RadioBanter - View Single Post

June 20th 06, 12:36 AM posted to rec.radio.amateur.antenna

wrote:
On Mon, 19 Jun 2006 13:17:42 -0500, Chris W wrote:

wrote:

On Mon, 19 Jun 2006 12:11:07 -0500, "Ken Bessler"
wrote:

How much power can a BNC handle? rg58 coax, 1.3:1 swr,
say, 54mhz, indoor connection. I'm using a BNC jumper between
my amp and my antenna switch. I use BNC so I can d/c quickly
when a t-storm comes in the area.

Comfortable at 100W, I doubt more would be reasonable.

Allison

I don't know that answer either but I'm sure it is higher than that. I
have seen coaxial relays with SMA connectors that can handle 400 watts
at a higher frequency than 50 Mhz. Also get an N connector and a BNC
connector and do a close comparison of the pin and the shield inside the
connector. They look pretty close. In fact an N male will connect to a
BNC female, just no way to hold them together. The other way around
doesn't work because the BNC retention housing gets in the way.

And how much power can RG58 take?

Now that is something I can answer. Or at least I have found charts
that give me values for that. Assuming you can trust them, rg-58 can
handle 300 watts at 50 Mhz and 160 watts at 150 Mhz. Times microwave
equivalent LMR-190 says it can handle 680 watts at 50 Mhz and 390 at 150
Mhz. It also has the following foot not on those power ratings, "Power:
VSWR=1.0; Ambient = +40°C; Inner Conductor = 100°C (212°F);
Sea Level; dry air; atmospheric pressure; no solar loading"

I have yet to find anything that tells how much power a BNC connector
can take though. I found one that gave it a voltage rating of 500V and
a current rating of 3.5A DC. If you use Ohms law 500V at 50 ohms would
be 10 amps which gives 5,000 watts, I seriously doubt it can really
handle that. That calculation probably didn't help any. If you take
the 3.5A with 50 ohms you get 175 V and 612.5 watts. However that 3.5A
was DC and generally it is easier to carry the same number of amps with
AC, but not sure how that changes as the frequency goes way up.

In the end I still don't know how much power it can handle, but I still
think it is well over 100 watts. If I were using the LMR cable (which I
do) I would probably trust it up to 300 watts at 50 Mhz. With the RG-58
unless my VSWR were perfect and or the ambient temperature were pretty
low, I would probably keep it down to 200 watts.

--
Chris W
KE5GIX

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