I bought the boat last season; it's a 1987. Had problems with the VHF all season. Usually can receive, but when try to transmit, no one can hear me. I can hear my transmissions on my handheld VHF, but no one else seems to. Sent the radio (VXL7500) back to Apelco & they said it checked out fine. Now I'm troubleshooting the antenna & its connections. Does anyone know if there is a connection at the base of the mast on the 28.5, or is it one piece of coax from the top of the mast to the bottom of the compression post?
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Same problem on a 25
I'm sorry, I don't know how the antenna cable runs on a 28.5, but a couple of seasons ago, I had the same problem on my 25 and it turned out to be a loose connection at the antenna through-deck fitting. Cleaned, re-attached and suddenly people would respond to my calls. Cruised for 2 weeks cursing the state dock harbor-masters for ignoring my calls. Now I check that connection regularly. Good luck John
I'm sorry, I don't know how the antenna cable runs on a 28.5, but a couple of seasons ago, I had the same problem on my 25 and it turned out to be a loose connection at the antenna through-deck fitting. Cleaned, re-attached and suddenly people would respond to my calls. Cruised for 2 weeks cursing the state dock harbor-masters for ignoring my calls. Now I check that connection regularly. Good luck John
VHF
There is a connector at the base of the mast but the only way to get to it is to step the mast. It sounds like you have a bad connection or bad RF cable somewhere so you are doing the right thing by tracing it. It is possible for the transmitter module to go bad in your VHF, but since your handheld picks it up and you had the unit checked out, I would sooner think that the cable and/or connectors are bad.
There is a connector at the base of the mast but the only way to get to it is to step the mast. It sounds like you have a bad connection or bad RF cable somewhere so you are doing the right thing by tracing it. It is possible for the transmitter module to go bad in your VHF, but since your handheld picks it up and you had the unit checked out, I would sooner think that the cable and/or connectors are bad.
First thing to try...
Try your VHF on another boat that's having no trouble with his VHF. If yours doesn't work there either, the problem is in your radio or mike. But if it does, the odds are 99% that the RJ (something or other) jack on your antenna coax cable has corroded and needs replacing. If so, just cut the old one off and solder a new one...be sure you solder ALL the wires completely. RJ whatsit connections typically only last 2-3 years...so it's really just another routine little aggrevation.
Try your VHF on another boat that's having no trouble with his VHF. If yours doesn't work there either, the problem is in your radio or mike. But if it does, the odds are 99% that the RJ (something or other) jack on your antenna coax cable has corroded and needs replacing. If so, just cut the old one off and solder a new one...be sure you solder ALL the wires completely. RJ whatsit connections typically only last 2-3 years...so it's really just another routine little aggrevation.
PL-259 Connector
Most of the antennas have what is called a UHF fitting. The connector that is on the coax is normally a PL-259. If your coax is the smaller RG-58 cable, there is an adaptor nut on the back-side of the connector. When the connector is attached to the coax, the shield (or braid) is combed out back over the adaptor when screwed in. The center conductor of the coax is then soldered to the connector. Ideally, the shield is soldered to the body of the connector through 4 small holes. This takes a good amount of heat, and of course the proper solder (rosin core). Quite often, installers do not solder the shield, letting the mechanical connection of the adaptor make the necessary ground connection. Over time, the nut may work lose, or oxidation may occur at the shield/connector junction, causing loss of a good ground. Without a good ground at the coax, the radio will receive with little problem. It won't want to transmit however, and the radio will probably cut back on output power because of high VSWR. Try Peggie's idea first. If the radio is OK, go up the mast and remove the coax connector from the antenna. Try holding the coax with one hand while twisting the body of the connector with the other. If the connector twists on the cable, it needs to be removed and replaced. Take a look at the center pin on the connector. It should be a good looking solder joint within the pin. If not, heat with a large soldering iron or small gun and re-solder. You may also have to do this exersize at the base of your mast, since you should also have a connector there somewhere. Try your local Radio Shack for parts and instructions on doing this job. Good luck. Ken Palmer, S/V Liberty
Most of the antennas have what is called a UHF fitting. The connector that is on the coax is normally a PL-259. If your coax is the smaller RG-58 cable, there is an adaptor nut on the back-side of the connector. When the connector is attached to the coax, the shield (or braid) is combed out back over the adaptor when screwed in. The center conductor of the coax is then soldered to the connector. Ideally, the shield is soldered to the body of the connector through 4 small holes. This takes a good amount of heat, and of course the proper solder (rosin core). Quite often, installers do not solder the shield, letting the mechanical connection of the adaptor make the necessary ground connection. Over time, the nut may work lose, or oxidation may occur at the shield/connector junction, causing loss of a good ground. Without a good ground at the coax, the radio will receive with little problem. It won't want to transmit however, and the radio will probably cut back on output power because of high VSWR. Try Peggie's idea first. If the radio is OK, go up the mast and remove the coax connector from the antenna. Try holding the coax with one hand while twisting the body of the connector with the other. If the connector twists on the cable, it needs to be removed and replaced. Take a look at the center pin on the connector. It should be a good looking solder joint within the pin. If not, heat with a large soldering iron or small gun and re-solder. You may also have to do this exersize at the base of your mast, since you should also have a connector there somewhere. Try your local Radio Shack for parts and instructions on doing this job. Good luck. Ken Palmer, S/V Liberty
Thanks everybody
Stephen solved the biggest mystery by confirming that there is a connector at the base of the mast which means on this boat unstepping to gain access. The other points about the reliability of the connectors are good, too. I think I'll replace them all. BTW, Ken, what is a VSWR?
