Now working on:

Still measuring.
I do have now 20 good measurments.
But making a map of the sky is no succes.
I have to program some simulations on the 64 by 64 pixel
When done i will post the results here.

Today i have data of 9 days of measuring.
Still trying to measure as much as possible

Tonight i did a last checking measurement.
The distance between the 2 antennas was 20 m.
And again a wonderfull graph.

The amplitude of the fringes is slightly less then yesterday.
So there is a so called "daily variation".

But i see a strange problem. (Also yesterday)
Until 4 hours UTC you see nice fringes, increasing in amplitude
at 2:30 UTC reaching a maximum, and thereafter decreasing in
amplitude. So this looks nice because at 2:30 UTC Cygnus-A is
exact in de maximum beam direction of the antennas.
Then at 3:45 UTC suddenly the pattern changes.
I would expect the fringes from Cygnus-A would decrease.
But, no. The fringes disappear....and the curve grows broader.
Maybe it is caused by Cassiopeia-A which comes in the beam
by that time. I do not understand this.
But more measurements and making maps possibly solves this
problem in the future.

The red vertical line is the moment of sunrise.
(I must find out when the sunrise is exactly....)
For the time being this is good anough.

Now i will start measuring every day at an other position
following a rectangular grid.
First a quick mapping of a 4 by 3 positions grid around
11 meter baselength.

19-1-2015 The telescope is now ready for use.

To night i received very nice fringes with a base
of 20 m. That is not bad for a distance of 10 wavelenghts.

I put some photograps in the menu item:
Experiment 6: 146 MHz Phasing Interferometry.

After some trial and error i found the best lenght
of the extra coax cable in the Eastchannel.
0.23 m. was the best lenght.
Now the two telescope channels are exact in phase.

The extra piece of coax in the eastchannel of the telescope
just before the frequency convertor.

The graph above proves the coherency of both channels.
If i put a noise-transmitter at equal distance to both antennas
the phase is exact 180 degrees.
see below for explanation.

This is the phase calibration experiment in the field.
Left the marking stones on which i put the small noisetransmittor
and right the 2 antannas of the telescope.

I think, i am ready for the measuring of the stars....

I measured the distances from the antennas to the point
where the graph tells me that that point is the middle.
The one distance is 20.30 m. and the other distance is 20.65 m.
So the difference is 0.35 m.
So the time the signal needed to travel from the antenna to
the soundcard is in the one channel x seconds longer than
in the other channel. x is the time the signal travels
over 0.35 m. of air.
So i must add in the other channel a piece of coaxial cable in
which i get a delay of x seconds.
That will be something like 0.25 m. ( i think )

I have to do the experiment after that an other time.
Let's see what happens.


I made a plan to check the phase difference between the
two channels:
I made a very small noise transmitter.
I draw a line parallel to the base of the two antennas.
The distance between the base and this line will be
something like 20 m.
I have to find the middle of that line so that the distances
to the 2 antennas are exactly the same.
Then i put the noise transmitter on a lot of points on
this line and do a measurement for every point.
If i put the calculated crosscorrelations into a graph,
i have to find a minimum at the middle of the line.
But this days it's raining cats and dogs.. so i have
to wait until we have a dry day.

( Why a minimum? You would expect a maximum.... because
the distances to the 2 antennas are the same.
Well, the left antenna receives the signal from the right
and the right antenna receives the signal from the left.
So there must be a phase difference of 180 degrees.. so
a minimum in the graph)

If i am wrong, so please inform me.....

In the evening is was not raining anymore, so i did the
phase calibrating experiment.

Above the result of 29 measurements with the noise-transmittor
on the line parallel to the Baseline.
At the red line, the transmittor was just in the middle
At that point the distance to both antennas is exactly the same.
Every dot is a measurement 20 cm farther afield from this centre.

I expected that the minimum of the curve would be at the red line.
But it is not......
I have to think about this.

Yesterday at 16:00 UTC i changed the Base between the two
antennas from 8 to 12 meter. Let's see what happens.
there are still 2 things to do:
1. I have to find out why the signalstrenght of one channel
varies much more then the other.
2. I have to measure the phase difference between the
two channels.....

What shall i do:

The telescope is ready to use now.

With the 3 elements beam i can see fringes coming
from Cygnus-A and a few hours later fringes coming
from Cassiopeia-A
There is only a small timespan in which i measure
the two sources.
If i make a map of the sky at that time, i will see
both sources.
But is that what i want?
I showed that already with my 31 MHz experiment.

I like to see something else.. but what?
Are there other sources within my sensitivity?
Maybe it is an idea to measure just between
Cass-A and Cygn-A. In that case , my antenna
attenuates both sources and so i can maybe find
something between that sources....
Maybe i need then an antenna with more gain and
a smaller opening angle.

I have to think about that the next days.

I can have a look at the astronomical atlas and
see which sources i can try to find.
But that is not my hobby, i like to find it
by myself! Finally, for me it is a sort of
retro investigation. Just for the fun.

