Another coax question and update!

Another coax question and update!

Post by stry.. » Sat, 22 Jan 2005 04:27:37

Well, I just got rg 8 cable about 20 feet for free! The thing about it
it has two pl259 connectors on it. I need to have one end free so i can
wire up the slim jim or j pole I build this weekend. I really do not
eant to cut the cable as I would like to use it when I put the
permanent station up. See any way around this?

Can I use copper house wire 12/ 2 or so to connect to the points on the
j pole then bring them to a so connector Then***the rg8 pl
connector into that? Will this through off the swr? What ohms is 12/2
wire?

He also gave me a short cable with two pl 259 connectors to connect
between my radio and the swr meter. It was a guy at a motorola dealer.
This cable is pretty thin and not rg8 but he said it was 50 ohms.
I plan on hooking the 20 feet from the swr to the antenna.

 
 
 

Another coax question and update!

Post by Fred McKenz » Sat, 22 Jan 2005 14:49:16


<< Can I use copper house wire 12/ 2 or so to connect to the points on the
j pole then bring them to a so connector Then***the rg8 pl
connector into that? Will this through off the swr? What ohms is 12/2
wire? >>

Stryped-

I suggest you obtain an SO-239 connector that mates with the PL-259 connector
on the cables.  Connect it as close to the antenna terminals as possible.

Once you finish building and testing it, you need some way to connect to it.
Why not just make an SO-239 part of the antenna?  Otherwise you would need a
piece of co-ax to connect permanently to the antenna.

The 12/2 wire's impedance can be calculated, but you would need a handbook to
find the formula.  It depends on the diameter of the wires and spacing between
them.  Insulation on the wires may affect the impedance, but probably not very
much unless they were twisted together.  I think it would be best to keep any
such connecting wires as short as possible.

<< This cable is pretty thin and not rg8 but he said it was 50 ohms.
I plan on hooking the 20 feet from the swr to the antenna. >>

Smaller cable might be RG-58 if it is a little less than a quarter inch in
diameter.  If it is around an eighth of an inch, it might be RG-174.  If you
examine it closely you may find some markings.

73, Fred, K4DII

 
 
 

Another coax question and update!

Post by Doug Smith W9W » Sat, 22 Jan 2005 15:35:32


> Well, I just got rg 8 cable about 20 feet for free! The thing about it
> it has two pl259 connectors on it. I need to have one end free so i can
> wire up the slim jim or j pole I build this weekend. I really do not
> eant to cut the cable as I would like to use it when I put the
> permanent station up. See any way around this?

> Can I use copper house wire 12/ 2 or so to connect to the points on the
> j pole then bring them to a so connector Then***the rg8 pl
> connector into that?

Yep, that's the right way to do it.  Keep the copper wires as short as
possible.  Try to find a way to physically fasten the shell of the SO239
connector directly to the point where the shield side of the coax would
go, eliminating the house wire on that side altogether if possible.

Quote:>Will this through off the swr?

It will, but if you keep the wire short the difference will be
negligible.  Try to keep it shorter than 2 inches if at all possible.

 >What ohms is 12/2 wire?

The wire itself has no impedance.

Two pieces of wire in proximity, and near the rest of the antenna, will
exhibit a characteristic impedance.  This will be difficult to predict -
and unimportant if the length of the wires is kept short.

Quote:> He also gave me a short cable with two pl 259 connectors to connect
> between my radio and the swr meter. It was a guy at a motorola dealer.
> This cable is pretty thin and not rg8 but he said it was 50 ohms.
> I plan on hooking the 20 feet from the swr to the antenna.

For the purposes of setting up the match, the "thickness" of the cable
between the radio and the SWR meter is not very important.  It may cause
power loss, but as long as there's enough power to operate the SWR meter
it doesn't matter.  It may cause the SWR at the radio to be lower than
that at the antenna, but it won't affect the SWR at the SWR meter which
is where you're measuring it.
--
Doug Smith W9WI
Pleasant View (Nashville), TN  EM66
http://www.redwaveradio.com/
 
 
 

Another coax question and update!

Post by stry.. » Sat, 22 Jan 2005 22:46:06

Hey, I am in Kentucky not real far from Nashville. Do you know anything
about the 440 mhz repeaters used for Skywarn and how far their coverage
is? I am trying to decide what I need to reach those from my house in
terms of equipment.

ALso, what is your web page about it says something abotu tv dxing. How
does that work?

 
 
 

Another coax question and update!

Post by Doug Smith W9W » Sat, 22 Jan 2005 23:55:25


> Hey, I am in Kentucky not real far from Nashville. Do you know anything
> about the 440 mhz repeaters used for Skywarn and how far their coverage
> is? I am trying to decide what I need to reach those from my house in
> terms of equipment.

Where in Kentucky are you?

I have to be honest not been all that impressed by the coverage of the
Nashville Skywarn repeaters.  But I don't have a very high UHF antenna.
  I'd think if you could get something 25-30 feet in the air you ought
to be able to hear at least one of them reasonably well.  Assuming you
aren't any further north than Russellville or Hopkinsville.

Quote:> ALso, what is your web page about it says something abotu tv dxing. How
> does that work?

Are you the same guy who asked that question in private email this
morning?  (if not, then let me know & I'll answer here)

--
Doug Smith W9WI
Pleasant View (Nashville), TN  EM66
http://www.w9wi.com

 
 
 

Another coax question and update!

Post by stry.. » Sun, 23 Jan 2005 00:17:13



> > Hey, I am in Kentucky not real far from Nashville. Do you know
anything
> > about the 440 mhz repeaters used for Skywarn and how far their
coverage
> > is? I am trying to decide what I need to reach those from my house
in
> > terms of equipment.

> Where in Kentucky are you?

> I have to be honest not been all that impressed by the coverage of
the
> Nashville Skywarn repeaters.  But I don't have a very high UHF
antenna.
>   I'd think if you could get something 25-30 feet in the air you
ought
> to be able to hear at least one of them reasonably well.  Assuming
you
> aren't any further north than Russellville or Hopkinsville.

> > ALso, what is your web page about it says something abotu tv dxing.
How
> > does that work?

> Are you the same guy who asked that question in private email this
> morning?  (if not, then let me know & I'll answer here)

> --
> Doug Smith W9WI
> Pleasant View (Nashville), TN  EM66
> http://www.w9wi.com

Yea that was me. I did not know if that address worked or not.

I live about 10 miles north of Russellville. I would have my antenna
25-30 feet. Was going to try a gain yagi for 440.