dinsdag 15 april 2014

Ribbon of the Inverted Vee damaged

Last year the top of my Inverted Vee broke.
I fixed the antenna temporarily, so the height of the antenna was reduced with 2 meters.
When I wanted to replace the broken stick by a new one, I noticed that the
300 ohm ribbon was damaged.
Obviously the ribbon had made contact with the rough tiles.
Wear by continually moving over the rough tiles by the wind took its toll.
One wire of the ribbon was completely gone over a length of 5 cm. (2 inches)
So only wire  of the inverted vee was and is still connected.
Actually my antenna is just one wire of 10 m.

vrijdag 11 april 2014

"WSPR Propagation Analysis" for WSPR spots of G3XBM on 10 m

Roger, G3XBM wrote:
Nothing at all was seen until mid-afternoon and then the band just opened wide!  
K9AN (6505km) last spotted my 2W signal at 2308z, which is after midnight local time and HOURS after the band has normally died out. It had been dark for hours. One wonders if this was F2 or even multi-hop Es? I wonder what was happening on 6m transatlantic?  I must check.
(Spots made on 2014-04-08) Click to visit the article.

I was interested, so I made an WSPR Propagation Analysis of the spots on that day and the days before. The second table shows the last spot at 23:08 UTC, but also reveals the rapid change in propagation around 22:20 UTC.

How to read the table 
In the analysis above, I show the "Calculated Lowest possible Power" in milliwatt and the hours of the day in UTC. The lower the "Calculated Lowest Possible Power", the better the propagation.
To compare the propagation over several days, 
I included 2014-03-28 till 2014-04-08.


Roger is refering to WSPR spots made on 2014-04-08.
At the bottom of the table above.
From 10 UTC to 22 UTC the propagation gets better.
The best propagation occurred in the spot with the red star made on 22:20 UTC.



Even more spectacular
The best propagation on 2014-03-28, at the top of the table, occurred between 13:00 and 15:59 UTC in the aftenoon.
But even more spectacular is the change in propagation in the 3 spots * that were made between 22:00 and 22:22 UTC, that show a very rapid chang in propagation. (See the red arrows)

Thanks to Roger for the interesting experiments with WSPR.

vrijdag 4 april 2014

/QRP

I always use QRP, which is 5 watts or less in CW.  But I never use the tag /QRP.
In contest QSO's in CW, I rather send my call a second time in stead of /QRP.
In the BSCI contest I made a QSO with a station that was not in the contest.
I met a station from Guensey (GU) which is rather rare.

The signal was very strong, so I immediately reduced my power to 50 mW.
The FT-817 was set to 500 mW and I switched in the 10 dB attenuator.
The 10 dB attenuator reduces the power with a factor 10.
So my power was 500 mW diveded by 10 = 50 mW.
I received the usual 599 and I was happy to log MU0GRU.

But when I looked at the S-meter, I was surprised by the signal strenght.
Then I realized that I could have made the QSO with 5 mW.
In a contest it's (almost) impossible to make a second QSO (dupe).
But I decided to give it a try.
I switched in the 20 dB attenuator and gave my call PA1B/QRP, now using the tag /QRP,
now with just 5 mW.
To increase my luck, I decided to use the tag /QRP for a second QSO.
I thought that if I did not use the /QRP, I could not make the dupe, but MU0GRU came back for me
and I could make the second QSO, now with 5 mW. hi
Thanks to the friendly operator of MU0GRU.

I hope to receive a QSL. Until now I received a card for a QSO with 500 mW from Guensey.

zondag 30 maart 2014

CQ WPX SSB

On Saturday I made 7 QSO's in the CQ WPX SSB.
I wondered if I could make QSO's in phone with my crippled inverted V.
Last year the top broke.
I temporarily repaired the antenna, but one wire lays flat on the roof.
In the last months, I noticed that I need more power than before in CW contest QSO's.
Also I had to rediscover the "tuner settings" for each band, after the antenna had changed.

SSB also works
Using SSB in stead of CW gives a lot more QRM in the house.
Sometime I want to hold the microphone to my ear, to listen. hi
Saturday afternoon I had one hour to operate, in which I made 5 QSO's on 21 MHz with
LZ, IS0, I and EU.    I responded to signals that were S+.

Tuning
In the evening I went on, but could not be heard. The in coming signals were S+, thus strong enough, but my QRP signal could not be heard. After not being heard by 3 different very loud stations I checked my power.
After tuning with CW, as I always do, I had forgotten to switch back to SSB, so I had no power at all.
After that I made two additional QSO's. Then I had to QRT, since the XYL went to bed.

Your signal is weak
On Sunday morning I easily made 5 QSO's on 7 MHz over short distances with DL, ON , PA and G.
Many operators told me that my signal was weak. But I have no tower, no Yagi, a less than perfect Inverted Vee and QRP and still managed to make QSO's, somtimes pushing the operating pratice to the limit at both ends.
Using QRP and a simple antenna, shows that Progation is more important than the Antenna. hi.

zaterdag 29 maart 2014

Pacemaker

De pacemaker heeft vanaf 1958 een enorme ontwikkeling doorgemaakt, zowel in de electronica als de behuizing. De eerste pacemakers waren uitwendig en waren uitgevoerd met buizen, in kasten op wieltjes.
Later kwamen de uitvoeringen met transisitoren, die toen nog op het lichaam gedragen werden.

