Coax Connectors Question
 

Hi,

Great group; really appreciate the help.

Do receiving only.

Have been going around a bit in trying to configure several radios and
antennas, including HF receivers and Scanners, with multiple antennas. If I
use "good" quality multi-position switches to do it, the $ are getting up a
bit.

Since I don't really switch all that often, two or three times a day
perhaps, I was wondering about just forgetting the switches and just make a
simple plug panel using, I imagine, BNC connectors and coax.

So, what kind of life might I expect with BNC's, plugging and unplugging
them ?
They certainly weren't designed with multiple in and outs in mind, but they
are kind of
well built, and I imagine they would take a fair amount of usage this way;
perhaps ?

Anyone have any experience with this kind of an application ?
What would degrade first in them; the center pin ?

Any better coax connectors for this kind of patch panel usage in your
opinions ?

Thanks again,
Bob

Coax Connectors Question
 

Robert11 wrote:
Do receiving only.

Have been going around a bit in trying to configure several radios and
antennas, including HF receivers and Scanners, with multiple antennas. If I
use "good" quality multi-position switches to do it, the $ are getting up a
bit.

The cheap coax switches that Radio Shack used to sell (and may still do)
will do fine. They are 75 ohm if any reasonable impedence instead of 50,
which should not matter at all for reception.

The better ones have 75 ohm dummy loads switched to the unused positions,
it helps isolate them. I use one to swtich between a dipole and satellite
TV box on my computer TV card and there is enough leakage that I don't have
to switch, the satellite box leaks through enough. :-)

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

Coax Connectors Question
 

"Robert11" wrote in message
...
Hi,

Great group; really appreciate the help.

Do receiving only.

Have been going around a bit in trying to configure several radios and
antennas, including HF receivers and Scanners, with multiple antennas. If
I
use "good" quality multi-position switches to do it, the $ are getting up
a
bit.

Since I don't really switch all that often, two or three times a day
perhaps, I was wondering about just forgetting the switches and just make
a
simple plug panel using, I imagine, BNC connectors and coax.

So, what kind of life might I expect with BNC's, plugging and unplugging
them ?
They certainly weren't designed with multiple in and outs in mind, but
they
are kind of
well built, and I imagine they would take a fair amount of usage this way;
perhaps ?

Anyone have any experience with this kind of an application ?
What would degrade first in them; the center pin ?

Any better coax connectors for this kind of patch panel usage in your
opinions ?

Thanks again,
Bob

BNC connectors can be had for as low as 50 cents. They last a long time if
you are careful and I have many surplus connectors in use. I never bothered
with patch panels, but it would be a natural if you are using Hardline or
1/2" cables up the tower anyway. Heavier coax to N connectors then 2-3 ft
rg 58c patch cables to radios. There are Cable connectors to BNC but you
might want to shop around. It might be cheaper than using N - BNC adapters.
I have never had to replace any connectors, but wear and tear has had me
replace a few patch cables. About once a year I smash a Q tip and soak it
in 90% Isopropyl and clean the grunge that gets down in the connectors.

There have been a few radios, scanners, that I have modified with bulkhead
BNC females

At one point I was a factory tech for a several HT models and would add
crystals and align en masse. The radios all had TNC connectors (Threaded
rather than Bayonet) After removing the bayonet shell from the patch cable,
it was a quick disconnect for either BNC or TNC. Not particularly proper
but fast. In any case Stock BNC is quick and good to 2Gig but I wouldn't
put more than 50 watts through them at that frequency.

Coax Connectors Question
 

So, what kind of life might I expect with BNC's, plugging and unplugging
them ?
They certainly weren't designed with multiple in and outs in mind, but
they
are kind of
well built, and I imagine they would take a fair amount of usage this
way;
perhaps ?

Anyone have any experience with this kind of an application ?
What would degrade first in them; the center pin ?


Just use BNC's and don't worry about it, they will last for ever.
After all almost every bit of test equipment uses BNC's and they endure
multiple connections/disconnections without worry.

73
Jeff

Coax Connectors Question
 

On Mon, 7 Sep 2009 09:23:40 -0400, "Robert11"
wrote:

So, what kind of life might I expect with BNC's, plugging and unplugging
them ?

