160 ft coaxial run

[keegster17]

guys, will I lose anything on a coaxial run about 160ft? I am setting up a dish at my cottage, but with all the trees I have to run the cable thru the bush/woods. I was eventually thinking of adding a motor, but with this long run not sure this would work. If this is possible any recommendations on rg6 cable brand, everyone sells Phillips, not sure if it is any good. also will I lose anything if i add a joiner to the cable joiner to two sets of cable, I want to save a bit of money, and lengths come either 100 ft or 250ft, so I thought I would buy (2) 100 ft lengths and cut to what i need then join them, but worried with the run as long as it is a joiner, will cause more signal loss? this doesn't have to be perfect, as it is the cottage.

[Costactc]

Phillips brand will do and you shouldn't have any issues with length and joiner. My ku feed is about 125' and I have a joiner outside near the dish- no signal quality issues at all.

[steveOtoo]

Also Dishpro lnb's can handle up to 200feet of cable run.

[ruthie]

You will loose close to 3-5db of loss per 100ft of rg6 cable....thats cable tv specs...most digital boxes will run in the minuses----depends on your box specs etc.....you will also loose signal on switches and splitters......i ran rg11 from my motor/dish to my receiver as its over 150 ft......

[keegster17]

for now i am going to use 18" dish with standard lnb. Would i be smart to switch to dish pro lnb's? How much signal do you lose on a cable joiner? just asking in case I added a second one.

[jvvh5897]

Don't think a joiner has loss. It basically is just a small piece of coax.

[Terryl]

Every splice or joint in an RF coax connection will loose about 3 dB of signal, the connectors have loss, and the "F" barrel connectors have loss, about 1 dB per connector, and about 1 dB for the "F" barrel connector, and this will change, the higher in frequency you go, the more loss there will be. (basic RF 101)

Also be careful as to what "F" barrel connector you use, there are some made for the high frequency signals used for satellite LNB outputs,(900 MHz to 2.5 GHz) and there are some for CATV or TV antenna coax, (5 MHz to 900MHz) the high frequency ones can be ID'ed by the color of the center insulator, it will be gray for the high frequency ones, and white (or clear) for the CATV/TV ones.

Using the wrong splice can lead to too much signal loss.



Also using the wrong coax can cause problems, there are 2 types of RG-6, one type for CATV/TV work, and the stuff used for satellite systems, the frequency range of the coax is normally marked on the jacket, the coax for satellite work should say 2.5 GHz, or swept to 3 GHz.


Remember, the more splices and things inline from the LNB on the dish to the receiver, the more signal loss there will be.

Switches have loss, ground blocks have loss, splices have loss, coax has loss, it all adds up.

A normal satellite receiver may not notice a single splice, switch or ground block due to the internal AGC* used in the tuner to keep the signals at a constant level.
(*AGC, Automatic Gain Control)

But the more you add the harder it has to work, AGC effect can be seen when you don't have the dish centered on a satellite, the "S" reading may bounce up and down as the tuner searches for a satellite to lock onto.

[Terryl]

guys, will I lose anything on a coaxial run about 160ft? I am setting up a dish at my cottage, but with all the trees I have to run the cable thru the bush/woods. I was eventually thinking of adding a motor, but with this long run not sure this would work. If this is possible any recommendations on rg6 cable brand, everyone sells Phillips, not sure if it is any good. also will I lose anything if i add a joiner to the cable joiner to two sets of cable, I want to save a bit of money, and lengths come either 100 ft or 250ft, so I thought I would buy (2) 100 ft lengths and cut to what i need then join them, but worried with the run as long as it is a joiner, will cause more signal loss? this doesn't have to be perfect, as it is the cottage.

I highly recommend you use good RG-6 quad coax rated to 3 GHz, with the pure copper center conductor, and try to get one solid run without splices, less of a problem with any type of water intrusion at the splice.

Trying to save money by buying the cheap coax for a satellite system is like buying the cheap set of brakes for your car, they may work, but would you really trust them on that steep downgrade after a few thousand miles?


You want it to work right for a long time, then do it right the first time, don't skimp on the coax.

[keegster17]

terryl, i appreciate your input, I am in Toronto, anyone know where to get good cable?

[keegster17]

Terryl

what about a blue "F" barrel connector? is this high freg. this interesting about this i did not know about the differnt barrel connectors. I just used whatever.
what point of signal loss do you lose quality of picture? you mentioned 1 db per connector, I am just curious what total db would you notice loss in picture quality?

[Terryl]

The blue ones will do fine.

Now for the picture quality.

Remember this is a digital signal, it's not like back in the old analog days, were you have to get every micro volt of signal you could to get a good picture, in the digital world that is what the FEC code is for.

In the RF world 3 dB is equal to 1/4 of your RF voltage (RMS, Peak or Peak to Peak) , or 1/2 of your RF wattage (mW uW or nW), so if you add 6 dB of attenuation you will loos 1/2 of your system RF voltage. (no not your DC voltage)

Lets say your LNB puts out around 10 milli volts RMS at it's connector, (-27 dBM) if you add a switch (-6 dB with connectors) the coax (say 100 feet of RG-6 at -9 dB) and a ground block (another 3 dB) for a total of 18 dB of signal loss, at the receivers LNB input you will have around a 1.2 mV RMS (-45 dBm) signal to work with.

This is fine as the normal FTA receivers LNB input will work from a -25 dBM to a -65 dBM RF input, (12.5 mV RMS to 125 micro volts RMS).

