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bought a new setup
- Thread starter brad218
- Start date
If you were to tune them you would simply disconnect one of the coaxes from it's antenna then connect a 50 ohm dummyload to that coax and tune the other antenna in place the repeat the operation to the second antenna but if you have a 1.2:1 match already with a known quality meter then you're good to go but now you have the info on tuning co-phased mobile antennas/
Yeah but we all went through this phase and it's a good feeling when things you pay good money for work as it should.
brad,
do you know how to calibrate and properly use that SWR meter?
im not being condescending; there are lots of misconceptions out there.
either way, if you want to run co-phased antennas, you need to invest in a dummy load. check mack's post above for how to tune co-phased antennas.
also, did you know that co-phased antennas need to be between 8-9 feet apart for them to work properly?
just be aware that you are not getting the "benefit" that co-phased antennas offer if they are closer to eachother than that.
LC
do you know how to calibrate and properly use that SWR meter?
im not being condescending; there are lots of misconceptions out there.
either way, if you want to run co-phased antennas, you need to invest in a dummy load. check mack's post above for how to tune co-phased antennas.
also, did you know that co-phased antennas need to be between 8-9 feet apart for them to work properly?
just be aware that you are not getting the "benefit" that co-phased antennas offer if they are closer to eachother than that.
LC
Well.........
First of all, unless the antennas are 9 ft apart - you won't have any benefits but you will have all the headaches of trying to make it work on your vehicle.
I would save yourself a lot of frustrastion, grief, and money and just use one antenna and a single piece of 50 ohm coax. Either that - or take it to a CB shop and have them sort it all out for you. Chances are - that if the antennas aren't 9 ft apart - the guys at the CB shop will tell you pretty much the same thing I just did. Personally, I would just run one really decent antenna with a mag mount on the center of your roof. That is what I have, and I have seen zero problems with it. My SWR is 1.1 to 1.2 accross the band. Cophase antenna setups were meant to be used primarily with a diesel tractor - not on a mom 'n dad grocery getter ('regular autos').
To explain what needs to be done to check out the antenna system you've got and to try to make it work isn't impossible. It kinda ranks with explaining how to do a jigsaw puzzle.
First of all, unless the antennas are 9 ft apart - you won't have any benefits but you will have all the headaches of trying to make it work on your vehicle.
I would save yourself a lot of frustrastion, grief, and money and just use one antenna and a single piece of 50 ohm coax. Either that - or take it to a CB shop and have them sort it all out for you. Chances are - that if the antennas aren't 9 ft apart - the guys at the CB shop will tell you pretty much the same thing I just did. Personally, I would just run one really decent antenna with a mag mount on the center of your roof. That is what I have, and I have seen zero problems with it. My SWR is 1.1 to 1.2 accross the band. Cophase antenna setups were meant to be used primarily with a diesel tractor - not on a mom 'n dad grocery getter ('regular autos').
To explain what needs to be done to check out the antenna system you've got and to try to make it work isn't impossible. It kinda ranks with explaining how to do a jigsaw puzzle.
Last edited:
B
BOOTY MONSTER
Guest
dont use the radios meter for tuning the antenna . use a seperate meter .
you'll want to mount the antenna so the coil is above the roof of the vehicle for best results . in the center of the roof is best IMO but it can be used on the side or corner with some directional effects that some like and some dont seem to mind .
you'll want to mount the antenna so the coil is above the roof of the vehicle for best results . in the center of the roof is best IMO but it can be used on the side or corner with some directional effects that some like and some dont seem to mind .
yes, a 5 watt dummy load will work fine.
im not a fan of mirror mounting because when it comes to mobile antenna mounting, its all about having as big a piece of metal under the antenna as you can.
the mirror is connected to the door, but the door is not connected to the chassis of the vehicle by anything but the hinges, and im sure you can see how grease and corrosion might make that connection pretty bad.
if you mount that wilson up as high as you can on the side of your toolbox, and the toolbox is bolted to the truck bed, you should be good to go.
yes, it is better to use an external meter to set your SWR on the antenna, but if the one in the radio is all you got, then use it.
here's how:
after you have your antenna mounted where you want it, and have run the coax to your radio, being very careful not to nick the jacket or kink the coax in any way; get in the truck and close both doors. (open doors can make an antenna act funny)
turn the radio on and set it like this:
channel 20
the first knob on the left is the VOL/SQ knob.
the inner knob is your volume control which is pretty self explanatory.
the outer knob is your SQUELCH control. it cuts out the noise in the receiver depending on where its set. the further clockwise you turn it, the more powerful a signal has to be to "break" the squelch and be heard.
just leave the SQ knob all the way counter clockwise for now.
the next knob to the right is the DYNAMIKE control. this sets the gain of the microphone. all the way to the left and no one will hear your voice.
all the way to the right and its at its most sensitive.
just trust me when i say that for normal communications you should just leave it all the way up.
for checking/setting the SWR however, turn it all the way down.
next over you will find the RF GAIN knob.
this is your receive sensitivity control.
just leave it all the way up unless you happen to be having a long conversation with someone who is just slamming the needle in your meter all the way to the right. then you can turn it down a bit to talk to them, and then turn it all the way back up again.
next knob to the right is the DELTA TUNE control.
this is basically a "fine tuning" control, and you will rarely if ever need to use it. just set it to its "center" mark and leave it there.
last is the T BACK/ SWR CAL controls. the inner knob is your TALKBACK control. it will allow you to hear your voice through the speaker when you transmit so you can sort of hear how you sound on the air. the further to the right you turn it, the louder your voice will come through the speaker.
it has no effect on the loudness of your voice as it relates to how others hear you.
