Date   
Re: Reception of C band - Problem #aero

Patrick Lindecker
 

Hello Paul,

 

>Just re-reading your original post, did you align your dish with your L band antenna, this is what I do, I fix my L band helix in place of the LNB and carry out basic alignment and then put the LNB back in >place. I usually have to tweak the alignment to maximise the C-band signal. I take my receiving laptop outside and have it next to my dish and watch the signal strength as I tweaking.

I will try to apply your method next time (fixing my poor helix antenna for L band).

 

>Regarding precision, yes with a 1.1m dish the signal is weak at best so you do have to be accurate, I find just 2 or 3 degrees off can make a big difference - I also notice on my off set dish, the indicator >scale on the dish has no relation to reality, it's showing around 30  deg elevation when it's actually pointing around 10 degrees - by looks alone the dish appears to be pointing into the ground but this is a >feature of being "off set".

My method is the following for elevation: I place my offset dish in vertical position, note the index on the dish indicator and rotate the dish by 10° according to the dish indicator. I hope it is a correct way to do for an offset dish (?).

With a gap of 5° compared to the ideal pointing (in azimuth and elevation), do you see at least a weak signal (from which you can refine the pointing) or no signal at all?

 

>Hope you have better luck today,

I must go into my sister garden as I have no direct vision of 3F5 (only 4AF4), so it is a bit complicated ☺.

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Paul Gulliver
Envoyé : jeudi 27 décembre 2018 10:29
À : multipsk@groups.io
Objet : Re: [multipsk] Reception of C band - Problem #AERO

 

Hi Patrick,

 

Just re-reading your original post, did you align your dish with your L band antenna, this is what I do, I fix my L band helix in place of the LNB and carry out basic alignment and then put the LNB back in place.

I usually have to tweak the alignment to maximise the C-band signal. I take my receiving laptop outside and have it next to my dish and watch the signal strength as I tweaking.

 

Regarding precision, yes with a 1.1m dish the signal is weak at best so you do have to be accurate, I find just 2 or 3 degrees off can make a big difference - I also notice on my off set dish, the indicator scale on the dish has no relation to reality, it's showing around 30  deg elevation when it's actually pointing around 10 degrees - by looks alone the dish appears to be pointing into the ground but this is a feature of being "off set".

 

I can't help you with the testing of the LNB but the increase in noise level when you apply power must be a good sign, I get the same effect

 

Hope you have better luck today, as I write this I have around 50 aircraft showing on my Plane Plotter map - all from my own data.

 

Cheers

 

Paul

 

On 26/12/2018 at 21:50, Patrick Lindecker <f6cte@...> wrote:

Hello Paul,

 

TKS for the advice.

Yes I tried to reverse polarity, but there was no effect ( I tried also to remove the dielectric without any effect).

 

I tried this afternoon. But I received the L band transmissions so I suppose that I could have received the C band.

 

I wonder if my LNB works. But it is difficult to test it because 3.6 GHz sources are rare.

 

>as you have the dish aligned correctly.

I have a compass for azimuth and a setting at about 10 ° of elevation is not a big problem (there is a raw indicator of the dish). My alignment was perhaps at +/-5 ° maximum, in azimuth and elevation, but I don’t think it needs to be extremely precise (in general I get a first signal and then try to adjust elevation and azimuth so to have the maximum signal). But here I had no signal at all.

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Paul Gulliver
Envoyé : mercredi 26 décembre 2018 21:57
À : multipsk@groups.io
Objet : Re: [multipsk] Reception of C band - Problem #AERO

 

Hi Patrick,

 I've been receiving 3F5 all day so I can confirm there is no problem with the satellite.

Have you tried reversing the polarity, applying 12 volts instead of 18. I notice if the dielectric is in the wrong slots within the lnb this has the same effect as changing the voltage. Ie reversing the polarity. 

 I can't think of anything else that could cause the problem as you have the dish aligned correctly.

What time of day did you try? I always find the strongest signal is when the satellite is above the equator, at the moment between 06.00 and 12.00 gmt 

 

Cheers

 

Paul

 

On Wed, 26 Dec 2018, 17:05 Patrick Lindecker <f6cte@... wrote:

Hello to all,

 

Today, I tried to receive C band from 3F5, with a 1.1 m diameter dish, applying the diagram (for a possible “Easy” document), below.

I received absolutely no signal on the expected C band frequencies (tested with SDR# and Multipsk). I checked that I could receive L band signals from this satellite (with the same RTL/SDR receiver, a LNA and a patch antenna) and this works well.

I checked the voltage on the LNBF which was correct (about 18 V but it’s true that I did not checked the quality of the filtering). If you have ideas of possible causes of problem, don’t hesitate.

 

Note: when I switched on the LNBF with the 18 V, the level on the SDR# waterfall increases of about 10 dB (which is reassuring).

 

73

Patrick

 

 

 


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Re: Reception of C band - Problem #aero

Patrick Lindecker
 

Hello Chris,

 

Up to yesterday, I thought that the TERRA P1010 also filtered the 18V but I dismounted it today and there is no capacity, so it is just a polarity switch (14/18 + 22 KHz).

I just measure the continuous voltage and the residual alternative voltage, with the LNB in charge. I find respectively 17.5 V and 0.04 V (rms) for these voltages. It seems correct, doesn’t it?

