Roger,
Great overview on connectors !
One thing that I am wondering about is whether or not to get the solder
type
center pin on the DIN connectors. I see them clamp or crimp style for
the outer shield and also
solder or non solder on the center pin. I like the crimp style outer
and clamp is fine too, but not sure
if getting a non solder center pin is a concern. Whats your view on
the center pin attachment ?
I remember discussions here on Tower Talk in the past about center pin
creep in type N connectors.
The DIN is a different animal though...........
Bob
K6UJ
On 9/5/16 5:08 PM, Roger (K8RI) on TT wrote:
I see a lot of preferences from UHF, To :N: type, to DIN, but for the
average ham, does it make a difference?
Take UHF, essentially the design is crude and they are cheap! The loss
figures are high, but those figures are for frequencies few hams ever
approach and the connector specs say up to 300 MHz and 500 volts.. On
HF the loss is minuscule. The arguments are those figures add up and
they do, but it's still a very small value. With SO2R and remote
antenna switches, plus the rotator loops and pigtails to the antennas
I've counted as many as ten connectors between the rig and antennas,
but the loss was barely detectable. Impedance bumps? Yes, they are
there, but what do the mean? Added up for the 160 through 10 meter
bands, they are insignificant. I can see where the reflections "might"
make a difference with digital modes, but it's still very small. The
only down side I can see is the learning curve for the solder types.
"Probably" the average ham does a miserable job of soldering them,
over heating the connector and coax when soldering the braid, turning
the coax dielectric into a mass of goo, while getting solder on the
exterior of the center conductor pin.
Off brand UHF connectors: Many adherents say Amphenol
http://www.amphenolrf.com/connectors/uhf.html is the only way to go
and they do have reasonably good quality control. As I said at the
beginning, the original connector design is crude, but it was designed
long ago. They are easy to make, so there are many off brand
connectors of various qualities. Amphenol lists both Nickel and silver
finish as well as a whole slew of dielectrics from Phenolic and
Styrene, to Teflon and more. The off brand stuff varies, but a good
inspection by the Ham who knows what to look for, there are good ones
out there. The typical Ham would do better sticking with known
brands, but with the UHF design, the important point is whether the
particular connector will pass the test of time. OTOH even
top-of-the-line connectors are inexpensive and if you purchase very
many, the discount makes them about the price of the stuff you see at
the swaps..
Installed according to the directions (braid on the inside and
properly soldered), the connector will provide reasonable
strength. NOTE UHF connectors are not weatherproof!
N-Type. Not for those running "high power". By high power, I'm nor
referring to 1500 watts.
http://www.amphenolrf.com/connectors/n-type.html OK, so they
represent less insertion loss with less impedance, but what do they
gain us at 160 through 10?. Amphenol lists them "These connectors are
used in all systems where excellent RF and mechanical performance is
critical." I'm not sure by what they mean when they refer to
mechanical performance, but I've never found the typical N-type
connector I couldn't pull off the coax with my hands (crimp type
excepted) In my experience, They have two limitations. Mechanical
strength and center pin migration are the problems I've seen.
Mechanical strength is pretty much self explanatory. Center Pin
Migration? On vertical runs, the center conductor in many, if not most
coax cables will slowly move downward This tends to pull the center
pin, in on the top connector, and push the center pin out on the
bottom connector. This doesn't happen with connectors where the center
pin is captive.
DIN (7-16) connectors.
https://en.wikipedia.org/wiki/7/16_DIN_connector Is kinda like an
N-connectors on steroids. The 7-16, or 7/16 is the size of the center
pin (7 mm) and the ID of the outer connector (16 mm) They are still a
bit on the expensive side and not for the ham who purchases connectors
at swaps to save a buck, but " It is among the most widely used high
power RF connectors in cellular network
<https://en.wikipedia.org/wiki/Cellular_network> antenna systems." and
"The 7-16 DIN connector out performs other non-flange options, such as
N connectors <https://en.wikipedia.org/wiki/N_connector> or BNC
connectors <https://en.wikipedia.org/wiki/BNC_connector>, when it
comes to interference and intermodulation rejection or higher power
handling at RF frequencies.^[1]
<https://en.wikipedia.org/wiki/7/16_DIN_connector#cite_note-UTC-1>"
(Quoted from the above Link)
Adapters: Amphenol lists 689 adapters. Pages from
http://www.amphenolrf.com/adapters.html However, other than the most
common it's likely the distributor would need to special order them.
Crimp, Vs solder. Other than requiring a specialized crimp tool, crimp
connectors tend to be more uniform, faster to install, and
mechanically stronger than the solder type. Properly adjusted cable
prep tools (strippers) really speed things up and present identical
cable ends to the connectors with the proper dimensions. Nearly
identical crimp tools can be found with widely varying prices. One
crimp tool with two sets of inserts can cover cables from RG-58
through RG-8 (LMR-400) sizes. Depending on the vendor, nearly all
connectors for these cables are available in solder or crimp versions.
NOTE The RG designation has not been a specification for many years.
It simply refers to cable sizes. Nothing more.
So the question is, why would the average, or typical ham need
anything other than the crimp, or solder, UHF connector?
A SIDE NOTE: on weather proofing: There are several approaches to
weatherproofing. One uses vinyl electrical tape wound sticky side out
over the connectors, to keep the weatherproofing material (coax seal,
various self vulcanizing tapes, and "flooded" heat shrink tubing)
from sticking to the connector Flooded heat shrink tubing has a layer
of hot melt glue on the inside. If you don't want the glue to stick to
the connector, a film of Silicone grease or mold release agent, will
allow for a seal without the glue sticking to the connector. Just
don't get any on the coax jacket. Me? I make sure it's all clean and
bond to the whole works.
By bonding to the coax jackets and the connectors, the flooded heat
shrink tubing makes for a very strong mechanical connection.
One other comment: In over 55 years as a ham, I've only seen two bad
connectors from Amphenol. I can't say that for the few "brand
unknown", I've purchased from swaps.
73
Roger (K8RI)
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