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Frank Gilliland wrote:
On Mon, 1 Aug 2005 14:46:55 -0700, "John Smith" wrote in : Frank: FOOL!!! His original post makes ALL of that clear, if not, one or two of his other posts after will fill you in... Well, let's find out just what he said, shall we? ===== On Sat, 30 Jul 2005 11:45:50 -0500, driver42 wrote in : Hi, If I'm not able to set the SWR in the trucks that I drive will it hurt the radio or just give me decreased range? ===== I don't see anything about a 5:1 SWR. I don't see anything about being "forced" to use a matching device. Now is a good time to dispell more CB mythology: Many of you already know that in order to double your range you need -four- times the power. But it also works the other way -- if you reduce your power to one fourth (i.e, you are losing 3/4 of your power, which would mean a pretty high SWR) you have -only- decreased your range by one half. So an SWR of 2:1 or 3:1 (or, conversely, squeezing a couple extra watts with a tweak-n-peak) isn't going to have a noticable effect on your range. Let's continue with the scenario that you are losing 3 watts (3/4 of your power) due purely to reflection. Ok, so that power gets dumped back into the final where it's dissipated as heat. That's three extra watts in a transistor conservatively rated to handle a certain amount of -continuous- heat dissipation, which is usually something along the lines of 4 watts. Mind you that 3 or 4 watts isn't a whole lot of power; if the heat sink can handle 4 watts without a problem then an extra 3 watts isn't exactly going to melt the knobs. Regardless, the final -isn't- dissipating this heat continuously (unless the OP is one of those asshole broadcast types that keys down for half an hour), so normal operation certainly isn't going to "cook" the transistor. And I already mentioned that these transistors are rated to handle 30:1 SWR -continuously- without damage. If you want proof of these FACTS then feel free to refer to the data sheets for the final transistors most commonly used in CB finals. ===== On Sat, 30 Jul 2005 13:27:48 -0500, driver42 wrote in : My problem is that I'll be moving from truck to truck so I wont have time to set the SWR correctly. Most of our trucks have factory installed double antenna's which I'm not too thrilled about. ===== I don't see anything about a 5:1 SWR. I don't see anything about being "forced" to use a matching device. Looks to me like he said the trucks already have antennas installed. Assuming they are CB antennas, it's more than likely that the antennas have already been trimmed for use with a 50-ohm radio (since all CB radios are 50-ohm radios). Unless something is broke, the antennas are probably going to give a reasonably good match to -whatever- radio he picks (because, once again, all CB radios are 50-ohm radios). ===== On Sat, 30 Jul 2005 21:33:43 -0500, driver42 wrote in : My problem is that I'll be in a different truck everyday and wont be able to set the SWR the way I want to. ===== I don't see anything about a 5:1 SWR. I don't see anything about being "forced" to use a matching device. What I -do- see is concern about setting the SWR, which is another mythconception (and not just with CBers but with a lot of hams). A 1:1 SWR does -NOT- mean the antenna is operating at it's best efficiency. It -DOES- mean that the load is 50 ohms nonreactive. But a 50 ohm nonreactive load can be darn near anything: a carbon resistor, a dummy load, a bad coax working as a tuned stub, or even a corroded 9' whip with a mount caked in mud (seen both scenarios firsthand). As I stated before, an SWR meter is a go/no-go meter. If it normally reads 2:1 then suddenly jumps to 6:1, that's a good indication that something has gone wrong with the antenna or coax. And -THAT'S- what an SWR meter is good for..... a "something's wrong" meter (IMO, they should probably be replaced with idiot lights like those in a car.) If you want to tune your antenna for best efficiency you -NEED- to use a field strenght meter. Period. Now........ once again........ 1) Where did the original poster say he was being "forced" to use any type of matching device? 2) Where did the original poster say his SWR was 5:1? 3) Since very few CBers use a matchbox, why don't the millions of other CB radios have blown finals? ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- I have to agree with you Frank. This 'John' comes on this board denigrating CBer's and is now a know all see all. You definitely aren't a people person yourself but at least you are honest in your beliefs. John, Frank did make some direct points which you waffle on. **** or get off the pot... |
Jim:
