How much signal lost through barrel connector?

[Mr Tony]

Want some opinions before I decide if I can do the easy route or the hard route for the next project

Since G18 is pretty much kaput programing wise, I decided to move the dish there. Its motorized so it makes it easy. I was trying to figure out where to put it for the time being. Already have fixed dish at 105. So was working with it making sure signals look good and they look good

Then I had an idea :
Motorize the receiver in computer room. Right now its fixed with G16, 105W and a feed from the "main" motorized.

But now I have a dilemma. I have two options with this
1. run a brand new cable from the computer room to the motor
2. use a barrel connector and combine the cable that comes into the house from the motorized to the cable that goes to the comp room. Right now its hooked to a diseqc switch in the basement.

Normally I would just run a new cable but the way my house is up it would be something like this
from the roof run down side of house into hole where cables are (drop ceiling in basement), run it through ceiling into laundry room out the hole there into the garage. Run along ceiling in garage into hole in top of garage into computer room (bedrooms sit on top of garage) at the opposite end of house......total length 110-115 feet

or just use the barrel connector and take my chances with a loss of signal? Right now the cables are about 30 feet (from roof to basement) and 75 feet (from basement to computer room).

How much loss is there with a barrel connector?

 

[tvropro]

Good Question? I would say very little. I use them on my Primestar dish and my C band dish (inside) You have so much gain, 60db+ typical on an LNB that the little bit of loss will never show up.

 

[Mr Tony]

and since its only 110 feet with 2.2ghz swept cable it shouldnt be that much of an issue?

If I lose a point or 2 on the Coolsat meter (or say 4-5 pts on the Pansat meter) then I shouldnt worry? After all, there is a diseqc switch now in line so removing that and adding a barrel should be the same results??

 

[brentb636]

I generally figure about 0.5 dbm per barrel connector. This is an old number from when I used to troubleshoot our broadband system and measure losses at various points. Our 2 to 1 splitters were typically about 1.2 dbm loss , in comparision ( though they were marked for 2.5 dbm loss). Just numbers we used to engineer system and hopefully predict results. [eidt] I'd be surprised if you could document a signal loss with the receiver's signal meter. Let us know, though . [/edit]

 

[tvropro]

and since its only 110 feet with 2.2ghz swept cable it shouldnt be that much of an issue?

If I lose a point or 2 on the Coolsat meter (or say 4-5 pts on the Pansat meter) then I shouldnt worry? After all, there is a diseqc switch now in line so removing that and adding a barrel should be the same results??

I got 1450 mhz swept satellite and 1000 mhz Commscope cable tv coax cable on my Primestar dish leads. That is fed through a high block V/H relay switch I built then to the diseqc and finally to my Pansat and I don't have any problems. My C band is all 1450 swept cable with a barrel (extended when I built my home theater room) through a commercial high block splitter to the 4DTV and the other port goes through the diseqc to the Pansat.

I wouldn't worry about it Ice. Your actually loosing more through the diseqc then a barrel.

 

[Cham]

Just use the best quality you can find... I have some that are "supposed" to be good to 3ghz and they seem to have minimal insertion loss. I have had trouble with the cheap gold-color ones from Rad Shack; think the spring contacts inside were too weak and caused poor contact with the wire center conductors. The good ones I have have a green insulator/dielectric.
Have fun!
-C.

 

[Smith P.]

From Dish training material (probably I had the tape somewhere ):
output at LNBF: -33 dB
min level at IRD input: -63 dB
F-connector: -2 dB.

So, if you insert a barrel and connect cables by 2 F-connectors, you would drop the signal -4...5 dB. According Dish numbers.

 

[ericha]

A "barrel connector" usually has to ports--e.g. 2 female F connectors. But you said you wanted to combine. Does this mean you want to disconnect the cable from the digiseq, and then join it to the cable to the computer room? I guess that's what you mean, and this takes a barrel connector.

The losses in these (and any adaptor) depend on the connector type (I think F connectors are pretty lousy, but I work in a company that makes high-end instruments, and we are pretty picky) and the frequency. That said, I've got 4 barrels between my switch and receiver (ground block and 3 wall panels) with no problems at all.

Losses, by the way (to brentb636) are stated in "dB", not "dBm". dB is used for a ratio, like gain or loss; dBm is a unit of power, like Watts.
A loss of 0.5 dB for a few GHz for an F connector sounds about right--I'd measure some with a Vector Network Analyzer (my company makes very nice ones), but a good measurement requires a through connect for calibration--and getting a precision F connector is pretty difficult! It would be fairly easy to see how much they vary, but I can't think of an easy way to get a precise measurement of about 1/2 dB on an F connector.

 

[brentb636]

"Losses, by the way (to brentb636) are stated in "dB", not "dBm". dB is used for a ratio, like gain or loss; dBm is a unit of power, like Watts."
Thank you for the correction. I'm retired now, and about 10 years away from working with the equipment. What struck me , when working on the systems is that good installation techniques frequently resulted in lower losses that the OEM of the equipment quoted.
I'm inclined to agree with TVROPRO that insertion of a barrel connector is not going to be a major event.

 

[Larobpra]

I have 2 barrel connectors between the motorized dish (SG2100) and the MercII in the living room, probably a 80-90' run at most. I can only move the dish on horizontal transponders from the living room, but both work with a short cable out at the dish. Don't notice much signal loss though.

 

[MikeinBaja]

I use only the swept blue barrels - but with a twist. I ALWAYS use "MIL spec, electronics grade" silicone (Rat Shack - in a tube - about 6 bucks a tube) on both ends of the connector before assembly and at the barrel itself.