If you have an idea.. please mail me.... ---> without the xxx

Just for the fun: 3 presentations of one day measuring.
Uh... only the first 9 hours

The frequency spectrum of a 35 seconds during measurement at
06:00 UTC. Horizontally the frequency from 0 to 5 KHz and
vertically the amplitude.
Upper left graph is the West-channel and the upper right graph
is the East-channel.
You see a 5 KHz band with a dip just in the middle. That is
the Weaver frequency... ( produced by the weaver detector)
The lower graphs represent just a millisecond of the signal
amplitude plotted against the time ( horiontal)
Left graph is the West-channel and the right graph is
The East-channel

A waterfall graph of all measurements from 00:00 UTC to 9:30 UTC.
You see only the West-channel
It looks as a "noisy business"
Horizontally the frequency and vertically the time of measurement.
the colors are the amplitudes.. Red is strong and blue is week and
yellow and green in the middle.
the only thing you can see is the "Weaver frequency" at 1.5 KHz

This is whatfore i am measuring: The crosscorrelation of the West-
and the East-channel.
Every dot is a calculated crosscorrelation of the West and
East channel measurements.
Horizontally the time in UTC and vertically the value of
the crosscorrelation.
The calculation of this graph takes about 20 minutes.
about 540 crosscorrelation calculations. One for every minute.

I can only measure fringes during the night, because
the signals coming from our sun are awful strong
and disturbe the week signals from the stars.....
That is a pitty.

This is the new almost operational radio telescope.
The result of 3 months solving all sorts of problems.

Left the stationairy antenna.
In the waterproof tube is the frontend and the extra
10 db broadband amplifier.
Something more to the right the waterproof box with
amplifiers and frequency convertor
Behind that the Astro Rover with the mobile antenna on it.
At the right side 60 meter away the darkbrown caravan with
the receivers and the computer.

The setup now is: ( 2 times )
3 element beam
frontend for 146 MHz with noise figure of 0.2 db
That is the maximum nowadays without Helium Cooling.
10 db broadband amplifier
20 m. coaxial cable
10 db broadband amplifier
the frequency convertor, which transforms the 146 MHz
to 31 MHz.
18 db broadband amplifier
80 m. coaxial cable to the caravan
The 31 MHz direct conversion ssb receiver (weaver detector)
A Old XP computer with soundcart ( 2 channels )

And that all for listening to the very week signals from
the stars......

Now i have to check the coherency between the 2 systems.
When Cassiopeia-A is exact in the Norht, i have to get
a maximum in the fringes.....
But that is not the case... so i have still to do
some homework.
i can do 2 things: Or with the calculation of the
crosscorrelation between the 2 channels or changing
the lenght of one of the 146 MHz coaxial

The Astro rover

I rebuild the astro rover. Now is has a 3 element 146 MHz beam on it.
So it is easy te place the mobile antenna at an other position.
For the measuring project, i have to do that every day.

This is the new 3 element beam in the final form.
It works very nice. The gain will be something like 5 db.


the 3 element beam and the waterproof tube containing
the frontend and an extra 10 db broadband amplifier.

Still struggling with a good frontend amplifier.
I build a new frontend and then measuring for a few
days. What i need is a frontend with a very low
noise figure. The better the noise figure the better
the fringes are.
The best i found now is a frontend with a ATF-54143.
This is a Low noise enhancement mode psdeudomorphic HEMT.
I think this the best FET there is nowadays.
The situation is now ( 2 times ):
first a 3 element beam pointing Norht. Then the ATF-54143,
then a 10 db broadband amplifier. Then 20 m. coaxial cable,
then again a 10 db broadband amplifier, then the frequency
convertor, then a 20 db broadband amplifier, then 80 m.
coaxial cable to the receiver on 31 MHz.
I have to measure still a few days to be sure, this is
the best possible situation.
So you see, i am fighting my way to the best solution.

I mounted a third element to the antennas ( a director)
and see the effect of it.

Above: The difference between a 2 element beam and a 3 element beam
The yellow curve is the crosscorrelation during the night
of a 2 element beam, and the white curve is of the 3 element
Horizontal is time between 0 and 9 hour UTC and vertical is
the calculated crosscorrelation. Each dot is a measurement of
35 seconds.
So a 3 element beam it will be!

The test 3 element beam.

i put some photographs of the test setup on the site.
see the menu item: Experiment 6
146 MHZ phasing interferometry

I found a quiet frequency. To night i did a
wonderfull measurement on that frequency.
This is good enough for the making of my map
of the sky! ( See below)

This night i did the perfect measurement. Good enough for a map of
the sky!
Baseline is 8 m. and the frequency is 146 MHz, antennas are
two times a 2 element beam pointing North with 30 degrees

30-11-2014 This night gave good fringes.
See below

With this fringes (above)i think i can make a map of the sky.....
frequency = 146.000 MHz and the Baseline is 8 m. West-East.
The red line at 08.4 hour is the sunrise. This gives extreme
strong fringes

After a awsome month of working, building coherent amplifiers and testing i get some
reasonable results.
The fringes which i got a month ago were coming from the sun.
When i calculated the Right Ascension and the declination i every time
came at the son. So is must be the sun.
But where are the fringes from CassA and CygnusA???