Stephen solved the biggest mystery by confirming that there is a connector at the base of the mast which means on this boat unstepping to gain access. The other points about the reliability of the connectors are good, too. I think I'll replace them all. BTW, Ken, what is a VSWR?
VSWR explained (I hope)
Simply speaking, the "SWR" part stands for "Standing-Wave Ratio". This is the ratio between forward and reflected power. If a transmission line is not matched (SWR>1:1), the difference between the forward and reflected powers measured at any point on the line is the net power going toward the load (antenna)from that point. Line loss increases when SWR is greater than 1:1. I could go into a bunch of technical jargon here, but I won't. Thank you very much! The bottom line is that if the transmitter doesn't see a 50 ohm load at the end of the 50 ohm coax, not all of the power is radiated out of the antenna. Reflected power is dissipated in the form of heat on the transmission line. You may have 25 watts coming out of your radio, and only a few watts actually being radiated from the antenna, thus, low range, especially in VHF. This is probably more than you ever wanted to know, but you asked.... Ken Palmer, S/V Liberty
Simply speaking, the "SWR" part stands for "Standing-Wave Ratio". This is the ratio between forward and reflected power. If a transmission line is not matched (SWR>1:1), the difference between the forward and reflected powers measured at any point on the line is the net power going toward the load (antenna)from that point. Line loss increases when SWR is greater than 1:1. I could go into a bunch of technical jargon here, but I won't. Thank you very much! The bottom line is that if the transmitter doesn't see a 50 ohm load at the end of the 50 ohm coax, not all of the power is radiated out of the antenna. Reflected power is dissipated in the form of heat on the transmission line. You may have 25 watts coming out of your radio, and only a few watts actually being radiated from the antenna, thus, low range, especially in VHF. This is probably more than you ever wanted to know, but you asked.... Ken Palmer, S/V Liberty
SWR Meter
If you go to the electronics store and somehow decide to buy an SWR meter, please realize that the CB SWR meter may work differently on marine band VHF. A friend of mine who is knowledgeable with electronics said CB meters were not compatible with marine band VHFs and will give incorrect readings. This is sort of a "heads-up" comment. Sounds like Mr Palmer would probably know if this is true (??).
If you go to the electronics store and somehow decide to buy an SWR meter, please realize that the CB SWR meter may work differently on marine band VHF. A friend of mine who is knowledgeable with electronics said CB meters were not compatible with marine band VHFs and will give incorrect readings. This is sort of a "heads-up" comment. Sounds like Mr Palmer would probably know if this is true (??).
Thanks Ken & John...
for all the info on SWR. West Marine has an Antenna/Radio Tester for $39.99. I assume this will work and can verify that somewhere along the antenna coax I have a bad connection. I've always heard that you shouldn't try to transmit without an antenna, and I think you've explained why. One last bit of curiosity. Another aspect of this is that I can't hear the local weather on my ship's VHF (WX2) but I can on my handheld. When I've mentioned this to other boaters, they claim to have had similar experiences. I would think that a VHF (which is line of sight, right?) radio with a 45' antenna should ALWAYS get better reception than a hand held VHF. Am I right, or are there other mysterious factors?
for all the info on SWR. West Marine has an Antenna/Radio Tester for $39.99. I assume this will work and can verify that somewhere along the antenna coax I have a bad connection. I've always heard that you shouldn't try to transmit without an antenna, and I think you've explained why. One last bit of curiosity. Another aspect of this is that I can't hear the local weather on my ship's VHF (WX2) but I can on my handheld. When I've mentioned this to other boaters, they claim to have had similar experiences. I would think that a VHF (which is line of sight, right?) radio with a 45' antenna should ALWAYS get better reception than a hand held VHF. Am I right, or are there other mysterious factors?
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