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Antennae too long

2K views 38 replies 25 participants last post by  sandiegobrass 
#1 ·
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Anyone ever cut about 2 inchec of the radio and CB antennae on there bike? Does it affect reception?
 
#2 ·
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If you cut off a CB antenna it affects the SWR (standing wave ratio) it could help it or hurt it but you would have to have an SWR meter to know if it changed it for good or bad. If it makes the SWR too high it can damage the radio.
 
#3 ·
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I alwayt thought that if ant.was not right it would effect standing wave.how would it hurt radio.just would not recive as good or get out as good.should not hurt radio unless there is a short.have done it to a lot of mobile radios did not hurt them.have even forgot to hook up ant.and tryed to talk did not hurt radios..
 
#6 ·
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Does the CB antennae fold down, because the radio one does. Why not just fold them down, before driving in? I fold mine every night when I cover it.
 
#7 ·
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mikef wrote:
Does the CB antennae fold down, because the radio one does. Why not just fold them down, before driving in? I fold mine every night when I cover it.
That's what I was wondering as the antennas on my brothers 1500 both fold down.
 
#12 ·
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You might think I am kidding , but I am not, I had that problem once, so I cut little channels in the garage door!!:cool::cool::cool: Kit
 
#13 ·
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krazy al wrote:
I alwayt thought that if ant.was not right it would effect standing wave.how would it hurt radio.just would not recive as good or get out as good.should not hurt radio unless there is a short.have done it to a lot of mobile radios did not hurt them.have even forgot to hook up ant.and tryed to talk did not hurt radios..
If you didn't hurt the radio without an antenna, you didn't transmit long enough. The way they work is that, when transmitting, the radio output transistors share the load with the antenna. The theoretical maximum power you can get is 50% through the output and 50% out the antenna if the SWR is perfect. In reality, it never gets that good. You will get above 50% power through the output and below 50% out the antenna. The worse the SWR gets, the more power that is sunk by the outputs. With no antenna, 100% of the power goes through the output transitor. Another word for power is heat (measured in watts), meaning lots of heat in the output transitors if no antenna is hooked up.

Anyway, the short story is, if you don't have an antenna hooked up, don't key the mike.
 
#14 ·
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kittyrat wrote:
What it doe's is cause high resistance, for the lack of a better word, and will eventually burn the finals out of the radio.
Not quite, what happens is a high VSWR. A standing wave can be measured point by point along a transmissin line. What you will see is points on the line that have higher voltage than other points. When the antenna matches impedance with the transmission line and the output impedance of the transmitter the VSWR is 1:1 or a flat line meaning that the voltage is the same all along the line. With poor match to the antenna the VSWR goes high at points on the line. If one of those points happens to be the transmitter output transistors they can be destroyed. To protect the transmitter and to get the most power from the transmitter to radiate from the antenna and not merely reflect back into the transmitter it's important to obtain a reasonable match. Your antenna has a center loading coil which electrically lengthens your CB antenna for a decent match to the cable and transmitte. Shorten the antenna and the VSWR will rise. That isn't beneficial. Don't cut it.
 
#15 ·
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Kit Carson wrote:
You might think I am kidding , but I am not, I had that problem once, so I cut little channels in the garage door!!:cool::cool::cool: Kit
The things we do for these bikes.....................:blushing:
 
#17 ·
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And the reason the high voltage reflected back to the final transistor damages them, is because that reflected voltage is higher than the reverse junction breakdown voltage. (This is called the Zener Effect)

once it arcs over through that junction, Game Over.

The punctured transistors short the collector pins to the emitter pins.

No recalls, no new footballs, it is Dead Duck and you get to pay to have the transmitter fixed.
 
#19 ·
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If that dosen't work let the air out of your tires.. That should be good for about 2 inches.........
 
#21 ·
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AZgl1500 wrote:
And the reason the high voltage reflected back to the final transistor damages them, is because that reflected voltage is higher than the reverse junction breakdown voltage. (This is called the Zener Effect)

once it arcs over through that junction, Game Over.

The punctured transistors short the collector pins to the emitter pins.

No recalls, no new footballs, it is Dead Duck and you get to pay to have the transmitter fixed.
Bravo, I concur completely! Luckily most modern transmitters are protected against the "key down with no antenna" syndrome but I don't think the older Honda CBs are. It's kind of expensive to find out empirically.:shock:
 
#22 ·
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Adjust your garage door opener, some are on the back or on top flat screw. you will need step ladder, look on both sides & on the back. Just look forwhite plastic screws, turn in the direction say UP. Or a metal screw that has metal spring behind it, turn it clockwise, that that for up position. ( 1/2 turn on the screw is about 1 inch travel on the door)

If your do not have garage door opener, Rise the door to up position then reset the springs. ( tighten up the wire to spring to tight. I hope this helps. Lee


PS most door height are 7-8 ft high, my GL1500 used to hit the bottom of the door when open, till adjust the opener. My door opening is 7 ft. high.
 
#23 ·
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My shop door is 16ft tall. That means I need extensions on my antennas so I will have to fold them down.:shock::cooldevil::cooldevil::cooldevil::cooldevil::cooldevil:
 
#24 ·
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mikef wrote:
Kit Carson wrote:
You might think I am kidding , but I am not, I had that problem once, so I cut little channels in the garage door!!:cool::cool::cool: Kit
The things we do for these bikes.....................:blushing:
Well I do have a constructive suggestion. It is very aggravating to have to get off the bike, fold the stupid things down, then they are in the way when you do that, open the garage door, go in, go out, fold them back up, yep that is a bit much.

But down har in the South, you see all these CB guys with the camo wheel fenders with a tennis ball on their 22 foot antenna with the antenna all tied down to the bumper in an arc.

Could you not just use a small diameter rope, tie it to the antenna, and take a rubber band and put it under the knot first (wrap it tight) to keep the knot from slipping down, gently arc them and tie them off to something. Would work fine and not hurt anything.

You would not have to tell your wife that termites ate the garage door. :DKit
 
#26 ·
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That's what I used to do when visiting my daughter and putting my bike in here garage, just let them hit and fold them down once inside. They never hit that hard and the bend wasn't severe.
 
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