Now i have a lot more amplification at 146 MH, and now i see the fringes
from the stars.

Above is my best result until now ( baseline between the 2 antennas is 8 m.)
the red line is the running mean of the crosscorrelation and the yellow line
is the calculated simulation of Cassiopeia-A
Between 0 and 8 hours UTC you see some fringes from the stars.
They are week but not bad at this stage.
And they look very much like the simulated fringes of Cassiopeia-A.
the fringes from 8 to 14 hours UTC are coming from the sun, and are
very strong. So strong that they disturb my plan to make a map of the sky.

The setup now is as follows:
The antenna is a simple dipole antenna for 146 MHz, then comes a smallband
amplifier which has a noise figure of 0.2 and amplifies 18 db's.
Then comes a 10 db broadband amplifier. Then comes 20 m. coaxial cable.
Then comes again a 10 db broadband amplifier. Thereafter comes the
frequency convertor which transforms the 146 MHz signals to 31 MHz.
Then comes a 18 db 31 MHz broadband amplifier.
Then comes 80 m. coaxial cable to the caravan in which is the
old weaver receiver.The signal from the weaver receivers goes to the
soundcard of a simpel XP computer.
Of course everything before the computer is double.
So after the dipole antenna i have 38 db amplification, and 18 db in the
31 MHz system. That makes 56 db amplification... this is unbelievable!
And still small fringes from the stars...
What to do now?... i need stronger fringes to make a map.....
I think i will start some experiments with 2 beam antennas.

The same picture in more detail.
Again: red is the measured crosscorrelation and yellow the calculated
simulation of Cassiopeia-A

After a long pause, i started again an interferometry project.
This time i like to make a map of the sky at 146 MHz.
During a month of experimenting i build a frequency convertor
to change the 146 MHz to 31 MHz. So i can use my old 31 MHz single
conversion ssb receiver with a weaver detector.
This receiver was used for my 31 MHz project and gave
nice fringes.
I also changed the 31 MHz frontend amplifiers to 146 MHz.
Now after days of experimenting i saw the first fringes.
The main problem is the signal loss at 146 MHz in the coaxial
cables. So i needed extra amplifiers and that was a big problem.
The amplifiers were most of the time nice oscillators.....
But to day i found a configuration which works stabil.
The situation now is: a 146 MHz dipole, a frontend amplifier
directly connected to it. 5 m. coaxial cable. Than a 10 db
cable amplifier. Then 20 m. coaxial cable to the frequency
convertor. Then after that again a 10 db cable amplifier.
Then 80 m. coaxial cable to the 31 MHz receiver in the caravan.
The lf signal from the receiver is connected to the soundcard
of a normal home computer.
This computer registrates all signals as .WAV files.
Then the same homebrew software as for the 31 MHz project
does the job.
It calculates the crosscorrelation between the 2 lf signals and
all other things i need.
This time i try to get a better map. Not a 16 * 16 pixel map,
but a 64 * 64 pixel map.

I will get all kinds of problems, but to solve this problems
is my hobby.

Above: this are the first fringes seen with a base of 8 m.

Eureka, i found noise coming from the center of the milkyway
at 146 MHz.

After looking at a lot of graphs i thought to find some
noise curves not correlating with the temperature graph.
After blowing up the graphs i saw for the first time
the evidence of noise coming from the stars.
See graph below.

As you see above, the noise curve ( white and red) shows a
small maximum at 1.25 hour UTC.
The temperature curve does not show a minimum at this time.
So, this must be a real maximum, not coming from the
receiver temperature, but coming from the stars.
At this time the centre of our milkyway was exactly in
the beam of the 5 element beam antenne, which was pointing
south. This is the evidence of receiving something from
the sky.

So now i can think about next steps to go.
Next step will be:
Building 2 HF amplifiers with 2 antennas for 146 MHz to do
some adding interferometry. Later i can use this
for phasing interferometry.

After 2 months of measuring with the 5 element beam
at 146 MHz, i am still not sure where the received noise is
coming from...
I do not know what to do now!
See below for a normal graph.

Above a daily receiving graph. The white/red line is the
received noise and the green line is the simultanely measured
temperature near the receiver in the caravan.
The two graphs seem to be mirrored.... So you only see the temperature
effect on the receiver.
A higher temperature gives a weeker noise signal.
So where is the noise coming from the stars...
Or all noise is coming from the stars or there is absolutely
no noise coming from the stars.
The small spikes are coming from a satelite.

