSPR propagation analysis)
Visit Dave's Blog entry on WSPR on 160 meters.

* The Calculated lowest possible power is the power that could  by received with a SNR of -29 dB.
The stronger the signal the lower the Calculated lowest possible power.  
     A signal with a SNR  of
 -29 dB is a solid copy in WSPR.

donderdag 26 februari 2015

WSPR with 5 watts

From time to time I visit the WSPR database to look for interesting spots that are made with very low power.
But this time I was wondering, if there are many operators, that use much more than 5 watts.

To my surprise only a few operators used 10 to 1000 watts.

The WSPR spots are collected on 10 meters in 24 hours.

I chose 24 hours to include all operators, that skip from band to band, following the changes in propagation, in all the parts of the world.

The interval lasted from 9:02 utc on the 20th of February to 9:00 utc on the 21st.

The choice for the band was not made consciously.
I selected the 10 meter band, because in the days before, I made an analysis of spots on 10 meters.

Power categories
The table shows the number of spots that were made in each power category from
1 mW to 5000 mW  (5 W) (QRP)
and the number of spots that were made with 10 to 1000 watts.

In the power categories from 1 milliwatt to 5 watts, most spots were made in the category of 5 watts.
This is 42 % of all spots.
I am pleased to see that many operators use  200 mW*  or  500 mW.
200 mW in 15% of all spots and 500 mW in 16% of all spots.
It's good to see that only a few operators use 10 W to 1000 W.  (See also "one kW")

One kW
Not all spots that show up in the database with 1000 W, are actually made with 1000 W.
In the past I have seen WSPR spots from an operator that used a homebrew QRP rig, that he proudly showed on QRZ. The setting in WSPR was wrong. He discovered the mistake.
Later spots showed a power of 2 watts in stead of 1000 watts. hi.

* Did you know that 200 mW in WSPR can be compared with 4 Watts in CW and 80 Watts in SSB.
    So with 200 mW in WSPR you can see where you 4 watt CW signal could be heard. hi.

zondag 15 februari 2015

PACC 2015

I did not expected much of the PACC, the annual contest from the Netherlands,
because of my antenna.

One wire of the ribbon of the Inverted V is damaged.
With no wind all is OK, but . . .
Frequently the wire does not connect briefly, when the ribbon moves in the wind.
While transmitting the SWR jumps briefly and on receive, the signal disappears shortly.
With S&P I have to repeat my call or exchange sometimes when the wind blows,
In several other contests in the last weeks, I could make QSO's with 8 mW, when the
propagation is very good, and there is NO wind. hi.

I started late and managed to make two QSO's, using Search and Pounce with 3.6 watts on 14 MHz on Saturday. (TA and UR)

In the first QSO on Sunday morning on 21 MHz my call was copied immediately correct
with just 360 mW. But then it took more than 5 times and 3 Watts to give my exchange, 599 UT.
When the ribbon moves, the signal briefly disappears.
After the QSO was completed, I realized that the power was NOT the problem,
because my call was received with 360 mW.

After that QSO's, I made 2 x 5 QSO's  in two runs of 10 minutes with S&P, all on 21 MHz. Not bad.

I did not expected to make many QSO's on 7 MHz, since this is a busy band.
Also I was convinced, that giving CQ would not work with the antenna in this state.
So I answered a CQ on 7 MHz.
Immediately after completing this QSO (with S&P), I was called by an other station.
The station went up in frequency, so I followed and answered.
After the QSO, 5 other stations came along, one after the other, without my calling CQ.

This is very unusual for my, because in major CW contests, I often use the lowest possible power with S&P.  hi.

With no (or little) wind, I now decided to call CQ.
So in the last hour of the contest I made many QSO's by calling CQ, between a few occasional gusts of wind.
In total I made 50 QSO's. WOW.

Even 2 QSO's were made with more than 1000 Miles per Watt, using QRPp.
I had a great time.

vrijdag 30 januari 2015

DARC 10 meter contest 2015

The DARC 10 meter contest is a contest with a length of 2 hours, organised by the  DARC. (German Radio Society) Because of the very short distance to Germany and the very short duration, I did not expected to make may QSO's, but I was very curious how it would go.
In total I made 6 QSO's with search and pounce.

dinsdag 20 januari 2015

De stad in MIJ

Bern en de Alpen  detail  (Click)
Vorige week ben ik naar Museum IJsselstein geweest.
De tentoonstelling: De stad in MIJ toont de bebouwde verbeelding.
Schilderijen, bijzondere 360 graden foto's, wandkleden en objecten.

Fascinerende stadslandschappen
Ik werd verrast door de zeer gedetaileerde stadstekeningen van
Stefan Bleekrode. (Klik voor het artikel in het AD)
Vooral Bern en de Alpen vind ik heel bijzonder
Ik ben bijna in de tekening gekropen, om alle details zoals schoorstenen, dakkapelllen en hun schaduwen goed te kunnen bekijken.
Zeer de moeite waard om te zien.

