Need to tune a vhf marine antenna to ham length... advice ???

[WSEM262]

Still, please do check the feeder; water causing losses in the coax will give a misleadingly good VSWR.

Its never been wet. The boat is garage kept.

 

[hill]

They are kind of high cost, but will most likely out last your boat see the the links below.

146 MHz (2-Meter Band) VHF Marine Antenna 3dB gain

Deluxe style marine VHF antenna with 3dB gain at 146 MHz. Morad Antenna Company, the best marine VHF antennas, made entirely in the USA. Our marine VHF antennas are trusted globally.

www.morad.com

Morad Antenna

Morad marine antennas are manufactured using stainless steel and anodized aluminum materials, proven by years of field use to be the most durable alloys in harsh marine environments. Our VHF HD antennas are used by the US Coast Guard.

www.morad.com

 

[hill]

Another one. Don't really see any dual band ones, but the first company had UHF only marine antennas.

Marine Ham Amateur Radio 2 meter 146MHz 8FT Fiberglass Antenna

Our Marine VHF Antenna is made of ultra-high grade materials delivering premium reception and transmission over standard VHF marine channels. Our Marine VHF Antenna is guaranteed not to splinter. Includes 18' cable with Proconnect. Easy set-up. Made in USA.

airwavemarine.com

 

[mmckenna]

Im using a Yaesu FTM200D

I'm not sure that amateur radio equipment has the same features as LMR gear. Never looked to see if they'll throttle back power when reflected. 2.5:1 for short periods probably isn't going to be an issue for short transmissions, but long winded ham discussions might be something to be concerned about. The heat build up is the issue.

I havent measured the arch but I believe it is approx 12-18" wide at the antenna... so that should suffice.

Yeah, that should be good for UHF, and while not ideal for VHF, is better than 'nuthin….

I will look at the thick mount NMO's. I completely forgot about those... and it should squeeze into the arch OK. The issue is that the arch also has a tow rope attachment on top... so there is extra thick aluminum reinforcement welded inside that adds to the thickness. Somuch so that it's super tight access inside.

The thick mounts do need access to both sides. Maybe hire a small child with little hands to assist. They tend to work cheap….

The radio in question is a Yaesu FTM200D. It's been "tuned-up" a bit so it puts out more than the advertised 50w. I dont plan to run it on high power nor Tx on GMRS, but I always test it there to see worst case/emergency scenarios. Typically low-mid (5w-25w) power is plenty in my repeater-saturated area. I could be mistaken on the 2.5 SWR and 48 watt numbers as I tested several frequencies. It may have been 48w @ 146.520 and 1.8 SWR. I will need to do some more testing and actually write down the results.

Something like a NanoVNA is a useful tool to have in situations like this. It takes the transmitter out of the equation and makes seeing the resonance points much easier.

Nice boat. And I'd love to have a post lift in my garage like that….

 

[prcguy]

Shakespeare makes a wideband triband VHF/UHF/700/800 marine antenna but they are very hard to find and sold mostly to Govt agencies.

 

[WSEM262]

The arch measures approx 14" wide... and I think im going to just leave this Tram antenna alone for now...

 

[AK9R]

Are you checking the SWR with the boat on the trailer inside the garage? If so, the SWR might not be correct.

 

[mmckenna]

Im using a Yaesu FTM200D….The radio in question is a Yaesu FTM200D. It's been "tuned-up" a bit so it puts out more than the advertised 50w. I dont plan to run it on high power nor Tx on GMRS, but I always test it there to see worst case/emergency scenarios. T

and I think im going to just leave this Tram antenna alone for now...

There's a whole lot of good reasons to not try and make one radio do all this stuff.

Amateur radios have no type acceptance on the transmitter. That means they can -only- be legally used on the ham bands.
I know, people don't care, but some of us do...
GMRS requires a Part 95 accepted radio, which that isn't.
MURS requires a Part 95 accepted radio, and the rules negate the use of that radio.
Marine VHF requires a Part 80 accepted radio, which that isn't. Programming Part 80 frequencies into a radio also requires that the person doing the programming have an FCC issued GROL license.

Rather than trying to make a ham radio and Chinese marine radio antenna do Marine VHF, GMRS, MURS, amateur, and who knows what else, it's always better to use the right tool for the job, plus have the correct licenses. Especially when lives may depend on it.


Keep the marine stuff on the marine radio, where you have DSC and the 'emergency button'. If you need a backup VHF radio, get a hand held that you can grab and take with you if the boat stops being a boat. That'll be much more useful.

But, whatever…..

 

[WSEM262]

Are you checking the SWR with the boat on the trailer inside the garage? If so, the SWR might not be correct.

Yes... but it shouldnt get any worse by pulling outside or sitting in the lake. It would likely get better.

 

[WSEM262]

There's a whole lot of good reasons to not try and make one radio do all this stuff.

Amateur radios have no type acceptance on the transmitter. That means they can -only- be legally used on the ham bands.
I know, people don't care, but some of us do...
GMRS requires a Part 95 accepted radio, which that isn't.
MURS requires a Part 95 accepted radio, and the rules negate the use of that radio.
Marine VHF requires a Part 80 accepted radio, which that isn't. Programming Part 80 frequencies into a radio also requires that the person doing the programming have an FCC issued GROL license.

Rather than trying to make a ham radio and Chinese marine radio antenna do Marine VHF, GMRS, MURS, amateur, and who knows what else, it's always better to use the right tool for the job, plus have the correct licenses. Especially when lives may depend on it.