 

RR for the doubler. My only source is my HF transceiver. I will add a diode between the output and the 50 ohm resistive load, as usual, to produce harmonics (of 30 MHz). I will see what happens.

 

73

Patrick

 

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Chris van Lint
Envoyé : jeudi 27 décembre 2018 02:23
À : multipsk@groups.io
Objet : Re: [multipsk] Reception of C band - Problem #AERO

 

Hi Patrick,

Just 2 comments; what is a TERRA P1010 polarity switch?.  Is it a commercial Bias-tee unit with a built-in filter?.  Is the filter a SAW filter or an LC unit?

If you have a signal source that goes up to 2GHz, you can easily obtain up tp 4.0 GHZ, by using a passive RF doubler  https://www.ebay.com/itm/RF-microwave-frequency-doubler-RFin-1-25-3GHz-RFout-2-50-6GHz/182972166464?hash=item2a99fdb140:g:jTwAAOSwlptaOSCR:rk:3:pf:0   

There are losses of course, but for this purpose that is not an issue.

Cheers,

C


At 03:05 AM 27/12/2018, you wrote:

Hello to all,
 
Today, I tried to receive C band from 3F5, with a 1.1 m diameter dish, applying the diagram (for a possible “Easy†document), below.
I received absolutely no signal on the expected C band frequencies (tested with SDR# and Multipsk). I checked that I could receive L band signals from this satellite (with the same RTL/SDR receiver, a LNA and a patch antenna) and this works well.
I checked the voltage on the LNBF which was correct (about 18 V but it’s true that I did not checked the quality of the filtering). If you have ideas of possible causes of problem, don’t hesitate.
 
Note: when I switched on the LNBF with the 18 V, the level on the SDR# waterfall increases of about 10 dB (which is reassuring).
 
73
Patrick
 
[]
 


Avast logo 

L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
www.avast.com




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www.avast.com


Re: Reception of C band - Problem #aero

Paul Gulliver
 

Hi Patrick,

Just re-reading your original post, did you align your dish with your L band antenna, this is what I do, I fix my L band helix in place of the LNB and carry out basic alignment and then put the LNB back in place.
I usually have to tweak the alignment to maximise the C-band signal. I take my receiving laptop outside and have it next to my dish and watch the signal strength as I tweaking.

Regarding precision, yes with a 1.1m dish the signal is weak at best so you do have to be accurate, I find just 2 or 3 degrees off can make a big difference - I also notice on my off set dish, the indicator scale on the dish has no relation to reality, it's showing around 30  deg elevation when it's actually pointing around 10 degrees - by looks alone the dish appears to be pointing into the ground but this is a feature of being "off set".

I can't help you with the testing of the LNB but the increase in noise level when you apply power must be a good sign, I get the same effect

Hope you have better luck today, as I write this I have around 50 aircraft showing on my Plane Plotter map - all from my own data.

Cheers

Paul


On 26/12/2018 at 21:50, Patrick Lindecker <f6cte@...> wrote:

Hello Paul,

 

TKS for the advice.

Yes I tried to reverse polarity, but there was no effect ( I tried also to remove the dielectric without any effect).

 

I tried this afternoon. But I received the L band transmissions so I suppose that I could have received the C band.

 

I wonder if my LNB works. But it is difficult to test it because 3.6 GHz sources are rare.

 

>as you have the dish aligned correctly.

I have a compass for azimuth and a setting at about 10 ° of elevation is not a big problem (there is a raw indicator of the dish). My alignment was perhaps at +/-5 ° maximum, in azimuth and elevation, but I don’t think it needs to be extremely precise (in general I get a first signal and then try to adjust elevation and azimuth so to have the maximum signal). But here I had no signal at all.

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Paul Gulliver
Envoyé : mercredi 26 décembre 2018 21:57
À : multipsk@groups.io
Objet : Re: [multipsk] Reception of C band - Problem #AERO

 

Hi Patrick,

 I've been receiving 3F5 all day so I can confirm there is no problem with the satellite.

Have you tried reversing the polarity, applying 12 volts instead of 18. I notice if the dielectric is in the wrong slots within the lnb this has the same effect as changing the voltage. Ie reversing the polarity. 

 I can't think of anything else that could cause the problem as you have the dish aligned correctly.

What time of day did you try? I always find the strongest signal is when the satellite is above the equator, at the moment between 06.00 and 12.00 gmt 

 

Cheers

 

Paul

 

On Wed, 26 Dec 2018, 17:05 Patrick Lindecker <f6cte@... wrote:

Hello to all,

 

Today, I tried to receive C band from 3F5, with a 1.1 m diameter dish, applying the diagram (for a possible “Easy” document), below.

I received absolutely no signal on the expected C band frequencies (tested with SDR# and Multipsk). I checked that I could receive L band signals from this satellite (with the same RTL/SDR receiver, a LNA and a patch antenna) and this works well.

I checked the voltage on the LNBF which was correct (about 18 V but it’s true that I did not checked the quality of the filtering). If you have ideas of possible causes of problem, don’t hesitate.

 

Note: when I switched on the LNBF with the 18 V, the level on the SDR# waterfall increases of about 10 dB (which is reassuring).

 

73

Patrick

 

 

 


Avast logo

L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
www.avast.com




Re: Reception of C band - Problem #aero

Chris van Lint
 

Hi Patrick,

Just 2 comments; what is a TERRA P1010 polarity switch?.  Is it a commercial Bias-tee unit with a built-in filter?.  Is the filter a SAW filter or an LC unit?

