Poor VHF radio performance

[magster65]

Is there anything I can do to test or tune up my VHF? We were boating with some friends and they couldn't hear our radio transmissions on some channels. I've checked all the connections and the antenna seems to be ok...

 

[mattttt25]

Re: Poor VHF radio performance

magster, hopefully someone will pipe in, but i think a metal whip antenna needs to be adjusted for height. remember hooking up your cb radio back in the day? i remember putting a little gadget inline between the radio and the antenna, and watching the needle. adjusted the height of the antenna (how much it went into the base, only about a 1/4 in adjustment) and when it was right, tightened it up. can't remember the name of the gizmo- maybe an s-meter? anyway, i think you do the same for those types of vhf antennas as well. could be way off here-

 

[Fly Rod]

Re: Poor VHF radio performance

Good Day Take your vhf to a full service marine electronics store and have them test it if there is one near. Your boat yard should know where there is one.And I don't mean a West Marine;Boat Us.etc: They just sell you a product for a little less and happy to see you go out the door,they don't provide maintance.<br /><br />Ask your self how far away were your friends?, any amount of land between you?,do you have one of those little 3' antennas? Moisture and temperture can play a part. I've called boats 15-20miles away and they could hear me but I couldn't hear them.

 

[magster65]

Re: Poor VHF radio performance

Matt, Fiberglass antenna about 5' or so... it should be ok for length.<br />Flyrod, My friends were only 100 feet away and I could hear them, thet couldn't hear me. I'm pretty sure moisture or temperature were not a factor.<br />Do you know if having your antenna leaning (for looks/about 15 degrees off vert.) affects it's performance?

 

[Fly Rod]

Re: Poor VHF radio performance

Magster I'm not an expert on this stuff. I'm a back yard mechanic and alot of what I do is trial & error and gather a little info; try to apply it and if it don't work;I look up a professional which may cost a couple of bucks.<br /><br />Check your male connector and see if the metal braid is fanned over the adapter also see that the wire comes to the end of nipple and soldered The adapter should also have 3-4 holes which should also be soldered. The metal braid fanned over the adapter acts as your ground.

 

[Reel Appeal]

Re: Poor VHF radio performance

List price:<br />$49.95 <br />Base price: <br />$44.07 <br /><br /> It's here in Iboats Mega Mall!<br /> <br /> Shakespeare Antenna & Radio Tester <br /><br />Features: Ultra compact meter provides an onboard check of the antenna and VHF radio. Device ... <br />Part # 167-ART2 <br />Available from Boat n RV Warehouse

 

[cpasseno03]

Re: Poor VHF radio performance

Magster, I am sure 15 degrees is no problem. It may make a very slight loss in performance if you are trying to converse with some people 25 miles away, but 100'...heck no. The only suggestion I can come up with is checking connections, I have had the male prong on those PL-259 antenna connectors get corroded a tad, only faded looking. That caused similar problems. Did they hear you a little, or even the click from your transmission, or just absolute silence? Could be you actually arent transmitting, another easy check is the microphone plug...<br />Craig

 

[magster65]

Re: Poor VHF radio performance

Okee dokee, I'll check out the easy stuff first... I got kinda' lazy on the diagnosis on this... Thanks

 

[TbaileyJr]

Re: Poor VHF radio performance

magster y0u need to find someone with a watt meter . It goes between the radio and the ant.two radio repair shop or marine radio repair shop. it will tell you if it's the ant or the radio.you don't want to by one.your ant rod could just need tunning.it has to be set to the right band frequency.

 

[Boatist]

Re: Poor VHF radio performance

Master<br />Really need a lot more info to be able to help you much. First what type antenna do you have. I have never herd of a 5 foot antenna. In the USA standards antenna are all 1/2 wave so do not need to be tuned like a 1/4 wave CB antenna. Sailboats usually use a 3DB masthead antenna 3 foot tall. Trailer boats use a 6DB 8 foot antenna. Large boats use a 8DB or 9db antenna 14 to 23 feet high. Your antenna will be affected if not straight up, the 6, 8, 9 db very directional and if leaning back will be transmiting into the air or into the water. However this is not the problem at 100 feet. At that distance if you were useing 25 watts then you may not have a problem at all, may have just been overloading their receiver.<br /><br />If you buy a Standing Wave Bridge to check your standing wave ratio (SWR) and a 50 ohm load you can isolate problem to radio or antenna. Make sure Standing wave bridge will support VHF, many CB SWR meters will not work at VHF frequency.<br /><br />Most common troubles.<br />Poor power connections to your radio either at the radio or at the battery. Poor antenna connection or bad pl259 connector. Broken mike cable or bad mike connection. Water in the coax. Broken wire inside antenna especialy on the 8 foot 6 db flexible fiberglass antennas. Radio itself could hav a problem.

 

[magster65]

Re: Poor VHF radio performance

I was guessing at the 5'. I'll have a closer look at these things next time I get a chance.

