Brian
The RG 8x has stranded core and a solid insulator. What you are saying is
it will be good but not perfect. If I have a 25 watt VHF transmitter, I
should expect ??? wattsoutput at the end of an 80' wire. I am trying to
decide if I should go through the aggrivation of the thicker wire or accept
a loss in power. I need to find a 10' piece of the GTO-15 for my Icom
700pro.
Thanks
Bruce
"Brian Whatcott" wrote in message
...
GTO-15 is a single conductor (often 14 gage stranded) rubber
insulated pvc clad unshielded cable used for neon signs and ignition
wires.

It is chosen for its 15 kVolt insulation, which can handle most any
3 - 30 Mhz transmitter signals, which may involve high voltages,
but it is unshielded.

If the RG-8X you have in mind has stranded conductor and foam
insulation, this will have a much lower working voltage
(they seem to rate between 300 volts and 1500 volts).

The people who get hot under the collar about foam insulation have a
point; you can easily wipe out transmitter range by treading on that
stuff just once. It is inevitably more delicate than solid insulation.

In a marine environment, it is reasonable to go for durability
where total runs are reasonably short.

It's true that a hundred feet of cable up a tall mast can give away a
lot of transmitter power at VHF and UHF; much more so at higher
frequencies still, and you might want to consider a well secured and
protected lower loss cable type there.
In general, if the cable type you have been using has
been satisfactory, that's the first option at renewal time.

Above all, you don't pick a regular co ax for GPS antennas, where the
losses mount rapidly.
Hope this helps somewhat, without making too many people mad.
I do have the FCC license to fool with these radio/radar installations
commercially, for what its worth.

Brian W

On Sat, 17 Jan 2004 17:06:09 -0500, "Bruce"
wrote:

I am looking at the Ancor brand RG-8x which has tined stranded core.
Could
I also use this type wire for the 10' run from my SSB tuner to the
backstay?
What I had on the SSB was GTO-15???
Thanks
Bruce
"Brian Whatcott" wrote in message
news
I recommend checking with suppliers' specifications for cable
construction materials: solid or stranded? solid or foam insulation?
%coverage of shield? Tape wrap? Non-acid outer sheath? before
blindly implementing Larry's recommendation below on choosing
cables. Yes: let's call it a reality check.

Brian W



On Sat, 17 Jan 2004 05:54:58 GMT, (Larry W4CSC) wrote:

... 55' mainmast has a Shakespeare 1/2 wave VHF antenna on top
with about 75' of RG-58A/U military surplus cable///
If I had to start from scratch, and couldn't buy a 500' roll of
surplus RG-58A/U for $10 at my local thrift shop...

I recommend using VERY flexible, and reliable,
Polyethelene-cored, finely stranded center conductor RG-58A/U (not
RG-58/U which has a solid center conductor) for your purpose. All
those fancy loss charts mean nothing when the fancy foam cables are
pulled through a sharp turn, somewhere. Hell, you can wind RG-58A/U
in a hangman's noose and it'll still work great! REALITY CHECK!!

Noone is forcing anyone to use it. It works well for us in poly
dielectric and stranded centers. It bends around corners without
damage, which in our application was key.

Bend foam 8X or 8 hard around a corner every boat has will destroy it.

That makes the cable spec sheet all BS......



Larry W4CSC

Noone is forcing anyone to use it. It works well for us in poly
dielectric and stranded centers. It bends around corners without
damage, which in our application was key.

Bend foam 8X or 8 hard around a corner every boat has will destroy it.

That makes the cable spec sheet all BS......



Larry W4CSC

Bruce,
this is a lift of Budgetmarine's site which carries notes in pdf
form:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~
Coaxial Cable
Coax cable transfers your radio transmitter's energy to the antenna.
It is precisely made, with the impedance matched to VHF-radios.
Bigger cable diameter results in less signal loss.We carry three kinds
of coaxial cable that are suitable for your VHF: RG-58, RG-8U, and
RG-8X. Use the RG-58 for short runs only, the RG-8X for runs up to
60' (18m) and the low loss RG-8U for longer runs. Note that splicing
co-ax cable can result in dramatic losses - by a factor of 10 if
done poorly or with improper connectors.

Coax Size vs Signal Loss
Cable Diameter Loss / 100’ Length for 3dB loss
RG-58 0.195" 6.1dB 49’
RG-8X 0.245" 4.5dB 66’
RG-8U 0.410" 2.7dB 111’
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ `

That strikes a fairly common sense note. But remember,
cable characteristics of the same nominal type vary, and some are more
delicate than others, and more susceptible to UV, and damp......

