This is why you're a tool... when someone actually presents you with what you asked for you still squawk what others say. If stupid hurts, you must be in agony.
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Amp coax jumper length
- Thread starter fireman32_14
- Start date
This is why you're a tool... when someone actually presents you with what you asked for you still squawk what others say. If stupid hurts, you must be in agony.
B
BOOTY MONSTER
Guest
where was i wrong ?
please stop calling me names and being offensive to me . you're hurting my itty bitty feelings
please stop calling me names and being offensive to me . you're hurting my itty bitty feelings
where was i wrong ?
please stop calling me names and being offensive to me . you're hurting my itty bitty feelings
where was I wrong - you said I didn't have a leg to stand on, implied I don't know what I'm talking about. Said I was skeered to give you proof. I gave it to you and now you're still crying. The point is, there are two different lines of thought on this subject - and you constantly repeating what others have said doesn't make you right. If you had a valid argument - like Doc does - I'd be less inclined to call you out, but you don't. I've watched you for a long time just spit out whatever freecell told you and it gets tiresome.
Go spend some time and model tranmission lines and see how the length affects the load presented at the input side... When you do you will understand both my position and Doc's. Here's a hint, the overall SWR and impedance don't change but the resistive portion and the reactance phase with the length and present differently along the way.
I get it must be hard for you to ever be wrong - anyone who has watched on this forum for any length of time knows that. Post counts doesn't equal knowledge, you need to spend less time writing and more time reading.
B
BOOTY MONSTER
Guest
you're still wrong .... you post a link to a article about using a certain lenght of coax to help a tuner tune a antenna our of its natural bandwidth to that band and think the same thing applies to a amp with crappy input tuning ?
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"ARRL Guide to Antenna Tuners.
Chapter 7 Transmission Lines
Page 7-4
"There are some interesting special cases with a mismatched line. The load impedance, resistive and complex, repeats evey "half-wave", for example. The impedance goes to the opposite extreme in odd multiples of "quarter-wave". For example our 25 ohm load would get TRANSFORMED to 100 ohms in a quarter-wave or 3/4 wave tranmission line sections and vice versa. This effect can be used to our advantage if we wish to TRANSFORM impedances at a specific frequences.""
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your leg is broken , i agree post count mean squat , and you need to comprehend what you're reading .
Of course the REAL solution is to fix the impedance mismatch on the amp.
But - does the 1/4 wavelength jumper ACT as a transformer/impedance matcher?
But - does the 1/4 wavelength jumper ACT as a transformer/impedance matcher?
Robb, any length of coax cable will act as an impedance transformer when the impedance is different at each end. What the input impedance becomes depends on what the impedance is at the far end, the impedance of the coax cable, as well as the length of the cable. If the coax is 1/4 wave long it will invert the impedance of the load. IOW if the load is 100 ohms then the input of the coax will present 25 ohms IF the coax is 50 ohms. Not knowing the input impedance of the amp it is impossible to say how long the cable must be to make a good match to the radio.With no standards for CB amps, the impedance can change from one unit to another. This is why some lengths work for some people and other lengths work for others. You can use coax to match the input impedance of an amp but the proper way is to have the amp tuned properly.
The transmission line in the example I gave has nothing to do with an antenna tuner and it woudn't matter if it did. Coax is it's own system... how the fock did you get so dense. This shows exactly how little you know about this stuff and why you shouldn't be giving advice to anyone. Read CK's explanation above.
B
BOOTY MONSTER
Guest
"The transmission line in the example I gave has nothing to do with an antenna tuner ......... "
"ARRL Guide to Antenna Tuners."
but im dense ..............
" IOW if the load is 100 ohms then the input of the coax will present 25 ohms IF the coax is 50 ohms."
CK , so using a 1/4 wave length of coax ( physical length or electrical length ?) 50 ohm coax the amp would need a 200 ohm input to the amp to to show 50 ohms to the radio ?
"ARRL Guide to Antenna Tuners."
but im dense ..............
" IOW if the load is 100 ohms then the input of the coax will present 25 ohms IF the coax is 50 ohms."
CK , so using a 1/4 wave length of coax ( physical length or electrical length ?) 50 ohm coax the amp would need a 200 ohm input to the amp to to show 50 ohms to the radio ?
im not the one cussing and calling people names .......
I'm not an expert in antennas or transmission lines, but I do know that specific lengths of coax are often used for impedance matching instead of the standard binocular transformers in many VHF and UHF amplifiers, so Captain Kilowatt's explanation is making sense to me. Doc was saying something similar as well..
Booty isn't learning... he's just arguing for God only know's why. He asked for an example, I gave it to him but he's still moaning like he just had his cherry picked. Why do you all put up with him?
Booty if I'm wrong then please show me some transmission line theory that proves it. Not what you're friends have told you but some honest to God research that shows I'm wrong. You wanted a sample, I gave it to you, you insist on taking it out of context so please by all means, show me something of substance that proves your theory... let's compare notes.
B
BOOTY MONSTER
Guest
please stop flaming me and calling me names , it hurts my feelings and contributes absolutely nothing positive to this thread
.please stop flaming me and calling me names , it hurts my feelings and contributes absolutely nothing positive to this thread
what positivity are contributing? please show me the information you have that supports your thoery.
Because he asks questions like other newbies do, please have a little patience, we all run it to people that are....how do I say it....a little slower to learn than others.
He can be a pain in the ass at times, but we put up with it. ( he really is not that bad,,,just difficult at times)
Sometimes we have to draw pictures, but after a while he learns and so do others who are too afraid to ask what some may consider Dumb questions.
Captain posted true Dat.
There are a lot of crappy CB style amp`s out there that have shit for input tuning, many guys do not understand that but that do understand that using a different length jumper solves the problem....it is good that those of us that understand WHY try to help those that do not understand WHY to help increase there knowledge of what is going on..... The proper thing is to FIX the input tuning, but some guys do not get what is going on.......
I do understand it is frustrating at times.
There are almost infinite matching conditions with different lengths of coax, many things affect this, velocity factor input impedance, length of coax, frequency being used, load impedance etc, as a simple rule, most CB guys just say use a XXX length jumper and it will be OK.
73
Jeff
He can be a pain in the ass at times, but we put up with it. ( he really is not that bad,,,just difficult at times)
Sometimes we have to draw pictures, but after a while he learns and so do others who are too afraid to ask what some may consider Dumb questions.
Captain posted true Dat.
There are a lot of crappy CB style amp`s out there that have shit for input tuning, many guys do not understand that but that do understand that using a different length jumper solves the problem....it is good that those of us that understand WHY try to help those that do not understand WHY to help increase there knowledge of what is going on..... The proper thing is to FIX the input tuning, but some guys do not get what is going on.......
I do understand it is frustrating at times.
There are almost infinite matching conditions with different lengths of coax, many things affect this, velocity factor input impedance, length of coax, frequency being used, load impedance etc, as a simple rule, most CB guys just say use a XXX length jumper and it will be OK.
73
Jeff
- No one is chatting at the moment.