VHF antenna height question

RG-8 to the masthead is pretty much a standard rig for masthead antennas and
if the connectors are well done the signal loss is acceptable. The benefit
of the additional height far and away overrides any signal loss. Try to make
the antenna cable in a single run from the masthead to the back of the
radio - no through-deck connectors.

If you don't want to run cable of that diameter, don't try for the masthead
because the loss in the smaller cable over a run of that length would be
pretty bad.

Tom Dacon

" Mika" <ace3889.RemoveThis@sci.fi> wrote in message
news:430201e2.2902290@news.nic.fi...
>
> Need to install a new VHF antenna to a sailboat. Masthead would give
> max antenna height, but drawback would be longer cable and extra
> connectors. Have some experience about cable and connector losses
> being a ham radio operator, and therefore give serious thought to
> putting the antenna to top a a short pole on deck. Shorter cable, no
> need for extra connectors as this would be permanent installation.
> Plus much easier to install.
>
> Lower antenna height (some 3-4 meters instead of >14m in masthead
> installations) will of course reduce range, but would it stll be ok
> for costal waters. In my home waters some 20 NM range is quit enough
> to contact coastguard or SAR if needed.
>
> Mika
>
 >> Stay informed about: VHF antenna height question 

Mika wrote:
> Need to install a new VHF antenna to a sailboat. Masthead would give
> max antenna height, but drawback would be longer cable and extra
> connectors. Have some experience about cable and connector losses
> being a ham radio operator, and therefore give serious thought to
> putting the antenna to top a a short pole on deck. Shorter cable, no
> need for extra connectors as this would be permanent installation.
> Plus much easier to install.
>
> Lower antenna height (some 3-4 meters instead of >14m in masthead
> installations) will of course reduce range, but would it stll be ok
> for costal waters. In my home waters some 20 NM range is quit enough
> to contact coastguard or SAR if needed.
>
> Mika

The "line of sight" at 3 metres would be about 7-8 miles. Is that enough?
 >> Stay informed about: VHF antenna height question 

Larry wrote:
> ace3889 DeleteThis @sci.fi ( Mika) wrote in news:430201e2.2902290@news.nic.fi:
>
>> Need to install a new VHF antenna to a sailboat.
>
> Put a 1/2 wave antenna as high as you can get it. 2000 meters is
> great! but the top of the tallest mast will do just fine.
>
> When you're screaming for help in a sinking boat, you can never have
> an antenna that's too high! The altitude of the mast antenna more
> than makes up for the length of the cabling losses. With a 25W Icom
> and 1/2 wavelength Metz whip at 55 ft on the other end of 30 meters
> of RG-58/U coax, Lionheart can call the US Coast Guard station way
> out of sight of land.

Couldn't agree more!

Dennis.
 >> Stay informed about: VHF antenna height question 

I have just seen a range of low-loss thin ad flexible 50 ohm coax -
aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be,
i would be great for use on boats for both HF and VHF. Has anyone used
it?
 >> Stay informed about: VHF antenna height question 

On Tue, 16 Aug 2005 13:47:27 -0400, Larry <noone.DeleteThis@home.com> wrote:

>ace3889@sci.fi ( Mika) wrote in news:430201e2.2902290@news.nic.fi:
>
>> Need to install a new VHF antenna to a sailboat.
>
>Put a 1/2 wave antenna as high as you can get it. 2000 meters is great!
>but the top of the tallest mast will do just fine.
>
>When you're screaming for help in a sinking boat, you can never have an
>antenna that's too high! The altitude of the mast antenna more than makes
>up for the length of the cabling losses. With a 25W Icom and 1/2
>wavelength Metz whip at 55 ft on the other end of 30 meters of RG-58/U
>coax, Lionheart can call the US Coast Guard station way out of sight of
>land.
>

but never, never, never ever use rg 58 cable. it's not shielded
properly. it has high loss.
---------------------------
to see who "wf3h" is, go to "qrz.com"
and enter 'wf3h' in the field
 >> Stay informed about: VHF antenna height question 

On Tue, 16 Aug 2005 14:57:34 -0700, "Tom Dacon" <Tom- DeleteThis @t-dacons.com>
wrote:

>RG-8 to the masthead is pretty much a standard rig for masthead antennas and
>if the connectors are well done the signal loss is acceptable. The benefit
>of the additional height far and away overrides any signal loss. Try to make
>the antenna cable in a single run from the masthead to the back of the
>radio - no through-deck connectors.
>
> If you don't want to run cable of that diameter, don't try for the masthead
>because the loss in the smaller cable over a run of that length would be
>pretty bad.
>

agreed. some folks have recommended rg 58 which has all the bad
characteristics and none of the good ones of proper coax.

---------------------------
to see who "wf3h" is, go to "qrz.com"
and enter 'wf3h' in the field
 >> Stay informed about: VHF antenna height question 

wf3h.DeleteThis@comcast.net (Bob) wrote in
news:43027dbe.42149636@newsgroups.comcast.net:

> but never, never, never ever use rg 58 cable. it's not shielded
> properly. it has high loss.
> ---------------------------
> to see who "wf3h" is, go to "qrz.com"
> and enter 'wf3h' in the field
>

Hogwash. There's RG-58 in every boat I work on and it works just
fine....all the way out to the radio horizon....which, of course, is the
limit of comms on VHF. At 50' if 2 watts makes it up there, it's full
quieting at 10 miles.