If you have a signal source that goes up to 2GHz, you can easily obtain up tp 4.0 GHZ, by using a passive RF doubler  https://www.ebay.com/itm/RF-microwave-frequency-doubler-RFin-1-25-3GHz-RFout-2-50-6GHz/182972166464?hash=item2a99fdb140:g:jTwAAOSwlptaOSCR:rk:3:pf:0   

There are losses of course, but for this purpose that is not an issue.

Cheers,

C


At 03:05 AM 27/12/2018, you wrote:
Hello to all,
 
Today, I tried to receive C band from 3F5, with a 1.1 m diameter dish, applying the diagram (for a possible “Easy� document), below.
I received absolutely no signal on the expected C band frequencies (tested with SDR# and Multipsk). I checked that I could receive L band signals from this satellite (with the same RTL/SDR receiver, a LNA and a patch antenna) and this works well.
I checked the voltage on the LNBF which was correct (about 18 V but it’s true that I did not checked the quality of the filtering). If you have ideas of possible causes of problem, don’t hesitate.
 
Note: when I switched on the LNBF with the 18 V, the level on the SDR# waterfall increases of about 10 dB (which is reassuring).
 
73
Patrick
 
[]
 



Avast logo  

L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
www.avast.com

Re: Reception of C band - Problem #aero

Patrick Lindecker
 

Hello Paul,

 

TKS for the advice.

Yes I tried to reverse polarity, but there was no effect ( I tried also to remove the dielectric without any effect).

 

I tried this afternoon. But I received the L band transmissions so I suppose that I could have received the C band.

 

I wonder if my LNB works. But it is difficult to test it because 3.6 GHz sources are rare.

 

>as you have the dish aligned correctly.

I have a compass for azimuth and a setting at about 10 ° of elevation is not a big problem (there is a raw indicator of the dish). My alignment was perhaps at +/-5 ° maximum, in azimuth and elevation, but I don’t think it needs to be extremely precise (in general I get a first signal and then try to adjust elevation and azimuth so to have the maximum signal). But here I had no signal at all.

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Paul Gulliver
Envoyé : mercredi 26 décembre 2018 21:57
À : multipsk@groups.io
Objet : Re: [multipsk] Reception of C band - Problem #AERO

 

Hi Patrick,

 I've been receiving 3F5 all day so I can confirm there is no problem with the satellite.

Have you tried reversing the polarity, applying 12 volts instead of 18. I notice if the dielectric is in the wrong slots within the lnb this has the same effect as changing the voltage. Ie reversing the polarity. 

 I can't think of anything else that could cause the problem as you have the dish aligned correctly.

What time of day did you try? I always find the strongest signal is when the satellite is above the equator, at the moment between 06.00 and 12.00 gmt 

 

Cheers

 

Paul

 

On Wed, 26 Dec 2018, 17:05 Patrick Lindecker <f6cte@... wrote:

Hello to all,

 

Today, I tried to receive C band from 3F5, with a 1.1 m diameter dish, applying the diagram (for a possible “Easy” document), below.

I received absolutely no signal on the expected C band frequencies (tested with SDR# and Multipsk). I checked that I could receive L band signals from this satellite (with the same RTL/SDR receiver, a LNA and a patch antenna) and this works well.

I checked the voltage on the LNBF which was correct (about 18 V but it’s true that I did not checked the quality of the filtering). If you have ideas of possible causes of problem, don’t hesitate.

 

Note: when I switched on the LNBF with the 18 V, the level on the SDR# waterfall increases of about 10 dB (which is reassuring).

 

73

Patrick

 

 

 


Avast logo

L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
www.avast.com



Re: Reception of C band - Problem #aero

Paul Gulliver
 

Hi Patrick,
 I've been receiving 3F5 all day so I can confirm there is no problem with the satellite.
Have you tried reversing the polarity, applying 12 volts instead of 18. I notice if the dielectric is in the wrong slots within the lnb this has the same effect as changing the voltage. Ie reversing the polarity. 
 I can't think of anything else that could cause the problem as you have the dish aligned correctly.
What time of day did you try? I always find the strongest signal is when the satellite is above the equator, at the moment between 06.00 and 12.00 gmt 

Cheers

Paul

On Wed, 26 Dec 2018, 17:05 Patrick Lindecker <f6cte@... wrote:

Hello to all,

 

Today, I tried to receive C band from 3F5, with a 1.1 m diameter dish, applying the diagram (for a possible “Easy” document), below.

I received absolutely no signal on the expected C band frequencies (tested with SDR# and Multipsk). I checked that I could receive L band signals from this satellite (with the same RTL/SDR receiver, a LNA and a patch antenna) and this works well.

I checked the voltage on the LNBF which was correct (about 18 V but it’s true that I did not checked the quality of the filtering). If you have ideas of possible causes of problem, don’t hesitate.

 

Note: when I switched on the LNBF with the 18 V, the level on the SDR# waterfall increases of about 10 dB (which is reassuring).

 

73

Patrick

 

 




Avast logo

L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
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Re: Install of 4.38 freezing on install

Patrick Lindecker
 

Hello Terry,

 

Do you install in a directory at the C:\ root (as C:Multipsk), as it seems a problem of right.

