I haven't fired up EZNEC yet, but I was wondering how a standard 3dBi
marine whip would perform on the 2m ham bands. Since the marine
frequencies are 156.050-157.425 MHz, what could I expect at 144-148 MHz?

If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon

"Jon Gauthier" wrote in message
...
I haven't fired up EZNEC yet, but I was wondering how a standard 3dBi
marine whip would perform on the 2m ham bands. Since the marine
frequencies are 156.050-157.425 MHz, what could I expect at 144-148 MHz?

If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon

You could expect 3:1 or worse SWR unless you found a "dip" at certain
frequencies in the 2 meter ham band. I believe Morad makes a 2 meter version
of one of their marine antennas, however, their web site says "under
construction" when I checked it today. I usually use a Larsen (Radiall)
antenna on a boat for 2 meter ham band or VHF high band public safety
frequencies.
Do not try using a ham rig and a marine VHF radio on the same antenna, as
sooner or later you will accidentally end up transmitting into the other
radios receiver. Modified ham rigs on the marine band are illegal.
73
Doug K7ABX

On Mon, 23 May 2005 11:24:44 -0400, Jon Gauthier
wrote:

I haven't fired up EZNEC yet, but I was wondering how a standard 3dBi
marine whip would perform on the 2m ham bands. Since the marine
frequencies are 156.050-157.425 MHz, what could I expect at 144-148 MHz?

If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon

I've used a 2m antenna on the marine band with a marine hand-held,
with no apparent problems - it gives much better performance than the
hand-held's "rubber duck". (but I didn't check SWR)



--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

"Peter Bennett" wrote in message
news.com...
On Mon, 23 May 2005 11:24:44 -0400, Jon Gauthier
wrote:

I haven't fired up EZNEC yet, but I was wondering how a standard 3dBi
marine whip would perform on the 2m ham bands. Since the marine
frequencies are 156.050-157.425 MHz, what could I expect at 144-148 MHz?

If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon

I've used a 2m antenna on the marine band with a marine hand-held,
with no apparent problems - it gives much better performance than the
hand-held's "rubber duck". (but I didn't check SWR)



My portable antenna for both marine and aviation use on 2 meter ham band for
a non-permanent install is to strip back 1/4 wavelength of coaxial cable
outer insulation, then push the braid back over the cable so I have 1/4
wavelength of coax center lead exposed and 1/4 wavelength of braid back over
the insulated portion of the cable, forming a sleeve dipole, then attach the
matching portable radio antenna connector on the other end. Fishing leader,
etc can be used to hang the antenna from an overhead supp-ort on the boat, a
tree limb when camping, etc. I Have used removable masking tape to tape the
antenna to the Plexiglas window in a rental airplane, etc. Works great. SWR
can be trimmed by starting long and working back to about 19 inches of braid
and center lead.
73
Doug K7ABX

Doug wrote:
"Peter Bennett" wrote in message
news.com...

On Mon, 23 May 2005 11:24:44 -0400, Jon Gauthier
wrote:


I haven't fired up EZNEC yet, but I was wondering how a standard 3dBi
marine whip would perform on the 2m ham bands. Since the marine
frequencies are 156.050-157.425 MHz, what could I expect at 144-148 MHz?

If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon

I've used a 2m antenna on the marine band with a marine hand-held,
with no apparent problems - it gives much better performance than the
hand-held's "rubber duck". (but I didn't check SWR)




My portable antenna for both marine and aviation use on 2 meter ham band for
a non-permanent install is to strip back 1/4 wavelength of coaxial cable
outer insulation, then push the braid back over the cable so I have 1/4
wavelength of coax center lead exposed and 1/4 wavelength of braid back over
the insulated portion of the cable, forming a sleeve dipole, then attach the
matching portable radio antenna connector on the other end. Fishing leader,
etc can be used to hang the antenna from an overhead supp-ort on the boat, a
tree limb when camping, etc. I Have used removable masking tape to tape the
antenna to the Plexiglas window in a rental airplane, etc. Works great. SWR
can be trimmed by starting long and working back to about 19 inches of braid
and center lead.
73
Doug K7ABX



I have the WAF to think about ;-)

Peter - I was asking the other way around - using my 2m ham radio
connected to the marine VHF antenna. I guess if the SWR is less than
something like 5:1, my Icom 706 won't shutdown...

Jon KB1HTW

On Mon, 23 May 2005 15:41:23 -0400, Jon Gauthier
wrote:



Peter - I was asking the other way around - using my 2m ham radio
connected to the marine VHF antenna. I guess if the SWR is less than
something like 5:1, my Icom 706 won't shutdown...