Last days i was also busy trying to receive some noise from
the stars at 146 MHz.
If i do receive signals, i will try to make 2 coherent receivers
for 146 MHz, and 2 small beam antennas.
This as a start of my 146 MHz phasing interferometry project.
In the beginning i put a 5 element yagi beam antenna just
beside the caravan.
It was not possible to be sure that the noise was coming
from the stars, because of all kinds of trouble coming
from the computer or the computerscreen.
Today i put the antenna about 30 m. from the caravan, using
a 35 m. long H43 coaxal cable.
I hope the received noise will now come from the stars and
not from the computer.
I hope i get now a certain pattern of the signal over 24 hours.
When i change the azimuth of the antenna by 90 degrees, i
must get an other pattern......
If that is the case, i am sure i receive noise from the stars.

Above 2 photographs of the 5 element 146 MHz Yagi beam pointing
azimuth 45 degrees and elevation 45 degrees.

Last day's i was busy with trying to find the beaming direction of
the 1.5 m. disk.
I made a computer program which has an auditable s-meter.
The stronger the signal, the higher the frequency of the beep.
With this tool i could find the exact position of the sun
into the disk when the disk is directed to the sun.
The maximum signal comes when the shadow of the lnb is 2 cm
out of the centre of the disk.. So , that is not bad, i think
If somebody likes to get this program,, so mail me.
It is programmed in Pure Basic and works in windows.

This days making a 2D-driftscan with the 1.5 m. disk and the new lnb.
Before i start Seti-receiving with this setup i must exactly know
from which direction the disk is receiving and what is the beamwith.
I stopped the 31 MHz seti-receiving because there are too much earthbound

I put now a new lnb in the big disk of 1.5 m. ( somebody gave me this lnb)
The Twin Universal LNB TTW 002 of Triax.( 10.7 to 11.7 GHz)
This lnb is more sensitive then my other ones.
First i will make a driftscan of the sun to see how it works.

I did listening now for about a month at 12 GHZ and at 31 MHz with 2 Seti stations

At 12 GHz i did receive a few times a carrier within the bandpass of the receiver.
The FFT plot shows it clearly, but when listening to the .WAV file i do not hear
anything. (That is because the FFT has 15 db more sensitivity than my ears.)
I do not know what to do with this carriers......
I am working on a program which does an autocorrelation on the data, but i can not
get it working... ( if somebody can help me... so please, help me)

At 31 MHz i did hear 3 things...
1. The sounds typicaly coming from Jupiter...
2. The signals coming from Tjirpers... ( MUF_diggers).
         If The MUF is high anough i can hear this signals.
         i do hear this signals only at daytime.
3. A telegraphy like signal with a changing frequency.
         80 years ago the militairy telegraphy transmitters made this kind of signals.
         But it is no morse telegraphy.. or it is made by a very bad telegraphist.
         You heare dashes and dots, but the lengths are not right.
         Because i do hear it only in the morning, it will probably come from Eastern
         Europe of Asia.
        I did hear it for 5 days during the whole morning.

Above the carrier at 12 GHz... To week to hear, but the FFT sees it.

Above the noise signal coming from Jupiter at 31 MHz

Above the morse-like signal at 31 MHz.

         My SETI-station is ready and working.

I installed my SETI-station and it is working now.
It is listening at 31 MHz with the same antenna and
amplifier i used for my adding interferometry and
my phasing interferometry station.
The amplifier is connected via 100 m. coaxial cable
to a AR3000 receiver in my house.
I put the antenna so far from my house to avoid
all the interference from my house apparatus.....

See for the setup, the results and all the software
i do use, experiment 5 in this site.

please, can somebody test the software and inform me?

Today the SETI software is ready and works perfect.
I can see the carriers of airplaines which i can not
hear with my ears from the loudspeaker.
The differece with my ears is 15 Db.
So my seti station shows signals which my ears do
not hear.... that's fun
When my experiment now with cassiopeia-a is finished
i will start this software.
The program does listen 15 seconds to the receiver.
It makes a .wav file of this 15 seconds.
Then i read 300000 values from this .wav file.
Then i do a FFT over this values.
When there is no signal in the Frequency domain the
.wav file will be deleted.
So after some days of listening i only need to listen
the the interesting files.
I know: i will not receive anything.. but it is just for
the fun.

The last days i was developping software for my Seti station.
The computer soundcard gets the noise from the receiver
and makes a .wav file of it.
I collect data during 15 seconds every minute.
Then i do a FFT on this data and if any value in
the frequency spectrum is higher than a certain value
i will keep this file. If not, this file will be deleted.
So if there is any carrier in the receiving bandwith
i can listen to it later.
When i will install this Seti station i must do a
Lot of calibration experiments before it will be
My first experiments will be at 120 MHz on the
airband. I will tune the receiver on a frequency
where week aircraft signals will be.
When it works okee i will change to 12 GHz and the small

Today a started a last attempt to receive some signal
from Cassiopeia-A.
Now after the sun-experiment i do exactly know the
beaming properties of the small disk.
with this information i directed the disk to
a point where Cassiopeia-A will pass.
After a few days of measuring i will know more.....