 

If there is no such problem, check the download with the MD5 signature:

The MD5 signature of the downloaded MULTIPSK_setup.exe file to, possibly, check (with WinMD5 for example), that the downloading works without error, is equal to: da63f8a4e0ab1bddd40e4f70b1d76e40

 

73

Patrick

 

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de segwin
Envoyé : mercredi 26 décembre 2018 20:07
À : multipsk@groups.io
Objet : [multipsk] Install of 4.38 freezing on install

 

Hello All,

In trying to install Multipsk 4.38 it get to one part of the install and just freezes (see picture). When I go into task manager it shows that the program is no responding. 

Any thoughts as to why?

Thanks & 73.

Terry K8TJM




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Install of 4.38 freezing on install

segwin
 

Hello All,

In trying to install Multipsk 4.38 it get to one part of the install and just freezes (see picture). When I go into task manager it shows that the program is no responding. 

Any thoughts as to why?

Thanks & 73.

Terry K8TJM

Reception of C band - Problem #aero

Patrick Lindecker
 

Hello to all,

 

Today, I tried to receive C band from 3F5, with a 1.1 m diameter dish, applying the diagram (for a possible “Easy” document), below.

I received absolutely no signal on the expected C band frequencies (tested with SDR# and Multipsk). I checked that I could receive L band signals from this satellite (with the same RTL/SDR receiver, a LNA and a patch antenna) and this works well.

I checked the voltage on the LNBF which was correct (about 18 V but it’s true that I did not checked the quality of the filtering). If you have ideas of possible causes of problem, don’t hesitate.

 

Note: when I switched on the LNBF with the 18 V, the level on the SDR# waterfall increases of about 10 dB (which is reassuring).

 

73

Patrick

 

 




Avast logo

L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
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Re: Att Chris - Dish elevation control

Steve Rose
 

Hi Chris,

Many thanks for incredible elevation control arrangement photos, that is some setup!

My experience of satellite tracking is total zero but remember many years ago used high power telescope to take photos of moon craters and the problems with Earth and Moon rotation as constant movement..
Motororised attachments were available but cost was prohibitive..

I guess there has been a huge change since then with dish gyroscopes and GPS tracking to track moving object with computer control with what could be astronomical  cost..

Thanks Chris, the whole science of tracking and decoding is fascinating.
My interest here in UK at moment with Multipsk is weather balloon tracking, another great facet of Multipsk .
Cheers
Steve

Re: Att Chris - Dish elevation control

Chris van Lint
 

Hi Steve,

In principle any mechanical contraption which is capable of around 100mm linear movement would be suitable, providing it can deliver the required lift power.

Emacs!

This shows my current elevation control arrangement.  It is not exactly a master piece of engineering, but it does the job.  My mate, who has a very well equipped mechanical workshop was recovering from cardiac surgery at the time I cobbled this arrangement together.  It has the disadvantage that the anchor point to the stand prevents me from re-positioning the dish more than 10 degrees.  At some time in the future we will change this so that the horizontal stay will be attached to the stand by  a moving ring (ball bearing maybe?) to allow complete 360 degree rotation without having to dismantle the structure.  The little guy in front is looking at the L-Band

Emacs!

A close-up view of the arrangement.

Cheers,

Chris


At 05:48 AM 26/12/2018, you wrote:
Hi Chris, just had a thought about motor control of dish and was wondering if any motor control in the Astronomy Telescope world has value for tracking?
73
Steve
UK

Re: Att Chris - Dish elevation control

Steve Rose
 

Hi Chris, just had a thought about motor control of dish and was wondering if any motor control in the Astronomy Telescope world has value for tracking?
73
Steve
UK

Re: Att Chris - Dish elevation control

Paul Gulliver
 

Hi Chris,
Thanks very much for a very comprehensive answer, certainly a lot to think about there. Interesting you are controlling the elevation by moving the bottom part of the dish, got me wondering if a threaded rod could be rotated by a motor with the rod passing through a fixed bracket and attached to the base of the dish. Something to think about in the new year.

I never got involved with NOAA HRTP, but I did receive the low res apt from the polar orbiters and also built a petal dish for the geostationary birds in the 1980's, all displayed on the RIG Framestore in the days before computers were common place - all good fun then :)

You seem to have a very well organised shack with the various pieces well built - even the switches labeled :)

Enjoy the rest of the Christmas and wishing you a great and productive New Year

Paul


On 25/12/2018 at 02:43, Chris van Lint <chrisvanlint@...> wrote:
Hi Paul,

As far as I am aware there is no affordable commercial equipment forautomatically controlling the Az / El for larger  satellitedishes.  Back in the 1980's when I was decoding NOAA HRPT images on1691MHz I was using an 80cm dish and a self designed active helixantenna.   These satellites are polar orbiting hence have to betracked.  They also are closer to earth compared to geosationarybirds. I could be control the dish by using a Kenwood (now Yaesu) KR5500azel rotator.  These rotators are intended for controlling beamantennas - not dishes.  However the dish being comparatively smalland light weight (aluminium), could with some mechanical modifications bemade to work quite well.  However this is about the limit of thetorque the rotator motors will handle, so I could not use it for my 2mdish, quite apart from the impossible mechanical challenges to fitbrackets etc.  The paid version of David Taylor's WXTrack program,includes a facility which will track and move the KW rotators to theexact coordinates the satellite is positioned at in real time, as long asthe Kepplerian data is up to date.

