The discussion about HV connectors involved DC power supply fittings, not RF
transmission.
RG8/U and PL-259's handle lots of power unless horribly mismatched.
Actually, I've tested PL-259's at 10 amperes, almost no discernible heating.
10A at 50 Ohms is 5kW. RG8/U has a 13ga copper center conductor, and
equivalent resistivity copper braid material. Its "insulated" rating is
~20A at 25 degrees C. It would be hard to melt this stuff from raw power;
usually, failures are from dielectric (voltage) breakdown due to high VSWR.
The arcing in your tuner should stay inside the tuner. I'd recommend
keeping the tuner cover in place at all times, when you're transmitting.
A "safety" ground needn't be a short length of #2 wire, although that sounds
like it would be good for jump-starting cars and welding. Whether one can
achieve a real "RF" ground over a broad range of frequencies is always
questionable, but the need for such a ground is also questionable if
current-fed, and matched, antennas are in use. A real RF ground, like a
"lightning" ground, is best made of flat, broad conductors and not stranded
wire of any gauge. For a true RF ground, in the broadcast industry I always
used flat sheets of copper flashing (like what used to be popular around
chimneys and gutters on building roofs -- nowadays, it's mostly aluminum).
WB2WIK/6
"Each success only buys an admission ticket to a more difficult problem." --
Henry Kissinger
> -----Original Message-----
> From: krishna [SMTP:kkanakas@cisco.com]
> Sent: Monday, January 28, 2002 8:51 AM
> To: amps@contesting.com
> Subject: [AMPS] Special connector for coax??
>
>
> Hi all,
> I have been watching the discussion on the coax and connectors for HV.
> I am going to be using my first amp an AL-811H. I have 100ft of RG-8/U
> (rated
> at 1200W at
> probably 1:1swr). Now i probably bought some cheap available connector
> and
> soldered it.
>
> Do i need to get a special HV connector?? Where can i find a few??
>
> Moreover, i was looking at some tuner reviews for the MFJ 1.5Kw and 3Kw
> tuners
> and got scared at the comments that folks had posted. This was on the use
> of
> Amps and fire hazard.
>
> Will good grounding prevent human exposure to arcing. Provided one
> doesn't open
> the AMP and
> have all connections intact, viz RIG-AMP-Antenna.
>
> I have some very heavy multistranded insulated coper wire. Probably #1 or
> #2
> guage.
>
> TO DIGRESS >>>>>
> They are setting up a DC power plant at work and have some left overs
> cables :)
>
> Gotta see those. I love em. They crimp the connectors at the end of this
> cable
> to run 48V DC for the telecom equipment. I wish we had some solid state
> amps to
> use the power :)
> The DC power modules are all plug in types.
> <<<<<<
>
> I am planning on using the power cable for running my ground wire.
>
> Here are my proposals.
>
> 1) connect all the equipment ( radio/baby tuner/amp/ big tuner etc) to a
> single
>
> ground using a heavy guage wire.
>
> 2) Connect the ground bus to this #1 or #2 insulated wire.
>
> 3) Can i run the insulated wire along with the coax and other stuff to
> outside
> the house ( where i am going to drive down ground rods). This will be
> a long
> run.
>
> 4) The other option to (3) is to drill a hole near the window and take the
> ground
> wire straight to the ground rod. And from the ground rod, i can run
> another
> piece of wire to the waterpipe that is outside the house ( of course
> will
> check
> for continuity of water pipe metallic sections). Doing this will avoid
> 90
> degree turns
> and keep the run short. My Qth is a split level and my shack is almost
> below
> ground
> level. The window lower frame is just a couple of feet from the ground
> level
> on the
> outside.
>
> So please let me know if i am asking for disaster with any of my ideas.
>
> thanks
> krish
> w4/vu2vku
>
>
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