On Sat, 5 Jun 2010 21:49:32 +0000 (UTC), "Geoffrey S. Mendelson"
wrote:

I recently was able to use a crimp on tool for F connectors for RG-6 quad
shield coax.

Hopefully, it was a "push-on" tool and connector
http://www.arrisistore.com/digicon/Digicon-F-Connector-Installation-Guide.pdf
not the piece of junk with the small crimped ring.

To make sure everyone understands, I am in Israel, and RG-6
quad shield coax is cheap and easy to find.

There's quality RG-6a/u and junk. On the left coast of the USA, we
have both in copious quantities. I obtain mine directly from a
satellite DTV install company, so the quality is more towards quality
than junk.

Pl-259 connectors, called
"UHF" connectors here are rare items.

Be thankful. I find them to be a necessary evil as most ham radios
require them. Meanwhile, commercial radios are moving away from UHF
and toward other connectors, such as Type-N, BNC, TNC, Mini-UHF, and
SMA. However, Comerica base antennas remain UHF or Type-N.

BNC to PL-259 adaptors, are easy to get, and can be ordered from a reliable
local souce for a relatively small price. The same with N to PL-259.

That's what I do. Most of my cables are NOT terminated with UHF
connectors. If I need to go to UHF, I use an adapter.

Looking around at the crimp-on F connectors before I ordered them, I found
that you can get crimp on BNC connectors for RG-6 quad shield coax.

Yes, they work. I use quite a bit of RG-6a/u and prefer to have
everything terminated by the same connector, which is the CATV
standard F connector. If I need BNC, I use an adapter.

Here's my questions, Note when I say crimp-on, I mean the ones that crimp
from the rear, like commerical F connectors, not the ones that crimp
around the plug. I have never been able to get any of them to "fit right":

Agreed. The good ones are "push on" F connectors.

1. Can I connect a 75ohm BNC plug (which is a different size) to a
50oHm BNC socket?

There are such things as real 75 ohm BNC plugs and jacks. They're
easy to recognize because they lack the PTFE dielectric. The 75 ohm
connectors will mate properly with the 50 ohm connectors. There is
little risk of VSWR problems from using 50 ohm connectors on RG-6a/u.
http://www.qsl.net/n9zia/wireless/75_ohm_hardline.html
Basically, any small loss from VSWR is compensated by the lower loss
per meter of RG-6a/u as compared to RG-58a/u. Methinks you're safe
using all 50 ohm connectors.[1]

2. Are there crimp on 50 ohm BNC plugs which will work with RG6 quad shield?
I know there are variations, but most are similar in size.

They're nearly identical in dimensions. The 50 ohm variety have some
manner of PTFE dielectric. The 75 ohm variety use a plastic disk and
no dielectric.
http://www.amphenolconnex.com/products/bnc.asp
"50 ohm and 75 ohm connectors are intermateable to ensure
non-destructive mating"
The catch is that there's no guarantee that this is true between
different manufacturers. I've blundered across mutations and
variations that are NOT interchangeable.

3. Are there crimp on N connectors that would fit the RG6 quad shield coax?
More likely due to the size a crimp on center element that screws into the
plug body?

Probably, but I wouldn't use one. Just terminate in an F connector,
and use an F to N adapter. The price will probably be the same or
less. However, if you must go direct, any N connector that will fit
RG-59a/u will usually work with RG-6a/u. The problem is that
depending on the number of shields in the RG-6a/u, the outer diameter
will vary, making the diameter of the crimp ring an issue. Doing this
is risky and may result in a non-fitting connector. I would use an
adapter, which will always work.

4. Are there crimp on PL-259 connectors?

Also probably, but again, methinks you're better off with an F
connector and an adapter.

[1] I just counted 7 assorted coaxial cables going between my roof and
various RF devices in my house. All but one are 75 ohm RG-6a/u. Some
are double shielded, while others are quad shielded. The connectors
are slightly different. All the HF and VHF/UHF antennas use 75 ohm
coax. The one 50 ohm LMR-400 run is for the 900MHz antenna.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558