In a commercial situation they use large rack and pinion arrangements forazimuth and worm gear or hydraulics for elevation.  The satellitecontinuously transmits a VHF signal, which is interpreted by an auto tunearrangement on the ground, which delivers a signal to the pointingmotors.  Some form of hystereses adjustment is needed to stop thedishes moving continually with small position changes.

Obviously none of these schemes will work in my present situation and theonly possible solution is to use dish actuators.  These can be usedquite easily to control azimuth.  However to automate the movementis not simple.  The KW rotator has an internal potentiometer whichfeeds a signal to the rotator controller in the shack and tells it whereit is pointing to.  The same scheme is used in the elevationcontrol.  Commercial dish actuators do not have build in sensorswhich would allow accurate positional data to be sent to thecontroller.  I have thought about modifying one, but filed it in thetoo difficult box.  The only solution for me was to tell theactuators where they should be pointing at any given time.  I usedan azimuth actuator for elevation control by installing it in a verticalposition and have it push the bottom periphery of the dish.  A 2mdish with a steel frame and in spite of having a perforated aluminiumskin, is quite heavy and some form of counterweight for elevation wasneeded.

I now had to construct the electronics to control the 2 actuators. Using David's excellent program (seriously anybody messing around withsatellites should have WXtrack installed on their PC), I used the manualtime facility and plotted the satellites predicted positions over aperiod of 24 hours.  I used two dual channel programmable timers(dual channel because the output to the actuators has to bereversable).  I could only get find 30 step timers, but as it turnsout, this is sufficient for 24 hours, because there is a 300 and 360minute period during the 24 hour period where the satellite does not movesignificantly and the dish does not need to be moved.  The timersimply tells the actuator something like: 10 seconds up - 60 minutes nomovement, 12 seconds up - 60 minutes no movement and so on.  Theprocess for the elevation control is the same. The relationship betweenseconds of applied power and movement needs to be determinedempirically.  I found that at the rated operating voltages of theseactuators (between 36-46 V), movement was so fast that it was difficultto get accurate results.  I constructed an adjustable power supplyand use 20V to drive the actuators.  Being V adjustable, this hasthe added advantage that I can fine-tune the seconds:movementratio.  The movements of the satellite are not static and every fewweeks I have to re-start the timers (usually 1 hour earlier) to get themto track reasonably accurately again.
If there is a power interruption I am in trouble, because I have notfound a way to start the timers at any point but "step#1"! so Ihave to wait for that time to come around.


This image basically shows the set-up.  The square multi-coloureddisplay in the top left-hand selects voltage and monitors current andpower.
The rectangular box on top of the PC above the SDR-RTL  is an active8 channel C-Band splitter, with the gain (amplifier on top) adjusted tounity as referred to the input strength.  This gives 8 independentdevices lossless access to the C-Band dish.  The actual timers arein the two ABS boxes with clear lids.


That's all there is to it.  It is a bit crude, I know, but it works(most of the time).

Cheers,

Chris






08:54 PM 24/12/2018, you wrote:
Hi Chris
In another thread you mention you use automated control for the azimuthand elevation of your dish.
I'm using a 1.1m dish to receive 3F5 at 54W, the elevation of thesatellite varies between 11 and 17 degrees and I have to adjust the dish3 or 4 times per day to keep a usable signal so I was wondering what youuse for elevation control.
I've searched for elevation motors but haven't had any success in findinganything suitable - is yours homemade or purchased?
Any pointers would be appreciated

Wishing you a Merry Christmas

Cheers,

Paul

Attachments:


Re: Att Chris - Dish elevation control

Chris van Lint
 

Hi Paul,

As far as I am aware there is no affordable commercial equipment for automatically controlling the Az / El for larger  satellite dishes.  Back in the 1980's when I was decoding NOAA HRPT images on 1691MHz I was using an 80cm dish and a self designed active helix antenna.   These satellites are polar orbiting hence have to be tracked.  They also are closer to earth compared to geosationary birds. I could be control the dish by using a Kenwood (now Yaesu) KR5500 azel rotator.  These rotators are intended for controlling beam antennas - not dishes.  However the dish being comparatively small and light weight (aluminium), could with some mechanical modifications be made to work quite well.  However this is about the limit of the torque the rotator motors will handle, so I could not use it for my 2m dish, quite apart from the impossible mechanical challenges to fit brackets etc.  The paid version of David Taylor's WXTrack program, includes a facility which will track and move the KW rotators to the exact coordinates the satellite is positioned at in real time, as long as the Kepplerian data is up to date.

In a commercial situation they use large rack and pinion arrangements for azimuth and worm gear or hydraulics for elevation.  The satellite continuously transmits a VHF signal, which is interpreted by an auto tune arrangement on the ground, which delivers a signal to the pointing motors.  Some form of hystereses adjustment is needed to stop the dishes moving continually with small position changes.

Obviously none of these schemes will work in my present situation and the only possible solution is to use dish actuators.  These can be used quite easily to control azimuth.  However to automate the movement is not simple.  The KW rotator has an internal potentiometer which feeds a signal to the rotator controller in the shack and tells it where it is pointing to.  The same scheme is used in the elevation control.  Commercial dish actuators do not have build in sensors which would allow accurate positional data to be sent to the controller.  I have thought about modifying one, but filed it in the too difficult box.  The only solution for me was to tell the actuators where they should be pointing at any given time.  I used an azimuth actuator for elevation control by installing it in a vertical position and have it push the bottom periphery of the dish.  A 2m dish with a steel frame and in spite of having a perforated aluminium skin, is quite heavy and some form of counterweight for elevation was needed.