Nostalgie
Net als mijn eerste zelfgebouwde radio, de Philips Pionier, waren de eerste getransistoriseerde pacemakers met PNP transistors uitgevoerd.
Schema van een pacemaker met PNP transistoren
Uitwendige pacemaker in Kiwi schoensmeer doosje 1958
Nu
De huidige pacemakers bevatten een complete computer, uiteraard zonder toetsenbord en monitor en worden in het lichaam gedragen. De computer maakt de pacemaker programmeerbaar en stelt deze in staat om onregelmatigheden in de hartslag op te merken en op te slaan in het geheugen. Zodat deze info later tijdens het bezoek een aan het ziekenhuis uigelezen kan worden. De pacemaker bevat ook een batterij, omdat deze langer meegaat dan een accu.


Voor het verbinden van de pacemaker met het hart worden twee elektrodengebruikt.
De elektrode

Uitvoeringsvormen van de punt van de elektrode 

De foto's zijn gemaakt tijdens de zeer informatieve bijeenkomst voor pacemakerdragers in het st Antonius ziekenhuis in Nieuwegein.  Ik heb mij hier beperkt tot het voor het "radio" Blog interessante gedeelte.

vrijdag 14 maart 2014

Homebrew 10 watt dummy load

For years I use a very simple homebrew 50 ohm - 10 watt dummy load.
At a moment, I realized that 20 resistor of 1000 ohm in parallel form a resistor of 50 ohms.

So I bought twenty 1000 ohm - 1/2 watt resistors and soldered them on a PL 259 connector.
Through the green tube runs a wire to connect the wires of the resistors to the left, with the
center conductor of the connector.
The twenty resisitors can dissipate a power of 10 watts.

The dummy was measured in a workshop of Rohde & Schwarz.
At the moment I can not find the report of the measurement.
I first wrote that the dummy load was 49.9 ohms, but I now remember
that it was 49.8 ohms.
I was surprised the resistors had an accuracy of better then 1%. hi

10 watts - 50 ohm HF dummy load
  

vrijdag 7 maart 2014

Spring

Looks like it will be spring.
We have very nice temperatures.
Yesterday my wife and I went for a walk in Rhijnauwen, along the Kromme Rijn.

Langs de Kromme Rijn
Sneeuwklokjes

vrijdag 28 februari 2014

Guust is 57

Guust
Guust is 57.
Wat een verassing.
Zo'n 40 Jaar geleden was Guust mijn favoriete stripfiguur.
De boeken zitten in een doos op zolder,
maar mogen (nog) niet weg.

Toen ik de Google doedel zag, moest ik ook aan de meeuw, juffrouw Jannie en de flaterfoon denken. Hi.

Flaterfoon

zaterdag 22 februari 2014

HA-DX contest 2014

I had great fun with low power in the HA-DX contest.

I had to rediscover, what my Inverted vee would do.
In earlier contest I experienced, that I would need the full power
on 7 MHz and 3.5 MHz.

From the Cabrillo log:
SOAPBOX:       I fixed my Inverted Vee temporarily after a storm last year
SOAPBOX:       One wire is flat on the roof, but I still make QSO's
SOAPBOX:       Had great fun with QRPp and QRP from 100 mW to 5 watts
SOAPBOX:       Thanks for the activity in the contest

On 14 MHz my antenna is still working well.


I many QSO's on 40 m and 15 m, I had to use the full power of the FT-817.
But when the S-meters goes up, I can reduce the power.
I could also make QSO's with QRPp.
I had a remarkable QSO with HG8C.
When I gave my call with 500 mW, there were other stations also calling, but he came back for me.
This doesn't happen often. hi. Most of the time I must wait, till the frequency is clear.
I even had a QSO with 50 mW with RM22HD outside the contest.

dinsdag 18 februari 2014

REF CW 2014

In the end of January I participated in the REF CW contest.
In recent years I made many QSO's in this contest with 50 mW.

The top of my inverted vee was broken last year in a storm and I made a temporaly repair. One of the wire lays on the roof.
So I had to experience how the antenna would work.

On Saturday I made 2 QSO's on 20 m with 50 mW and 100 mW.
On Sunday I made 14 QSO's on 40 m.
In these QSO's I had to use the full 5 watts of the FT-817 due to the antenna.

Further I made a number of QSO's on 20 m with a power of 50 mW to 500 mW.
The inverted vee with one wire on the roof works for 20 m.
But on 40 m it takes more power to make QSO's.

When the propagation is good, it's not that difficult the make QSO's with very low power.
On Sunday the signal of F6KNB was S9 + 10 dB. So I decided to try a power of 50 mW.
I gave my call just once and got an immediate respons. FB.


zondag 16 februari 2014

ARRL International DX CW

I started late, because the grand children stay with us this weekend.
This afternoon we went to the park in stead of participating in the ARRL int. DX contest.

