Is there a way to check the VHF radio antenna? Everytime I do a radio check, just boats that are close to me respond. Ozana
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SWR Meter
You need a SWR meter. you will be able to troubleshoot the problem with this and a DMM. I assume that you have a digital multimeter to work on the electrical system of your boat. Good Luck! I just had to replace all of the antenna cable, connectors and antenna on mine. old stuff was probably original on a 25 year old boat.
You need a SWR meter. you will be able to troubleshoot the problem with this and a DMM. I assume that you have a digital multimeter to work on the electrical system of your boat. Good Luck! I just had to replace all of the antenna cable, connectors and antenna on mine. old stuff was probably original on a 25 year old boat.
couple of cautions
The std response to these questions is an SWR meter and multimeter. unfortunately, they both can be misleading. For example, if you hook up water-laden coax to a regular light bulb, you'd get the expected results for low SWR and a open feedline conductivity - and nobody outside of 100 yards is going to hear you. Similarly, your antenna could fall off the boat but still test okay depending on the electrical length of the coax connected to the radio. That's not to say either instrument doesn't have some utility - just that they don't necessarily confirm everything is fine. Start with them and if the feedline tests satisfactorily, check the output power of the radio (at the antenna end, not at the radio). Also check for proper voltage under load (when transmitting). It could also be low deviation of the radio (analogous to low volume on an am radio) although you'll not likley have the equipment to test that but it's not expensive to have it done. Usually, by the time you try any/all of these, the problem becomes apparent. Don
The std response to these questions is an SWR meter and multimeter. unfortunately, they both can be misleading. For example, if you hook up water-laden coax to a regular light bulb, you'd get the expected results for low SWR and a open feedline conductivity - and nobody outside of 100 yards is going to hear you. Similarly, your antenna could fall off the boat but still test okay depending on the electrical length of the coax connected to the radio. That's not to say either instrument doesn't have some utility - just that they don't necessarily confirm everything is fine. Start with them and if the feedline tests satisfactorily, check the output power of the radio (at the antenna end, not at the radio). Also check for proper voltage under load (when transmitting). It could also be low deviation of the radio (analogous to low volume on an am radio) although you'll not likley have the equipment to test that but it's not expensive to have it done. Usually, by the time you try any/all of these, the problem becomes apparent. Don
CB SWR meter
The easiest SWR meter to find is one for CB radios. Correct me if I'm wrong, but I was told not to use a CB SWR meter for testing a VHF radio so if this is true, be careful what kind of SWR meter you use.
The easiest SWR meter to find is one for CB radios. Correct me if I'm wrong, but I was told not to use a CB SWR meter for testing a VHF radio so if this is true, be careful what kind of SWR meter you use.
A FIELD Strength Meter!
An SWR just measures the impedance matching of transmitter and antenna. To check your operation for effective power and range in all quadrants you need to use a 'Field Strength Meter'. Don't buy one as you should be able to borrow one from a HAM or at least have a local radio shop check you. Believe me this is the ONLY way you will get an indication of your transmitting range AND its real envelope(no antennas do NOT transmit or receive in perfect symmetry.
An SWR just measures the impedance matching of transmitter and antenna. To check your operation for effective power and range in all quadrants you need to use a 'Field Strength Meter'. Don't buy one as you should be able to borrow one from a HAM or at least have a local radio shop check you. Believe me this is the ONLY way you will get an indication of your transmitting range AND its real envelope(no antennas do NOT transmit or receive in perfect symmetry.
ART-2/3
The Shakespeare #ART-2 (Ellis previously linked) measures radio output wattage and the antenna SWR (standing wave ratio). The new Shakespeare #ART-3 Antenna/Radio Tester tests receiver function as well as output power and VSWR. It is powered by an internal battery or can be connected to ships 12 VDC with the supplied power cable. Battery level can be checked at the flip of a switch. http://www.shakespeare-marine.com/electronics/accessories/switches.htm
The Shakespeare #ART-2 (Ellis previously linked) measures radio output wattage and the antenna SWR (standing wave ratio). The new Shakespeare #ART-3 Antenna/Radio Tester tests receiver function as well as output power and VSWR. It is powered by an internal battery or can be connected to ships 12 VDC with the supplied power cable. Battery level can be checked at the flip of a switch. http://www.shakespeare-marine.com/electronics/accessories/switches.htm
Same question on cell phone?
With spotty cell phone coverage in my area, I bought a Shakespeare remote natenna, 3watt amplifier, and the various connecting cables. Antenna is on the radar tower about 9ft above the water. I still don't have good coverage. Sometimes I get more bars with the cell phone not connectd to the amp and antenna in the cabin than I do with it hooked to the system with an additional 8ft of height. The cell phone amp and antenna cables use BNC or TNC connectors (can't remember which). The SWR meter I have uses PL259/SO239s. Also with a cell phone you can't test its transmission by just listening to a receiver. Is there a way to check my amp/antenna setup? Maybe some type of adaptor from BNC/TNC to PL259?
With spotty cell phone coverage in my area, I bought a Shakespeare remote natenna, 3watt amplifier, and the various connecting cables. Antenna is on the radar tower about 9ft above the water. I still don't have good coverage. Sometimes I get more bars with the cell phone not connectd to the amp and antenna in the cabin than I do with it hooked to the system with an additional 8ft of height. The cell phone amp and antenna cables use BNC or TNC connectors (can't remember which). The SWR meter I have uses PL259/SO239s. Also with a cell phone you can't test its transmission by just listening to a receiver. Is there a way to check my amp/antenna setup? Maybe some type of adaptor from BNC/TNC to PL259?
Peter - cell phone power
Before trying to find adapter cables for the SWR meter, check to make sure your meter is good at 800 MHz - most are not and the readings therefore would be meaningless. It's more than likely that the so-called gain in signal you hoped for by installing an ext antenna and amp are lost in the inherent loss of signal by adding a length of coax and the connections - a 3 dB loss equates to half the power output of the cell phone. High loss RG58 coax with crimp-on connectors are your enemy! Don
Before trying to find adapter cables for the SWR meter, check to make sure your meter is good at 800 MHz - most are not and the readings therefore would be meaningless. It's more than likely that the so-called gain in signal you hoped for by installing an ext antenna and amp are lost in the inherent loss of signal by adding a length of coax and the connections - a 3 dB loss equates to half the power output of the cell phone. High loss RG58 coax with crimp-on connectors are your enemy! Don
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