I now had to construct the electronics to control the 2 actuators.  Using David's excellent program (seriously anybody messing around with satellites should have WXtrack installed on their PC), I used the manual time facility and plotted the satellites predicted positions over a period of 24 hours.  I used two dual channel programmable timers (dual channel because the output to the actuators has to be reversable).  I could only get find 30 step timers, but as it turns out, this is sufficient for 24 hours, because there is a 300 and 360 minute period during the 24 hour period where the satellite does not move significantly and the dish does not need to be moved.  The timer simply tells the actuator something like: 10 seconds up - 60 minutes no movement, 12 seconds up - 60 minutes no movement and so on.  The process for the elevation control is the same. The relationship between seconds of applied power and movement needs to be determined empirically.  I found that at the rated operating voltages of these actuators (between 36-46 V), movement was so fast that it was difficult to get accurate results.  I constructed an adjustable power supply and use 20V to drive the actuators.  Being V adjustable, this has the added advantage that I can fine-tune the seconds:movement ratio.  The movements of the satellite are not static and every few weeks I have to re-start the timers (usually 1 hour earlier) to get them to track reasonably accurately again.
If there is a power interruption I am in trouble, because I have not found a way to start the timers at any point but "step#1"! so I have to wait for that time to come around.

Emacs!
This image basically shows the set-up.  The square multi-coloured display in the top left-hand selects voltage and monitors current and power.
The rectangular box on top of the PC above the SDR-RTL  is an active 8 channel C-Band splitter, with the gain (amplifier on top) adjusted to unity as referred to the input strength.  This gives 8 independent devices lossless access to the C-Band dish.  The actual timers are in the two ABS boxes with clear lids.


That's all there is to it.  It is a bit crude, I know, but it works (most of the time).

Cheers,

Chris






08:54 PM 24/12/2018, you wrote:

Hi Chris
In another thread you mention you use automated control for the azimuth and elevation of your dish.
I'm using a 1.1m dish to receive 3F5 at 54W, the elevation of the satellite varies between 11 and 17 degrees and I have to adjust the dish 3 or 4 times per day to keep a usable signal so I was wondering what you use for elevation control.
I've searched for elevation motors but haven't had any success in finding anything suitable - is yours homemade or purchased?
Any pointers would be appreciated

Wishing you a Merry Christmas

Cheers,

Paul

Att Chris - Dish elevation control

Paul Gulliver
 

Hi Chris
In another thread you mention you use automated control for the azimuth and elevation of your dish.
I'm using a 1.1m dish to receive 3F5 at 54W, the elevation of the satellite varies between 11 and 17 degrees and I have to adjust the dish 3 or 4 times per day to keep a usable signal so I was wondering what you use for elevation control.
I've searched for elevation motors but haven't had any success in finding anything suitable - is yours homemade or purchased? 
Any pointers would be appreciated 

Wishing you a Merry Christmas

Cheers,

Paul

Re: #aero #aero

Paul Gulliver
 

Hi Roland

I don't know what you call an "outrageous price" but this will suit your needs (at around 5 euros) providing you keep it indoors


There is no need for the bias tee to be at the dish end, usually more convenient for the power supply and bias tee to be indoors near the computer and mains power supply.

As Chris says you will still need to construct/ purchase a power supply that can be switched between 12 and 18 volts - I just used a ready made "plug in" psu that gave around 24 volts DC and a couple of 78 series regulator chips for 12 and 18 volts - seems to work ok.

Unable to help with Alphasat frequencies, here in the UK I'm unable to receive Alphasat C-band on my 1.1m dish and I suspect you will need a dish larger than 80cm to even see a signal.

Cheers

Paul




On 24/12/2018 at 09:00, Roland Fechter <fly-fechter@...> wrote:

Thank you very much, Chris !

Despite its outrageous price I have just ordered with UKW Berichte the Bias-T you show and apparently use.

As I am void even of basic technical knowledge re these gadgets I will leave my current Bias T supplying 12V only untouched.

Taking for granted that the  Titanium C1W PLL wide band  will function vertically plus horizontally  with this UKW Berichte Bias I I just ordered I still face

the problem of getting a link with some Inmarsat satellites ie. pointing my miserable 80cm dish towards Inmarsat. Apparently data from Alphasat at 24.8E

can be received at my location in central Germany but I am perfectly aware that a 80cm dish will show data at only a very few "odd" frequencies.

I will use these only as a pointing aid for my 80cm dish. Once I have the certainty of indeed linking with Alphasat I will replace my 80cm dish by a 1m

dish or bigger. Limited space allows me install a dish of up to around 1.10m.

I would be most obliged for your continued help re the "right" frequency/ies  as part of my Christmas gifts !.

I look forward to your continued support.

Regards,

Roland

Am 24.12.2018 um 03:19 schrieb Chris van Lint:

Hello Roland,

The speci state that the correct voltage for LHCP is 16-20V  This meand that 16V should be OK.   To be on the safe side I operate mine at 18V.  If I remember well the current consumption is around 180mA.

