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  #21   Report Post  
Bruce in Alaska
 
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Default How to use a simple SWR meter and what it means to your VHF

In article ,
"Jim Woodward" jameslwoodward at attbi dot com wrote:

We regularly talked to boats that were thirty to fifty miles away. Maybe
this is routine -- I don't know -- but I'd like to think that attention to
detail and the 9913 helped.


Jim, Just a note on the above, Out in the North Pacific, the fishing
fleet, routinely talks 90 -110 miles with 25 Watts on Vhf Maine
Frequencies. The antennas are in the 50' to 80' range above the water.
Some of the Coast Stations report contacts out to 120 Miles, using
120 Ft towers, and the 50 Watts at the antenna connection rule in
Part 80.

Bruce in alaska
--
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  #22   Report Post  
Stilz
 
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Default How to use a simple SWR meter and what it means to your VHF



Larry W4CSC wrote:

snipped


Good post Larry. For my two cents - I switched several years back from
Belden to Times Microwave cable for everything. Lower losses and
personal experiences has been much better weather resistance.

Mike KG4RRH


More CB myths. Most boats only have a 25-50' coax run. What I DO
recommend is a good Belden foil shielded cable, which will require
proper crimp connectors to make it work, not PL-259's from WalMart.
The 100% foil shield will keep locally generated noise OUT of the
cable on receive on its way from the antenna to your sensitive
receiver. You won't have to listen to the cheap straight plugs marine
engine manufacturers love to put in outboard and inboard motors,
instead of the resistor plugs they should be using. The foil coax
will also get a little more signal to the antenna on transmit, but
"big deal"....(c;

On Thu, 13 Nov 2003 09:33:27 -0500, Vito wrote:

Marcus AAkesson wrote:

On Wed, 12 Nov 2003 15:41:08 -0500, "Jim Woodward" jameslwoodward at
attbi dot com wrote:

4) What do you like other than the cheap white crap for antenna cable? I
used Belden 9913 (solid center conductor) on Swee****er. Is that still a
good choice?

RG214 or similar which is silver plated Cu in both conductor and
shield. Raw copper will in time oxidize and deteriorate in the salty
environment. I have seen some really ugly cables after only 5-6 years.


Check out http://www.therfc.com/attenrat.htm

Common RG-58A (the white crap) looses 7.4dB/100 ft at 200MHz. That's
over half your signal used to heat the coax! RG-8X (mini-RG8 - the other
white crap) is almost as bad at 5.4 dB/100'. Belden 9913 is excellent at
only 1.8dB/100. RG-214 has 3.3dB loss/100' but as Marcus suggests may
have better corrosion resistance. Of course if money, size and weight
are unimportant there's LDF5 (c:


Larry W4CSC

"Very funny, Scotty! Now, BEAM ME MY CLOTHES! KIRK OUT!"

  #23   Report Post  
Doug K7ABX
 
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Default How to use a simple SWR meter and what it means to your VHF

In addition to the trusty old Bird 43, I love my MFJ-259B HF/VHF SWR
Analyzer. It allow me to check an antenna without transmitting. Those
expensive Shakespeare antennas with the cell phone, VHF high band filters,
etc., are frequently mistuned right out of the box. Checking them at the
shop by sweeping through the marine band for good SWR has saved me a lot of
time and frustration of installing a brand new antenna on a boat and then
finding out it is bad out of box. Another use of the MFJ is trying
different positions of an antenna to find a location where adjacent metal is
not causing problem. I used it to find the best compromise location on my
van motorhome for a 2 meter bumper mounted colinear antenna that the close
proximity of the van metal sides interfered with.
Doug K7ABX
"Bruce in Alaska" wrote in message
...
In article ,
"Doug Dotson" wrote:

I prefer a reflected power meter. Much more inruitive than
an SWR meter. Converting from RP to SWR is a simple formula
as well.

Doug, k3qt
s/v Callista


Nothing like a good Bird Wattmeter, fresh out of the Cal Shop,
to see what's going on in an Antenna System.

Bruce in alaska
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  #24   Report Post  
Larry W4CSC
 
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Default How to use a simple SWR meter and what it means to your VHF

On Fri, 14 Nov 2003 14:48:06 -0500, Stilz wrote:



Good post Larry. For my two cents - I switched several years back from
Belden to Times Microwave cable for everything. Lower losses and
personal experiences has been much better weather resistance.

Mike KG4RRH

In the interest of accuracy and truthfulness, Lionheart's VHF radios
are running off US Navy RG-58A/U because I got a 1000' roll of it for
free from a friend who buys tons of surplus stuff. I mentioned to him
one day that I needed some RG-58 for the car and he just went around
to the storage building and said, "Is one enough? I got lots."

Free coax has no loss at all that I can measure, can you?....(c;



Larry W4CSC

"Very funny, Scotty! Now, BEAM ME MY CLOTHES! KIRK OUT!"

