one of the more common reasons, for either the azimuth or elevation
rotator losing calibration, is that the potentiometer, in one or other,
that controls positioning via voltage has either become worn or suffered
from the ingress of damp. Replacement is not rocket science, and spares
are available from agents for the Yeasu/Kenwood G4500 and G5500.
Additionally, the units seem not to be particularly robust, and a long
or hard-serving set-up can develop significant backlash in the drive
gears, which results in greater than ideal movement of the dish from
point-of-aim when tracking. This can certainly occur where a dish is
operated automatically for long periods 24/7 and thus unwittingly in
relatively high winds.
Any temptation to configure the software to park the dish pointing
directly upwards between passes should be avoided. Whilst this may
present the least resistance regardless of wind direction, it causes
wear on the gearwheel teeth in high winds at the most critical point of
the operating arc - the overhead. It is better to park the dish at the
horizon with its edge into the prevailing wind direction.
If replacing a "pot", do ensure that the positions of all gears and
components are carefully marked on disassembly, and replaced precisely
on reassembly. Doing this work offers a perfect opportunity to check the
bearings of the rotating shafts (particularly for the elevation unit -
which has poor water-resistance in this area). Corroded bearing cages
and ball-bearings can be replaced at the same time.
Sorry if this is all already known to you, but if not it is probably
Stefano Grassi wrote:
> So,Do you think,Should I change the rotator?Or dish?
> At present my dish is the same that I used for meteosat old generation
> obvioulsly with a different feed (It's the grid dish near the lower
> border of image
> > Stefano,
> > 44.525 is correct. However, as you are experiencing problems at low
> > elevations where the satellites are at much greater range, this is
> > clearly not the cause of your problem. I do not know what else to try.
> > Peter
> > In message <4BD9FFF5.1000705@...
> > <mailto:4BD9FFF5.1000705%40poste.it>>, Stefano Grassi <stefano.grassi-
> > bubo@... <mailto:bubo%40poste.it> <mailto:bubo%40poste.it>> writes
> > >Peter,
> > >I have tried to change my latitude as you said. It seems that better
> > >results for stability of tracking, happens with higher latitude.
> Are you
> > >sure 44.525 value was correct?
> > >Two days ago, I have used 44,9 (adding 0,2 degrees to my latitude) as
> > >you told me in the first mail and I had a good improvement of reception
> > >specially in low elevations (5/10°).
> > >Please let me know,
> > >
> > >Thank you,Stefano
> > --
> > Peter Wakelin
> [Non-text portions of this message have been removed]