Aerial install problem

D

DishDick

Regular Member
My Satellite Setup
.
My Location
Gran Canaria
Hi did an install on a complex and all went well. Used Televes HD Boss aerial. (All transmitters here are wideband). Strong signals on all occupied channels except channel 68 but it was more than accepable. I have today installed another aerial 55 feet from the other, and I could not get channel 68 at all (checked first aerial and that was ok). The transmitters are so close you could almost hit them with a stone. I will try again tomorrow with a couple of other aerials and will try different cable. My only thought is that there are two masts next to each other and maybe the other mast is masking the TV one at this position. I can get a transmitter further away with an acceptable CH68, but poor results on other channels and some missing all together.

Is there a device I can buy so if I put two aerials on the pole I can use the CH68 from the other transmitter to feed into the other aerial, without causing problems for the other channels?
 
What frequencies are in use and are they analogue or digital?
 
Not quite but there are phased array's which are extremely directional to minimise unwanted signals. Have you taken any meter readings, MER etc?
 
Hello,
polerazition is important as well.
if your antenna is mounted in the horz possion and they transmit in the vert pol then you will have some problems.
wrong pol will lower the signal by 15 db at least.
the pol is determined by the bars in the front of the uhf antenna.
if there is 2 signal sources in your area one direction it may be horz. another direction its vert.
you can not go by a picture on the box.
also the outer barid must be connected to the ground of the antenna mount.
if the barid and the center conductor short it will give problems as well.
ralph
 
Just one question about choice of aerial, why such a massive one? If your transmitter is close, then a log periodic antenna which gives an almost flat gain over the full spectrum would normally be better, as with the aerial you've used, the gain in the middle of the band is high, but drops off dramatically at both ends, so if you are distributing the signal over a distance, you may need to use an equaliser. What are you measuring the signals with?
 
Ok thanks for the replys.

Signal here is all digital.

Meter readings for good first aerial are:

Ch Noise Margin MER

28 16db 35.6db
32 16db 35.3db
35 16db 35.4db
38 13db 32.9db
60 7db 26.9db
65 12db 31.6db
67 10db 29.5db
68 7db 27.3db
69 12db 31.9db

I use this model of aerial as here the choice is quite limited - massive cheap aerial or massive half decent aerial. Can´t find log periodics for sale here. All aerials here are horizontally polorised but I will give vertical a go this pm.
 
If one mast is behind the other, it will be in the shadow, especially at the higher frequencies.

It could be nothing more than a faulty connection inside the yagi, or possibly the manufacturer has installed a duff component (choke ?)
 
A noticeable drop in noise margin for ch68 with... still passable MER measurements. Sounds like you are using a Rover ;)

I think trying another aerial would be my first choice based on the comments above.
 
Satelliteman, yes my trusty Rover STC!

OK tried another aerial, changed the cable, but still no CH68, think my original diagnosis is the correct one. On closer inspection there are three towers next to each other!! (Did try vertically polorised, but nothing at all with that).
 
Can you not try or get a phased aerial in?

You can build one by combining two aerials with the correct spacing; probably a tad complex for posting details of how to achieve this.
 

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