Besides, I can't imagine running hardline through those little holes to the
masthead....(c;

--
Larry
 >> Stay informed about: VHF antenna height question 

ineverlookatthis.TakeThisOut@yahoo.com wrote:
> I have just seen a range of low-loss thin ad flexible 50 ohm coax -
> aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be,
> i would be great for use on boats for both HF and VHF. Has anyone used
> it?
>

Yup, great stuff. Not as flexible and thin as RG-58, but a lot more than
RG-213 (?).

I run a combination GSM/VHF/FM antenna at 20m high, 30m cable. The range
and clarity on VHF improved a lot when I swapped from my old antenna +
RG-58 cable. At sea, range is about 60 +- 20 km. Cell phone range (900
MHz) is about 60% more than using a hand-held cell phone (eg. about
10-15 km). This means that during coastal hops we're now in (GSM)
coverage all the time.

Tip: if you sail around on the North Sea, check out cell phone coverage
near Norwegian oil rigs; they seem to have Telenor transmitters

Regards,
Kees
 >> Stay informed about: VHF antenna height question 

> > I have just seen a range of low-loss thin ad flexible 50 ohm coax -
> > aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be,
> > i would be great for use on boats for both HF and VHF. Has anyone used
> > it?
> >
>
> Yup, great stuff. Not as flexible and thin as RG-58, but a lot more than
> RG-213 (?).

As an installer and repairman, we used foam dielectric coax once in a while
for cell phone antennas because of UHF loss problems. It isn't as durable as
RG-213 (the standard for most installations around salt water, as it crushes
and flattens easier than solid dielectric.

There were some brands of foam dielectric coax that absorbed moisture that
degrades coax very quickly.

RG-58 is ok for short runs of 25 watt VHF, but in tall masts, it just
doesn't cut it. Also, it is a little light weight for 100 watt plus HF
installations.

The obvious weak link in most masthead installations is in the PL-259 coax
connector installation. There are not many out there who can do a proper,
watertight soldering job up at the top of a wavering, windy masthead. Been
there, done that, was not always proud of my work.

Old Chief Lynn, W7LTQ, PG-13-20604
 >> Stay informed about: VHF antenna height question 

"Larry" <noone.DeleteThis@home.com> wrote in message
news:Xns96B555BD5CA58noone@63.223.7.253...
> wf3h.DeleteThis@comcast.net (Bob) wrote in
> news:43027dbe.42149636@newsgroups.comcast.net:
>
>> but never, never, never ever use rg 58 cable. it's not shielded
>> properly. it has high loss.
>> ---------------------------
>> to see who "wf3h" is, go to "qrz.com"
>> and enter 'wf3h' in the field
>>
>
> Hogwash. There's RG-58 in every boat I work on and it works just
> fine....all the way out to the radio horizon....which, of course, is the
> limit of comms on VHF. At 50' if 2 watts makes it up there, it's full
> quieting at 10 miles.
>
> Besides, I can't imagine running hardline through those little holes to
> the
> masthead....(c;
>
> --
> Larry

I would agree that RG58 is very common. Its cheap and easy to run.
Probably gives acceptable performance on most boats. I recently replaced
mine with a single run of RG213 from masthead to radio. Didn't think I
could pull RG8 up the plastic pipe inside my mast and the RG213 was
recommended by a local communications shop so that's the way I went.
Sitting at the top of my mast I was getting pretty tired pulling up 50 feet
of 213. That stuff gets heavy. RG8 would be worse.
 >> Stay informed about: VHF antenna height question 

Lynn Coffelt wrote:
>>>I have just seen a range of low-loss thin ad flexible 50 ohm coax -
>>>aircell 7, ecoflex 10, ecoflex 15. If its as good as it claims to be,
>>>i would be great for use on boats for both HF and VHF. Has anyone used
>>>it?
>>>
>>
>>Yup, great stuff. Not as flexible and thin as RG-58, but a lot more than
>>RG-213 (?).
>
>
> As an installer and repairman, we used foam dielectric coax once in a while
> for cell phone antennas because of UHF loss problems. It isn't as durable as
> RG-213 (the standard for most installations around salt water, as it crushes
> and flattens easier than solid dielectric.
>
> There were some brands of foam dielectric coax that absorbed moisture that
> degrades coax very quickly.
>
> RG-58 is ok for short runs of 25 watt VHF, but in tall masts, it just
> doesn't cut it. Also, it is a little light weight for 100 watt plus HF
> installations.
>
> The obvious weak link in most masthead installations is in the PL-259 coax
> connector installation. There are not many out there who can do a proper,
> watertight soldering job up at the top of a wavering, windy masthead. Been
> there, done that, was not always proud of my work.
>
> Old Chief Lynn, W7LTQ, PG-13-20604
>
>
Hay, chief, did ya ever think to push the wire down the mast using a
messenger to guide it, like the old wire being replaced, or a fish
line? that way, you leave the end with the on deck pre installed
connector on it at the top and outside the mast with a drip loop*,
while you cut to length and terminate the bottom end below decks, or
at the mast base, an easy job, or at least not so awkward as at the
top of a wobbly mast, which you heel a bit to guide the messenger.
(Damn! dropped the flux, again;-) Is the soldering iron plugged in?)