and finally we come to the outer knob which is your SWR CALIBRATION control. every time you check your SWR, you should re-calibrate the meter so that the SWR reading is accurate.
look at the first switch on the left, next to the meter.
it is labeled S/RF SWR CAL.
the S/RF position allows you to read the strength of incoming signals (S), and the relative strength of your radio's transmissions. (RF)
the next position is SWR, this position allows you to read your Standing Wave Ratio. the better tuned the antenna is, the lower this ratio will be and the less the needle will move toward the right of the meter when you key the mic. when the needle hardly moves at all, you know you've got it tuned well.
but first, we need to CALibrate the meter.
set this switch to the CAL position and while keying the mic, adjust the SWR CAL knob until the needle moves underneath that triangle on the meter labeled CAL.
now, with the mic still keyed, switch the switch to the SWR position and make a note of the reading.
if the needle moves all the way over to the right in this position after you have calibrated the meter, then you have an antenna mounting problem and need to re check your installation.
now to tune the antenna.
you will see an allan screw at the base of the whip portion of the antenna.
this will allow you to move the whip up or down slightly.
re-calibrate the meter on channel 1, check the SWR, and make a note of the reading.
now go to channel 40, re-calibrate the meter, check the SWR and make a note of the reading.
if the reading on channel 1 is higher, then your antenna is too short and needs to be lengthened.
if the reading on channel 40 is higher, then your antenna is too long and needs to be shortened.
adjust the antenna in 1/4" increments and every time you adjust it, you have to re-calibrate the meter.
you will find a sweet spot where the SWR on channels 1 and 40 is about the same and the SWR on channel 20 will be just a bit lower.
good luck with it and let us know how it goes!
oh, and dont forget to turn your DYNAMIKE control back up when you want to talk to people! LOL
later,
LC
im not a fan of mirror mounting because when it comes to mobile antenna mounting, its all about having as big a piece of metal under the antenna as you can.
the mirror is connected to the door, but the door is not connected to the chassis of the vehicle by anything but the hinges, and im sure you can see how grease and corrosion might make that connection pretty bad.
if you mount that wilson up as high as you can on the side of your toolbox, and the toolbox is bolted to the truck bed, you should be good to go.
yes, it is better to use an external meter to set your SWR on the antenna, but if the one in the radio is all you got, then use it.
here's how:
after you have your antenna mounted where you want it, and have run the coax to your radio, being very careful not to nick the jacket or kink the coax in any way; get in the truck and close both doors. (open doors can make an antenna act funny)
turn the radio on and set it like this:
channel 20
the first knob on the left is the VOL/SQ knob.
the inner knob is your volume control which is pretty self explanatory.
the outer knob is your SQUELCH control. it cuts out the noise in the receiver depending on where its set. the further clockwise you turn it, the more powerful a signal has to be to "break" the squelch and be heard.
just leave the SQ knob all the way counter clockwise for now.
the next knob to the right is the DYNAMIKE control. this sets the gain of the microphone. all the way to the left and no one will hear your voice.
all the way to the right and its at its most sensitive.
just trust me when i say that for normal communications you should just leave it all the way up.
for checking/setting the SWR however, turn it all the way down.
next over you will find the RF GAIN knob.
this is your receive sensitivity control.
just leave it all the way up unless you happen to be having a long conversation with someone who is just slamming the needle in your meter all the way to the right. then you can turn it down a bit to talk to them, and then turn it all the way back up again.
next knob to the right is the DELTA TUNE control.
this is basically a "fine tuning" control, and you will rarely if ever need to use it. just set it to its "center" mark and leave it there.
last is the T BACK/ SWR CAL controls. the inner knob is your TALKBACK control. it will allow you to hear your voice through the speaker when you transmit so you can sort of hear how you sound on the air. the further to the right you turn it, the louder your voice will come through the speaker.
it has no effect on the loudness of your voice as it relates to how others hear you.
and finally we come to the outer knob which is your SWR CALIBRATION control. every time you check your SWR, you should re-calibrate the meter so that the SWR reading is accurate.
look at the first switch on the left, next to the meter.
it is labeled S/RF SWR CAL.
the S/RF position allows you to read the strength of incoming signals (S), and the relative strength of your radio's transmissions. (RF)
the next position is SWR, this position allows you to read your Standing Wave Ratio. the better tuned the antenna is, the lower this ratio will be and the less the needle will move toward the right of the meter when you key the mic. when the needle hardly moves at all, you know you've got it tuned well.
but first, we need to CALibrate the meter.
set this switch to the CAL position and while keying the mic, adjust the SWR CAL knob until the needle moves underneath that triangle on the meter labeled CAL.
now, with the mic still keyed, switch the switch to the SWR position and make a note of the reading.
if the needle moves all the way over to the right in this position after you have calibrated the meter, then you have an antenna mounting problem and need to re check your installation.
now to tune the antenna.
you will see an allan screw at the base of the whip portion of the antenna.
this will allow you to move the whip up or down slightly.
re-calibrate the meter on channel 1, check the SWR, and make a note of the reading.
now go to channel 40, re-calibrate the meter, check the SWR and make a note of the reading.
if the reading on channel 1 is higher, then your antenna is too short and needs to be lengthened.
if the reading on channel 40 is higher, then your antenna is too long and needs to be shortened.
adjust the antenna in 1/4" increments and every time you adjust it, you have to re-calibrate the meter.
you will find a sweet spot where the SWR on channels 1 and 40 is about the same and the SWR on channel 20 will be just a bit lower.
good luck with it and let us know how it goes!
oh, and dont forget to turn your DYNAMIKE control back up when you want to talk to people! LOL
later,
LC
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