Digital Signal Meter

Souriau

Souriau wrote: »

Since a lot of viewers had written in here having problems with digital TV signal so I decided to check on how low the signal can go before it break up
I had compare both Muliplexes on Saorview

I been checking signal strength between Mux 1 and Mux 2.
I received my Saorview signal from Clermont Carn


Mux 1||Mux 2
|Emitor DigiAir Pro signal meter|
47.7 dBµv| signal strength|45.7 dBµv
30 dB| SNR|29 dB
1.0e-4| Pre BER|1.0e-4
1.0e-8| Post BER|1.0e-8
30 dB| MER|28 dB
|Humax HDR-Fox T2 signal meter|
47|Strength|44
100|Quality|100
Both Muxs are perfect, no breakup


I put in a 9dB Attenuator to reduce the signal strength and again I did my measurement tests
Mux 1|| Mux 2
|Emitor DigiAir Pro signal meter|
38.8 dBµv| signal strength|37.0 dBµv
24.3 dB| SNR|21.0 dB
3.3e-3| Pre BER|3.9e-3
1.0e-8| Post BER|3.9e-8
25 dB| MER|22 dB
|Humax HDR-Fox T2 signal meter|
37|Strength|27
100|Quality|80
Again like above, both Muxs are still perfect with no breakup


I put in a 12dB Attenuator to reduce the signal strength and again I did my measurement tests
Mux 1|| Mux 2
|Emitor DigiAir Pro signal meter|
35.7 dBµv| signal strength|34 dBµv
21.1 dB| SNR|18.0 dB
6.7e-3| Pre BER|3.0e-2
2.3e-8| Post BER|2.5e-5
22 dB| MER|20 dB
|Humax HDR-Fox T2 signal meter|
37|Strength|20
100|Quality|20
At this point, RTE1 on Mux 1 is still very good while Mux 2 is breaking up full time
See pictures attached below


I put in a 15dB Attenuator to reduce the signal strength even more and again I did my measurement tests
Mux 1|| Mux 2
|Emitor DigiAir Pro signal meter|
32 dBµv| signal strength|30 dBµv
18 dB| SNR|
2.5e-2| Pre BER|
9.6e-6| Post BER|
20 dB| MER|
|Humax HDR-Fox T2 signal meter|
28|Strength|10
90|Quality|10
At this point, RTE1 on Mux 1 is watchable but on Mux 2 is not available

.

I had a closer look into this setup as to why Mux 2 is lower than Mux 1
I then found out that the aerial I am using is Group B not Group C/D as it should be, So this test does show a wrong group aerial do affect the results.
The reason I had installed Group B was that I used to get my analouge from Cairn Hill and then relign to Clermont Carn last year with no problem until Mux 2 came on-air, even still no problem til I done a test to see how weak the signal can go belore digital cliff kick in.

Peter Rhea

I still don't see anything in those meter readings that would cause me to look for reasons for the slight difference between mux 1 & 2.

The group B probably has as much gain at ch. 56 as the equivalent group C/D would have, anyway.

Souriau

Peter Rhea wrote: »

I still don't see anything in those meter readings that would cause me to look for reasons for the slight difference between mux 1 & 2.

The group B probably has as much gain at ch. 56 as the equivalent group C/D would have, anyway.

Where I am, I don't have direct sight to the transmitter, as there is a mountain blocking the path of the signal from the transmitter to my aerial.
This may have an effect on the reading I am getting, but I will redo this with a different transmitter when I get a chance.

Peter Rhea

Souriau wrote: »

. . . I will redo this with a different transmitter when I get a chance.

What exactly are you looking for?