Lousy. The ears on the BNC jack will get worn fairly quickly. Some
of my walkie talkies have BNC connectors for the antenna connector,
all with worn out ears.

What would degrade first in them; the center pin ?

The two ears on the jack will wear out. The electrical connections
will be fine for many years if you don't care about mechanical
retention.

Any better coax connectors for this kind of patch panel usage in your
opinions ?

For scanning, almost any kind of coax switch will work. A mechanical
(not electronic) 75 ohm video switch or IBM 3270 network switch will
do just fine. You'll never notice the impedance mismatch and losses,
except perhaps at 800MHz trunking frequencies.
http://www.blackbox.com/Store/Results.aspx/search-bnc+switch
The mechanical switch might also use phono connectors, not BNC.
Adapters are common. Of course, you can build your own.

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

Coax Connectors Question
 

"Robert11" wrote in message
...
Hi,

Great group; really appreciate the help.

Do receiving only.

Have been going around a bit in trying to configure several radios and
antennas, including HF receivers and Scanners, with multiple antennas. If
I use "good" quality multi-position switches to do it, the $ are getting
up a bit.

Since I don't really switch all that often, two or three times a day
perhaps, I was wondering about just forgetting the switches and just make
a simple plug panel using, I imagine, BNC connectors and coax.

So, what kind of life might I expect with BNC's, plugging and unplugging
them ?
They certainly weren't designed with multiple in and outs in mind, but
they are kind of
well built, and I imagine they would take a fair amount of usage this way;
perhaps ?

Anyone have any experience with this kind of an application ?
What would degrade first in them; the center pin ?

Any better coax connectors for this kind of patch panel usage in your
opinions ?

Thanks again,
Bob


That's exactly what BNCs were designed for; plugging and unplugging.
Take a look at all the test equipment using BNCs.
The big advantage of BNC over others is the ease on
connecting/disconnecting; they are extensively used in commercial and
military patch panels. Surplus patch panels are often a good source of
excellent connectors.

They are weatherproof, assuming you use good quality ones and not
el-cheapos; and install them correctly. I have used BNCs outside where they
have been in use through more than 20 Canadian winters and when I checked
them each spring and fall were perfectly clean inside - although the outside
showed definite signs of weathering.

The only failures I have ever observed in a properly installed BNC has been
the failure of the fingers in female receptacles on cheap connectors used in
some consumer devices - especially scanners. I usually take a close look at
any BNC on any non-professional device I purchase and if it looks suspect -
a good sign is only two fingers in the receptacle - I replace it because the
odds are it will eventually fail.
Any BNC connector which doesn't have a name and/or number on it is probably
not a good idea!

The only precaution I would take is if you have to leave a BNC - or for that
matter any connector - disconnected for any length of time outside is to
protect it from the elements. If you don't have a proper protector (they can
be hard to find) then put a piece of plastic bag over it and seal it with a
ty-wrap. I have just such a spare cable sitting out in the weather for the
last 4 years and with two layers of plastic bag material the outer layer was
starting to deteriorate after 3 years so I replaced both layers this spring.


Hope this helps.
Dave VE3HLU

Coax Connectors Question
 

On Mon, 7 Sep 2009 09:23:40 -0400, "Robert11"
wrote:

I was wondering about just forgetting the switches and just make a
simple plug panel using, I imagine, BNC connectors and coax.

This is your best option offering the greatest flexibility, best
isolation, lowest loss, and lowest cost.

So, what kind of life might I expect with BNC's, plugging and unplugging
them ?

They will last forever at your described usage.

73's
Richard Clark, KB7QHC

Coax Connectors Question
 

Richard Clark wrote:
On Mon, 7 Sep 2009 09:23:40 -0400, "Robert11"
wrote:

I was wondering about just forgetting the switches and just make a
simple plug panel using, I imagine, BNC connectors and coax.

This is your best option offering the greatest flexibility, best
isolation, lowest loss, and lowest cost.

So, what kind of life might I expect with BNC's, plugging and unplugging
them ?

They will last forever at your described usage.

73's
Richard Clark, KB7QHC

Just my thoughts...

--
RigReference.com - Reference guide for ham radio equipment
http://rigreference.com/