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Predator 10k

C

chec0

Member
Feb 18, 2007
46
0
16
Massachusetts
Hello all you wonderful guru's of the CB world
i just got my 10k yesterday and it has a 17'' shaft i got it mounted at the top of my back rack on my pickup (can post pics if you want) im having problems matching it out the best i got was a 1.5 across all 40 it was with a different stinger that i didnt care about cause i cut a damn foot and a half out of it but than i went to cut more and now the match is way above 3, so my question to you is should I ground out my back rack from the antenna bracket??? Or should I move the whole antenna dow the rack seeing as how it has a 17'' shaft and just keep the coil above my roof or would the shaft be too close to the rack???
 

ok , I see you have a 10K with problems on your end , Go to the 10K section and read some threads or put your own question in there , you can even write the guy at 10K , he is very helpful. Sometimes taking the time to read up , you can find answers to your questions , but hey ! I totally understand , we usually want are stuff to work yesterday. :p Good luck to you
 
im no guru....im just a parrot... ^5 SK ;)
a 27 or 22 inch shaft is usually recomended for mounting the 10k behind the cab of a pickup to keep the bottom of the coil above the roof of the cab . is the bottom of your coil above the roof of the cab ? you had a 1.5 on all channels and kept cutting suggest you simply cut too much off . did you cut it more than 1 inch at a time ? they're is a few inches of play in the seating of the stinger to pull it back out some if it is a lil too short and then secureing it with the set screw . 1.5 swr is acceptable if your not running a amp .

if your coil is above the roof get a new stinger and be a lil more careful when cutting/tuning it . wilsons will fit it and theyre available at any cb store .
 
To go one step further, there's nothing wrong with an SWR of 1.5:1, there's no practical difference between that and a 1:1. You'll never see a 1:1 on anything except by blind luck, then it'll change the first time a leaf wiggles.
Sounds like you sort of 'pushed' your luck a little too far when cutting that stinger. Lots more common than people would have you think. ;)
- 'Doc
 
1.5 is a great match.I never get better than that with a mobile.You can spend alot time chasing down the perfect match and it will not make a difference.
 
W5LZ said:
To go one step further, there's nothing wrong with an SWR of 1.5:1, there's no practical difference between that and a 1:1. You'll never see a 1:1 on anything except by blind luck, then it'll change the first time a leaf wiggles.
Sounds like you sort of 'pushed' your luck a little too far when cutting that stinger. Lots more common than people would have you think. ;)
- 'Doc
Click to expand...

just to comment IN SMALL STEPS there is a difference in 1.5 or 1.1
just to clear that up IN SMALL STEPS 95% is a difference from 100%..:p
 
Assuming a 5% increase in efficiency;
At 5 watts that would mean .25 watt.
At 10 watts it would mean .5 watt.
At 100 watts it would mean 5 watts.
At 1000 watts it would mean 50 watts.
Hmm... So from 4.75 to 5 watts, or 9.5 to 10 watts, or 95 to 100 watts, or 950 to 1000 watts. I couldn't hear a difference, much less see a difference in meter readings at that kind'a 'gain'. Sort of doubt if anyone else could either. So why worry about it? A 100% efficiency is a great idea! It's also not ever going to be something obtainable. Sort of like those gas millage figures you see on new car stickers. Certainly possible under very strict and controlled conditions, but not in ordinary, everyday circumstances with 'normal' people driving. You know?
- 'Doc
 
Just wondering...You said you had a swr of 1.5...Is that on channel 1 and 40? And what are you using for a swr meter?

The 17" shaft single coil 10K should tune lower than 1.5, as long as the antenna is "above" the roof line. (whole antenna, not just the coil)
 
It is my understanding that the quest for 1.1 or a 1.2 match by some is because of the mega watts the some run.

The relect watts for 3k to 5k watts may fry their finals. Right?

So my question is how many relect watts does it take to fry the finals of a transistor linear?
 
Here's another way of thinking about it.

Thinking of it in terms of watts is misleading, and not very informative. Think in terms of what makes up one of those reflected watts, voltage and current. Also think of the output of the transistor/tube in terms of voltage and current. An impedance mismatch, what causes SWR, can make the voltage and current at any particular point on the feed line change. That change can be in both directions, more, or less, than was put into the feed line by the amplifying device. So, there is a varying voltage on the feed line. That varying voltage affects everything that it touches/passes through. At some voltage level, something in the antenna system can break down because it can't handle the particular voltage at whatever point it happens to be. (As the SWR gets greater, so does the voltage.) Then theres sort of a cascading sequence of events, "I don't have to take that!" sort of thing, and eventually the 'faults' from too high a voltage get to the point where the amplifying device is affected, so it quits too (pop goes the transistor/tube). One example (not a very good one though) is the coax breaking down, shorting just like it was 'pinned'. The first reaction is that the coax wasn't any good. But that's not really true. Sure, it's ratings were exceeded, but why? That 'why' is the real answer. In this hypothetical example, the 'why' is because of SWR or an improper impedance mismatch. If the output is very high then the possible range of that variation in voltage gets very high too. It's possible for things to 'pop' quicker, sort of. In this instance, antenna system doesn't mean just the antenna and feed line, but everything that's affected by, or is fed by, the output from the amplifying device (final in the radio or amplifier, doesn't matter which). So if a part, a capacitor for instance, connected to the final device is presented with a voltage it wasn't made to handle, 'pop'. If that particular part is in the right/wrong place in the circuit, the transistor/tube goes 'pop' too.
So what wattage will kill a particular transistor/tube? Hmm... that depends, doesn't it? So I don't think there is a 'standard' wattage level for killing transistors. Too many other variables in that equation! (Dam, just like politics, ain't it? 'Nuthin simple anymore...)
- 'Doc
 
.... should have put this in the one above, just forgot/didn't think of it soon enough.

A good question to ask when trouble-shooting is, did the transistor take-out the other parts, or did the 'other' parts take out the transistor? And why? Can make a BIG difference...
- 'Doc
 

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