Cable loss of signal between satellite dish and receiver

Captain Jack

Retired human
Joined
Oct 21, 2006
Messages
11,832
Reaction score
8,017
Points
113
My Satellite Setup
See signature
My Location
North Somerset
Just ran a cable from my dish to my "play-room" and found that I had quite a nasty cable loss. At the dish, I have a signal level of around 11.1dB on 11919H on 5E (according to FS1). However, in my room I only get a signal of around 9.5dB. That's a huge loss.

Granted, my WF100 cable run of around 30m leaves a lot to be desired. It goes through a window "flat cable" and there are two more joins using the F barrel connectors due to not having a complete long run. Before I go out and get a new cable drum, would it be feasible to get a better cable such as CT125? Or perhaps an inline amplifier to put near the dish?
 

rolfw

Believe it when I see it Admin.
Staff member
Joined
May 1, 1999
Messages
38,315
Reaction score
1,631
Points
113
My Satellite Setup
Technomate 5402 HD M2 Ci, DM7000s, Transparent 80cm Dish, Moteck SG2100 DiseqC motor, lots of legacy gear. Meters: Satlook Digital NIT, Promax HD Ranger+ spectrum analyser.
My Location
Berkshire
What type of db measurement are you using, SNR? I normally use db per microvolt on signal strength and get figures of between 60db and 80db, loss on 30m of WF100 at that frequency would be around 6db.

Two "F" joins would be a db or so, not sure about the flat cable, they can be horribly lossy.
 

Captain Jack

Retired human
Joined
Oct 21, 2006
Messages
11,832
Reaction score
8,017
Points
113
My Satellite Setup
See signature
My Location
North Somerset
Hi Rolf

Yes it's the SNR dB that I am measuring. One thing I found is that 5e is not a stable satellite and I get about 2dB lower in the evening than I do in the morning, so this accounts for some of the "loss". Still, I have measured around 9.4dB at the LNB and 8.7dB at the receiver end. Will defo get a new cable ...should help out.

Thanks
CJ
 

Huevos

Satellite Freak
Joined
Sep 11, 2008
Messages
6,038
Reaction score
1,277
Points
113
My Satellite Setup
57E to 58W, C-band and Ku, DVB-S2, 4:2:2 and blindscan.
My Location
38.5ºN, 0.5ºW
At the dish, I have a signal level of around 11.1dB on 11919H on 5E (according to FS1). However, in my room I only get a signal of around 9.5dB. That's a huge loss.
A properly made back to back 'F' join shouldn't show any change in SNR, and like Rolf say less than a dB of signal loss on each joint (depending on frequency) but the reality is the loss through a join is the same as the loss through a few feet of cable.

How old is the cable?

Personally I'd start by checking all the terminations. If you have a meter go along the cable and open each 'F' join and take a meter reading so you can isolate the piece of cable that has the loss. Also, is it using a wall plate as some of these can be really losy too.
 

Captain Jack

Retired human
Joined
Oct 21, 2006
Messages
11,832
Reaction score
8,017
Points
113
My Satellite Setup
See signature
My Location
North Somerset
I measured the joints and each cable length of around 7m adds about 0.3dB loss on the SNR scale. Will check tomorrow what the dBuV scale looks like. The cable is a couple of years old at most. No horrible wall plates used...the cable goes directly to the receiver.
 
Top