LNB Threshold frequency

[buzzbomb]

Hi guys I am having some problems with my new Dreambox 500s (clone from china). What appears to be happening is that the signal and quality on the Horizontal frequencies in the higher range (above 11720) are very erratic and not getting a signal or sync lock and therefore will not scan in any channels.

In the dreambox lnb setting it has LOF/L 09750, LOF/H 10600 and Threshold at 11600. Can anyone tell me the purpose of the Threshold setting as I have found that if I change it to a higher figure ie 13700, the signal on the higher Horizontal frequencies of Astra 19e become more stable and lock. Unfortunately this does not apply to all the other sats that I use so any info on the threshold purpose or anything else I can try with the DB would be appreciated.

 

[Analoguesat]

Try changing the lnb to begin with.

 

[buzzbomb]

Analoguesat forgot to mention that my other box is also connected to the same LNB (DB first then looped out to the other box) and I get 97%Quality and 99% signal on all frequencies.

 

[rolfw]

The threshold is the frequency at which the receiver tells the LNB to switch to high band, it can be anywhere from 11,500 to 11,700 (possibly a little higher, as the highest frequency on the satellite is less than 13,000, all you are doing by setting the threshold at 13,770 is telling the dreambox not to switch to upper band.

 

[buzzbomb]

Thanks for that explanation Rolfw. Can u think of any reason why it is only the Horizontal freqs that r affected.

 

[rolfw]

If it is looped through, does the same thing happen when the other box is not connected?

 

[buzzbomb]

Rolfw I am pretty sure it made no difference when I disconnected the loopthro but it was last week that I tried it so will try again tomorrow and let u know how I get on . Thanks for your help so far.

 

[buzzbomb]

Rolfw have disconnected the loopthro and the results are the exact same. ie erratic horizontal signal above 11720. Have also simplified the dreambox setup by making it an only 1 direct satellite configuration. In this config it does not give any change parameters for the LNB so I assume the box sets it as a standard universal lnb. Beginning to think it is a dreambox problem. Can u think of any other possibilities.

 

[rolfw]

Hate to say it, but yes, it does sound like a box problem, or at least a lack of tuner sensitivity. If one box works but another doesn't, then it can only be the box.

 

[buzzbomb]

Thanks Rolfw will contact the dealer and see what they say.

 

[buzzbomb]

I know this is an old thread but thought I would give an update on my horizontal frequency problem. Eventualy did as Analoguesat suggested and fitted an new Invacom 0.3 lnb and low and behold am now getting the signal on all polarities. Hope this info helps anyone else with a similar problem.

 

[guest]

Very good.

Always make sure you have at least one spare LNB, if not two or three.

They all have different characteristics in many respects and rather than believing (or trying to interpret) the spec., it's much more expedient just to try a bit of swapping around.