Better VHF antenna/reception

[McZube]

The surveyor commented that we needed to replace out VHF antenna. I assume that doing so will improve our reception. Then I started thinking that mounting the new antenna at the masthead when the mast is unstepped will improve the range of reception. Is mounting the antenna at the masthead a wise idea? Will it improve the range of reception? Will an antenna cable of that length affect adversely reception? I'm planning to keep a spare antenna on hand in case the masthead antenna gets damaged somehow.

Thanks

 

[KD3PC]

VHF is mostly line of sight and the higher you can mount the antenna, the better. The added length of cable is a non-issue, provided you use a quality cable, ie LMR, etc.

A Metz antenna on the mast head is the cat's meow.

Make sure your connections are well made and as weatherproof as possible. I would still have (and I do) an arch or stern rail mounted VHF as a spare.

Best of luck

 

[SEMIJim]

I started thinking that mounting the new antenna at the masthead when the mast is unstepped will improve the range of reception. Is mounting the antenna at the masthead a wise idea?

Only you can determine that

Will it improve the range of reception?

It will almost certainly improve your VHF range. VHF is mostly a line-of-sight kind of thing. Height is king. Some numbers:

Height of antenna:   6 ft ( 1.8 m)
LOS to horizon:  3.0 nm ( 3.5 mi,  5.6 km)

Height of antenna:  40 ft (12.2 m)
LOS to horizon:  7.8 nm ( 8.9 mi, 14.4 km)

Height of antenna #1:   6 ft ( 1.8 m)
Height of antenna #2:   6 ft ( 1.8 m)
LOS between antennas:  6.0 nm ( 6.9 mi, 11.2 km)

Height of antenna #1:   6 ft ( 1.8 m)
Height of antenna #2:  40 ft (12.2 m)
LOS between antennas: 10.8 nm (12.4 mi, 20.0 km)

Height of antenna #1:  40 ft (12.2 m)
Height of antenna #2:  40 ft (12.2 m)
LOS between antennas: 15.6 nm (17.9 mi, 28.8 km)

Will an antenna cable of that length affect adversely reception?

More cable = more loss, but more height generally trumps that.

What size boat? How tall is your mast? Are you a racer or otherwise concerned about weight aloft? Is your mast deck or keel stepped? If the former: Any limitations on the size of wire/cable you can get through the step?

I'm planning to keep a spare antenna on hand in case the masthead antenna gets damaged somehow.

Good plan.

For your masthead antenna: Most sailors seem enamoured of the Metz antenna. I recently did some research and it looked to me like Digital Antenna's 222-V would be the best way to go.

Jim

 

[kenn]

The surveyor commented that we needed to replace our VHF antenna. I assume that doing so will improve our reception.

Might also save your transmitter - if the antenna is lousy the load it presents might cause failure of the transmitter.

We have the classic Shakespeare masthead antenna. Works fine. But we're just a little trailer sailor.

 

[McZube]

What size boat? How tall is your mast? Are you a racer or otherwise concerned about weight aloft? Is your mast deck or keel stepped? If the former: Any limitations on the size of wire/cable you can get through the step?

31'-4". 47' from waterline to masthead. Won't be racing. Deck-stepped. Plenty of room for wiring as far as I know.

 

[Bill Roosa]

All coax is not the same. You HAVE to use 50 ohm coax. Regular TV coax is 75 ohm and will not work well no matter how much you pay for it.
The masthead location certianly improves you POTENTIAL range of reception and transmission however. If you go with a "high gain" antenna it will not work as well when you are in a sea way and moving about. high gain is more like a spot light aimed in just a single narrow plane around the antenna. low gain is more like a light bulb. If the boat is healed or rocking you might be transmitting above the horizon and anybody located there. Great if you need to talk to an airplane (in that direction). The other side is "shining" in the water.

 

[Don12364]

Low antennas e.g. on pushpit - boat to boat - lucky to get much more than 3 - 5 miles.
Low boat antenna to CG (who have high antennas) 12 - 15 mi.
Boat to boat both with masthead antennas approx 20 - 25 miles.
All on 25 watts.
PLEASE use low power whenever possible else you will be interfering with every other user within a 25 mile radius - and that's a lot boats AND a lot of interference.