Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Fran3
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Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by Fran3 » Mon Apr 29, 2019 10:35 am

What cable do you guys suggest for running balanced audio around the building when the studio is co-located with the transmitter?

Long run case...
- In this case we have two studio's...
- one requires a run of about 20-feet...
- the other requires a run of about 50 feet.

Short run case...
- In studio between console and audio sources and also console to nearby DA.
- In transmitter room between EAS equipment and audio processor and transmitter audio input

Of course cost is an issue but we need stuff that works... also flexibility/bend-ability of the cable is nice but may not be required...

Thanks for any help.

TPT
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by TPT » Mon Apr 29, 2019 1:19 pm

Belden 8451 two wires, foil shield. Thousands of feet in use around the country in all kinds of studios. $32 for 100 foot at Markertek, Google it, you can probably find it cheaper.

CAT5 is OK...it is twisted pair so some RF cancellation, but no shielding. Also solid wire, easy to break if a tight pull. Star-quad is geek overkill, it is expensive and bulky.

A tip on wiring in general. Pick up the little cloth number books--Lowe's has them in the electrical parts section. Then get some 1/4" clear shrink tube (Amazon), and--to really do it right, splurge for a heat gun (try Jameco). You can make a 3 column table on a word processor, and as you install the cables put the numbers on each end and cover with the clear shrink tube (I've found the current crop of cloth numbers tend to dry up and peal off). Then list where each cable starts and ends. E.G Wire #1--program to EAS input #2 EAS to transmitter #3 Mod monitor audio to console air monitor...

I know--seems like a lot of work for just a few wires. Then you add --a satellite receiver. Or another computer needs an audio feed for streaming. A Barix box for some network broadcast. Audio from the EAS weather receiver so they can here the forecast in the control room...you get the idea. If you start with a numbering plan you will be grateful in a few years when you have to figure out what a particular wire does in a bundle of 20 different wires.

I have a 25X50 building with two control rooms for a pair of FM stations, and a production studio, one FM station co-located (17 KW, bottom bay 175' above the roof). One control room, where the racks are with the satellite receivers, EAS etc., has numbered wires ending at #176. For the moment.

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kkiddkkidd
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by kkiddkkidd » Mon Apr 29, 2019 6:40 pm

Multi pair Gepco (or whatever the replacement for Gepco is these days). One pull, many pairs... Pull about 2x the pairs that you think you need. Punch it down onto your choice of terminal blocks and enjoy many years of not having to pull a wire every time something changes.

Cat5 is great if you are absolutely certain of all balanced circuits. Shielded Cat5 is readily available but not as cheap as UTP. I have a couple co-located studios wired with StudioHub capable consoles and adapters and are as RF quiet as Beldon or Gepco audio wire.

Unbalanced.... Not so much.
--
Kevin C. Kidd CSRE/AMD
WD4RAT
AM Ground Systems Company
http://www.amgroundsystems.com
KK Broadcast Engineering
http://www.kkbc.com

TPT
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by TPT » Tue Apr 30, 2019 5:20 am

When we built the station back in 1983 I had acquired a 50' piece of Belden cable with 27 shielded pairs. Ran between what was originally the main studio and what was originally the transmitter room. Still in use..and does save time--but expensive if bought new. Sometime you can find these cables on E-Bay.

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Dale H. Cook
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by Dale H. Cook » Tue Apr 30, 2019 5:32 am

TPT wrote:
Mon Apr 29, 2019 1:19 pm
Belden 8451 two wires, foil shield.
Or Belden 8723, 2 pair, individually shielded with common drain wire, for stereo.
TPT wrote:
Mon Apr 29, 2019 1:19 pm
Pick up the little cloth number books ... Then get some 1/4" clear shrink tube (Amazon), and--to really do it right, splurge for a heat gun (try Jameco)
I abandoned the books for 3M ScotchCode numbering. I'll second the heat shrink. That, ScotchCode, and heat guns are all at my local parts jobber.
Dale H. Cook, Contract Engineer, Roanoke/Lynchburg, VA
http://plymouthcolony.net/starcityeng/index.html

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PID_Stop
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by PID_Stop » Tue Apr 30, 2019 7:30 am

Since we have a diversity of opinion here, I'll broaden it a bit:

1) Belden 8451 is excellent for analog line-level signals, but 9451 is easier to work with: the foil shield is bonded to the jacket, so it strips cleanly. Otherwise, the two are identical. In our plant, 20-50 feet is a relatively short run; it's more like 200 feet from our rack room to some of the edit bays. Electrically it's okay with short mic-level feeds, so long as you aren't moving it -- the foil shield isn't meant for constant flexing. If you are wiring to a mic that moves around, a star-quad cable like Canare L4E6S is our go-to type. It's really robust, easy to work with, and resists kinking about as well as anything we've seen (nearly reporter-proof).

