Swiftech VHF Antenna Wiring

I've been trying to run a new piece of co-ax into my (used) Swiftech VHF
antenna, with little success.

The old bit of co-ax that was removed just had the core exposed, some core
insulation, then some of the shield pulled back. This was all screwed into
the bottom of the antenna. When checked with a multimeter, it showed a
short between the core and shield.

Is this right or should I need some type of insulation or fitting kit? The
antenna is a SL Swiftech for marine VHF use.

Adam H

"Adam H" <turbo.bitz@gmail.com> wrote in message
news:exlWd.1984$847.756@newsfe5-gui.ntli.net...
> I've been trying to run a new piece of co-ax into my (used) Swiftech VHF
> antenna, with little success.
>
> The old bit of co-ax that was removed just had the core exposed, some core
> insulation, then some of the shield pulled back. This was all screwed
into
> the bottom of the antenna. When checked with a multimeter, it showed a
> short between the core and shield.
>
> Is this right or should I need some type of insulation or fitting kit?
The
> antenna is a SL Swiftech for marine VHF use.
>
> Adam H
>
>

As the performance (or otherwise) in a marine installation
may be a matter of life-and-death, I seriously suggest that
you seek professional help.

"TonyB" <Norfolk@soxclara.co.uk> wrote in message
news:d0csev$bhm$1@titan.btinternet.com...
> "Adam H" <turbo.bitz@gmail.com> wrote in message
> news:exlWd.1984$847.756@newsfe5-gui.ntli.net...
> > I've been trying to run a new piece of co-ax into my (used) Swiftech VHF
> > antenna, with little success.
> > The old bit of co-ax that was removed just had the core exposed, some
core
> > insulation, then some of the shield pulled back. This was all screwed
> into
> > the bottom of the antenna. When checked with a multimeter, it showed a
> > short between the core and shield.
> > Is this right or should I need some type of insulation or fitting kit?
> The
> > antenna is a SL Swiftech for marine VHF use.

> The old bit of co-ax that was removed just had the core exposed, some core
> insulation, then some of the shield pulled back. This was all screwed
into
> the bottom of the antenna. When checked with a multimeter, it showed a
> short between the core and shield.

I'm sure that's not right, although I'm not an electrician! I guess you
don't actually need the shield to be connected to anything at the antenna
end, although there is usually provision for this. The reason I am saying
( guessing) this is that the shield is there to stop the core from acting as
an aerial in its own right. (Which would make the aerial the wrong length
which is bad when transmitting. Without the right Standing Wave Ratio (SWR)
[which is controlled by the aerial length] your transmitted signal can
bounce back down the core and destroy the output section of your radio.)

Any signals are received by the core and earthed. The shield should be
earthed at the other end to the radio case which is usually done via the
connector at that end.

Hopefully a proper electrician should be along shortly to put us both right!
TonyB

On Sat, 5 Mar 2005 18:08:46 -0000, Airy R.Bean wrote:

>As the performance (or otherwise) in a marine installation
>may be a matter of life-and-death, I seriously suggest that
>you seek professional help.

I suggest you replace the words 'marine installation' with the words
'motor vehicle', and then carry out an assessment of any relevance
that the message may have for you in the light of recent events about
which you have posted extensively.
--
from
Aero Spike

"Adam H" <turbo.bitz@gmail.com> wrote in message
news:exlWd.1984$847.756@newsfe5-gui.ntli.net...
> I've been trying to run a new piece of co-ax into my (used) Swiftech VHF
> antenna, with little success.
>
> The old bit of co-ax that was removed just had the core exposed, some core
> insulation, then some of the shield pulled back. This was all screwed
into
> the bottom of the antenna. When checked with a multimeter, it showed a
> short between the core and shield.
>
> Is this right

Could be, all depends on the antenna detail. Some antennas have a matching
arrangement which will show a short circuit at DC.

>or should I need some type of insulation or fitting kit? The
> antenna is a SL Swiftech for marine VHF use.

I suggest you find the details for the antenna and connect as per the
manufacturers recommendation.