To get the value of the beam elevation of the small disk, i made
during the last 19 days a 2D-driftscan of the sun.
Now i can see at what elevation this disk receives maximum

Above a 2D-Driftscan of the sun, made with the small disk.
Every peak is a sun pass through the disk-beam.
The disk was fixed to one position.
In this graph the peaks where shifted to the same y position and some time
to the right. So vertically stands the strenght of the signal and horizontaly
is time in this graph.
Every day the sun has a smaller elevation at the azimuth of the
disk. So the first day the sun stood above the disk-beam.
The second day the sun stood a bit lower and gave some more
signal to the receiver.
So about day 9 ( in the middle of the graph) the sun
gave maximum signal to the receiver. So the elevation of
the sun at that day gives the exact elevation of the disk-beam.
When you work with a fixed disk position, this is a nice and simple
methode to find out at what direction your disk is looking exactly.
Just one pass is anough to get the azimuth of the beam.

I installed a smaller disk to see what happens.
The disk is asymetrical, horizontal 70 cm and vertical 80 cm.
See menu item photographs

Last days i was busy with measuring the sun.
I made a graph of the moments the sun was in the centre of the beam.
There is a system in it.
It must be caused by the excentricity of the earth track around the sun.
See menu-item Results for this graph.


5 days drift scan of the sun.
first day is white, second is red, then green, blue and yellow.
The maximimun shifts every day 1 minute.
the graphs show only the running mean of 10 values.
At the left side of the left slope you see a side lobe of the
antenna system.
Horizontal scale is time in hours UTC and vertical a sort of voltage.

I plan to measure the sun for about 10 days and see what happens.
I do not change anything... just continuous measuring.
At this moment i already have 4 very nice pictures of the sun passing.
In the mean time i am thinking about my new experiment.
The phasing interferometry with 4 antennas and 4 ssb receivers
at 150 MHz.

Yes, i measured the sun!!!
Now i can get an idea about the openings angle of the system
and the sensitivity. ( not very sensitive!!)
The openings angle is something like 2 degrees.

Ohhh still nothing to see in the graphs.
So i did change the orientation of the disk to the sun.
This was an easy job, because the sun was shining.
I only had to turn the disk in a way that the shadow of the
LNB was at the centre of the disk.

I start to do 2 weeks of measuring and changing nothing to get
a feeling of what i am measuring.
The disk is still pointing to the point where Cassiopeia-A will pass.

Ohhhh nothing to see... i do see only a changing in signalstrenght
by day and night. I think this will be caused by temperature.

The system is ready.
When i connect a spectrum analyser to the LNB i can see some
noise caused by satellites. So the system is okay!
So today starting measuring at 12 GHz with the disk orientated at a point where
Cassiopeia-A will pass. ( Azimuth = 40 degrees and Elevation = 40 degrees
Pass at 15:15 UTC)

After a break of a few month i decided to do a quick and dirty experiment
with a 12 GHz rig.
A few years ago somebody gave me an old 1.5 m disk.
Now it was nice to do an experiment with it.
(Just thinking about something else than phasing interferometry for
a few days)
I found a LNB and started setting up the installation.
In house a had all the needed apparatatus and most of the software.

         Phase Interferometry

One month of measuring (with the same baselength and direction) gave 19 reasonable measurements.
The others had big thunderstorms and all kind of trouble.

Below two graphs of this 19 measurements.
Only the nightly part of them. The day parts are very bad.

Above the 19 measurements plotted at different heights in
the graph. It looks good.....
(Only the walking mean of 20 minutes is plotted)

Above the same 19 measurements plotted at the measured y-axis position.
What you see is the socalled daily variation.....
Again only the walking mean of 20 minutes is plotted.
So i concluded that the daily variation of any measurement
gives a variation of 20 percent of the amplitude.
(the bandwith of all the curves along the y-axis)
So any crosscorrelation value has a fault range of 20 percent!
I think The 2D-FFT algoritme that makes the maps of the
radio sky can handle this..... ( i hope)

All sceduled measurements are done.
In night time the measurements are usable, in day time not!
Now i am measuring for some 20 days with the same base line to
get a good insight in the so called "daily variation"
I will here publish all this 20 measurements when they are done.
In the mean time i start calculating a lot of maps of the sky.

The new measurements give splended results.
Below you see a map of the sky with only 25 measurements.
13 new ones ( the left part with the shortest baselines) and
12 old ones ( of a year ago ) ( the right colums)
At night times the measurements are perfect, but during the daytime they
are hopeless.....

The upper circle is Cassiopeia-A
The middel circle is Cygnus-A
The lower circle is the milkyway.

After a long time of trouble, i can start measuring again.
I have to measure the short distances again ( the last 90 measurements)

The antenna amplifier is repaired. the first fringes are seen now.
First i am going to put the astrorover at known locations to check
the fringe picture and then i can calibrate the time problem
with the latest 90 measurements...

One antenna amplifier broke down. The transistor is blown up.
And, the computer which did measure the last 90 days, had probably a wrong running clock.
It was running at dutch winter time, but i am not sure.
So i have to do a few days measuring to check the time calibration.
But i can not measure now.

First repair the amplifier. I have to find the good transistor and than replace it.
But i made the amplifier so small and did use so much copper shielding that i have
to dismantle the complete box.....It is a bloody job.

