Gang,
While I agree with Bob that the UHF to BNC adapter is more rugged
than the BNC to UHF adapter, I disagree that the UHF connector
alone is more rugged than the BNC connector, except on RG-8 or
RG-213, 9913, etc. It's another story on the smaller cables.
I have had several UHF small coax failures, since the jacket
is NOT secured to the connector on the smaller cable types, such
as RG-59 or RG-58. RG-8 connections seem to be pretty tough,
since the body of the PL-259 actually threads onto the cable's
outer jacket, making for a good strain resistant mechanical
joint. The smaller cable isn't secured this well, and I have had
rotation occur in the UG-175 or UG-176 adapter that allowed the
shield and / or center conductor to separate.
I currently have been having better luck with the UG adapters for
UHF connectors by folding the sheild back over the end of
the adapter, holding it tightly against the outside of the end of the
adapter with a piece of small bus wire twisted around the braid.
I then sweat solder the entire braid to the adapter with a fairly
large solder iron, and then remove the small bus wire that
was wrapped around the shield strands. I trim any un-even
shield wires with a sharp knife, scraping the solder and wires
together down to the UG adapter surface.
To make this work right, you need to either use silver-plated
UG-175, UG-176 adapters, or pre-tin the more common nickel
plated ones, since they do not solder well and will cause you to
use too much heat to tin the adapter and solder the shield to it
simultaneously.
Be sure to use low melting point solder, such as 63/37 alloy, as it
melts at a much lower temperature than the other alloys, and it also
has nearly no plastic state when solidifying from the liquid
state. Pull the shield away from the coax's center insulator at
the end of the connector before soldering to minimize melting
the insulation into the shield as you solder the braid to the
adaptor surface. Cool the finished adaptor on your wet soldering
iron sponge before you handle it.
This method beats the heck out of the "solder the braid thru the
holes in the PL-259 body" method. It has the added advantage
that the ENTIRE coax shield is soldered to the adaptor, making
for a much stronger and better electrical connection.
It also has the advantage that the connector is much easier
to dis-assemble and re-use. I cut the cable about two inches
from the connector and un-screw the adaptor out of the PL-259.
The center conductor and insulation will remain in the connector
to be removed with a brief application of the soldering iron.
Try that with the "official" assembly method recommend for the
UG type adapters! The only thing to be careful about, is you
should tightly screw the adapter into the PL-259 after you
prepare it, so it doesn't become loose in use (!) and cause
failure of the center conductor connection.
Using BNCs, I always prefer the solder and clamp type fitting,
since the gland nut with its compression washer tightly grips
the outer jacket, making for a water-tight and mechanically
secure joint. I have never had one of these fittings fail. The
smaller size of the BNC connector also puts less strain on the
end of the cable when handling coax path cables, and it also
protrudes less than the PL-259 / UG-175, UG-176 connections.
On small radios for QRP like many of us use, the BNC adds much
less depth and weight to the wattmeters and transceivers. As
a result, your radio gear tends to stay put better and take up less
room on the operating desk. It's not quite as bad as having a big
piece of RG-8 hooked to the back of your QRP rig, but the PL-259
sure looks and feels like overkill when making attachments to
your itty bitty rig. :-)
Bob is correct about the UHF to BNC adapter being much more rugged
than the reverse, a BNC to UHF adapter. I use a bunch of those around
my shack to accomodate various mis-fitting cables. The solution I
have come up with that works very well for me, is I use a cable
with a PL-259 on one end and a BNC on the opposite end of the
same patch cable to make the adaptation between dissimilar
connectors. But that would not be necessary if all my gear were
BNCs to begin with! An OHR WM-1 with BNCs, pretty please!
There is something about a 4 hole BNC chassis connector that appeals
to me for QRP gear. I don't like the threaded type chassis mount, but
I have come to accept the PCB mount BNC jacks of my S&S gear
as an acceptable alternative.
The difference in the UHF not being a constant impedance type
connector like the BNC is, is not much of a concern at HF frequencies,
so the preference for BNCs is merely one of appearance and security
over the less rugged UHF type. Current trends toward coomercial radios
becoming smaller and smaller as the ICOM 706 demonstrates, make
me wish for BNCs as standard equipment.
The only shortcoming I find with BNCs, is the female center contact
seems to suffer a bit with extended use, like on your HT when you
change antennas a lot. I use a straight pin to pry the contacts toward
the center-line of the connector when the split contacts become
wallowed out.
I hope this helps anyone who dreads UHF / UG connector assemby.
Try it and let me know what you think.
73/72,
Gary Surrency AB7MY
S&S TAC-1(40&80m) and ARK30, AT-11 (QRO and QRP)
QRP-L #571 Chandler, AZ (near Phoenix)Grid Square DM43BH
Az ScQRPions
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