 

[mattttt25]

Re: Poor VHF radio performance

magster- sorry i didn't say this before, but i had the same problem- could hear fine, but not transmit worth a damn. i checked everything, but still no good. just replaced the radio and everything is fine. you just might have a bad radio like me.

 

[Fly Rod]

Re: Poor VHF radio performance

While we are on this radio subject I'd like to stress that those of us that need a bridge to open that is monitored on channel #13 bridge to bridge. It is unbelivable how many people ask what channel is the bridge on.<br /><br />Safe and good boating to all!!!

 

[magster65]

Re: Poor VHF radio performance

OK thanks guys. I'll try the following:<br /><br />1 - Check and clean all connections (even though they look like new still)<br />2 - I'll test my mike with another boat at the marina<br />3 - If it's still not working I'll try and borrow the watt meter<br />4 - Failing that I'll buy a new one<br /><br />What the heck <br />B-O-A-T

 

[BillDawg]

Re: Poor VHF radio performance

Hi, This is my first post on iboats although I've been reading them for a few months now. Regarding the radio - if your friend can't hear you 100 feet away, you probably are not transmitting. The antenna angle you spoke about won't have any effect at that range. Maybe I can help you troubleshoot the problem with minimal effort. You seem to think it might be the mic. Le't see, you can receive fine but no detectable transmission. Here's what we want to find out - Is it transmitting RF with no audio or no RF at all? A couple questions you can answer - did the radio ever work? Have you ever transmitted without an antenna? When you transmit on high power(25 watts) watch the ammeter on the boat. Does it move at all?(Toward the negative) This might be easier to detect with the engine off. If it does, you might have RF with no audio and it might be your mic. If no movement on the meter you might not have RF out and then it might be cheaper to get a new radio unless you have a high end radio then you can probably get it repaired because it might just be the final output transistors.(you might have tried to transmit without an antenna and blown the transistors.) whew. thus ends my first long winded post.

 

[Bob in Calif.]

Re: Poor VHF radio performance

The marine VHF antenas come with a standard legnth cable that should not be cut. The fiberglass antenna's are an "omnidirectional" antenna that should be in a verticle position, for optimum performance. If you have cut the antenna cable to shorten it, you should get an "SWR" meter and check the standing wave ratio. The ideal reading is 1.0 to 1.0. If you are getting a reading of over 3.0 to 1.0, you are losing your "match". The higher the first number,(such as 3.0, the less efficient you transceiver is functioning). Unlike the cb type radios, where you can adjust the "SWR" by moving the antenna up and down in it's base setting, the standard marine antennas are fixed, again thru the height of the antenna and the legnth of the cable. <br />You can buy an adjustable antenna for marine VHF use, but you will pay a lot mnore that $40 or $50 bucks for one.<br />One thing you can use to prevent corosion is dielectric grease, the same stuff you use on your spark plug wires and other electrical connections.<br />One last thing. You should NOT transmit on your radio without the antenna being connected. This can be fatal for some circuts in your radio.<br />Some handheld VHF radiso can be used with a fixed mount marine antenna. You will beable to hear much better and your transmission distance will improve. Buttttt....youi are putting out fewer watts on your hand held as compaired to your normal transceiver, which should have the select switch to transmitt putting out 1 watt for close or local use or normal output of 25 watts for distance. Your reception will be the same whether using the 1 or 25 watt mode. One last note. If your "SWR" is even 10.0 to 1.0, you will still be able to hear in a normal fashion, but your transmission distance will be poor.<br /> ...Bob in Calif...

 

[Boatist]

Re: Poor VHF radio performance

Bob in Calif<br />VHF Marine antennas are all 1/2 wave 50 ohm inpedence so cable length makes no difference. Still could have shorted connector or broken wire in antenna. VHF SWR meter and a 50 ohm load resistor is all that is needed to isolate to radio or antenna system. Most VHF radios today with SWR over about 3 to 1 will go into protect mode and shut down the transmitter.<br /><br />I am starting to think could be radio as he states ON SOME CHANNELS.

 

[Capn Mike]

Re: Poor VHF radio performance

I suspect the radio may be the culprit as well, although it never hurts to check the ground. I notice, in general, aluminum boats seem to have much better reception than fiberglass boats do. When he built his boat, a friend of mine glassed in a large steel plate in his bilge, and grounds everything to it. Gets better reception than I do, with the same equipment.

 

[Reel Appeal]

Re: Poor VHF radio performance

http://www.aosc.org/vhfmar.html <br /><br />After re-reading magsters original post he said he cannot be heard on some channels instead of all.There are many VHF channels that are not available for use to the general public.Here's a link for the list.

 

[magster65]

Re: Poor VHF radio performance

Thank you. My radio seems to work now.(?) Although I couldn't get it to do the same problem I suspect the mic. wire(s) has a bad connection, it's one of these jobs where the cable is permanently attached.