A new -9 volt dc-isolated power supply cube arrived.
Now the receivers are working nicely.

The receivers stopped working. One of the power supplies stopped... ( the receiver
uses 4 power supplies... ( 3 Volt, 5 Volt, 12 Volt and a -9 Volt)
The -9 Volt one stopped.

I had to stop measuring because of "conditions" on the HF-bands.
At day time i do receive too much earthbound disturbances.

Most of the interferometry measurements are corrected now.
(Automatic data collection from the measurements to make maps of the sky
can not use faulty data)
Below you see a raw data measurement and the corrected version.

Above a raw data graph

Above the same graph but now corrected.

In 200 days i collected 1 TByte of raw interferometry data.
Next weeks i have to correct faulty data
For that i am writing a grafical correction program.

Still measuring with short baselines, but daily thunderstorms disturb the results.

My new Pure Basic 2D-FFT program is a fabulous tool !

Because i can not do now real star measurements i decided to do some stand-alone experiments.
I took an old computer with an unknown soundcart and installed it in the caravan.
I put a noise-transmitter at 250 m. from my antenna field and measured a lot of positions with
the astrorover.
I did 42 measurements and calculated maps with a different amount of measurements.
With only 4 measurement you get allready some sort of a map.
with 9 measurements the map is some better.
with 16 measuremts it is allready a real map.
with 25 measurements the map is better.
with 36 measurements the map is still better.
with all 42 measurements the map is the best of all and the direction of the found source is
exactly the azimuth of the noise transmitter.
See the maps below

So i am sure my method of measuring is good!

The measuring computer crashed..... The hard disk crashed.
So, for the time beeing i can not measure anymore.

I had a good look at my new 2d-fft program ( now in Pure Basic) and saw that it gave a nice map of the
sky. Only north , south east and west where at the wrong position, but flipping each quadrant
solves that problem.
I don't know why, but the old Quick Basic program did not gave a readable map....
So, while not knowing why, i am happy with the new results.
Now i could do the quadrant-flipping and did some cosmetics on it to produce nice maps.
Below you see a map calculated and plotted with the new Pure Basic programs.

You see the measured map top-left.
More to the right you see the positions of the astro-rover ( second antenna) and the crosscorrelation
values of that positions. Norht is above and the first antenna is top-left.
Further you see the simulated maps of CassiopeiaA, CygnusA, TaurusA, and 2 of the milkyway.
Bottom-right is a normal star-map of the radiosky.
Blue dot is CassiopeiaA, green is CygnusA, yellow is TaurusA and red is the milkyway.
For all maps: the north is above, the south is bottom and east is at the right side.
The elevation is at circles whith 90 degrees at the middel of the maps.
Because the left part of the map is symmetrical i did not draw it.
So TaurusA has an azimuth of 315 degrees, but it will be measured and plotted at 135 degrees.

You see most of the simulated radio-sources in the measured map at about the same position as
in the simulatied maps and in the map of the sky bottom-right. TaurusA is to week to see.

I am halfway my measuring scedule and the results are great.
Below are 2 plots of the results.
I did now use new programmed Pure Basic compiled software.
The program which does the 2D-FFT calculations and the plotting has about 4000 basic code lines.....
The calculation of the crosscorrelation together with the temperature compensation is an
other program. This program uses 15 minutes of calculating for 1 day of measurinig. (!)
(Realise one day of measuring gives 4.5 GByte of data)

Upper left graph is the result of the 2d-fft calculation of the measurements, together with the locations
of astro-rover ( black dots). More to the right is a location map of the astrorover ( second antenna).
The color represents the relative value of the crosscorrelation at this position.
Below right is the normal plot of the known radio sources at the sky.
Blue is CassiopeiaA, green is CygnusA and yellow is TaurusA. Red are 2 parts of the milkyway.
All other graphs are simulations of this sources in the same way i calculated the map upper left.

I am now halfway my mapping scedule.
I transfered all my Quick Basic and Just Basic programs to Pure Basic.
I learned a method to corrigate for temperature variances in the antenna amplifiers.
So the day to day temperature problems are solved.
The first mapping results are growing.
In a few days i will publish a few maps here.

Below you see one of my new measurements with the soundcard and 36 seconds of measuring per minute.
Base = 54.6 m. West-East           freq = 30.984 MHz

I am using now a soundcard as digitiser.
TheFigure below shows the difference between my old measurements and the new ones.

All my measurements until now are done like the lowest curve.. ( I digitised
every minute for 0.5 sec)
The middle curve is digitised with the soundcard for 3 seconds per measurement.
The upper curve is done with the soundcard for 36 seconds per measurement.

So, this will improve my maps!!
I will start now with a new mapping scedule.

Last months i was busy with a new compiler, to calculate and make the graphs.
It is the Pure Basic compiler.
A very fast, modern compiler, which is windows orientated. It works also under Linux.
This compiler can handle a computer soundcard. So this gives new challenges!
I made a setup to measure every minute for 3 seconds.. i get then 66000 samples per antenna.
I costed me 3 weeks to translate the quick basic programs to this new compiler.
In the mean time measuring everyday.
I made the grid smaller... grid distance is now 4 meter. (was 8 meter).
I had no time to make maps....

