Recs for scanner antenna for a vessel

[Brentorious]

Planning to outfit a vessel with two scanners with GPS capability. Plan to split the duties of police/fire/EMS, Coast Guard, Civilian air, Mil air, and VHF marine band btw the two. Is there a good marine grade tri-band antenna, or should I just go with a hood quality VHF marine antenna? Thanks.

 

[krokus]

Planning to outfit a vessel with two scanners with GPS capability. Plan to split the duties of police/fire/EMS, Coast Guard, Civilian air, Mil air, and VHF marine band btw the two. Is there a good marine grade tri-band antenna, or should I just go with a hood quality VHF marine antenna? Thanks.

By vessel, I am presuming a boat or ship. What type and size? (The hull's construction matters in selection.) Where are you wanting to mount the antenna(s)? How far away from the scanner, and antenna, is your marine radio and antenna?

 

[Brentorious]

By vessel, I am presuming a boat or ship. What type and size? (The hull's construction matters in selection.) Where are you wanting to mount the antenna(s)? How far away from the scanner, and antenna, is your marine radio and antenna?

It’s going to be a 31’ Ranger Tug. The marine radio and antenna can’t be too far from the scanners and antenna. A matter of feet. But now is the time for me to plan how to optimize the spacing.

 

[krokus]

If you can vertically separate the antennas, that will help. Put the scanner antenna a few feet below the marine radio antenna.

The public safety agencies you want to monitor, do you know which frequencies they operate on?

 

[Brentorious]

If you can vertically separate the antennas, that will help. Put the scanner antenna a few feet below the marine radio antenna.

The public safety agencies you want to monitor, do you know which frequencies they operate on?

Thanks, that’s good advice. I’m going to be using the GPS puck as I travel along the coast, so the frequencies will be varied. Locally I have a 700mhz system for public safety.
Thought: is there a way to use the antenna I’ll have for the VHF Marine radio for receive only on a scanner? I’m assuming transmitting would damage the scanner. Is there a way to isolate or block to protect the scanner?

 

[krokus]

Thanks, that’s good advice. I’m going to be using the GPS puck as I travel along the coast, so the frequencies will be varied. Locally I have a 700mhz system for public safety.
Thought: is there a way to use the antenna I’ll have for the VHF Marine radio for receive only on a scanner? I’m assuming transmitting would damage the scanner. Is there a way to isolate or block to protect the scanner?

There is, but it is rather involved, and only for one transmit frequency. It would be using can filters, like a repeater site, and maybe a circulator.

 

[krokus]

@mmckenna Can you provide a bit of guidance?

 

[mmckenna]

You can get marine antennas in different bands, VHF, UHF and 800. But I've never seen a multiband antenna. Doesn't mean they are not out there, though.

You could do three different antennas and add a triplexer to feed them to the scanner via one coaxial cable. But then you'd have to buy and add three antennas. Looks like you have some space to deal with on those, and you could probably make it work, but it would be expensive.

If it was me (and I really wish it was…) I'd probably use one of the Larsen NMO-150/450/800 antennas and use a thick mount NMO to get through the roof. I'd seal carefully around the base of the antenna to keep it dry.

 

[krokus]

If it was me (and I really wish it was…) I'd probably use one of the Larsen NMO-150/450/800 antennas and use a thick mount NMO to get through the roof. I'd seal carefully around the base of the antenna to keep it dry.

Just to clarify, is that for the scanner, or combo use with the marine radio? (I'm pretty sure I know the answer.)

 

[mmckenna]

Just to clarify, is that for the scanner, or combo use with the marine radio? (I'm pretty sure I know the answer.)

Just for the scanner was my thinking. While it could TX with marine VHF just fine, I think keeping the two separate would be a wise idea. Sharing the antenna is possible.

Ideally, the scanner antenna would want to see a ground plane, and that can be done on the underside.

For clarification, using separate marine grade antennas for each band would be expensive, and result in the boat looking akin to the old "Russian trawlers".

Or, just get a second VHF marine antenna and use that. While not ideal, any metal up in the air will receive something, just not as well as band specific antenna(s).

Doing an install on a boat that nice would come with some sort of obligation to make it look decent. I think that would be the bigger challenge.

 

[jonwienke]

I would consider a discone antenna for scanner RX. It has its own ground plane, and too much gain can be a negative on a boat that is pitching and rolling anyway.

 

[hill]

I would try to see some antenna installs on the local public safety boats. Our local public safety agencies have radios and antennas for 700/800 installed. Vessel antennas are made if look online that are made for fiberglass vessels for the public safety bands.

 

[Brentorious]

You can get marine antennas in different bands, VHF, UHF and 800. But I've never seen a multiband antenna. Doesn't mean they are not out there, though.

You could do three different antennas and add a triplexer to feed them to the scanner via one coaxial cable. But then you'd have to buy and add three antennas. Looks like you have some space to deal with on those, and you could probably make it work, but it would be expensive.

If it was me (and I really wish it was…) I'd probably use one of the Larsen NMO-150/450/800 antennas and use a thick mount NMO to get through the roof. I'd seal carefully around the base of the antenna to keep it dry.

I have the Larsen tri band on my automobile and it has exceeded expectations. As for the installation, I’m planning on sending radios and antenna to the factory and ha e them install.
Thanks for all of the feedback everyone.