Given the importance of a the installation being reliable, I also suggest
you seek help from someone familiar with this type of thing.

--
Brian Reay
www.g8osn.org.uk
www.amateurradiotraining.org.uk
FP#898

"Airy R.Bean" <Me@privacy.net> wrote in message
news:38ub3uF5spnogU1@individual.net...
> As the performance (or otherwise) in a marine installation
> may be a matter of life-and-death, I seriously suggest that
> you seek professional help.
>

Oh no, what is this twat doing in uk.rec.radio.cb.

Piss off you Cheltenham Breaker.

On Sat, 05 Mar 2005 16:56:42 GMT, "Adam H" <turbo.bitz@gmail.com> wrote:

>I've been trying to run a new piece of co-ax into my (used) Swiftech VHF
>antenna, with little success.
>
>The old bit of co-ax that was removed just had the core exposed, some core
>insulation, then some of the shield pulled back. This was all screwed into
>the bottom of the antenna. When checked with a multimeter, it showed a
>short between the core and shield.
>
>Is this right or should I need some type of insulation or fitting kit? The
>antenna is a SL Swiftech for marine VHF use.

Isn't possible to say without a knowledge of the aerial.

Some aerials, depending on their configuration, will show a DC
short circuit others will not.

73 de Jock.
--

"My father was a simple man. My mother was a simple
woman. You see the result standing in front of you."
-- Chic Murray.

"Adam H" <turbo.bitz@gmail.com> wrote:

: The old bit of co-ax that was removed just had the core exposed, some core
: insulation, then some of the shield pulled back. This was all screwed into
: the bottom of the antenna. When checked with a multimeter, it showed a
: short between the core and shield.
:
: Is this right or should I need some type of insulation or fitting kit? The
: antenna is a SL Swiftech for marine VHF use.

depends on the length of the ''shorted'' coax length.

rf moves in mysterious ways my son :-)

	#1
Adam H	Swiftech VHF Antenna Wiring I've been trying to run a new piece of co-ax into my (used) Swiftech VHF antenna, with little success. The old bit of co-ax that was removed just had the core exposed, some core insulation, then some of the shield pulled back. This was all screwed into the bottom of the antenna. When checked with a multimeter, it showed a short between the core and shield. Is this right or should I need some type of insulation or fitting kit? The antenna is a SL Swiftech for marine VHF use. Adam H

	#2
TonyB	Re: Swiftech VHF Antenna Wiring "Adam H" <turbo.bitz@gmail.com> wrote in message news:exlWd.1984$847.756@newsfe5-gui.ntli.net... > I've been trying to run a new piece of co-ax into my (used) Swiftech VHF > antenna, with little success. > > The old bit of co-ax that was removed just had the core exposed, some core > insulation, then some of the shield pulled back. This was all screwed into > the bottom of the antenna. When checked with a multimeter, it showed a > short between the core and shield. > > Is this right or should I need some type of insulation or fitting kit? The > antenna is a SL Swiftech for marine VHF use. > > Adam H > >

	#3
Airy R.Bean	Re: Swiftech VHF Antenna Wiring As the performance (or otherwise) in a marine installation may be a matter of life-and-death, I seriously suggest that you seek professional help. "TonyB" <Norfolk@soxclara.co.uk> wrote in message news:d0csev$bhm$1@titan.btinternet.com... > "Adam H" <turbo.bitz@gmail.com> wrote in message > news:exlWd.1984$847.756@newsfe5-gui.ntli.net... > > I've been trying to run a new piece of co-ax into my (used) Swiftech VHF > > antenna, with little success. > > The old bit of co-ax that was removed just had the core exposed, some core > > insulation, then some of the shield pulled back. This was all screwed > into > > the bottom of the antenna. When checked with a multimeter, it showed a > > short between the core and shield. > > Is this right or should I need some type of insulation or fitting kit? > The > > antenna is a SL Swiftech for marine VHF use.