Keep the marine stuff on the marine radio, where you have DSC and the 'emergency button'. If you need a backup VHF radio, get a hand held that you can grab and take with you if the boat stops being a boat. That'll be much more useful.

But, whatever…..

Maybe I wasnt clear in my previous replies...
I have NO plans to remove the marine radio. NONE.
Its tied to my Garmin and is registered with MMSI.
I am only repurposing its antenna to use with the FTM200.
Ive already ordered a 4ft Shakespeare VHF antenna for the marine radio along with all supporting hardware... so I will maintain TWO complete and separate radio systems.

 

[prcguy]

Maybe I wasnt clear in my previous replies...
I have NO plans to remove the marine radio. NONE.
Its tied to my Garmin and is registered with MMSI.
I am only repurposing its antenna to use with the FTM200.
Ive already ordered a 4ft Shakespeare VHF antenna for the marine radio along with all supporting hardware... so I will maintain TWO complete and separate radio systems.

Ahhh, nope. You have a boat, a ham license and a GMRS license so you will be spending much more $$ on radios and antennas. Don't think it ends here or ends easy. Once your new marine band antenna gets here and installed I might recommend a Larsen NMO2/10B dual band 2m and 70cm amateur antenna, probably the best dual band mobile I've ever used. Then a modest GMRS antenna like the Laird B4505CN or similar. And we don't see a GMRS radio mounted in the boat so you'll need one of those too. As mmckenna mentioned, you don't want to use your Yaesu ham radio on GMRS. Not just because its not legal but because you have more dash space on the boat for a separate GMRS radio.

 

[WSEM262]

Ahhh, nope. You have a boat, a ham license and a GMRS license so you will be spending much more $$ on radios and antennas. Don't think it ends here or ends easy. Once your new marine band antenna gets here and installed I might recommend a Larsen NMO2/10B dual band 2m and 70cm amateur antenna, probably the best dual band mobile I've ever used. Then a modest GMRS antenna like the Laird B4505CN or similar. And we don't see a GMRS radio mounted in the boat so you'll need one of those too. As mmckenna mentioned, you don't want to use your Yaesu ham radio on GMRS. Not just because its not legal but because you have more dash space on the boat for a separate GMRS radio.

lol... Im not putting three radios in the boat. Two is enough.
I have two radios in my Tundra... an FTM500 and DB20G... then theres an FTM200 in wifes car.

And I know the deal with multiplying radios.... as ive got too many already.
This is whats left after I already sold 43 radios in the last few months.

Sofar I stll have:
3-FTM200D's
2-FTM500Ds
2-DB20G's
2-FT65's
3-FT70D's
2-FT2980's
1-UV5RA
1-XPR2500
2-XPR7550's
5-XPR7350e's
1-XPR3300e
2-XPR3500e

Along with a Motorola XR8300 backyard repeater system, complete with TPL amplifier and Celwave 6 cavity duplexer.

 

[mmckenna]

Ive already ordered a 4ft Shakespeare VHF antenna for the marine radio along with all supporting hardware... so I will maintain TWO complete and separate radio systems.

Then don't worry about high SWR on marine VHF or GMRS.

Use the marine VHF radio for your marine VHF needs. It's the right tool for the job.
For the hammy radio, do like suggested above, get a Larsen NMO-2/70 and you'll have low SWR on the ham bands.

As for GMRS, get the right tool for the job. Hacked amateur radios ain't it.

 

[hill]

If you want to operate on 2 meters and 70 CM, plus GMRS. I would do two different radios one for VHF and the other for UHF.

One of companies antennas on my earlier links they have marine UHF antennas.

 

[WSEM262]

Then don't worry about high SWR on marine VHF or GMRS.

Use the marine VHF radio for your marine VHF needs. It's the right tool for the job.
For the hammy radio, do like suggested above, get a Larsen NMO-2/70 and you'll have low SWR on the ham bands.

As for GMRS, get the right tool for the job. Hacked amateur radios ain't it.

Ive got a couple Tram 1180's in the garage and they are fantastic on 2m/70cm but dont play nice outside the ham bands. The Comet 2x4SR is absolutely amazing and works everywhere between 136-512mhz. Problem is that it's quite tall and might be a problem going under bridges if mounted atop the arch. Right now the Tram 1600 is just a touch under 14ft at the very tip of the antenna while the boat is on the trailer... so I think best thing to do here is just leave the FTM200 system "as-is" and just add the 4ft Shakespeare to the side of the arch... since it will be mounted to a ratcheting hinge that I can manually fold down for transportation.
The Tram on top of the arch is unreachable without putting a ladder on the boat.

 

[WSEM262]

If you want to operate on 2 meters and 70 CM, plus GMRS. I would do two different radios one for VHF and the other for UHF.

One of companies antennas on my earlier links they have marine UHF antennas.

While its "nice to have" MURS/GMRS on the boat, it is not my priority. I primarily want 2m/70cm capability, but also want to listen to the GMRS repeaters. The whole area is saturated with repeaters... 2m/70cm/GMRS. I can literally key probably a dozen+ repeaters from the middle of Lake Lanier.

 

[AK9R]

If all you want to do is listen to GMRS repeaters, then don't worry about the antenna's SWR on GMRS frequencies. Tune the antenna for the 2m/70cm amateur radio bands and move on.

 

[WSEM262]

Still waiting for the Shakespeare antenna to arrive but did manage to get the mount installed awhile.