Jon KB1HTW

I suspect that if it marine radio - ham antenna works, then ham radio
- marine antenna probably will also work - the frequencies are still
"pretty close".

Perhaps I should qualify things a bit - I primarily used the ham
antenna - marine radio for receiving - I usually used a marine
fixed-mount radio with marine antenna for transmitting.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

Jon Gauthier wrote in
:

If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon


Put using ONE antenna, dual band or not, out of your mind for the MARINE
and TWO METER radios, which CANNOT be PARALLELED on ONE antenna....(sigh)

The duplexer that would allow you to do this is bigger than a 4-cylinder
auxiliary diesel, its transmission and small fuel tank.....

Noone makes one....no market.

Modified ham rigs on the marine band are illegal.

Whoops!

In article et,
"Doug" wrote:

"Jon Gauthier" wrote in message
...
I haven't fired up EZNEC yet, but I was wondering how a standard 3dBi
marine whip would perform on the 2m ham bands. Since the marine
frequencies are 156.050-157.425 MHz, what could I expect at 144-148 MHz?

If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon

You could expect 3:1 or worse SWR unless you found a "dip" at certain
frequencies in the 2 meter ham band. I believe Morad makes a 2 meter version
of one of their marine antennas, however, their web site says "under
construction" when I checked it today. I usually use a Larsen (Radiall)
antenna on a boat for 2 meter ham band or VHF high band public safety
frequencies.
Do not try using a ham rig and a marine VHF radio on the same antenna, as
sooner or later you will accidentally end up transmitting into the other
radios receiver. Modified ham rigs on the marine band are illegal.
73
Doug K7ABX




Actually Morad has both a 146HD and a 146HD10db in their designs,
as I have one of each, of the original prototypes, that Eddie Zanbergen
gave me years ago. The 146HD is up on the roof of the cabin and the
146HD10db is in a tube out back waiting for the new "Retirement House"
to be constructed. All the designs for Morad antennas were first
tested in the associated Ham Bands next to the Maritime Mobile Bands.

Most any VHF Antenna will work just fine on both 146 and 156, if
one is just trying to communicate, as SWR isn't really all that important
at frequencies that are horizon limited, and have Sufficent Power
(25 watts) to reach the Radio Horizon. A leaky dummy Load can
communicate a couple of miles at this frequency. Efficent coupling
into the ether at VHF Frequencies is relatively simple, when compared to
the MF and HF counterparts. The higher frequency, the less finiky, and
wider bandwidth, an antenna will operate over, for just communicating.
At the 25 Watt output power level, just about anything including a "Wet
Noodle" will communicate to the Radio Horizon at VHF Frequencies.
Ever wonder why you don't see a whole pile of "Antenna tuners" for VHF
Frequencies? It is because what little you would gain, by any tuning,
wouldn't show up by increasing the Radio Horizon in any meaninful way.

This isn't like your trying to do Moonbounce, or anything. It is like
going for 25 to 30 miles over water and looking at a Path Loss in the
high 80 or low 90 db's. Not a very difficult proposition in the radio
world.


Bruce in alaska
--
add a 2 before @

Larry W4CSC wrote:
Jon Gauthier wrote in
:


If it won't cut it, then does anyone have any recommendations for a
dual-band antenna (commercial or home-built)?

Jon



Put using ONE antenna, dual band or not, out of your mind for the MARINE
and TWO METER radios, which CANNOT be PARALLELED on ONE antenna....(sigh)

The duplexer that would allow you to do this is bigger than a 4-cylinder
auxiliary diesel, its transmission and small fuel tank.....

Noone makes one....no market.


Larry, perhaps I wasn't specific enough in my description. I'm
definitely NOT trying to have both radios operational at the same time
on the same antenna.

What I was asking was, if I have a proper VHF switch (with the
unselected radio switched to a dummy load to prevent burning out the
finals if inadvertantly keyed), what kind of performance (SWR-wise)
could I expect out of a either a marine VHF antenna and a ham 2m radio,
or a 2m antenna and a marine VHF radio. Since you are a boater, I would
assume you would know how precious space can be on a relatively small
sailboat, and how expensive marine-grade equipment tends to be.

It was just a simple question. I'm not trying to act like a commercial
tower radiating multiple freqs from a single radiator for multiple
customers. I would have thought that being a licensed amateur radio
operator (Extra), one would not be such a reluctant elmer....