....but to answer your question:
25 watts into 80 ft of RG-8X (using the specs given above which
apply at VHF) implies 50% loss at 66 ft, and there's another 10% over
the remaining 14 ft --so about 10 watts get into the antenna.

(Could you hoist the whole radio up the stick? It would boost output
power to more than double if you just ran audio and power up 80 ft!
- Jest kidding...)

Their RG8U numbers give an 80 ft loss of about 36% leaving
16 watts available for the antenna.

Here's the thing:
You probably could not notice the difference between 16 watts and 10
watts emitted. So I suggest you avoid the aggravation of going with
the thicker stuff.

Brian W


On Sat, 17 Jan 2004 20:21:41 -0500, "McCampbell"
wrote:

Brian
The RG 8x has stranded core and a solid insulator. What you are saying is
it will be good but not perfect. If I have a 25 watt VHF transmitter, I
should expect ??? wattsoutput at the end of an 80' wire. I am trying to
decide if I should go through the aggrivation of the thicker wire or accept
a loss in power. I need to find a 10' piece of the GTO-15 for my Icom
700pro.
Thanks
Bruce
"Brian Whatcott" wrote in message
.. .
GTO-15 is a single conductor (often 14 gage stranded) rubber
insulated pvc clad unshielded cable used for neon signs and ignition
wires.

It is chosen for its 15 kVolt insulation, which can handle most any
3 - 30 Mhz transmitter signals, which may involve high voltages,
but it is unshielded.

If the RG-8X you have in mind has stranded conductor and foam
insulation, this will have a much lower working voltage
(they seem to rate between 300 volts and 1500 volts).

The people who get hot under the collar about foam insulation have a
point; you can easily wipe out transmitter range by treading on that
stuff just once. It is inevitably more delicate than solid insulation.

In a marine environment, it is reasonable to go for durability
where total runs are reasonably short.

It's true that a hundred feet of cable up a tall mast can give away a
lot of transmitter power at VHF and UHF; much more so at higher
frequencies still, and you might want to consider a well secured and
protected lower loss cable type there.
In general, if the cable type you have been using has
been satisfactory, that's the first option at renewal time.

Above all, you don't pick a regular co ax for GPS antennas, where the
losses mount rapidly.
Hope this helps somewhat, without making too many people mad.
I do have the FCC license to fool with these radio/radar installations
commercially, for what its worth.

Brian W

On Sat, 17 Jan 2004 17:06:09 -0500, "Bruce"
wrote:

I am looking at the Ancor brand RG-8x which has tined stranded core.
Could
I also use this type wire for the 10' run from my SSB tuner to the
backstay?
What I had on the SSB was GTO-15???
Thanks
Bruce

Bruce,
this is a lift of Budgetmarine's site which carries notes in pdf
form:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~
Coaxial Cable
Coax cable transfers your radio transmitter's energy to the antenna.
It is precisely made, with the impedance matched to VHF-radios.
Bigger cable diameter results in less signal loss.We carry three kinds
of coaxial cable that are suitable for your VHF: RG-58, RG-8U, and
RG-8X. Use the RG-58 for short runs only, the RG-8X for runs up to
60' (18m) and the low loss RG-8U for longer runs. Note that splicing
co-ax cable can result in dramatic losses - by a factor of 10 if
done poorly or with improper connectors.

Coax Size vs Signal Loss
Cable Diameter Loss / 100’ Length for 3dB loss
RG-58 0.195" 6.1dB 49’
RG-8X 0.245" 4.5dB 66’
RG-8U 0.410" 2.7dB 111’
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ `

That strikes a fairly common sense note. But remember,
cable characteristics of the same nominal type vary, and some are more
delicate than others, and more susceptible to UV, and damp......

....but to answer your question:
25 watts into 80 ft of RG-8X (using the specs given above which
apply at VHF) implies 50% loss at 66 ft, and there's another 10% over
the remaining 14 ft --so about 10 watts get into the antenna.

(Could you hoist the whole radio up the stick? It would boost output
power to more than double if you just ran audio and power up 80 ft!
- Jest kidding...)

Their RG8U numbers give an 80 ft loss of about 36% leaving
16 watts available for the antenna.

