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Discussion Starter #1
My new-old boat has a vhf antenna mounted atop the mast with cable inside the mast. How can I test my antenna and cable before I put up the mast? I have a servicable multimeter and the mast is down. Everything's accessable now. The radio, I was told, no longer works and I don't want to plug the antenna into a new radio and ruin it.
Mike
 

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Testing with a multimeter is of limited benefit. It can tell you if there is a short or no continuity but will not indicate a marginally corroded connection, impedance mismatch, moisture inside the coax braid or high reflected power (SWR).
Start with the multimeter to verify no shorts exist, if in doubt, replace all coax connections which also allows inspection of the coax ends to see if there is moisture entrapped and use an SWR meter to verify everything works properly.
 

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Get a radio that works. Get a handheld VHF. Try transmitting on channel 68 with and without the antenna. TADA! The antenna works, now put it on top of the mast!
 

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old guy :)
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Ask around and find out where your local HAM radio club is. Find their web site. Call up the president or any member and say to them:

"I have a problem I am not sure if you can help me with. I have a VHF radio on my boat. I am told it is in the 2 metre range. Do you know anyone who might have a 2 m SWR meter and might be able to take a few minutes and tell me if the antenna is tuned right? I would be happy to buy them a coffee or a beer after."

Rational
  1. Everyone likes to solve someone else's problem
  2. HAM radio guys like to share their expertise
  3. HAM radio guys usually have SWR meters
    many HAM radio guys like coffee or beer
  4. And lots of them are retired and have lots of time on their hands

I know - I am a HAM radio guy, retired, with time on my hands, and know which HAM guy I could borrow a 2 M SWR meter from.

:)

Information:

  • The 2 metre band is the band that VHF is in
  • The SWR meter or VSWR (voltage standing wave ratio) meter measures the standing wave ratio in a transmission line. This is an item of radio equipment used to check the quality of the match between the antenna and the transmission line.

Rik
(VE9RIK)
 

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Telstar 28
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IIRC, transmitting on a VHF without an antenna attached may fry the radio. Not a good idea.
Get a radio that works. Get a handheld VHF. Try transmitting on channel 68 with and without the antenna. TADA! The antenna works, now put it on top of the mast!
 

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Discussion Starter #6
I believe it will

Sailingdog: that's why I don't want to plug a new radio into an untested antenna. For all I know, that's why the existing radio is kaput. I have fried a CB by keying the mike without an antenna connected. :eek:
 

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If it is at all suspect, this would be a great time to run a new cable and replace the antenna. Very suprised SD did not say this:D
 

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Telstar 28
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I'd have to agree.. if you've got any doubts, it is far better to run new cable than worry about it... :) A new Metz 3 dB 3' whip is only about $40, and they're bulletproof.
 

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when in doubt, throw it out. since mast is down, its better to fix what need be done. if the cable is several years old might as well change it or you may have to change it later (regret...regret).
 

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hummm not even a total replacement will guarantee your antena is working (soldering, connectors, splices, running clables, etc). Your VHF will not be damaged by a 1 second call to a hadheld for a quick check, your multimeter will grant "phisycal shorts", and only a SWR meter could tell you about performance also. Indeed, you should not take my advices as granted, this is just what I've done myself on several occasions I faced this same problem. If you go "by the book", taking strictly all advices, you'll might end up concluding your antana may cause cancer ....
 

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As a professional radio guy, I'm astonished at the good and the bad advice on this very simple question.

DO NOT transmit without an antenna. It won't tell you anything.

FORGET transmitting to a nearby handheld. It won't tell you anything useful.

REPLACE the coax. It's very cheap insurance on a very important system on your boat. Be sure that all connections are properly made. Test for shorts and opens after putting the PL-259's on, using your multimeter.

If the antenna itself is at all suspect, replace it. Very inexpensive to do.

