VHF Range?

kappykaplan · Mar 25, 2021

@SailorElliot , welcome to the forum. What matters for range is the height of the antenna, since VHF is a line-of-sight frequency.

chip veres · Mar 25, 2021

Assuming the set works and the antenna works, the height of the antenna is everything. VHF radio signals travel a little beyond the optical horizon. 4/3 of the horizon distance is the common assumption of radio operators. With your 31' mast, you should be able to work a similarly-equipped Flicka at a range of 18 nautical miles. Costal stations, including USCG and Sea Tow often pay money to get their antenna on the highest tower available. So they can have considerably more range than my ship-to-ship example. The USCG is not usually available for radio checks, but Sea Tow is usually game.

Chip Veres
s/v Sand Dollar

Parsons · Mar 25, 2021

SailorElliot said:
Thank you so much, that's very helpful! Do you think 18 nautical miles is enough, or should I replace my antenna with a larger one?

VHF range has not changed in decades, as it is limited by line-of-sight as noted above. Reliability and "features" (most of which no one uses) have improved. What do you need more than 10 - 20 miles range for - Calling for help? There probably is a boat, perhaps listening to Channel 16, within the 1,000 square miles you are sailing in, even if you are out of range of land. As far as the normal use of VHF, an even split between collision avoidance and arranging for meet-ups with your buddies for fishing, both can be probably achieved with a hand-held VHF from the deck as they are normally done within a couple miles. You will be surprised how little you use the thing. A "larger antenna" on a sailboat VHF is a waste of cash (and makes it harder to get under bridges).

If you really are concerned about being off-shore by 20+ miles, perhaps invest in a satellite-based EPIRB, which is much more reliable, useful, and resilient than your VHF set.

rgranger · Mar 25, 2021

If you think of it in hours rather than miles you might feel more comfortable with 18 kts. Assume you are well trimmed in a stiff breeze \making 5 kts true (ideal situation), a VHF range of 18 kts is 3.6 hours away. Lets round up to 4. How useful is it to communicate with another vessel that is 4 hours away? Even if you head right at each other and they are a lot faster, they are probably over an hour away. I think you range is adequate.

I have found that the only times I really use the VHF is either on approach to secure a slip or berth at a marina... to call a "sea taxi" while tied off someplace or to guage the intentions of another vessel. All of these situations are ones where I am relatively close to the target. I have also had another sailboat hail me and ask if I would give way even though I was the stand-on vessel. The other boat was having electronic troubles and was afraid of getting out of the channel. Again, it was a situation that was relatively close.

Richard19068 · Mar 25, 2021

SailorElliot said:
Thank you so much, that's very helpful! Do you think 18 nautical miles is enough, or should I replace my antenna with a larger one?

It's not the size of your antenna. It is the height of the antenna above the surface that determines potential range. Assuming the antenna and radio work and the connections are sound getting a "larger" antenna is not going to gain any distance.

If your radio and mast head antenna work you should be able to contact Coast Guard Los Angeles / Long Beach and/or Tow Boat US from anywhere between MDR and Catalina. Their land based antennas are very high.

EPIRBS are great but are limited to life and death type emergancies.

You mentioned your radio is old. If it is not DSC equipped I would replace it with a new VHF before getting an EPIRB or related item. Make sure to enter the MMSI and that it has a GPS connection.

rgranger · Mar 25, 2021

SailorElliot said:
Thank you for replying! I just want to be able to call for help from far out, not sure if that is necessary, but me, being a new sailor, thinks I should. I am thinking of buying an EPIRB because it seems great for pretty much everything.

If you are in enough trouble to call for a rescue, I think the EPIRB will do what you need it to do. If you want to feel more safe, maybe upgrade the radio to one that also has AIS. You will get more bang for the buck than with a new antenea. With AIS you can set alarms and it will alert you if you are on a collision course with a super tanker etc. It also has a panic button that wil send out an SOS with GPS coordinates. I got the Remote Mic (RAM) option so I have a mic in the cockpit and I can controll the radio and see the AIS from the nav station.

Welcome to StandardHorizon.com

www.standardhorizon.com

rgranger · Mar 25, 2021

Richard19068 said:
It's not the size of your antenna. It is the height of the antenna above the surface ...