Here's the thing:
You probably could not notice the difference between 16 watts and 10
watts emitted. So I suggest you avoid the aggravation of going with
the thicker stuff.

Brian W


On Sat, 17 Jan 2004 20:21:41 -0500, "McCampbell"
wrote:

Brian
The RG 8x has stranded core and a solid insulator. What you are saying is
it will be good but not perfect. If I have a 25 watt VHF transmitter, I
should expect ??? wattsoutput at the end of an 80' wire. I am trying to
decide if I should go through the aggrivation of the thicker wire or accept
a loss in power. I need to find a 10' piece of the GTO-15 for my Icom
700pro.
Thanks
Bruce
"Brian Whatcott" wrote in message
.. .
GTO-15 is a single conductor (often 14 gage stranded) rubber
insulated pvc clad unshielded cable used for neon signs and ignition
wires.

It is chosen for its 15 kVolt insulation, which can handle most any
3 - 30 Mhz transmitter signals, which may involve high voltages,
but it is unshielded.

If the RG-8X you have in mind has stranded conductor and foam
insulation, this will have a much lower working voltage
(they seem to rate between 300 volts and 1500 volts).

The people who get hot under the collar about foam insulation have a
point; you can easily wipe out transmitter range by treading on that
stuff just once. It is inevitably more delicate than solid insulation.

In a marine environment, it is reasonable to go for durability
where total runs are reasonably short.

It's true that a hundred feet of cable up a tall mast can give away a
lot of transmitter power at VHF and UHF; much more so at higher
frequencies still, and you might want to consider a well secured and
protected lower loss cable type there.
In general, if the cable type you have been using has
been satisfactory, that's the first option at renewal time.

Above all, you don't pick a regular co ax for GPS antennas, where the
losses mount rapidly.
Hope this helps somewhat, without making too many people mad.
I do have the FCC license to fool with these radio/radar installations
commercially, for what its worth.

Brian W

On Sat, 17 Jan 2004 17:06:09 -0500, "Bruce"
wrote:

I am looking at the Ancor brand RG-8x which has tined stranded core.
Could
I also use this type wire for the 10' run from my SSB tuner to the
backstay?
What I had on the SSB was GTO-15???
Thanks
Bruce

Brian and Gary...good stuff. Now understanding the loss of power, it
would make sense to get an amp (Idon't think it would be legal) or have a
second line run to the spreader on the mizzen.That would drop the run down
to 30' and a corresponding increase in power.
Thanks for you help
Bruce
"Gary Schafer" wrote in message
...
This is the same Larry that says that he has a 150 watt VHF amplifier
to switch in the antenna line if he can't be heard.
Yet he recommends using lossy rg58 cable. Old surplus stuff at that!
When cable ages it does not always do so gracefully. The dielectric
breaks down and the losses can be considerably higher than new cable.

For the amount of work involved and the minimal cost of 100 feet of
RG8 type cable, use the best NEW cable.
RG8 with polyethylene insulation is the way to go unless you have a
size restraint. And forget the aluminum wrap shield stuff. You are
asking for trouble in the marine environment with aluminum.
You do not need "high shielding" for a VHF radio.
Foam insulation is not a good idea on a boat though. The center does
migrate at bends. It is also very difficult to install connectors on
foam cable. The heat from the soldering iron melts the insulation
quickly and lets the center wire move to the side. Sometimes even
shorting it.

Regards
Gary


On Sat, 17 Jan 2004 18:53:08 GMT, Brian Whatcott
wrote:

I recommend checking with suppliers' specifications for cable
construction materials: solid or stranded? solid or foam insulation?
%coverage of shield? Tape wrap? Non-acid outer sheath? before
blindly implementing Larry's recommendation below on choosing
cables. Yes: let's call it a reality check.

Brian W



On Sat, 17 Jan 2004 05:54:58 GMT, (Larry W4CSC) wrote:

... 55' mainmast has a Shakespeare 1/2 wave VHF antenna on top
with about 75' of RG-58A/U military surplus cable///
If I had to start from scratch, and couldn't buy a 500' roll of
surplus RG-58A/U for $10 at my local thrift shop...

I recommend using VERY flexible, and reliable,
Polyethelene-cored, finely stranded center conductor RG-58A/U (not
RG-58/U which has a solid center conductor) for your purpose. All
those fancy loss charts mean nothing when the fancy foam cables are
pulled through a sharp turn, somewhere. Hell, you can wind RG-58A/U
in a hangman's noose and it'll still work great! REALITY CHECK!!

