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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