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Weather on vhf radio

Posted: Wed May 25, 2022 6:45 am
by Ixneigh
I can barely get the noaa forcasts on my radio. Anyone know if they changed the signal output? Both handhelds seem affected. I did look the antenna connectors also.

Ix

Re: Weather on vhf radio

Posted: Wed May 25, 2022 8:28 am
by Stickinthemud57
These are questions from someone with no knowledge of salt water sailing beyond the confines of Corpus Christi Bay, so please understand I am truly trying to learn...

-How far will VHF weather forecast broadcasts reach?
-What factors affect the receiving distance?
-What is the coverage of the standard VHF weather forecast? 25 miles? 50 miles? More?

I depend solely on weather apps on my cell phone for my go/no go decisions, which works fine for me since I sail on lakes with good cellular coverage. -How far does one have to get from the coast before weather apps on one's cell phone become unusable?

I guess to state the questions another way, when does a VHF forecast become better than a weather app on a cell phone?

Re: Weather on vhf radio

Posted: Wed May 25, 2022 12:14 pm
by Russ
Stickinthemud57 wrote: Wed May 25, 2022 8:28 am
I guess to state the questions another way, when does a VHF forecast become better than a weather app on a cell phone?
I no longer bother with NOAA weather channel on VHF when I can get great radar images from my cell phone.

Re: Weather on vhf radio

Posted: Wed May 25, 2022 12:44 pm
by Be Free
Ixneigh wrote: Wed May 25, 2022 6:45 am I can barely get the noaa forcasts on my radio. Anyone know if they changed the signal output? Both handhelds seem affected. I did look the antenna connectors also.

Ix
All of the NOAA stations in your area are working at full strength. The closest reported outage is Carthage, MS. I just checked locally on my handheld and I can pick up three stations. One is near me; the other two are at least 50 miles away in different directions.

Re: Weather on vhf radio

Posted: Wed May 25, 2022 1:05 pm
by Be Free
Stickinthemud57 wrote: Wed May 25, 2022 8:28 am These are questions from someone with no knowledge of salt water sailing beyond the confines of Corpus Christi Bay, so please understand I am truly trying to learn...

-How far will VHF weather forecast broadcasts reach?
-What factors affect the receiving distance?
-What is the coverage of the standard VHF weather forecast? 25 miles? 50 miles? More?

I depend solely on weather apps on my cell phone for my go/no go decisions, which works fine for me since I sail on lakes with good cellular coverage. -How far does one have to get from the coast before weather apps on one's cell phone become unusable?

I guess to state the questions another way, when does a VHF forecast become better than a weather app on a cell phone?
Distance: I just lied to Ixneigh. I just measured the distance to the two distant stations I'm picking up on a handheld. One is 60 miles, the other is almost 70. That is probably about as far as you are going to receive with a handheld radio on flat ground (or water). If you have an antenna on the top of your mast you should expect better.

Factors: Receive distance is related to transmit power, receiver sensitivity, atmospheric interference, terrain, and antenna height (on both ends). The only one you can control is your own antenna height.

Coverage: Coverage overlaps but you should be able to get a strong signal anywhere you take your boat (and a lot of places you can't take one).

Close to shore your weather apps should work fine. I've never had problems within 15 miles or so from shore. Beyond that you may begin to have problems unless someone has put some cell towers offshore in your area. Your weather radio signal should be good for 50+ miles. That's a lot farther than I intend to get offshore.

If you are like me your go/no go decisions are made with your feet firmly on dry land so use the weather tool you trust and know how to interpret. Once I've left port I may be gone for a week or more so I usually plan on using the NOAA broadcasts. I'm never too far from shore to pick them up. I also keep my fixed VHF with the tall antenna listening for NOAA alerts in addition to channel 16 (you do monitor your VHF when you are underway don't you?) I've received warnings on the weather radio hours before the same information pops up on any of my weather apps.

Re: Weather on vhf radio

Posted: Wed May 25, 2022 3:48 pm
by Stickinthemud57
Good stuff, thanks!

So now that gets me to wondering - how do trans-oceanic sailors monitor the weather?

Re: Weather on vhf radio

Posted: Wed May 25, 2022 3:58 pm
by Be Free
There are satellite and long range weather tools available to use for use mid-ocean. They are expensive and presume a higher level of weather planning skills than we need for coastal use.

Re: Weather on vhf radio

Posted: Wed May 25, 2022 4:21 pm
by 787Sailor
Stickinthemud57 wrote: Wed May 25, 2022 8:28 am -How far will VHF weather forecast broadcasts reach?
-What factors affect the receiving distance?
-What is the coverage of the standard VHF weather forecast? 25 miles? 50 miles? More?
There is an old aviation rule of thumb that VHF reception range is 1.2 nautical miles times the square root of your altitude. VHF radio waves are line of sight. They don’t propagate like HF waves do so you are limited by the curvature of the earth, which is what that formula approximates.
So if you have a masthead antenna at 36 feet up, you can receive a signal transmitted from the surface at a maximum of 7.2 miles. However most transmitters have their antenna up on a tower so the same principle applies. If it was, say, a 100 foot tower, it’s “horizon” is 12 miles, so you could theoretically receive that signal with your masthead antenna at almost 20 miles.

Atmospheric effects are pretty minimal on VHF but quality of the receiving antenna and how it is mounted can make a big difference, however the technical reasons for that are well outside my area of competence.

Re: Weather on vhf radio

Posted: Thu May 26, 2022 3:39 pm
by Ixneigh
Well I moved the boat 14 miles and now I’m getting it fine at Tarpon Belly Key. Cel signal out here is limited. I never rely on it for weather.

Ix

Re: Weather on vhf radio

Posted: Thu May 26, 2022 4:42 pm
by WD
Stickinthemud57 wrote: ↑Wed May 25, 2022 9:28 am

I guess to state the questions another way, when does a VHF forecast become better than a weather app on a cell phone?
I no longer bother with NOAA weather channel on VHF when I can get great radar images from my cell phone.
--Russ
Are there prefered apps for weather radar info on cell phone? Personal preferences? Suggestions anyone? Please :)


Cheers, Bill

Re: Weather on vhf radio

Posted: Fri May 27, 2022 7:05 am
by Be Free
My personal preference on an Android is RadarNow! (all one word and the "!" is part of the name). I'm using the free version.