Electronics

[quadrille38]

Actually you could talk to the international space station if you knew the frequency and type of modulation (and had equipment to do so.) There is a good reason that is kept secret. Can you imagine how bad communications would get if all over the planet were people interfering with the signal trying to talk to them? Ken

LOL - just imagine what it would be like with all those people who keep doing radio checks on channel 16, or those who got stuck in the 60s - breaker breaker 16 - all trying to call the space station. Chaos ?


But true that antenna height is only one part of the equation. The right equipment, as in a transmitter with enough power is also important.

 

[Jackdaw]

LOL - just imagine what it would be like with all those people who keep doing radio checks on channel 16, or those who got stuck in the 60s - breaker breaker 16 - all trying to call the space station. Chaos ?

LOL indeed. VHF is ancient WWI radio tech...no way they 'talk' to the ISS with simple simplex frequency-modulation technology.

 

[walt]

http://www.boatus.com/husick/c_hheld.asp

This article is from 2009 and has the snip below

The Rescue 21 VHF/DSC communication system now being completed is designed to provide reliable communication with a 1 watt radio, 1 meter above the water, at a distance of up to 20 nautical miles from shore

I really dont know much about this at all but would find it interesing if someone did know and how far the DSC actually does work with a handheld and not drain the batteries quickly... I think to do the above, the radio's must incorporate more modern modulation technology and take advantage of that very little info is actually transmitted.. 20 miles, 1 meter height and 1 watt goes beond the line of sight for normal VHF voice com..

 

[Jackdaw]

http://www.boatus.com/husick/c_hheld.asp

This article is from 2009 and has the snip below



I really dont know much about this at all but would find it interesing if someone did know and how far the DSC actually does work with a handheld and not drain the batteries quickly... I think to do the above, the radio's must incorporate more modern modulation technology and take advantage of that very little info is actually transmitted.. 20 miles, 1 meter height and 1 watt goes beond the line of sight for normal VHF voice com..

Several things come into play here. The 'Rescue 21' is now operational and uses a network of land-based antennas to combine incoming signals for optimal reception. Your 'call' is received by one or more antennas and combined. They also convert them to a digital stream and do noise reduction and amplification based on DSP (Digital Signal Processing) technology. The DSC/AIS portion is also digital and is designed for reception under sub-optimal conditions.

 

[Bill Roosa]

Guys, I can talk to Europe on 5 watts on my ham radio. do it pretty frequently too. during some weather conditions (tropo ducting) my marine VHF can pick up the NY USCG from MD bay area, actually talked to them too!!, so power is not the real issue with VHF. On HF the radio waves can bounce off the upper atmosphere (60ish miles high effective tower height) so you get pretty good "line of sight".
now if you have a noisy background more power has some advantage. All the transceivers are pretty much the same radio wise so pick you features. The best thing you can spend your money on is a good antenna. Even more so with hand helds which have VERY bad "shorty" antennas. The longer ones for hand helds are much better for transmitting and receiving. I think you will find that a hand held with a good antenna will preform just as good as a panel mounted 25 watt unit.
And again, ask yourself how often you talk to some one more than a few miles away outside the USCG (who has a tall tower for their great antenna)?

 

[Bill Roosa]

Well I would beg to differ with you Ken
try http://www.zarya.info/Frequencies/FrequenciesISS.php

and dont forget to do your doppler freq shift calculations to keep the station tuned in.

 

[Captn TJ]

Guys, I can talk to Europe on 5 watts on my ham radio. do it pretty frequently too. during some weather conditions (tropo ducting) my marine VHF can pick up the NY USCG from MD bay area, actually talked to them too!!, so power is not the real issue with VHF. On HF the radio waves can bounce off the upper atmosphere (60ish miles high effective tower height) so you get pretty good "line of sight". now if you have a noisy background more power has some advantage. All the transceivers are pretty much the same radio wise so pick you features. The best thing you can spend your money on is a good antenna. Even more so with hand helds which have VERY bad "shorty" antennas. The longer ones for hand helds are much better for transmitting and receiving. I think you will find that a hand held with a good antenna will preform just as good as a panel mounted 25 watt unit. And again, ask yourself how often you talk to some one more than a few miles away outside the USCG (who has a tall tower for their great antenna)?

Sorry but common sense tells me that a regular VHF with an antenna 40-50 ft in the air will out perform a handheld. I only use my handheld coming into harbors.

Where do I use my regular VHF?

To call marinas - an hour out to get dockage info. Some cruising grounds have a check in service, i.e. North Channel - a handheld will never give you a enough power unless you're adjacent to the check in station. I regularly monitor 16 on my regular VHF for everything from shipping notifications (securite) to emergencies. And when I'm in the middle of a Great Lake I'd rather rely on the VHF with more power and a taller antenna to give me advance notice of an impending squall. Like with other safety equipment - I'd never want to be in a situation where I regret not spending the extra $200. Just my 2 cents.

 

[Ron20324]

Sorry but common sense tells me that a regular VHF with an antenna 40-50 ft in the air will out perform a handheld. I only use my handheld coming into harbors. ...just my 2 cents.

A previous boat partner bought a Compac 23 and a fix-mount VHF. I said he should have bought a handheld and told him why. Convinced, he took back the un-installed fixed to get a hand held. The guy at West talked him onto the fixed, so he kept it and installed it below. Some time later as my friend sat on his comings heeled over because he drifted out of that south channel out of Havre DeGrace, he recalled my words as he contemplated how to climb into the cabin on a 45-degree slant. Not to mention his new antenna alignment. He later told me he should have listened to me. Not my 2 cents, it is his.

 

[gettinthere]

Thats why a RAM mic is perfect. Cant imagine not having the RAM mic at the helm. I rarely ever use the base at the nav, certainly not while under weigh

 

[Captn TJ]

Thats why a RAM mic is perfect. Cant imagine not having the RAM mic at the helm. I rarely ever use the base at the nav, certainly not while under weigh

+1 on the remote mic - an essential part of the VHF install.