At what length of coax should I be concerned about signal loss?

#3
There are too many variables to say for sure. You will likely need to run your cable and see what results you get.

Attenuation for RG-6 is approx. 10db/100ft.

Is there a specific reason for asking?

One thing to remember is this:

Engineering basics related to cable say use the 3 "S"s.
1. shielded -always use shielded cable
2. short - always use the shortest cable to do the job
3. single - and avoid using connectors to extend cable length

It will be a factor in your installation if you ignore these simple rules. It is especially important to avoid connections by using a single cable.

Rg Each F-81 barrel connector that you put in a run will attenuate (lessen) your signal by approx. 1 db. What is worse than that is that there is no shielding at connections allowing ingress of EMI that will also affect your signal quality. Avoid connectors.

Hope this helps.
 

IDRick

DTVUSA Member
#4
Hi Jeff,

I like your 3 S's. Very good tip! :)

Your cable loss estimate is a bit too high. See: Antenna Basics

Typical loss for rg-6 cable ranges from 1.5 to 6 dB per 100 feet of run and varies with channel frequency.

Best,

Rick
 
Last edited:

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#5
highdefjeff wrote:

... "One thing to remember is this:

Engineering basics related to cable say use the 3 "S"s.
1. shielded -always use shielded cable
2. short - always use the shortest cable to do the job
3. single - and avoid using connectors to extend cable length ..."
-------------------------------------------------------------------
I suggest adding another 's' to the list. Seal the outdoor antenna fitting with silicone (RTV) to weatherproof it and to keep water out of the coax!
Jim :gossip:
 

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#7
Geez, what would someone from Seattle know about rain... Oh wait! ;)

Great addition Jim!
---------------------------------------------------
Rick,
Not including tonight (more rain is expected) Seattle has had just over 9" of rain this month alone, whereas during an average November we have 5 1/2". Perhaps its time to build an ark.
Jim

Update: It's raining again!
 

FOX TV

Contributor
#10
Hi Jeff,

I like your 3 S's. Very good tip! :)

Your cable loss estimate is a bit too high. See: Antenna Basics

Typical loss for rg-6 cable ranges from 1.5 to 6 dB per 100 feet of run and varies with channel frequency.

Best,

Rick
But..Couldn't that figure be different among different manufacturers at different frequencies? I have a Belden cable catalog, and I will try to remember to look it up and see what they say it says for their brand of RG-6.
 

IDRick

DTVUSA Member
#12
But..Couldn't that figure be different among different manufacturers at different frequencies? I have a Belden cable catalog, and I will try to remember to look it up and see what they say it says for their brand of RG-6.
Correct, it does vary by cable manufacturer, specific cable design/components, and frequency. Apologies for not stating that in my original comment... 6dB loss per 100 ft is a common number used for estimating distribution losses on the web. That number is too high for my specific cable and the available channels in the area but really didn't overestimate distributions losses too bad (< 2 dB).
 

FOX TV

Contributor
#13
Cable Attenuation data for RG-6U

Correct, it does vary by cable manufacturer, specific cable design/components, and frequency. Apologies for not stating that in my original comment... 6dB loss per 100 ft is a common number used for estimating distribution losses on the web. That number is too high for my specific cable and the available channels in the area but really didn't overestimate distributions losses too bad (< 2 dB).
I have a Belden cable catalog that states Belden RG-6U series number 8238 at 400 mHz. that the loss factor is 4.2 dB per 100 feet, and at 700 mHz, it is 5.8 db per 100 feet. This is 18 guage center conductor with 97% shielding.
 

Similar threads

Top