2) If you are wiring stereo, I would suggest Belden 9451D over 8723. It looks like zip cord, essentially a black 9451 bonded to a red 9451. This makes terminating the cable much cleaner: each channel goes separately to its own connector, and each channel has its own drain wire. Since a given channel's jacket goes unbroken right into the connector, the strain relief actually works. By contrast, 8723 has only one drain wire for the two pairs, and you have to come up with a clean way to split out the pairs (heat shrink tubing, for instance). On the other hand, we use 8723 quite a bit for RS422 data cables, where you have two balanced pairs and a single shield.

3) In a high RF environment, you do well to minimize the number of connection points that can get flaky. Yes, you can use punchdown blocks... but I wouldn't unless there is a compelling reason. I've been burned too many times -- especially by ADC QCP panels, but even by 66 blocks on several occasions.

4) We've used a number of labeling schemes over the years. When we built our current facility (1984), 3M had just come out with nifty little dispensers with rolls of plastic adhesive numeral marker tapes (0 - 9). Within two years, about half of these had failed, leaving us with hundreds of cables with one or more digits missing, and a pile of dead tape in the bottom of each rack. I spent weeks retracing cables and relabeling them with cloth numerals. Again, some had adhesive failure, and we ended up going exclusively to Panduit PCM-series cards (PCM-0, for instance is a card with 36 zeros). About 20 years ago we gave up on peel-and-stick numerals, moving to a succession of Brady label printers that give us a laminated label that not only does not fail, it can provide more helpful information than just a wire number. The only real downside was price: not only is the label stock somewhat expensive, the printers themselves ran through battery packs and ribbons fairly quickly. Today most of our cables are labeled using Panduit LJSL5-Y3 self-laminating labels: there are 49 labels on 8-1/2" x 11" sheets, seven across by seven high, and you can either hand-write them or print them using inkjet or laser printers. Since most of our wiring work is for installation projects, I will make a drawing of the new system with all of the wire numbers shown, and at the same time enter the numbers on an Excel spreadsheet that is formatted to print correctly on the label stock. The end result is labels that are highly legible, contain useful information, and stay put even in adverse conditions or handling.

Jeff

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PID_Stop
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by PID_Stop » Tue Apr 30, 2019 7:45 am

TPT wrote:
Mon Apr 29, 2019 1:19 pm
Belden 8451 two wires, foil shield. Thousands of feet in use around the country in all kinds of studios.
Heck, we have literally miles of 8451 and 9451 just in our building alone!

:lol:

Jeff

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Dale H. Cook
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by Dale H. Cook » Tue Apr 30, 2019 9:05 am

PID_Stop wrote:
Tue Apr 30, 2019 7:30 am
... 3M had just come out with nifty little dispensers with rolls of plastic adhesive numeral marker tapes (0 - 9).
Those are the ScotchCode numbers of which I wrote.
Dale H. Cook, Contract Engineer, Roanoke/Lynchburg, VA
http://plymouthcolony.net/starcityeng/index.html

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PID_Stop
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by PID_Stop » Tue Apr 30, 2019 10:19 am

Dale H. Cook wrote:
Tue Apr 30, 2019 9:05 am
PID_Stop wrote:
Tue Apr 30, 2019 7:30 am
... 3M had just come out with nifty little dispensers with rolls of plastic adhesive numeral marker tapes (0 - 9).
Those are the ScotchCode numbers of which I wrote.
I certainly hope they've improved the adhesive since 1985!

(And kudos for not ending that sentence with a preposition -- my English teacher daughter would be proud!)

Jeff

Fran3
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by Fran3 » Tue Apr 30, 2019 11:50 am

Belden 8451. I'm ordering it today. FYI, free shipping using Amazon Prime.

