300 watt + NMO antenna? Does it exist?

[Beetle]

An NMO antenna will handle full legal power on 11 meters in the USA.

 

[w9cll]

full legal power

Yep

 

[BigKahuna]

I just remembered that Breedlove makes some heavy duty looking NMO mounts. I use one of his stake hole mounts for a ham stick and it's very high quality. This might be what your looking for if you want to replace your current NMO with something more power capable. You can email him and ask what they are rated at.

https://breedlovemounts.com/NMO_Mounts.php

Awesome. If the existing mount wont do the trick those certainly will. Thank you for the link! Glad to know the type of stuff I was asking about is out there.

 

[BigKahuna]

I got mfj adapters, I had ordered both nmo to 3/8 and nmo to so-239. Worked like they supposed to used 3/8 model with old base load steel whip I had. After tuning 1.2 barefoot and 1.4 at 225w. The adapters seem good material.

 

[Slowmover]

MFJ-7707

NMO to 3/8-24 Adapter

“This is a quality adapter that lets you use an HF whip
with an NMO-style mount”.

$7.95

 

[Slowmover]

Well, Big Kahuna, what’s your assessment if any long-term use?

 

[WECSOG]

Good quality RG-58 will indeed handle that power level. Belden for example rates its RG-58/U at 782 watts at 50 MHz and 1937 watts at 10 MHz. Extrapolated, it should handle over 1000 watts at 10/11 Meters.
I see absolutely no reason why a decent quality NMO connector wouldn't handle 1500 watts. I can tell you with certainty that a PL-259 will.
I second Slowmover's recommendation of the MFJ-7707 adapter.

 

[Slowmover]

BK s choice. I just linked it.

 

[Mudfoot]

Even if the antenna is rated at 500W or more, the RG58 coax isn't.

There is absolutely no advantage at all going above 300W and even that is excessive. The difference between 300W and 600W is 3dB which is half a S point. The difference between 100W and 600W is just over one S point. From an installation point of view, the difference between 300W and 600W is massive. Any shortcutting on grounding, bonding, the 12V supply will all massively affect the 600W install. You're not going to get away with magmounts or lip mounts with a 600W install or even a 300W install without issues. You have to use fixed body mounts attached by drilling holes in the vehicle.

Short run of 58 will handle that and more.

 

[Mudfoot]

People keep yammering about 0.5 S-Units. I've had numerous QSO's where that half an S-Unit allowed us to talk. If you want it and can afford it, then buy it.

 

[Mudfoot]

This is the Breedlove adapter I use for NMO. I have a UHF adapter for it. Both are heavy duty and work well.

 

[Mudfoot]

View attachment 35189

MFJ-7707

NMO to 3/8-24 Adapter

“This is a quality adapter that lets you use an HF whip
with an NMO-style mount”.

$7.95

Those work, but there are heavier duty ones.

 

[Slowmover]

I wondered about that. And asked the question elsewhere. All I remember is OPEK brand (otherwise).

 

[Mudfoot]

Apparently not.

Why? Its pointless.

One who apparently doesn't know the difference between 100W and 300W isn't worth bothering with.

I rest my case.

It will work and work well. Maybe his wallet is fatter. Pretty harsh comments.

 

[Mudfoot]

Do those antennas come with NMO mount versions? I can't find any one selling such a mount for those antennas. While you can definitely get an adapter, I still don't think I would personally run a Sirio 4000 or 5000 series antenna with such a mount...


The DB

I've ran a 5000 like that, but I used Breedlove NMO mounts and adapters. Quite strong and stout. It was a confident installation.