Keeps all the moisture out and ensures a great connection. I see no DB loss with this, but generally run well under 100'.

Started doing this years ago because of the salt air environment. Works like a dream.

 

[mikelib]

http://www.rmscommunications.net/pdf/rmsconn.pdf

Ice, check out page 25 and if you need further information call the company and ask for Eddie. Tell him your a FTA guy and he will help you out.

 

[visiter555]

Every connector is normally a 3 db loss. If the cable connections or the barrell connector are crappy there can be even greater loss. If it is outdoowrs there is a potential for rust adding to the loss.

Cable is cheap. I normally run a new one in these situations.

 

[Mr Tony]

A "barrel connector" usually has to ports--e.g. 2 female F connectors. But you said you wanted to combine. Does this mean you want to disconnect the cable from the digiseq, and then join it to the cable to the computer room? I guess that's what you mean, and this takes a barrel connector.

correct. Disconnect the diseqc switch and hook the cable from that (that runs to the computer room) to the cable that comes off the roof right now into the basement. So it basically would be like this

receiver----------------------75 feet-----barrel---------30 feet----motor-----LNB

The losses in these (and any adaptor) depend on the connector type (I think F connectors are pretty lousy, but I work in a company that makes high-end instruments, and we are pretty picky) and the frequency. That said, I've got 4 barrels between my switch and receiver (ground block and 3 wall panels) with no problems at all.

compression connectors on all cables here.

 

[Mr Tony]

Every connector is normally a 3 db loss. If the cable connections or the barrell connector are crappy there can be even greater loss. If it is outdoowrs there is a potential for rust adding to the loss.

it would be inside. The only switches I have outside are the 22k switch for the Shaw Direct setup and a 4x4 on the main motorized but that is covered. All other switches are inside (in ceiling in basement)

Cable is cheap. I normally run a new one in these situations.

the issue is how it has to be run through the house. Having to remove part of the ceiling then running it through the garage is a pain in the ass for lack of a better term. Done that a couple times

 

[Mr Tony]

MikeinBaja

I have some of the blue barrel connectors. I guess what I can try is a 20 foot run from the motor and take some results then hook up the setup and see how bad it goes down

I wont have all the sats logged in this setup. Just the "main" ones

 

[pendragon]

http://www.rmscommunications.net/pdf/rmsconn.pdf

Ice, check out page 25 and if you need further information call the company and ask for Eddie. Tell him your a FTA guy and he will help you out.

My experience is this reference is closer to reality than some of the other losses quoted. They basically measured 0.027 dB of loss at 1500 MHz for a decent quality barrel.

Coincidentally a few months ago I had a signal up on the spectrum analyzer and inserted a F barrel for some reason. The level dropped by nearly 1 dB. That took me by surprise, but I soon discovered it was a cheap, ancient barrel that had ended up in my spare parts box. Substituting a better one, I could no longer measure any appreciable loss. This degenerated into a farce where I strung a number of short cables through multiple barrels and compared the result to a similar single length of cable. My very rough conclusion was the loss for each connection was probably less than 0.1 dB, and therefore insignificant.

If you're losing 1-3 dB per connector, something is wrong. I appreciate that the F-connector is no match in the instrumentation world, but it is a very inexpensive part that with simple tools and little training can work very effectively in the FTA, DBS and cable domains.

 

[Mr Tony]

well I tried it

hooked up cable from motor to Pansat 1500 and took some numbers from 93 (true south), 95, 101, 103, 105, 123, 125, 72, 74, 79, 83, 85, 91

Then hooked up cable that was already there and put barrel connector (blue ends on the barrel connector) in line and hooked up cable in computer room. Used same receiver and tried it

No difference that I saw on various TP's across 14 sats. All were the same signals. The Pansat 1500 has a better meter (IMO) then the Coolsat 5000. Coolsat shows 73 quality when the Pansat could show 60 or 70.

Larobpra...Pansat 1500 ran the motor on V just fine. Sat there on 91 trying to figure out why the dish wouldnt move....tried different TP's and nothing....then I say motor was set to "disable" instead of USALS.....whoops

 

[tvropro]

If anything the barrel would cause an impedance bump and a change in Standing Wave Ratio. The reflected power would show up as the loss. But were splitting hairs here, get a decent one and be done with it if there is a concern. I used standard ones which I have laying around here and they work fine in everyday instances.

 

[tvropro]

well I tried it

hooked up cable from motor to Pansat 1500 and took some numbers from 93 (true south), 95, 101, 103, 105, 123, 125, 72, 74, 79, 83, 85, 91

Then hooked up cable that was already there and put barrel connector (blue ends on the barrel connector) in line and hooked up cable in computer room. Used same receiver and tried it

No difference that I saw on various TP's across 14 sats. All were the same signals. The Pansat 1500 has a better meter (IMO) then the Coolsat 5000. Coolsat shows 73 quality when the Pansat could show 60 or 70.

Larobpra...Pansat 1500 ran the motor on V just fine. Sat there on 91 trying to figure out why the dish wouldnt move....tried different TP's and nothing....then I say motor was set to "disable" instead of USALS.....whoops

See Ice they do work fine Problem is here on Satellite Guys sometimes we get into all the super technical aspect discussions of stuff which may show up on an O-scope etc, but in the real world don't say it won't work. Sometimes using the KISS Method (Keep it Simple Stupid) is the best route to use with things.