I once climbed to the top of a big fir to cut off the top for a
Christmas tree, but dropped the axe after I got up there. Had to go
down and up three times all together, once just to get my arms,
which fell off next!

If you were a masthead radio tech, and not proud of your work, you
would have done it again, unless it was your own life at risk.
Cobbler's shoes? Dija ever go up just to unscrew, remove and then
rescrew the connector, then wait for a radio check after pulling
gently on the feeder? It could benefit from doing it once every year.

How long do hams spend sending? Rael hams use code, light duty
cycle, to set up fax, etc, with old contacts. Or do they want full
duplex stereo video to remote studios, at 450 megs using meteor
scatter at days' ends, with gigantic yagis doublesteered at the
masthead? I saw one like that, once, on a 40 foot ketch in green
lapstrake on Grand Lake.

Mil RG58 is good enough for most, cheap, light.
Communications is our most valuable resource.

*Note: A typical drip loop style exit from the mast head would
cause compression of the dielectric. Soft cable with long heights
hanging should be clamped above the exit hole, sealed with caulk,
double clamped or wirehung to the mast, properly sized and torqued,
No drip loop, unless needed to meet the antenna mount. Masts should
be able to drain at the heel anyway. Matching coils should be below
the masthead, 2"-3" away from the mast. Tilting the antenna a little
to avoid instrumentation is ok, though it may affect directivity at
extremes.

Terry K -Yeah, yeah, we *can* build monster cables. -SofDevCo-
 >> Stay informed about: VHF antenna height question 

> Hay, chief, did ya ever think to push the wire down the mast using a
> messenger to guide it, like the old wire being replaced, or a fish
> line? that way, you leave the end with the on deck pre installed
> connector on it at the top and outside the mast with a drip loop*,
> while you cut to length and terminate the bottom end below decks, or
> at the mast base, an easy job, or at least not so awkward as at the
> top of a wobbly mast, which you heel a bit to guide the messenger.
> (Damn! dropped the flux, again;-) Is the soldering iron plugged in?)
>
> I once climbed to the top of a big fir to cut off the top for a
> Christmas tree, but dropped the axe after I got up there. Had to go
> down and up three times all together, once just to get my arms,
> which fell off next!
>
> If you were a masthead radio tech, and not proud of your work, you
> would have done it again, unless it was your own life at risk.
> Cobbler's shoes? Dija ever go up just to unscrew, remove and then
> rescrew the connector, then wait for a radio check after pulling
> gently on the feeder? It could benefit from doing it once every year.
>
> How long do hams spend sending? Rael hams use code, light duty
> cycle, to set up fax, etc, with old contacts. Or do they want full
> duplex stereo video to remote studios, at 450 megs using meteor
> scatter at days' ends, with gigantic yagis doublesteered at the
> masthead? I saw one like that, once, on a 40 foot ketch in green
> lapstrake on Grand Lake.
>
> Mil RG58 is good enough for most, cheap, light.
> Communications is our most valuable resource.
>
> *Note: A typical drip loop style exit from the mast head would
> cause compression of the dielectric. Soft cable with long heights
> hanging should be clamped above the exit hole, sealed with caulk,
> double clamped or wirehung to the mast, properly sized and torqued,
> No drip loop, unless needed to meet the antenna mount. Masts should
> be able to drain at the heel anyway. Matching coils should be below
> the masthead, 2"-3" away from the mast. Tilting the antenna a little
> to avoid instrumentation is ok, though it may affect directivity at
> extremes.
>
> Terry K -Yeah, yeah, we *can* build monster cables. -SofDevCo-

Hey, Terry! I like it, I like it! Can tell you've been there!
Yes, when customers wanted to put the cable in themselves, (Glee!) I would
sometimes help them figger a suitable length, and put one connector on in
the nice warm shop, advising them to put the cable in, top down, and call me
for the bottom connector.

When you told of the tree, I initially knew you were bragging about the
size of your Christmas tree. Upon closer inspection, I now know that you
only used the top!

The duty cycle on my 10 meter CW rig is way less than a thousandth of a
percent. Usually giving it 8 to 10 months to cool down between contacts.
However if one chose some of the FSK modes (I don't, personally), and had a
little less than perfect SWR (and 100 watts or so) One can melt or soften
current nodes in RG-58. Contributing, one would assume to Global Warming.

Old Chief Lynn
 >> Stay informed about: VHF antenna height question 

Terry Spragg <tspragg567nospam.TakeThisOut@rogers.com> wrote in
news:tpGdne5wSeEBMZneRVn-iA@rogers.com:

> Rael hams use code

Yeah....Pactor code, Amtor code, Packet code, PSK31 code, Baudot
code....(c;

REAL hams use digital modes.

--
Larry
 >> Stay informed about: VHF antenna height question