[c-nsp] DS3 Cables

[Barton F Bruce]

>What's wrong with RG-59?  As far as I understand, the most important
 >thing is "impedance 75 Ohms", which RG-59 fulfills...

RG-59's impedance is fine, but it isn't what telcos traditionally use and it
has other issues.

Doing T3 cables at a customer site, or needing to do them fast in a strange
city in the evening, go to RadioShack and even get the premade ones with F
fittings and then get their F to BNC adapters. It will work well. Same goes
for RG-6 which is much better for UHF than RG-59, but for T3 speed just
shouldn't matter.

If you have the high density BNC bulkheads on both the A nd B (left and
right) side of the back of a cisco 15454 chassis (aka Cerent), you are
facing 192 BNC connectors and with 4 of these fitting in a 7' rack,  you
simply don't want RG-59.

RG-59 typical construction is PE and that burns way too well. You may be
able to get a PVC jacket, but then it is toxic smoke. I'm sure there are
plenum grades available, too, but it is a lower quality cable than 734 or
735, and it is way stiffer. It also comes in stranded or solid center and
the F fitting folks rely on a solid center as that is their crappy center
connector pin. Know what you are getting if you plan to use it. We normally
stock it ONLY to use for use with the Symmetricom GPS dildo/antenna on the
roof for CO master BITs clocks (takes a Trompeter TNC connector, same
tooling...), and for any security cameras that are not IP.

735 is the small cable that is most commonly seen in bundles of "8-pack", or
9, 12, 16, or even 24. The center wire is 26 ga and is silver plated. A few
years ago when several other cable providers were trying to capture more of
Lucent's business, there was a lot of propaganda about the guage and
percentage coverage of the braid which is already over foil. The supposedly
important issue here was pull off strength for a BNC installed by joe q tech
who may be a bit sloppy.

If techs are equipped with good tools and good connectors (more on that in a
minute) and have had even brief training, I think they will do very well
with any of the available 735 cable.

As the other brands tried to steal telco connector business from Trompeter,
there were various telcos using the one-crimp connectors with the colored
plastic rearends for 734 and 735. There were a couple of different styles
from one vendor and the tooling and the connectors could not be
interchanged. The tooling was even more expensive than the traditional all
metal BNC two-crimp tooling, but these newer connectors were less expensive
and claimed faster installation. I hated them, and think they were not as
reliable, and have not been seeing them as much so I suspect others felt the
same way. These one crimp ones predated the current waterproof with
colorcoded ring one squeeze F and BNC connectors for RG-6 and RG-6 quad
shield the cable guys now use, and I doubt these newest ones are made for
734 or 735.

If you have any amount of connectors to do, you really need the "Trompeter"
stripper that looks like a flashlight with a big head. These are actually
made by the Eraser Co. in upstate NY. so shop for your best price. They come
adjusted and with a sample stripped cable end. But learn the internal
adjustments as they get fiddled with by differnet people and you may need to
reset everything. The 734 cutter head in the standard 734 & 735 kit will
strip RG59 in a pinch (with the correct strip length for Trompeter
connectors if you have the correct one for your cable). The Trompeter
ferrule crimp dies leave the die number embossed in the hex crimp. Their
12-point center pin crimper is really simple and just works well and isn't
that much more than the 8-point one.

If you buy these BNCs in large quantity direct, the price gets quite
attractive. The Trompeter ones are well made here in the USA of quality
materials. Single plastic bags that are scored to rip open are good for tool
bags, but the 50 connector trays are best if you have a lot to do. It used
to be that MilesTek had a supposedly imported BNC for 735 cable that was
almost 1/2 what a Trompeter costs, but their prices have crept up and the
Trompeter ones are very good. One dead T3 because of bad connectors, and you
paid what you would have for premium connectors. OTOH, MilesTek is a huge
Trompeter customer, so at least some of what they sell is the good domestic
stuff, though I don't know what is imported vs OEM'd from Trompeter.

One big problem with 735 is that it has about double the loss that 734 does
(RG-59 is similar to 734 for loss) and all those LBO settings in feet to
normalize signal levels at the DSX bays are assuming you have 734 cable.
DOUBLE your actual 735 footage to get its 734 equivalent loss. Or to put it
in practical terms,  you can only go half as far on 735 cable.

An additional plug for Trompeter is that after the mass confusion caused by
there being NO standards for 75 ohm SMBs (which was standardized at 50 ohms)
and every connector manufacturer doing a 75 ohm version differently and
cisco having at least 2 DIFFERENT bastard versions (probably due to acquired
company's earlier choices), Trompeter came out with a 75 ohm mini-BNC that
is really nice and that some equipment vendors use and that "OF COURSE"
crimps with the same standard Trompeter 734/735 tool kit. It is actually the
strip length that is the biggest issue that they did do "right". Cutter
heads are large, expensive, and having other strip length heads around would
mean they WOULD be misapplied.