Increasing handheld range

Skipper · Feb 15, 2016

It sounds like you already have a ship's radio 25 watt, since there's an antenna. So I'm guessing you want a reasonable-range backup in case the battery goes dead.
If this is true, the money that would be spent on minimal improvement would go a long way towards installing a 2nd battery. Also, am guessing that you have an outboard, which is small enough to pull start, yet big enough to have an alternator(?)
I may be way off, and not answering the question

But the reality is that there's not much you can do to improve the range of a handheld, except to get the antenna higher, which you've done. If you're concerned about the cable length, look at rail-mount antenna, to be attached to the stern pulpit.

Capt jgw · Feb 15, 2016

Power has little to do with range, it's all about antenna height. Even with a fixed radio, you're supposed to try your call on one watt and only switch to 25 if you can't be heard on one, which you usually can. Given that, your handled is six times more power than you need. I hardly ever use the 25 watt setting on my radios. There's no need for someone 25 miles away to hear you when you're talking to someone else only five miles away. Just makes more congestion for everyone.
The handheld is going to lose the same amount of power due to coax length as the fixed mount does, so that's also kind of moot. Just make sure the cable and all the connections are in good shape. Most of your signal loss will be due to corroded connectors and damaged or wet coax.

Ken Cross · Feb 15, 2016

Boson's chair?

Actually the linear amp you referred to could help some, but remember the 2nd half of your range is reception. The amp won't help reception because signal to noise ratio gets in the way. Because VHF is generally line of sight the higher antenna even with losses should still provide much more range.

Ken

Brian D · Feb 15, 2016

Yes you can, but it must be a marine grade amplifier for 150 MHz to 175 MHz operations. It will only increase the Tx gain of your radio and not the Rx gain. You would want the amplifier only to offset the lost of the cable not to exceed 25 Watts. But as others have said, it is the height of the antenna not the power. Although it will not hurt to have most of your RF leave the antenna and not used to heat up your cable.

If you have more than 3 dB of loss in your cable then there is something terribly wrong and you should have it inspected. I looked at the tables for RG8X and found 3.6 dB of loss for 100 ft @ 100 MHz. So roughly that equates to about 1 dB of loss for your 29 feet. But not knowing your cable I just used RG8X for the example.

Have your system checked out to include cable, connectors, antenna switch, and anything/everything in between.

Ken Cross · Feb 15, 2016

I think most often I've seen RG58a used. An interesting thing. 2 airplanes (in the 128 MHz range if I remember right) one 747 at 35,000 feet and one Cessna flying much lower and flying opposite direction talking to each other. The Cessna was transmitting 3 watts, the 747 was around 25. The signal in both airplanes faded at about the same time (around 320 miles) if power were the ticket, the Cessna would have lost the 747 long after the 747 lost the Cessna, but receivers faded out at about the same time. I'm guessing the curve of the earth was the limiting factor as it also normally is with a boat.

Mark Maulden · Feb 15, 2016

I've talked between Seattle and climbers half way up Mt. Rainier both using handhelds on 2m. (145MHz ham). Line of sight. The climbers had altitude. With both at sea level, you're limited to 5-6 miles if i remember right (line of sight). (Not going to do the math)....So, again, it all depends what you want to do with your radio.

druid · Feb 16, 2016

As others have said, antenna is much more important than power (on the Ham HF bands, guys have communicated halfway around the world with 100 mW). And yes, the cable is as important as the antenna: there's a HUGE difference in losses between different types of cable, especially at VHF frequencies. Do some research...

But one thing: on MY handheld, output power is restricted when I'm on internal battery - it only goes to FULL power when attached to an external 12V source. Might want to try that...

druid

bawlmer · Feb 16, 2016

Height =distance. Power = penetration. Without getting scientific there will always be significant loss in your signal's trip to the antenna. It is not an issue as there should be nothing between your antenna and the antenna you are trying to reach. Transmitters mounted in satellites transmit only milliwatts but manage to successfully make the long trip to earth without issue. If your transmission line is in halfway decent shape it would be an advantage for you to hook your handheld into it. One caveat is make sure the clunky adapters you will have to use don't damage the antenna jack of your HH. I even think that was covered on a previous post. Best of luck.