  #25   Report Post  
Jim Woodward
 
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Default How to use a simple SWR meter and what it means to your VHF

"Larry W4CSC" wrote in message
...
snip

The only reason you need the power is to overcome noise
and the damned marinas docking boats from a 70' tower with a 9 dB
antenna running 25 watts to get to the end of the dock. Why the FCC
doesn't restrict marinas to 1W and 10' AGL has always been a mystery
to me. They're NOT part of any rescue party, manned by teenage girls.


Actually, don't the rules say that we all MUST use 1W when possible? Thus
the marinas are actually in violation if they're using 25 watts. Of course,
the FCC has better things to do than enforce its own rules.

And thanks to all for comments in this thread. So many decisions, so little
solid information available on subjects like this. While you guys don't
always agree, at least I get a spectrum of views from people who mostly
don't have a horse in the race.


--
Jim Woodward
www.mvFintry.com


..




  #26   Report Post  
Bruce in Alaska
 
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Default How to use a simple SWR meter and what it means to your VHF

In article t,
"Doug K7ABX" wrote:

In addition to the trusty old Bird 43, I love my MFJ-259B HF/VHF SWR
Analyzer. It allow me to check an antenna without transmitting. Those
expensive Shakespeare antennas with the cell phone, VHF high band filters,
etc., are frequently mistuned right out of the box. Checking them at the
shop by sweeping through the marine band for good SWR has saved me a lot of
time and frustration of installing a brand new antenna on a boat and then
finding out it is bad out of box. Another use of the MFJ is trying
different positions of an antenna to find a location where adjacent metal is
not causing problem. I used it to find the best compromise location on my
van motorhome for a 2 meter bumper mounted colinear antenna that the close
proximity of the van metal sides interfered with.
Doug K7ABX


Yep, I use an Impedance Bridge on my Cushman CE50A1 for doing that job.
It is very nice to have all the right tools, to do the job.

Bruce in alaska
--
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  #27   Report Post  
Doug Dotson
 
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Default How to use a simple SWR meter and what it means to your VHF

I suppose that is a matter of judgement. 1 watt is pretty useless when you
are an hour away trying to secure a slip for the night. Trying to secure a
slip 10 minutes before arrival is inconsiderate and places the marina on
the spot and can leave one with few alternatives if they cannot accomodate
you. Try reducing your power to 1 watt everytime you are communicating with
a marina and see how life is?

I just have to ask what the thinly vailed insult has to do with anything? I
think
Larry's explanation of SWR was quite valuable and others who chimed in
had valuable contributions as well. Certainly more useful than the Battery
Water
thread

Doug

"Jim Woodward" jameslwoodward at attbi dot com wrote in message
...
"Larry W4CSC" wrote in message
...
snip

The only reason you need the power is to overcome noise
and the damned marinas docking boats from a 70' tower with a 9 dB
antenna running 25 watts to get to the end of the dock. Why the FCC
doesn't restrict marinas to 1W and 10' AGL has always been a mystery
to me. They're NOT part of any rescue party, manned by teenage girls.


Actually, don't the rules say that we all MUST use 1W when possible? Thus
the marinas are actually in violation if they're using 25 watts. Of

course,
the FCC has better things to do than enforce its own rules.

And thanks to all for comments in this thread. So many decisions, so

little
solid information available on subjects like this. While you guys don't
always agree, at least I get a spectrum of views from people who mostly
don't have a horse in the race.


--
Jim Woodward
www.mvFintry.com


.




  #28   Report Post  
Harry Krause
 
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Default How to use a simple SWR meter and what it means to your VHF

Doug Dotson wrote:

I suppose that is a matter of judgement. 1 watt is pretty useless when you
are an hour away trying to secure a slip for the night. Trying to secure a
slip 10 minutes before arrival is inconsiderate and places the marina on
the spot and can leave one with few alternatives if they cannot accomodate
you. Try reducing your power to 1 watt everytime you are communicating with
a marina and see how life is?

I just have to ask what the thinly vailed insult has to do with anything? I
think
Larry's explanation of SWR was quite valuable and others who chimed in
had valuable contributions as well. Certainly more useful than the Battery
Water
thread

Doug



Good grief...that battery water thread has to be in the running for the
longest, dullest, most useless string of discombubulated thoughts ever
to be regurgitated on usenet.

Q: What kind of water do you use in your batteries?

A: Whatever's left in the Miller Lite cans.*





* I use AGM batteries, and drink the water.










--
Email sent to is never read.
  #29   Report Post  
Leanne
 
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Default How to use a simple SWR meter and what it means to your VHF


" * I use AGM batteries, and drink the water.

We do too, but remember that water will rust your plumbing.
Though is great for cooking, washing, or brushing teeth.

Leanne
S/V Fundy


  #30   Report Post  
Doug Dotson
 
Posts: n/a
Default How to use a simple SWR meter and what it means to your VHF

I've never seen a boat with metal plumbing. We use AGM as well and
avoid the battery water probem. Liquid electrolyte battery are obsolete
IMHO.

Doug

"Leanne" wrote in message
...

" * I use AGM batteries, and drink the water.

We do too, but remember that water will rust your plumbing.
Though is great for cooking, washing, or brushing teeth.

Leanne
S/V Fundy




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