> ... with a dish with a 8 degree beamwidth.
> There is a strong null even when right overhead,
> if the tracking system is way off. The maximum range
> I can receive a TV signal is 800Km to the ISS.
As usual, I shot from the hip and pontificated about the disadvantage of
an XY mount when in general they are ideal overhead if you don't need the
two horizon points that are problematic. Now that I understand that you
are only targeting the high elevation portion of all passes, then you are
absolutely correct, that the XY will be better since it gives you
un-hindered overhead high elevation successs without the zenith keyhole.
> The aim is to use the entire pass without a gap in the middle,
> and then hand over to another European station to continue the contact.
AMEN. Great plan and I agree the XY is ideal since you don't care about
the low E/W horizon.
> With 800KM range I will not be able to pick up the signal from ISS at
>Would you recommend XY or ordinary AZ/EL?
You are right to choose the XY for this mission. Thanks for hanging in
there. Devil is always in the details.
> ... it says " the X-Y pedestal has its limitations at low elevation
> (< 2°) around 90° and 270° in azimuth." which ... is West and East
My bad. Our XY here is N and S. So I "assumed" that was what they all
were. But E and W would seem to be worse because you have the problem on
both assending and descending passes that cross east -or- west. Where as
with N/S, nothing much passes North.
Oops, wrong again. I am remembering our problems with the SHUTTLE on 28
deg launches so all passes always were to the south, never north. So we
only had to deal with low southern pass problems. But with ISS in a 52
degree inclined orbit, then it goes north just as much as south.
Ah, Ha, Maybe E/W is best, then, since the only time you are down low on
the horizon to the due east or due west, the entire pass is so low it
probably isn’t worth bothering with anway!
So ignore my stream of consciousness. Looks like they did their homework
and so they have a good design with E/W axis and it will not be a problem.
On the other hand, as I suggested before, the number of times that an
AZ/EL gets into trouble directly overhead (when the signal is so strong
one doesn’t even need a beam anways) is so exceedllingly small with
typical LEO passes, it might not be worth changing.
Not saying either is better. Just filling in some details to think about.
Thakns for the correction about the E/W. Also I have not read the link,
so you can ignore anything I say too... <wink>
From the early planning stage of the project we decided that we would
make telemetry information available
to end users.
Since deployment the warehouse has displayed the latest data:
and of course the upload rankings.
Additionally we have made available small csv files for WOD and HiRes.
Starting today, we will be making all captured WOD available as weekly
To start the ball rolling, we have dumped the WOD for 21st-30th Nov 2013
(incl.) into a csv file.
Please see: http://warehouse.funcube.org.uk/wod.html?satelliteId=2 for
the link to the
We will play catch up over the next few days and then automate the process.
This is a LARGE file of 11558 rows (we will test out compression on the
If you want to graph it, I would advise you to edit in a text editor
before trying it in Excel or LibreOffice Calc
It it really intended for consumption by an analytical suite such as
MatLab, or a DIY one, in a language of your
Feedback would be appreciated.
FUNcube Team Member
New Rotator X/Y as opposed to Azimuth/Elevation
SPX X-Y Rotor
I am thinking of purchasing a new tracking system design, which uses
an unusual way of pointing the antenna. I was wondering if anyone else
has used this product or even the nearly identical non XY model?
Youtube video at the bottom does not work.
The benefits of it are supposedly better/faster positioning at the
elevation peak, due to the "two elevation, one over another" design.
There is a good description of why it might be good here:
Scroll down to conclusions
There are other benefits:
630 Euro plus shipping including USB computer interface (cheaper than Yaesu)
Fast motor movement (50 seconds for 360 degrees)
Can be compatable with Yaesu GS232 protocol or SPID driver
Low strength 80nM only suitable for light antennas (such as the arrow etc)
Brand new model may have bugs or weaknesses
1 degree max position accurancy sensed by reed switch. Not 0.1 degrees
as per some expensive systems.
Cheaper computer interface/features compared to more expensive models.
Not available from anywhere else (yet)
3 weeks minimum delivery time
Strange to understand design
Strange to understand config. The az & el degrees are converted to XY positions.
The main reason for taking the risk, is I want to do some small dish
tests for HAMTV from the ISS, and even most expensive tracking
systems, are too slow at fast peak elevations, particularly with
narrow beamwidth dishes.
So has anyone used one of these or any thoughts/comments on the design?
i would concur with everything the first responder said. Cranky I love mine
for satellites. I've used it since I bought in new many years ago. CAT
works great but it does require a less typical null modem cable. Mine is
completely unmodified and I really should buy some filters for it, but
despite the filters I've worked tons of DX with it on HF. Does it compare
to my Flex5000....no! But it doesn't cost that much. The only thing I could
recommend more at this point would be a fully loaded Flex5000a with the 2nd
RX and V/U module. It works very well for satellites with satpc32 and has
the added advantage of the panadapter where you can see signals including
As for repairs, the only repair I had to have done with my 847 was the
on-off power switch. I should add that I also had a TS-2000 for a time but
sold it in favor of keeping my 847 largely because of one or two features,
the primary one being that unlike the 2000 the Yaesu powers your external
preamps through the coax with no problems. I found that other rigs that
don't offer is feature just add additional issues, though to be fair some
guys prefer separating their preamps in terms of DC power.
So that's my vote, get a good 847 if you can find one.
I've never used a 736r, so I can't compare, but I presently have an 847. It is an excellent satellite rig but not nearly as good as my TS-690s was on HF, (I chase DX) However I've been learning to adapt and still bagging new ones. Plus the extra 50 watts on 6m is nice. I also found it is not nearly as user friendly with my MFJ external tuner... I have to adjust power on the rig before hitting the tune button on the tuner. With my kenwood, it was one button tuning right on the rig.
Some of it's quirks... it is prone to having problems with the power switch going out. Mine has lost the 'catch' and won't stay closed, others have had the contacts burn out. I have mine 'jumpered' in behind the switch and I turn power on and off at the supply. Some have an issue of low headphone volume, but that mostly is because it's designed for low impedance headphones, not the 32 ohms ones commonly available today. If you plan
to use computer control the very earliest models did not have
bi-directional serial ports, but that can be checked by the serial
number... I believe it's a small number of rigs. Google is your friend
for information on that. =^)
For satellite, the named sat memories are nice and it has built in preamps or it can power remote preamps. The extra filters are a little hard to come by and can be expensive.I've only acquired a CW filter. Their are no birdies that I am aware of. The rig was designed for satellite and that remains it's forte. I had both rigs on my bench until my 690 developed a problem. Once I got used to the 847 on HF, it was nice not to have to switch my key back and forth or have two sets of headphones. What I am saying is, if you want a great sat rig and an adequate HF rig, it is a fine choice. But if HF is your primary goal and satellite is an after thought, keep your 736 and get another HF rig.
Prices run $800 to $1000 for a used 847. I paid $1000 for mine on a local purchase in very nice condition and sold the external speaker that came with it. Prices have dropped in the last year or so and I wouldn't pay more than $900 shipped unless it had the FC-20 external tuner with it. They can be found for $800, but consider the condition. These rigs are coming up on 20 years and many parts are reaching the point of becoming unobtainium. - Bottom line though... outside of a IC-910 or 9100, it's probably the best satellite rig you can own. (personally, I like the layout better than the 910/9100s) If I had the money, I'd buy a spare.
As always... your mileage may vary, batteries not included, no warranties expressed or implied. =^D
73, Kevin N4UFO
"Control is the need of the fearful mind. Trust is the need of the courageous heart."