As Patrick mentioned a bias-tee delivering 4-12V is not usable as you need a minimum of 12V.  Unless your bias-tee is a box which plugs into the main power supply, you might be able to modify it to supply 18V.  Usually the bias-tee (

Bias-T Fernspeiseweiche) has an input socket for the operating voltage.  This voltage is then supplied at the "hot" end of the bias-tee.



Emacs!
If you supply 18-20V DC at the BNC connector "DC point" in the above image, you will get 18-20V at the output N connector marked "RF DC" which goes to the LNB.  The other N connector contains the DC block capacitor and goes to the SDR .

Can you open up the bias-tee you have.  If yes it might be a simple matter to convert it to 16-18V.  Why don't you post an image for us to have a look at?

Don't worry about the 15m cable length.  The Zinwell LNB has sufficient gain to cope with that.  You will also have to think about connectors.  The LNB takes a male "F" connector.  The receiver connector will depend on the type.  Most TCXO SDR-RTL devices have a female SMA connector and you may need a conversion piece to connect your LNB cable.

C



Re: #aero #aero

Chris van Lint
 

Hi Roland,

So that there is no misunderstanding, I just used that image to illustrate what a stand-alone Bias-tee looks like, I myself do not use it, as I have built my own, which is not that difficult if you have the facilities.   I agree that the UKW Berichte products are all extremely expensive, but having said that, I have to also add that they are of exceptional quality and engineering integrity. 
Do not forget that you still have to supply 16-18V to the Bias-Tee.

Also don't get confused about the Bias-tee working with the Horizontal and Vertical capabilities of the LNB.  Remember you are going to fit the dielectric slab between the probes in the LNB, to make it work as a circularly polarised feed.  All the Bias-tee does is provide the correct voltage to choose polarity.

As for suggesting the right frequencies and satellites, you partners there are Patrick and Paul.  They have experience and they can tell where to look and what to look for.  I cannot help there, as I am in a totally different geographical location.

If you give us your GPS coordinates, I and many others on the list will be able to give you the details regarding the azimuth and elevation.

With regards to dish size, keep in mind that there is a fundamental restriction associated with large diameter dishes.  The larger dishes have a very limited beam width (Strahlbreite) and require much more accurate directional adjustment both in azimuth as well as in elevation, which is why I am forced to use automated azimuth and elevation controls.

C


At 07:00 PM 24/12/2018, you wrote:

Thank you very much, Chris !

Despite its outrageous price I have just ordered with UKW Berichte the Bias-T you show and apparently use.

As I am void even of basic technical knowledge re these gadgets I will leave my current Bias T supplying 12V only untouched.

Taking for granted that the  Titanium C1W PLL wide band  will function vertically plus horizontally  with this UKW Berichte Bias I I just ordered I still face

the problem of getting a link with some Inmarsat satellites ie. pointing my miserable 80cm dish towards Inmarsat. Apparently data from Alphasat at 24.8E

can be received at my location in central Germany but I am perfectly aware that a 80cm dish will show data at only a very few "odd" frequencies.

I will use these only as a pointing aid for my 80cm dish. Once I have the certainty of indeed linking with Alphasat I will replace my 80cm dish by a 1m

dish or bigger. Limited space allows me install a dish of up to around 1.10m.

I would be most obliged for your continued help re the "right" frequency/ies  as part of my Christmas gifts !.

I look forward to your continued support.

Regards,

Roland

Am 24.12.2018 um 03:19 schrieb Chris van Lint:
Hello Roland,

The speci state that the correct voltage for LHCP is 16-20V  This meand that 16V should be OK.   To be on the safe side I operate mine at 18V.  If I remember well the current consumption is around 180mA.

As Patrick mentioned a bias-tee delivering 4-12V is not usable as you need a minimum of 12V.  Unless your bias-tee is a box which plugs into the main power supply, you might be able to modify it to supply 18V.  Usually the bias-tee (

Bias-T Fernspeiseweiche) has an input socket for the operating voltage.  This voltage is then supplied at the "hot" end of the bias-tee.

 
If you supply 18-20V DC at the BNC connector "DC point" in the above image, you will get 18-20V at the output N connector marked "RF DC" which goes to the LNB.  The other N connector contains the DC block capacitor and goes to the SDR .

Can you open up the bias-tee you have.  If yes it might be a simple matter to convert it to 16-18V.  Why don't you post an image for us to have a look at?

Don't worry about the 15m cable length.  The Zinwell LNB has sufficient gain to cope with that.  You will also have to think about connectors.  The LNB takes a male "F" connector.  The receiver connector will depend on the type.  Most TCXO SDR-RTL devices have a female SMA connector and you may need a conversion piece to connect your LNB cable.

C


Re: #aero #aero

billcoombes
 

I'm not sure what you paid for the Bias T box but it is such a simple circuit and is very very easy to make.
Bill - G4ERV

----- Original Message -----
From: "Roland Fechter" <fly-fechter@...>
To: multipsk@groups.io
Date: Mon, 24 Dec 2018 10:00:05 +0100
Subject: Re: [multipsk] #aero

Thank you very much, Chris !

Despite its outrageous price I have just ordered with UKW Berichte the
Bias-T you show and apparently use.

As I am void even of basic technical knowledge re these gadgets I will
leave my current Bias T supplying 12V only untouched.