TPT
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by TPT » Tue Apr 30, 2019 1:42 pm

Appealing to have labels that identify what the cable is used for (as opposed to numbers). Unfortunately, nothing stays the same for long--that's why I stick with numbers and a WordPerfect table to keep track of what goes where. If I could find an old list for my backbone 27 pair cable I would bet that 75% of the pairs are now used for different feeds.

radio_guru
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by radio_guru » Tue Apr 30, 2019 3:42 pm

I have historically used the Gepco 86xxx series wire for mono and split stereo. Belden 8723 for unified connector stereo (think DB9, etc.) The Gepco (now General wire) strips easier than Belden by a country mile and is a bit softer than the 8451/9451 jacket. If you need to pull multiple pairs (trunk), the Gepco wins hands down.

Let me also add, a number of former Gepco employees formed a company called Lake Cable located in Bensenville, IL. They distribute through Stattuc distributors in Waukegan, IL. They make a set of basic audio and video cables very similar to Gepco and will custom label and color code jackets for runs as low as 10K ft.

https://www.lakecable.com/index.php/pro ... al-channel

https://www.shattuc.com/vendors/bulk-cable/lake-cable.

With General Cable having destroyed the industry relationship with contractors Gary Geppert had forged, and my preference for AoIP, I'm not sure when or if I will again buy the legacy multi-pair Gepco product however. My cost went up 20% or more instantly when that occurred.

Now, for AoIP. Buy as good of cable as you can afford. Blackbox 350Mhz series and Belden 1212 are my preferred cables, but will use Belden 1500 if I need to minimize conduit fill. And Belden does have a 6 cable composite version of the 1500.

I also know people who have successfully pulled 25 pair CAT5 cable for trunk runs. But as others have alluded, the balance must be precise so as to avoid RFI.

RG

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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by w9wi » Tue Apr 30, 2019 3:44 pm

We bought a Brady BMP41. https://www.bradyid.com/en-us/product/bmp41 A bit expensive but not horrible. It'll make labels for a variety of wire sizes. (including 8451/9451 audio; 8723 data; 1855/1694 video, among others) They stick reliably and are easy to print & apply.

We made the mistake of wiring one room with the cables tagged with the room/rack numbers of each end. The "correctness" of the labels survives reassignment of spaces, but they're too small to read in difficult conditions. We went back to using code numbers & entering them in an Excel spreadsheet.

Now, the problem with *that* is that we have seven engineers & an IT guy running wires. If two are working in different places at the same time... we've had duplicate numbers assigned. Once we get out of major project hell I need to get back into seeing if Corporate will let us run some kind of database server (Access, SQL Server, MySQL, PostgeSql, something) that'll do record locking.

I suppose if you're the lone engineer, Excel would work fine.

We usually use 8723 for analog audio. As PID_Stop says, it's good for RS-422; it's also fine for RS-232 and has come in handy for some other data circuits. I suppose 9451D would work just as well for data - just tie the two shields together.
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Doug Smith W9WI
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kkiddkkidd
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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by kkiddkkidd » Wed May 01, 2019 7:01 am

I have been using a Dymo Ryno 4200 for several years. Other than the obscenely expensive large format label maker that I have stashed at the shop, it is the best that I have every used. IF you get the good tape, the labels stay put. I bought some knockoff tape and it was a disaster...

I too typically only number the bundle or multiconductor cable and then keep the wire source / destinations in a file. Most of the time... I have never found a fool proof method of cable documentation that this fool can't somehow screw up.

Later,
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Kevin C. Kidd CSRE/AMD
WD4RAT
AM Ground Systems Company
http://www.amgroundsystems.com
KK Broadcast Engineering
http://www.kkbc.com

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Re: Audio cable for AM transmitter site? Star Quad or Ethernet or What?

Post by jthorusen » Thu May 02, 2019 1:49 am

Re Labeling:

Back at KCBS in the good old days, we used an Excel spread sheet sized to make the characters visible when laid parallel and curved to fit the wire (Belden 8451 or the West-Penn equivalent). We cut out the "labels" (cells) with scissors and slipped them under clear shrink. A touch of the heat gun and you had a permanent label. If you duplicate the Excel columns, it will help you keep track of which numbers you have used and where you left off for the day.

Don't forget to put the shrink on BEFORE terminating the wire! :D

Regards,
James K. (Jim) Thorusen
KB6GM
Central Coast Electronics
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NW Oregon Consulting Bdcst Eng.

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