De stad in MIJ. Bebouwde verbeelding van realistisch tot utopisch.
Museum IJsselstein. Nog te zien t.e.m. 15 maart 2015.

Bern en de Alpen   Stefan Bleekrode

zaterdag 3 januari 2015

WSPR Propagation Analysis - G3XBM 28 MHz Dec 2014 (2)

The propagation changes from day to day, as can read in the blog of Roger G3XBM.

Here is an analysis of the WSPR spots of G3XBM that were received by K9AN 
on the 24th and the 28th of December 2014.  
The time is given in UTC.
The diagrams show a lot of spots, since K9AN listens every two minutes. hi

The lower the calculated lowest possible power, the better the propagation.
On the 24th, the propagation is at it's best around 13:50 UTC and 17:06 UTC,
with a calculated lowest possible power of 5 milliwatts.
 Click to enlarge.     G3XBM  received by  K9AN  on  2014-12-24
On the 28th the propagation has a short peak at 14:52 UTC.

Around that time there are seven successive spots, every two minutes.
In the spot of 16:36 utc, the full power of 500 mW is needed, to be spot. hi. 
G3XBM received by K9AN  on   2014-12-28
In most of the spots, the calculated lowest possible power is 50 mW or less, on both days.
This means that, if you would use CW instead of WSPR, that 1 watt (20 * 50 mW) could be used to make QSO's in CW.

vrijdag 2 januari 2015

WSPR Propagation Analysis - G3XBM 28 MHz Dec 2014

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 the diagrams.

The first two diagrams, show spots that are collected over several days.
The strongest spots are given in red

The first two diagrams show the calculated electrical field strength in micro volt per meter.
If spots show the same field strength, the voltage on the antenna will be the same, 
for a simple wire antenna.
The difference between the successive values of the field strength is 5 dB.
This is about one S-point, since 6 dB is one S-point. 
The lower the value, the better the propagation.
So 0.03 micro volt/meter is about 1 S-point stronger than 0.06 micro volt/meter.

The strongest spot over 900 km was 2 S-points down, compared to the spot over 5300 km

The strongest (in red) spots show the same field strength.

Notice that the spots over 5300, 6500 and 14700 km were made with the same field strength at the receiving antenna, so the strength of the signal that arrived on the antenna  was the same in these three spots.

Further analysis shows which receiving stations have Excellent Ears. See the spots in red.
The spots in red in the table below correspond to the spots in red in the tables above.
The stations with excellent ears.
Power in CWI was wondering, how much power would be needed to make  CW QSO's.
For a CW QSO you need  (Click)  twenty times more power, than for a WSPR spot. (13 dB)
The diagram below shows the  (Click)  Calculated lowest possible power in milliwatt for each spot.

For the strongest WSPR signal, received by K9AN the calculated lowest possible power is 2 mW.
Thsi means that the that 2 mW would be received with a SNR of -29 dB. (Solid copy in WSPR)
To be received in CW, a power of 20 * 2 = 40 mW would be needed.
This does not surprise me a bit, since I made a CW contest QSO with K3WW on 21 MHz in 2012 with 36 mW.

Rogers signal was also heard in VK. The calculated lowest possible power was 5 mW.
So in CW his signal would be heard with 20 * 5 = 100 mW.
This seem too low, but please notice that to double the distance it takes an increase of 1 S-point (6 dB) to get the same field strength.
One  S-point means four times more power.
Further notice that WSPR is patient and tireless.
It is even possible that one of the operators was a sleep during the time that the spot was made. hi.

donderdag 1 januari 2015

CQ WW DX CW 2014

I had great fun in the CQ WW DX CW contest of 2014.
I had my inverted vee repaired just in time for the contest.

But most of all, I was very curious, how fast the
PA1B Fast and Accurate 40 dB Power Attenuator
would be in a large contest with enormous activity.

I am very happy with the attenuator.
As I mentioned before, the fast attenuator can be switched instandly.
So I am immediately ready to answer a CQ.

I started on 10 m and went to a lower frequency each time a band closed.
At times when the signals were getting stronger, I tried to use a lower power in the next QSO's.
On 40 m the band was too busy to use a very low power.
When I was on 40 m, the other bands were closed, so all other operators were also on this band.
So I made most QSO's on 40 m with 3.6 W. (Category less than 5 watts)

The inverted V works fine.
Since a long time I could make a few QSO's with less than 10 mW.
I used a power of about 4 watts down to 1.6 milliwatts.
The two QSO's in the column of  2.5 mW in the table were made with 1.6 mW and 1.8 mW.
(500 mW means more than 250 mW and less than 500 mW)