Taking for granted that the Titanium C1W PLL wide band will function
vertically plus horizontally with this UKW Berichte Bias I I just
ordered I still face

the problem of getting a link with some Inmarsat satellites ie. pointing
my miserable 80cm dish towards Inmarsat. Apparently data from Alphasat
at 24.8E

can be received at my location in central Germany but I am perfectly
aware that a 80cm dish will show data at only a very few "odd" frequencies.

I will use these only as a pointing aid for my 80cm dish. Once I have
the certainty of indeed linking with Alphasat I will replace my 80cm
dish by a 1m

dish or bigger. Limited space allows me install a dish of up to around
1.10m.

I would be most obliged for your continued help re the "right"
frequency/ies as part of my Christmas gifts !.

I look forward to your continued support.

Regards,

Roland

Am 24.12.2018 um 03:19 schrieb Chris van Lint:

Hello Roland,

The speci state that the correct voltage for LHCP is 16-20V This meand
that 16V should be OK. To be on the safe side I operate mine at
18V. If I remember well the current consumption is around 180mA.

As Patrick mentioned a bias-tee delivering 4-12V is not usable as you
need a minimum of 12V. Unless your bias-tee is a box which plugs into
the main power supply, you might be able to modify it to supply 18V.
Usually the bias-tee (


*Bias-T Fernspeiseweiche)* has an input socket for the operating
voltage. This voltage is then supplied at the "hot" end of the
bias-tee.



Emacs!
If you supply 18-20V DC at the BNC connector "DC point" in the above
image, you will get 18-20V at the output N connector marked "RF DC"
which goes to the LNB. The other N connector contains the DC block
capacitor and goes to the SDR .

Can you open up the bias-tee you have. If yes it might be a simple
matter to convert it to 16-18V. Why don't you post an image for us to
have a look at?

Don't worry about the 15m cable length. The Zinwell LNB has
sufficient gain to cope with that. You will also have to think about
connectors. The LNB takes a male "F" connector. The receiver
connector will depend on the type. Most TCXO SDR-RTL devices have a
female SMA connector and you may need a conversion piece to connect
your LNB cable.

C





Re: #aero #aero

Roland Fechter
 

Thank you very much, Chris !

Despite its outrageous price I have just ordered with UKW Berichte the Bias-T you show and apparently use.

As I am void even of basic technical knowledge re these gadgets I will leave my current Bias T supplying 12V only untouched.

Taking for granted that the  Titanium C1W PLL wide band  will function vertically plus horizontally  with this UKW Berichte Bias I I just ordered I still face

the problem of getting a link with some Inmarsat satellites ie. pointing my miserable 80cm dish towards Inmarsat. Apparently data from Alphasat at 24.8E

can be received at my location in central Germany but I am perfectly aware that a 80cm dish will show data at only a very few "odd" frequencies.

I will use these only as a pointing aid for my 80cm dish. Once I have the certainty of indeed linking with Alphasat I will replace my 80cm dish by a 1m

dish or bigger. Limited space allows me install a dish of up to around 1.10m.

I would be most obliged for your continued help re the "right" frequency/ies  as part of my Christmas gifts !.

I look forward to your continued support.

Regards,

Roland

Am 24.12.2018 um 03:19 schrieb Chris van Lint:

Hello Roland,

The speci state that the correct voltage for LHCP is 16-20V  This meand that 16V should be OK.   To be on the safe side I operate mine at 18V.  If I remember well the current consumption is around 180mA.

As Patrick mentioned a bias-tee delivering 4-12V is not usable as you need a minimum of 12V.  Unless your bias-tee is a box which plugs into the main power supply, you might be able to modify it to supply 18V.  Usually the bias-tee (

Bias-T Fernspeiseweiche) has an input socket for the operating voltage.  This voltage is then supplied at the "hot" end of the bias-tee.



Emacs!
If you supply 18-20V DC at the BNC connector "DC point" in the above image, you will get 18-20V at the output N connector marked "RF DC" which goes to the LNB.  The other N connector contains the DC block capacitor and goes to the SDR .

Can you open up the bias-tee you have.  If yes it might be a simple matter to convert it to 16-18V.  Why don't you post an image for us to have a look at?

Don't worry about the 15m cable length.  The Zinwell LNB has sufficient gain to cope with that.  You will also have to think about connectors.  The LNB takes a male "F" connector.  The receiver connector will depend on the type.  Most TCXO SDR-RTL devices have a female SMA connector and you may need a conversion piece to connect your LNB cable.

C


Re: What about the 4F3 satellite in Oceania #aero

Patrick Lindecker
 

Thanks for the information Chris.

 

73 et bon Noël également

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Chris van Lint
Envoyé : lundi 24 décembre 2018 03:31
À : multipsk@groups.io
Objet : Re: [multipsk] What about the 4F3 satellite in Oceania #aero

 

Hi Patrick,

Unfortunately 4F3 is well outside my foot-print area.

I can "see" the Japanese Meteoroligal satellite Himawari also known as Mtsat, which used to carry some AERO traffic, but there is not much traffic on that now especially after the recent migration.

73  - joyeux Noel et bonne année


At 06:15 AM 24/12/2018, you wrote:

Hello Chris,
 
I remember that you say that your dish was 2 m diameter pointing to 4F1 (so with a weak power similar as the 4AF4 satellite here) and the polarization of 4F1 was LHCP so RHCP at LNBF level.
However, I wonder if you tried to monitor the 4F3 satellite that you might be able to receive, no?
 




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