	#4
TonyB	Re: Swiftech VHF Antenna Wiring > The old bit of co-ax that was removed just had the core exposed, some core > insulation, then some of the shield pulled back. This was all screwed into > the bottom of the antenna. When checked with a multimeter, it showed a > short between the core and shield. I'm sure that's not right, although I'm not an electrician! I guess you don't actually need the shield to be connected to anything at the antenna end, although there is usually provision for this. The reason I am saying ( guessing) this is that the shield is there to stop the core from acting as an aerial in its own right. (Which would make the aerial the wrong length which is bad when transmitting. Without the right Standing Wave Ratio (SWR) [which is controlled by the aerial length] your transmitted signal can bounce back down the core and destroy the output section of your radio.) Any signals are received by the core and earthed. The shield should be earthed at the other end to the radio case which is usually done via the connector at that end. Hopefully a proper electrician should be along shortly to put us both right! TonyB

	#5
Spike	Re: Swiftech VHF Antenna Wiring On Sat, 5 Mar 2005 18:08:46 -0000, Airy R.Bean wrote: >As the performance (or otherwise) in a marine installation >may be a matter of life-and-death, I seriously suggest that >you seek professional help. I suggest you replace the words 'marine installation' with the words 'motor vehicle', and then carry out an assessment of any relevance that the message may have for you in the light of recent events about which you have posted extensively. -- from Aero Spike

	#6
Brian Reay	Re: Swiftech VHF Antenna Wiring "Adam H" <turbo.bitz@gmail.com> wrote in message news:exlWd.1984$847.756@newsfe5-gui.ntli.net... > I've been trying to run a new piece of co-ax into my (used) Swiftech VHF > antenna, with little success. > > The old bit of co-ax that was removed just had the core exposed, some core > insulation, then some of the shield pulled back. This was all screwed into > the bottom of the antenna. When checked with a multimeter, it showed a > short between the core and shield. > > Is this right Could be, all depends on the antenna detail. Some antennas have a matching arrangement which will show a short circuit at DC. >or should I need some type of insulation or fitting kit? The > antenna is a SL Swiftech for marine VHF use. I suggest you find the details for the antenna and connect as per the manufacturers recommendation. Given the importance of a the installation being reliable, I also suggest you seek help from someone familiar with this type of thing. -- Brian Reay www.g8osn.org.uk www.amateurradiotraining.org.uk FP#898

	#7
Road_Hog®	Re: Swiftech VHF Antenna Wiring "Airy R.Bean" <Me@privacy.net> wrote in message news:38ub3uF5spnogU1@individual.net... > As the performance (or otherwise) in a marine installation > may be a matter of life-and-death, I seriously suggest that > you seek professional help. > Oh no, what is this twat doing in uk.rec.radio.cb. Piss off you Cheltenham Breaker.

	#8
Jock.	Re: Swiftech VHF Antenna Wiring On Sat, 05 Mar 2005 16:56:42 GMT, "Adam H" <turbo.bitz@gmail.com> wrote: >I've been trying to run a new piece of co-ax into my (used) Swiftech VHF >antenna, with little success. > >The old bit of co-ax that was removed just had the core exposed, some core >insulation, then some of the shield pulled back. This was all screwed into >the bottom of the antenna. When checked with a multimeter, it showed a >short between the core and shield. > >Is this right or should I need some type of insulation or fitting kit? The >antenna is a SL Swiftech for marine VHF use. Isn't possible to say without a knowledge of the aerial. Some aerials, depending on their configuration, will show a DC short circuit others will not. 73 de Jock. -- "My father was a simple man. My mother was a simple woman. You see the result standing in front of you." -- Chic Murray.

	#9
ZZZPK omenwilliams@web-mail.com.ar pacificlottery2004@yahoo.com powilliams600	Re: Swiftech VHF Antenna Wiring "Adam H" <turbo.bitz@gmail.com> wrote: : The old bit of co-ax that was removed just had the core exposed, some core : insulation, then some of the shield pulled back. This was all screwed into : the bottom of the antenna. When checked with a multimeter, it showed a : short between the core and shield. : : Is this right or should I need some type of insulation or fitting kit? The : antenna is a SL Swiftech for marine VHF use. depends on the length of the ''shorted'' coax length. rf moves in mysterious ways my son :-)