The 13 year-old that lives inside me is dying right now...

rgranger · Mar 25, 2021

SailorElliot said:
That one looks good, but I just love Garmin so maybe this one could work too.

Yeah... and if you can afford the RAM that is a nice option but not critical.

Richard19068 · Mar 25, 2021

rgranger said:
The 13 year-old that lives inside me is dying right now...

Yes. I'm enough of a 13 year old to have laughed at that while I was typing it in. I was wondering if anyone would comment!

Richard19068 · Mar 25, 2021

rgranger said:
If you are in enough trouble to call for a rescue, I think the EPIRB will do what you need it to do. If you want to feel more safe, maybe upgrade the radio to one that also has AIS. You will get more bang for the buck than with a new antenea. With AIS you can set alarms and it will alert you if you are on a collision course with a super tanker etc. It also has a panic button that wil send out an SOS with GPS coordinates. I got the Remote Mic (RAM) option so I have a mic in the cockpit and I can controll the radio and see the AIS from the nav station.

Welcome to StandardHorizon.com

www.standardhorizon.com

EPIRB responses take "forever" Great if you are lost at sea. Not so good if your boat is sinking or someone has a heart attack.

DSC and VHF responses are "immediate"

That's a good radio. I would get that before an EPIRB

tfox2069 · Mar 25, 2021

Here's a simple VHF line of sight calculator you can play with: VHF / UHF Antenna Line of Sight Distance Calculator (easycalculation.com)

I ran a quick calc, and found that if you added 10 feet of antenna to what you have now on your you'd essentially only buy another mile of range. That assumes your Flicka 20's mast height above water is 31', and your standard length VHF antenna is another two feet, for 33 feet in total. Try changing that to 43 feet and you'll see my point. So, not worth it, as everyone here has agreed. Now you have some numbers

I can't vouch for the accuracy of the online calculator, but I did check one other source and the DIFFERENCE was the same from 33 to 43 feet of antenna, though the line of sight range was a little more conservative.

Brian D · Mar 25, 2021

@SailorElliot, seeing how you are in Marina Del Ray, you should have no troubles talking to USCG in L.A. or Long Beach, or even in San Diego. USCG on this coast plot their antennas on tops of mountains. It has been documented that USCGS San Diego communicated with a distressed C36 200+ nautical miles out. Now, there are circumstances in which that was possible, but it was possible.

Don't ask for a comm check on channel 16, and never reply to a comm check on channel 16. Listen on channel 9. If you hear boaters chatting, wait for them to finish then you can ask for a radio check.

Parsons · Mar 25, 2021

Brian D said:
Don't ask for a comm check on channel 16, and never reply to a comm check on channel 16.

If only you could communicate this to the yahoos in my area! I would guess a full quarter of the Channel 16 calls are "radio check"! It's like we are using old tube sets, or everyone has just re-stepped their mast. Why do they expect a modern, solid state VHF to suddenly fail? I think they just like hearing themselves talk (perhaps they are all politicians?). Anyhow, back to work.

tfox2069 · Mar 25, 2021

Parsons said:
If only you could communicate this to the yahoos in my area! I would guess a full quarter of the Channel 16 calls are "radio check"! It's like we are using old tube sets, or everyone has just re-stepped their mast. Why do they expect a modern, solid state VHF to suddenly fail? I think they just like hearing themselves talk (perhaps they are all politicians?). Anyhow, back to work. <end rant>

Welllllllll, things happen. When I bought my current boat in 2018 the surveyor noted that the VHF radio was working fine. After purchase I fairly quickly found that no one could pick me up transmitting (including someone on the dock with my handheld), but I could hear folks just fine. Turned out after some diagnostics that the transmit on the radio was not working and the antenna was fine. I hooked up a new VHF radio and everything has worked well since. The old, and original VHF from 2009 went into the trash. The surveyor did a great job everywhere else, but had just turned on the VHF and listened for traffic, and then checked the box.

We could argue exactly what was wrong, and I'm not smart enough to defend myself on that subject in any depth, but functionally, my modern solid state VHF radio quit transmitting, and the antenna and its connections tested perfectly fine.

Anyway, Channel 9 for radio checks...yup.