Brian and Gary...good stuff. Now understanding the loss of power, it
would make sense to get an amp (Idon't think it would be legal) or have a
second line run to the spreader on the mizzen.That would drop the run down
to 30' and a corresponding increase in power.
Thanks for you help
Bruce
"Gary Schafer" wrote in message
...
This is the same Larry that says that he has a 150 watt VHF amplifier
to switch in the antenna line if he can't be heard.
Yet he recommends using lossy rg58 cable. Old surplus stuff at that!
When cable ages it does not always do so gracefully. The dielectric
breaks down and the losses can be considerably higher than new cable.

For the amount of work involved and the minimal cost of 100 feet of
RG8 type cable, use the best NEW cable.
RG8 with polyethylene insulation is the way to go unless you have a
size restraint. And forget the aluminum wrap shield stuff. You are
asking for trouble in the marine environment with aluminum.
You do not need "high shielding" for a VHF radio.
Foam insulation is not a good idea on a boat though. The center does
migrate at bends. It is also very difficult to install connectors on
foam cable. The heat from the soldering iron melts the insulation
quickly and lets the center wire move to the side. Sometimes even
shorting it.

Regards
Gary


On Sat, 17 Jan 2004 18:53:08 GMT, Brian Whatcott
wrote:

I recommend checking with suppliers' specifications for cable
construction materials: solid or stranded? solid or foam insulation?
%coverage of shield? Tape wrap? Non-acid outer sheath? before
blindly implementing Larry's recommendation below on choosing
cables. Yes: let's call it a reality check.

Brian W



On Sat, 17 Jan 2004 05:54:58 GMT, (Larry W4CSC) wrote:

... 55' mainmast has a Shakespeare 1/2 wave VHF antenna on top
with about 75' of RG-58A/U military surplus cable///
If I had to start from scratch, and couldn't buy a 500' roll of
surplus RG-58A/U for $10 at my local thrift shop...

I recommend using VERY flexible, and reliable,
Polyethelene-cored, finely stranded center conductor RG-58A/U (not
RG-58/U which has a solid center conductor) for your purpose. All
those fancy loss charts mean nothing when the fancy foam cables are
pulled through a sharp turn, somewhere. Hell, you can wind RG-58A/U
in a hangman's noose and it'll still work great! REALITY CHECK!!

On Sun, 18 Jan 2004 04:30:59 GMT, Brian Whatcott
wrote:


Coax Size vs Signal Loss
Cable Diameter Loss / 100’ Length for 3dB loss
RG-58 0.195" 6.1dB 49’
RG-8X 0.245" 4.5dB 66’
RG-8U 0.410" 2.7dB 111’
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~`


Is now an ok time to point out that 3db of signal on any receiver
S-meter is about the width of the needle? The 1.6 dB loss between 8X
and 58A is almost impossible to see on any S-meter you'll ever see.

It's why we boost power in 10-20 dB increments on ham radio. You are
hard pressed to see any difference between 25W - 4.5 dB and 25W -
6.1dB actually on the air.



Larry W4CSC

On Sun, 18 Jan 2004 04:30:59 GMT, Brian Whatcott
wrote:


Coax Size vs Signal Loss
Cable Diameter Loss / 100’ Length for 3dB loss
RG-58 0.195" 6.1dB 49’
RG-8X 0.245" 4.5dB 66’
RG-8U 0.410" 2.7dB 111’
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~`


Is now an ok time to point out that 3db of signal on any receiver
S-meter is about the width of the needle? The 1.6 dB loss between 8X
and 58A is almost impossible to see on any S-meter you'll ever see.

It's why we boost power in 10-20 dB increments on ham radio. You are
hard pressed to see any difference between 25W - 4.5 dB and 25W -
6.1dB actually on the air.



Larry W4CSC

On Sun, 18 Jan 2004 06:15:40 -0500, "Bruce"
wrote:

Brian and Gary...good stuff. Now understanding the loss of power, it
would make sense to get an amp (Idon't think it would be legal) or have a
second line run to the spreader on the mizzen.That would drop the run down
to 30' and a corresponding increase in power.
Thanks for you help
Bruce

The amp IS illegal under normal use. However, most don't realize that
in an emergency situation where life is endangered, all radio laws are
null and void and any power is fine if it saves lives.



Larry W4CSC