missing channels

[woodbud]

I recently installed a 1 meter dish with 2 lnbs to receive 16° &28.2 both lnbs give excellent signal readings but channel 4 sd is virtually non existent on astra , hd spot on, also rts on eutelsat missing with very low signal on 10720mhz yet every other channel booms in. I wondered if high pressure weather system could knock out a certain frequency both ch 4 & rts are transmitted on similar frequencies around 10.7mhz admittedly on different satellites .I checked to see if rts (serbia) was working on other sites at the time and it was so I am perplexed as to the cause I did try various lnbs receivers all with the same result any clues

[Mickha]

If using a Diseqc switch, remove it, from the system, and connect both LNB's, one at a time, directly to your receiver, and see if the channels return.
You might also want to check your LNB settings, and anything that might be causing interference, like a DECT telephone.

[woodbud]

I have tried removing diseq switch doesn't make a difference and there isnt a phone I've done dozens of these before it is most peculiar there doesn't appear to be any 4 g masts nearby or anything you would nomally associate with interference there is a huge high pressure system over the uk at the moment but I've never known this to cause probls with sat transmissions. I have tried mpeg 4 receivers old receivers that work elsewhere , different lnbs 1db to4db all give the same outcome

[Mickha]

I would try a new, short, high quality, cable run, and connections, outside, using your receiver, and a small television. Again just one LNB, at a time, and see if you then pick up either transponder.

[DJSat79]

Hi Woodbud,
After trying what Mickha suggests,
Try looking at hotbird on 13°E 10719 V 27500 5/6. If you have problems with the "TVS" channel (FTA) then it looks like interference.
The Intermediate frequency is 964 MHz. This is used for "Aeronautical radio navigation" and "fixed mobile broadcasting" according to the UK Ofcom frequency allocation list.
I have seen intermittent "spikes" on a spectrum analyser at various different frequencies on various satellites and have been able to "cure" some of this by the following non health & safety approved method...
Try covering the whole of the receiver in tin foil, earth this to the LNB earth and see what happens. CAUTION - do this for a minute or two only as a test!

[ABA]

a silly question
where abouts are you

[ALIBE]

Hi Woodbud.

POSSIBLE Cause

I note that you have a new large dish and presumably two new lnb's.

This may be the cause of your problem with the resulting signal strength being too strong.

Your satellite box may then try to compensate for this by turning the signal gain down with the effect that certain transponder frequencies may be lost.

IF this is happening, the insertion of attenuators ( one for each lnb) may solve the problem by allowing your receiver to operate within usable signal strengths.

This is simply done:
a) Buy two attenuators (about £2 each for 3 / 6dB attenuators)
b) Unscrew the aerial cable (one for each lnb) from the back of your receiver.
c) Screw the attenuator to the aerial cable.
d) Screw the attenuator into the the receiver's aerial (lnb) socket


Another possible way to attenuate your signal is to increase the length of the cable run from your lnb to the satellite receiver.
The longer the cable, the more the signal will be attenuated.

This is not really a viable solution unless you have spare cable and fittings lying around.

Try doing a Google search of "Satellite LNB signal attenuator " and this may lead you to a satellite cure.

Of course, I cannot guarantee that this is the right solution to your problem but it's worth looking at.

[satwyn]

1m dish should not overload the astra signal i'm using a 1.8m precision prime focus dish on astra c4 is not a problem