You should say: you see 4 sources.....

Still measuring every day
I also made some extra software, to get a better overview of the measurements.
Below you see 37 days of measuring. Every line is one day measuring.
The time x-as is in MST. (not UTC)

This 37 measurements give at 14:30 MST the map below.

The figure right below is a calculated map of the sky here in Delfzijl at the same time
as my measeured map.
It is good to know that the milkyway is a broad line of radiosources from what i call "top milkyway"
over the "mid milkyway" to outside of this picture.

Probably there is nothing wrong in my software, so i think i have to live with the ambiguous
character of the results and simulations.
So i decided to do it the other way around: ( not very scientific...... )
First calculate a map of my measurements, than make simulationmaps of the brithtest radiosources and
then try to find the simulated sources in the map.
Therefore i made some overview software:
In one picture i can see the map of my measurements, the location of the used antenna positions,
the simulated maps of CassiopeiaA, CygnusA and the milkyway (or TaurusA)
Because of the way of sampling, i can make a picture for every minute.
At some moments i can find the simulated sources in the measured map.
At other moments it is completely rubish....
In the mean time i take every day an other location for the antenne and continue the measuring.

There is something terribly wrong with the maps i can make now.
When i simulate posititons for CassiopeiaA for all 24 hours a day, i see that it comes a few times at the
the same location on the map.
That is rather ambiguous... so my maps do not tell where the source is!!!!

I made some nice programs:
A 2D-FFT program, A mapping program and a 2D-Simulation program

My mapping sequence will follow a rectangular 16 by 16 grid with nodes every 8 meter.
Every measurement will will take one day of measuring.
This 256 measurements ( 256 days of measuring.....) will give me a map of the sky.(i hope)
At node (0,0) stands one inverted V antenna.
The other inverted v antenna ( on the astro-rover) will stand every day at an other location,
following the 16 * 16 grid.
So i get every day a graph like i showed earlyer.
To be sure that the whole thing will work, i made a simulation program which calculates the
crosscorrelation value of every antenna position in the grid on a certain time. Let us say at 01:00 Hours MST.

Then i made a mapping program which can show all values at the right position within the grid.
It is a program which shows 16 * 16 coloured pixels. Every pixel is one antenna position.
Because the pixels give a coarse picture, i made a contouring program as well.
This program shows contourlines within the pixelmap.
Now slopes in values are clearly visible.

To be able to make a map i developped a 2d_FFT program.
I am not sure... but they say: it will give a map.....
When i did experiment with this 2d_FFT program it was clear that it delivers a map indeed.
So i can now make a map of my simulated data, and maybe of my real measurered data.

A map of the simulated crosscorrelations at 03:00 hours Mean Sideral Time.
The map has 2 identical parts. The upper and the lower part. This parts are mirrored.
I don't know why... but i can live with it.
The yellow dot is the position of CassiopeieA at 03:00 hours MST.

To control all program's i made a map for every hour. This proved my program's are correct.

             01:00 MST                          02:00 MST                          03:00 MST                          04:00 MST

             05:00 MST                          06:00 MST

Above: For every measurement, i made until today, you see one square at the top of this graph.
So you see 25 measurements. The color is the value of the crosscorrelation value at
0.4 Hour MST. The North is pointing to the top of the map.

Above you see the map i made with this 25 measurements....
In the upper-right corner you see CassiopeiaA..... ( i hope....)

Above you see the map i calulated from the simulated crosscorrelation values of the same 25 grid nodes.
In the upper-right corner you see CassiopeiaA.

30 august 2010

Before i can start my mapping program, i needed a method to change one antenna to lots of places
without too much difficulties.
Therefore i made a small vehicle with an antenna on top of it, and i called it: The AstroRover.

The AstroRover.....

I put the antenne on an old metal frame of a caravan, and so i
can move the antenna to any place i want in a few seconds.
The wind can not blow it away because it is quit heavy.

Now i can start my mapping program. I will put the antenna every day at an other place,
following a rectangular grid.
First grid will be 4 by 4 positions. ( So 16 days of measuring)
In the mean time i can create the software programs to make a map of the sky.
I also try to get, compile, and use the Miriad software program.
Miriad is an radio interferometry data reduction package for users of the
Australia Telescope Compact Array (ATCA)
It is a free program which is running on Linux computers.
So i took an old PC and put Ubuntu (Linux) on it, and tried to compile the Miriad progam...
.... a hell of a job......
But maybe i will succeed.....

         I made some nice examen programs


16-July-2010 This program shows all the information of one day measuring.