Don S/V ILLusion · Feb 16, 2016

flynhi4u said:
I am looking into how to increase the range of our 6 watt handheld. I have it set up to tie into our masthead antenna but with 29 total feet of coax I am sure I am loosing probably close to half the 6 watts to signal loss. Could I use a signal amplifier to regain the lost signal strength and maybe gain a little extra? If so which one would you recommend? Thanks

Sam

Without getting off track from your request, the simplest way to ncrease range of any handheld is to replace the small 'rubber duck' antenna original equipment with a better one.

Note advertising is often misleading with antennas claiming both range or signal strength 'gain' without any reference so choose wisely. Also, some flimsy radios often have poor quality connectors to which the antenna is connected. Some can't handle the sheer stress of an extendable antenna.

I won't waste time suggesting possible choices unless someone asks

Ken Cross · Feb 16, 2016

flynhi4u said:
I do also have a extendable metal antenna I can use in place of the flexible antenna if the masthead antenna gets damaged or we are stranded out in the dinghy.

Sam

Actually replacing an antenna with a longer one on a handheld is problematic. The antenna that comes with a handheld is tuned with inductors and capacitors to make an impedance match with the internals of the radio at the frequency being used. To change dimensions of the radio antenna is sure to decrease performance dramatically. Often it can damage the transmitter output by causing the output stage inside the radio to overheat. Coax connections to handhelds are constructed to match the 52 ohm impedance of the antenna and cable, making it work properly. It's good to note that the impedance mismatch we are talking about here also effects receiver sensitivity in the same way.

You don't want to go there unless you re-engineer the interface with the radio. If you want to check up on me or just want more information here is a fairly basic link:

http://www.antenna-theory.com/basics/impedance.php

Ken

Brian D · Feb 16, 2016

@bawlmer, you analogy of satellite signals is actually not correct. There is a reason why certain types of radio waves can travel longer distances with less power. However, you point is valid.

bawlmer · Feb 16, 2016

Brian D said:
@bawlmer, you analogy of satellite signals is actually not correct. There is a reason why certain types of radio waves can travel longer distances with less power. However, you point is valid.

You are correct that my statement is not exactly correct as the wavelengths and antenna types are much different than VHF. I thought it would help explain my point without getting too deep in the weeds.

bawlmer · Feb 16, 2016

This is probably what you need to hook up to your antenna. Check your HH antenna port. Apologies for the long URL.

http://www.buytwowayradios.com/prod...B0DfhxLnjaUKFuEzRekaAtnp8P8HAQ&ad=53736626959

CharlzO · Feb 16, 2016

clicking the link provided under that range gives:

Range
It is important to be aware that the number of miles of range advertised by two way radio manufactures is always the maximum range that the radio will get under perfect circumstances. Many things can affect the range, such as trees, bushes, buildings, vehicles, or almost anything that could interfere with line of sight.
***
Must be like "tested" mpg ratings in some cars I've seen.

EDIT: Just noticed they list the same 27 mile range on one of the Cobra fixed mount 1/25w models too. Definitely funky.

Nick · Feb 16, 2016

As a licensed amateur, you are allowed to modify the marine gear to transmit on amateur band

You cannot modify, adjust, repair, or anything else that affects the transmitted signal on a marine radio unless you possess a commercial FCC license. FCC Fines are $10000 and possibly jail, confiscation of equipment and perhaps your vessel!

Mark Maulden · Feb 16, 2016

Would like to see chapter and verse on that!

Don S/V ILLusion · Feb 17, 2016

Mark Maulden said:
Would like to see chapter and verse on that!

Among the misconceptions is that changing an antenna would constitute a 'modification' which it does not.