My inverted Vee is still temporaly fixed after a storm last year.
One wire lays on the roof.
But I can still make QSO's even with low power in many different contests.

I need more power than the usual 1 or 2 watts, that I use most the time.
So I use the maximum power, that is about 4 or 5 watts.
Even the stations that I receive with S8 are more difficult to QSO than last year.

After a few hours in the contests there are 15 QSO's in the log.
But it's still fun to participate in this fine contest.
There was only one station, that was puzzled by my exchange 599 003, when I use about 2.5 Watts. hi
Let see what tomorrow brings.

zaterdag 8 februari 2014

DL1SDZ's WSPR spots with 0,5 milliwatt

On his blog Hajo DL1SDZ reports spots made with 200 mW down to 0,5 mW on 30 meters.
He reduced the power from day to day.

Hajo wrote me that the 4 last spots with 1 milliwatt were actually made with 0.5 milliwatt.
In the WSPR data Hajo uploaded the spots of 0,5 mW as 1 milliwatt, since this is the lowest value that can be used. (1 mW is 0 dBm)
Because my excell sheet can not calculate with a power lower than 1 milliwatt, I left the values for 1 milliwatt in the analysis of yesterday .

But today I calculated the lowest possible power for the value of 0.5 mW by hand
and made the next table exclusively for the spots with 0.5 mW.
The calculated lowest possible power is, in some spots, only one step lower.



This table show 4 spots in stead of 3.

The table below that I made yesterday, does include spots of 400 km or more,
so it does not include the spot by HB9JAQ

Click to enlarge
This analysis shows the calculated lowest possible power.
The lowest possible power is calculated from the power sent and the SNR.
The lower the lowest possible power, the better the propagation.





vrijdag 7 februari 2014

WSPR with 200 mW down to 1 mW by Hajo DL1SDZ

More and more operators discover the use of very low power with WSPR.
On his blog Hajo DL1SDZ reports of spots made with 200 mW down to 1 mW.
He reduced the power from day to day, as shown in the second analysis.

The first analysis shows the calculated lowest possible power.
The lowest p[ossible power is calculated from the power sent and the SNR.
The lower the lowest possible power, the better the propagation.

Click to enlarge
The analysis below shows electrical field strength.
In this calculation the distance is also included.
The lower the field strength, the better the propagation.

Click to enlarge
In the analysis all spot over 400 km and more are in cluded.
Thanks Hajo, for the interesting experiment.

maandag 27 januari 2014

Analysis of G3XBM's 40m WSPR spots with 5 mW

G3XBM left WSPR running with 5 mW on 40m for 24 hours.
Roger concluded that his signal was in the noise most  of the time.
He also concluded that he would need 2 W.
http://g3xbm-qrp.blogspot.nl/2014/01/40m-5mw-summary.html
The analysis below shows that the conditions changed dramaticly after the 7 spots with 5 mW.

The header of the table shows the Calculated  Lowest Possible Power in mW (Click for info), 
which is calculated from the used power (Pwr Sent  in mW) and the SNR.

The better the propagation, higher the SNR and
the lower the Calculated Lowest Possible Power will be.

The analysis
9 UTC gives the spots that were made in the hour from 9:00 till 9:59 utc.
This first line shows, that the power that was needed for the spots was 1 W down to 2 mW
In this hour, half of the spots that were made with 2 W could be made with 100 mW.
The white circles indicate the power with which half of the spots could be made.
The lower the power needed, the better the propagation.


From 9 utc till 14 utc on the 18th there are 11 spots with a calculated lowest possible power of 5 mW or less. So it was possible to make spots with 5 mW.

WSPR with 5 mW
From 14 utc Roger reduces further to 5 mW and over 24 hours only 7 spots were made, shown in the yellow coloured part of the table. In the red part of the table there are no spots since the power that was used is 5 mW. In the red part I show the receiving stations and their SNR.

Back to 2 W
You would expect more spots, since the 24 hours before showed many more spots that could have been made with 5 mW. But the conditions changed dramaticly.
The last part of the table shows spots that were made with 2 W.
At 20 utc on the 20th at least 500 mW is needed.
And at 5 utc and 7 utc spots could have been made made 5mW




dinsdag 14 januari 2014

G4ILO Whispering with 20mW and 1 mW

Julian G4ILO did an interesting experiment with WSPR
He used a power of 20 mW and 1 mW and was heard over large distances.
I made a table of the spots with both 1 mW and 20 mW.
I left out the few spots that were made with 50 mW.

The table below shows an interesting phenomena.
When 20 mW is used, the  calculated lowest possible power is 20 mW or less.
When 1 mW is used the calculated possible power is 1 mW or less.



The Lowest Possible Power is calculated from the used power and the SNR.
The SNR for a solid copy with WSPR is -29 dB.
When a signal is received with a SNR of -19 dB, this signal is 10 dB stronger, 
so the power could be 10 dB reduced and still be solid copy, but then with a SNR of -29 dB.
The Lowest Possible Power is 20/10 = 2 mW 
22 Spots were made with a Lowest Possible Power of 2 mW.

The tables below show the distance, the receiving station and the power that was used.