Above results of the 15-july-2010 day measuring. Base = 8.54 m. Freq = 31.0 MHz
Top left is the cross correlation of the two receiver signals.
Top right is the total power of the same signals
Base Left is the maximum top-top voltage of both signals.
One receiver produces some more signal than the other.
Base right is the offset voltage of both signals which are being digitised
by the digitiser. Because this digitiser only can digitise voltages between zero
and 5 volt the receivers produces this offset voltage.
to calculate a crosscorrelation, you must subtract this voltage from the measured
voltages to get a nice graph.
In fact this offset voltage for this graph is calculated as the mean voltage of all
8192 ad-samples for one measurent of 0.5 sec.

Above the cross correlation of the same measurement in more detail and with a simulation of 4 possible sources.
Blue = CassiopeiaA
Green = CygnusA
Yellow = TaurusA
Red = Top Milkyway

Above is a picture of the program which i use to examen 0.5 second of measuring.
i can see the frequency spectrum of both receivers
when i push the WAV button, i hear the sound of this 0.5 seconds.

         First results are found

( 18 june 2010) The new phasing interferometry rig is ready and running.

The first fringes are seen.

The first quick and dirty results, a cross-correlation of the two receiver signals.

below the 3 simulations:
upper : CassiopeiaA
middle: CygnusA
below : Top Milkyway
The curve is measuring result of 18 june 2010

(6 june 2010) The last months i was busy creating and adjusting the new rig to do the phase-interferometry.
The software is almost ready; the digitiser is ready and works perfect.
The two coherent receivers will be ready in a few days.

The software i wrote in Just Basic, a free basic compiler with a windows alike look.

Just now a few examples of it.

the fase interferometry telescope uses 2 antennas, 2 coherent receivers and one digitiser.
The digitiser samples both receiver signals.
So the first sample is from receiver A and the second sample is from receiver B,
the next sample is again from receiver A and so on.....

The software makes for every channel one file and does a Fast Fourier Transformation on it.
The results gives the next graphs...
At least the software calculates the phasedifference at 1000 Hz between both signals.

above, both receiver channels got the same 1000 Hz signal.
The left upper and bottom graphs shows channel 1
the right upper and bottom graphs shows channel 2
the upper graphs shows the frequency spectra
the lower graphs shows the received signal ( the first 100 samples)

The upper right graph shows the phase difference between the two signals as white dots.
The phase diference at 1000 Hz is shown in a small text box in the center

This phase dots are scaled to fit into the graph.
When a phase dot is on the horizontal line of 20 000 the phase is zero.
You see that the phase difference increased with increasing frequency.

I think i have to filter the receiving signals...... ( is that so?)
the graph above shows the result of a filtering with a band-pass filter.
It filters the signal between 400 and 800 on the x-as. That is about 700 to 1300 Hz.
as a result the phase difference is changed to about zero...
So here is a problem, because the phase did not change.......
I do have a big problem...

Above you see what happens when i couple the lf-output of one receiver to the digitiser.
The receiver has a bandwith of about 3000 Hz.
The phasedifference between both signals is increasing with frequency.
This is caused by the way of sampling... For this the phase values must be
corrected. The graph shows clearly this effect!

Above you see again the filtering problem.
The signal is now again filtered between 400 and 800.
The phase is for the whole bandpass about zer0.....

I do not know what to do with this problem.....

Klaar voor de ontvangst van de Jupiterstorm van vanavond. Even een inverted-V dipole
op 8 m. hoogte geplaatst. Een tweede AR3000A ontvanger staat in de caravan buiten beeld.

De Inverted-V dipole van dichtbij. Hij is bemeten voor 25.6 MHz.

Ik hoor de hele middag op 25.6 MHz al de branding-ruis-geluiden die van Jupiter komen.
Op 35 MHz hoor ik ze niet, ook al richt ik de 4 elements beam op Jupiter.

Helaas bleken deze mooie geluiden uit de ontvanger zelf te komen, en dus niet van jupiter.

27-10-2008 Ik ben bezig geweest om een tweede AVR-computer te bouwen. Deze computer kan

elke 2 seconden het azimuth ( en de elevatie ) van een ster berekenen. (Zie het programma

VINDSTER.BAS van de software pagina.)

Tevens draait hij de antenne naar het berekende azimuth.

Als test ga ik een paar dagen de antenne op de zon gericht houden,

terwijl de oude AVR-computer elke 8 seconden een ruis-sterkte meting doet.


Kassa! een zonneuitbarsting gemeten.

Zonneuitbarsting van de zon gemeten op 29-10-2008

Hij begint ongeveer bij seconde 1200 en eindigt bij seconde 1800

Dit is de klassieke vorm van een uitbarsting: snelle toename en langzame afname van de ruis.

5-11-2008 De laatste dagen steeds continue metingen uitgevoerd. De antenne volgt constant het
azimuth van de zon. Ook al zit hij onder de horizon.
Het zijn metingen waarin niet zo veel gebeurt.
alleen op 6-11-2008 zie ik weer een aantal spykes.

De 3 spykes rechts op bovenstaande foto's uitvergroot.

De meest linkse spyke van bovenstaande foto verder uitvergroot

De tijden die in de grafiek staan, geven het begin en het einde
van de spyke aan.