If the radio is suspect, replace it. VHF radios are probably the biggest bargain in boating these days. You can get a full Class D DSC radio with bells and whistles for $169, e.g.,
Standard Horizon STD-GX3000SB Matrix Fixed-Mount VHF Radio - $169.49
Amazon.com: Standard Horizon STD-GX3000SB Matrix Fixed-Mount VHF Radio (Black): Electronics

A VHF radio is a critical piece of equipment for safety. Cheap insurance to be sure it's working well.

Bill
 

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"replace all coax connections" Not worth the time OR money, which can amount to half the cost of just buying a new premade cable run.

DO ask questions about the new cable you are getting. There are multiple types (a little web searching will enlighten you) and thicknesses and one of the obvious signs of "cheap" is "Made in China". Another is whether the cable has a 100% shield, or a 40-60-80% shield. The best stuff has a full (100%) shield on it.

Look into properly weatherproofing the connections for the new cable, and properly supporting it. Those are critical to keeping it working. Again, a little web searching...
 

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I'm not a pro but I installed a new ant. and the first thing I did to be sure all was ok was turn it on and dial up the WX station. I figured that if it was receiving then it should transmit.

I just used the low power setting and had a friend use the handheld.

All is well.
 

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Just because a radio receives, doesn't mean that it will transmit. Also, just because the guy in the next slip can hear you transmit, doesn't mean that the coax and antenna are in good condition and that you're getting 25 watts of power out of the setup. Try transmitting at high power and see if a guy 20-30 miles away can hear you.
I'm not a pro but I installed a new ant. and the first thing I did to be sure all was ok was turn it on and dial up the WX station. I figured that if it was receiving then it should transmit.

I just used the low power setting and had a friend use the handheld.

All is well.
 

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I don't think it will go that far with the mast down.

Just because a radio receives, doesn't mean that it will transmit. Also, just because the guy in the next slip can hear you transmit, doesn't mean that the coax and antenna are in good condition and that you're getting 25 watts of power out of the setup. Try transmitting at high power and see if a guy 20-30 miles away can hear you.
 

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I think that knowing how o replace RF connectors of various varieties is a good thing. A Saturday afternoon with a soldering iron, some tinned coax (if you're a neophyte) and a lot of patience will pay off big time.
Howard Keiper
 

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Discussion Starter #17
Great advice thread

thanks for all the input. This is a great advice thread for a newbie. I've been out of town for 3 days so I missed it in real time but I'm grateful for the replies.

I need to do a lot of reading up on antennas, cables and connections as advised. I'm totally clueless on the subject but I've always been a doityourselfer so I know I can learn. I'll probably go with all new since I'm pretty sure I have to buy a new radio.

Antennas are pretty inexpensive. The new radio with bells and whistles are inexpensive. I think this is the way to go.
 

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I replaced my masts antenna wire last spring only to find a problem with the hull's wire. I have replaced that, too. I also invested $75.00 in The Shakespeare ART-3 VHF Radio and Antenna Tester is the only meter in its class to test receiver function as well as output power and VSWR. I have a 1 meter coax patch cable and connect it between the radio and my antenna wire for testing. It is small and self powered. I test things from time to time rather than rely on just a "radio check". It can be left in line permenantly but I choose to connect it only for testing.

George
 

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Sure is pretty. Looks just like a conventional VHF SWR meter, except for the gold plating and the 2x marine price boost. I guess Shakespeare figured out that sailors don't know how to find ham radio equipment now that Radio Shack has gone over mainly to toys.
 

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That sounds right but the peace of mind and convenience made it worth the price to me. I guess there is a bit of vulnerability we suffer coping with the range of technologies a small cruising boat requires. I tell myself I make up for it in other areas. I have spread the word of its availability among locals. It might be a good group investment for clubs. It might behoove the Coast Guard to offer that kind of simple check to boaters along with their courtesy safety inspections. What could be more important to check, for safety reasons, than the function of the VHF radio, unless it is the existence of a proper anchor!
 
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