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Author Topic:   installing marine ship to shore radio

captbobb posted 07-15-2003 09:44 PM ET (US)

I plan on installing a ship to shore radio on the whaler this weekend. Do I need to purchase a marine antenna or
can I install an old whip 4 ft CB antena that I have kicking around my shop ?

djahncke posted 07-15-2003 10:58 PM ET (US)

You need a marine VHF antenna. A CB antenna is tuned to operate around 27MHz. A marine VHF radio operates around 156MHz. If you use a CB antenna with a marine VHF radio the impedance mismatch from a improperly tuned antenna could damage the radio when you press the transmit button.
captbobb posted 07-16-2003 08:41 AM ET (US)
thank you.
Sal DiMercurio posted 07-16-2003 02:42 PM ET (US)
They outlawed ship to shore radios in the early 70s.
They are called "VHF" [ very high frequency ] radios now.
If i'm not mistaken, the old ship to shore radios were called "loran A".
I had one in my first Alaska boat, a dozen tubes about 6" long & weighed about 40 - 50 lbs.
Sal
djahncke posted 07-16-2003 10:19 PM ET (US)

The old "ship to shore" radios were HF band AM units. If I recall they operated around 2MHz. The had much longer range than today's VHF units and were true boat anchors. For long range large boats now use SSB (Single Side Band) HF units.
jimh posted 07-16-2003 10:52 PM ET (US)
LORAN A was a hyperbolic radio location service developed in World War II. It was not a communications radio service.
Currently in the US and Canada, and most of the rest of planet as well, the Recreational Marine VHF Radio Service is allocated in the 156 MHz band and uses FM Radiotelephony. An efficient antenna is just 18-inches long. Propagation is typically line of sight
There is an allocation for Marine Radio Service in the 2 MHz band which at one time used AM Radiotelephony. The distress and calling channel was at 2.182 MHz. Antennas for this band for shipboard use typically long aerials strung in the ship's masts. An efficient antenna was often 200 feet long or a large base loaded whip. Over the horizon propagation is common after dark. This allocation still is in use for commerical vessels, but radiotelephony is now conducted using Single Side Band techniques.

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Author	Topic: installing marine ship to shore radio
captbobb	posted 07-15-2003 09:44 PM ET (US) I plan on installing a ship to shore radio on the whaler this weekend. Do I need to purchase a marine antenna or can I install an old whip 4 ft CB antena that I have kicking around my shop ?
djahncke	posted 07-15-2003 10:58 PM ET (US) You need a marine VHF antenna. A CB antenna is tuned to operate around 27MHz. A marine VHF radio operates around 156MHz. If you use a CB antenna with a marine VHF radio the impedance mismatch from a improperly tuned antenna could damage the radio when you press the transmit button.
captbobb	posted 07-16-2003 08:41 AM ET (US) thank you.
Sal DiMercurio	posted 07-16-2003 02:42 PM ET (US) They outlawed ship to shore radios in the early 70s. They are called "VHF" [ very high frequency ] radios now. If i'm not mistaken, the old ship to shore radios were called "loran A". I had one in my first Alaska boat, a dozen tubes about 6" long & weighed about 40 - 50 lbs. Sal
djahncke	posted 07-16-2003 10:19 PM ET (US) The old "ship to shore" radios were HF band AM units. If I recall they operated around 2MHz. The had much longer range than today's VHF units and were true boat anchors. For long range large boats now use SSB (Single Side Band) HF units.
jimh	posted 07-16-2003 10:52 PM ET (US) LORAN A was a hyperbolic radio location service developed in World War II. It was not a communications radio service. Currently in the US and Canada, and most of the rest of planet as well, the Recreational Marine VHF Radio Service is allocated in the 156 MHz band and uses FM Radiotelephony. An efficient antenna is just 18-inches long. Propagation is typically line of sight There is an allocation for Marine Radio Service in the 2 MHz band which at one time used AM Radiotelephony. The distress and calling channel was at 2.182 MHz. Antennas for this band for shipboard use typically long aerials strung in the ship's masts. An efficient antenna was often 200 feet long or a large base loaded whip. Over the horizon propagation is common after dark. This allocation still is in use for commerical vessels, but radiotelephony is now conducted using Single Side Band techniques.