So don't worry about the "S" signal too much, it can go down to around 40% before you would see any problems.

Now for that "Q" signal.

The "Q" or quality, is a software derived measurement, imbedded in the digital TV signal is a FEC code,(Forward Error Correction) this is what keeps your TV picture nice a clean looking, if due to some outside interference the main TV picture or audio signal data bit (or bits) is corrupted, the FEC steps in and fills in the blanks.

When it does this the "Q" signal on your receiver goes down (how far is anyone's guess) when the "Q" gets down to a certain point the FEC is working over time to correct for those missing data bits, when it cant you the get pixilation of the TV picture or sound.

I have satellite systems with a low "S" (40 %) and the "Q" is around 30% and still get a great picture, this is due to the FEC code, the more FEC code that is used the more data there is to transmit.

Dish uses Turbo FEC on their HD channels, so they also have to use 8PSK modulation to handle the larger data stream.



Oh oh. I'm rambling again....See what happens when you drink too much soda at lunch.

In answer to your question on how much dB loss you can have, it's all up to the output level of your LNB to the receivers input sensitivity, (this can be found in the receivers manual) I wouls say no more then 20 to 25 dB for a standard setup.

[swingbozo]

I got some quad shielded buriable RG6 with "goo" inside that I ordered from work. My cost? It was slightly over $1 a foot. Glad work bought it. The stuff is fantastic though, run of about 150 feet or so.

And what Terryl said.

[jvvh5897]

Here is what a ham tested and posted in a thread at a radio site:


The average insertion loss of the adapters was 0.006 dB, and that was at 1300 MHz! Pay attention to the installation of the mating connectors. Weatherproof well. Then treat the barrel adapter as invisible.

[Terryl]

Here is what a ham tested and posted in a thread at a radio site:

Well this all depends on the connector types, a "UHF" to "UHF" barrel splice will show some drop, look at the photos in the link below, and "N" to "N" splice connection will not show a drop, I don't have one for an "F" to "F" connection (and Hams don't use "F" connections) but my 45 years at RF engineering will back up my claim of at least 3 dB at 1.5 GHz per splice using "F" connectors. (two F connectors and one F barrel)

Link to the data.
http://www.qsl.net/vk3jeg/pl259tst.html


IF you all want to test this then go out an rent, borrow, buy a good RF generator that can go to 3 GHz, and RF millivolt meter that can go to 3 GHz, or an RF spectrum analyzer that can go to 3 GHz.

Use 100 feet of good RG-6 coax, 2 - 25 ohm adapters, 4 - "F" connectors and 1 - 3 GHz "F" barrel connector.

Connect one end of the coax (after you put a connector on it) plus one of the 25 ohm adapters (99% of the RF generators are 50 ohm outputs) to the RF generator, connect the other end of the coax to the RF millivolt meter or spectrum analyzer, (with the other 25 ohm adapter) set your reference level to -10 dBM at 1.5 GHz, (you don't want to swamp your meter or analyzer) once you have a refferance level then cut and splice the coax, retest without changing your RF output level.


Then report back with your findings.

If you rent the right stuff you can do a sweep of the coax and other stuff, but you will need special sweep generators and analyzers for this.

[jvvh5897]

OK. I'll puzzle you this in reply. A 2 way splitter will have 3 dB loss between in and any output conn. If you have 1 dB loss in just going from coax to F bulkhead connector and you have two such connectors on the splitter on any path, then the minimum rated loss should be 5 dB. I would argue that loss in bulkhead connector would be much greater than any barrel connector, but a quick google shows 2 way splitter markings are no more than 3.5 dB--so either your figures are wrong or the bulkhead connector is a better connector than a barrel and that is unlikely IMO, or the loss in F connection can not be as great as you suggest.

BTW on BNC type connectors the insertion loss listed is around .2 dB at 3 GHz, and I would argue that F connectors are better design than BNC for high frequency or we would be seeing a different type of connector on provider's installations.

[keegster17]

I just bought some Beldon cable from a guy, I asked if it was 3ghz, he said it is all hype, is there a differnce between 3HZ and 2.5GHZ? I thought Beldon was good, got a 1000ft for $60.

[Terryl]

2.5 GHZ Beldon will work fine, and that "Guy" needs to go back to school. (you can tell him that from me)

Some cable is tested to 2.5 GHZ, some cable says "Swept to 3 GHz" both will work fine.

As long as its not for TV or cable TV systems.


Tell him that if the coax does not handle the high end signals (above 900 MHz) it will give a very poor performance on the satellite system.


Info for him:
Some of the LNB's used by Dish use what is called "Band Stacking" this puts one part of the satellites transponder signals on a higher then normal frequency, one polarity at 900 to 1450 MHz, the other polarity at 1950 to 2500 MHz, (1.95 GHz to 2.5 GHz) so if the coax attenuates the high end frequency too much then it wont work too good in that system.

[keegster17]

guy came back and agreed with me. He apologized and would not sell to me. I bought some RCA cable as I was desperate. Did about a 180ft run and signal and quality strong. Best things that ever happened me for sat hook up is, had dish on pole jst put it roughly where i thought it was to be positioned for 110. big shocker turned on receiver and boom instant signal and quality, i almost crapped myself. lol. that never happens. used old pansat for signal searching as i find all new units are bad for sat finding. but i used one long run, and seemed to work.