Read the fellows posts, he indicates he CANNOT adjust the antenna or coax, DUH!!!--the matchbox is an excellent solution.... Are you some brain dead wacko that can't read too? John "jim" wrote in message ... Frank Gilliland wrote: On Mon, 1 Aug 2005 14:46:55 -0700, "John Smith" wrote in : Frank: FOOL!!! His original post makes ALL of that clear, if not, one or two of his other posts after will fill you in... Well, let's find out just what he said, shall we? ===== On Sat, 30 Jul 2005 11:45:50 -0500, driver42 wrote in : Hi, If I'm not able to set the SWR in the trucks that I drive will it hurt the radio or just give me decreased range? ===== I don't see anything about a 5:1 SWR. I don't see anything about being "forced" to use a matching device. Now is a good time to dispell more CB mythology: Many of you already know that in order to double your range you need -four- times the power. But it also works the other way -- if you reduce your power to one fourth (i.e, you are losing 3/4 of your power, which would mean a pretty high SWR) you have -only- decreased your range by one half. So an SWR of 2:1 or 3:1 (or, conversely, squeezing a couple extra watts with a tweak-n-peak) isn't going to have a noticable effect on your range. Let's continue with the scenario that you are losing 3 watts (3/4 of your power) due purely to reflection. Ok, so that power gets dumped back into the final where it's dissipated as heat. That's three extra watts in a transistor conservatively rated to handle a certain amount of -continuous- heat dissipation, which is usually something along the lines of 4 watts. Mind you that 3 or 4 watts isn't a whole lot of power; if the heat sink can handle 4 watts without a problem then an extra 3 watts isn't exactly going to melt the knobs. Regardless, the final -isn't- dissipating this heat continuously (unless the OP is one of those asshole broadcast types that keys down for half an hour), so normal operation certainly isn't going to "cook" the transistor. And I already mentioned that these transistors are rated to handle 30:1 SWR -continuously- without damage. If you want proof of these FACTS then feel free to refer to the data sheets for the final transistors most commonly used in CB finals. ===== On Sat, 30 Jul 2005 13:27:48 -0500, driver42 wrote in : My problem is that I'll be moving from truck to truck so I wont have time to set the SWR correctly. Most of our trucks have factory installed double antenna's which I'm not too thrilled about. ===== I don't see anything about a 5:1 SWR. I don't see anything about being "forced" to use a matching device. Looks to me like he said the trucks already have antennas installed. Assuming they are CB antennas, it's more than likely that the antennas have already been trimmed for use with a 50-ohm radio (since all CB radios are 50-ohm radios). Unless something is broke, the antennas are probably going to give a reasonably good match to -whatever- radio he picks (because, once again, all CB radios are 50-ohm radios). ===== On Sat, 30 Jul 2005 21:33:43 -0500, driver42 wrote in : My problem is that I'll be in a different truck everyday and wont be able to set the SWR the way I want to. ===== I don't see anything about a 5:1 SWR. I don't see anything about being "forced" to use a matching device. What I -do- see is concern about setting the SWR, which is another mythconception (and not just with CBers but with a lot of hams). A 1:1 SWR does -NOT- mean the antenna is operating at it's best efficiency. It -DOES- mean that the load is 50 ohms nonreactive. But a 50 ohm nonreactive load can be darn near anything: a carbon resistor, a dummy load, a bad coax working as a tuned stub, or even a corroded 9' whip with a mount caked in mud (seen both scenarios firsthand). As I stated before, an SWR meter is a go/no-go meter. If it normally reads 2:1 then suddenly jumps to 6:1, that's a good indication that something has gone wrong with the antenna or coax. And -THAT'S- what an SWR meter is good for..... a "something's wrong" meter (IMO, they should probably be replaced with idiot lights like those in a car.) If you want to tune your antenna for best efficiency you -NEED- to use a field strenght meter. Period. Now........ once again........ 1) Where did the original poster say he was being "forced" to use any type of matching device? 2) Where did the original poster say his SWR was 5:1? 3) Since very few CBers use a matchbox, why don't the millions of other CB radios have blown finals? ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- I have to agree with you Frank. This 'John' comes on this board denigrating CBer's and is now a know all see all. You definitely aren't a people person yourself but at least you are honest in your beliefs. John, Frank did make some direct points which you waffle on. **** or get off the pot... |
On Mon, 01 Aug 2005 22:04:01 -0400, jim wrote
in : snip I have to agree with you Frank. This 'John' comes on this board denigrating CBer's and is now a know all see all. He'll either leave, lurk, or start posting under another alias. It's too bad that some people have to be like that because I'm sure they could make positive contributions to the group. Even Dave had a lot of helpful advice; he just couldn't accept that sometimes he was wrong, which doesn't make a lot of sense to me since it's so easy to verify your facts -before- you post your opinions. But I'm sure he will be back..... when he's finished sulking. You definitely aren't a people person yourself but at least you are honest in your beliefs. I'll take that as a compliment. I really am a nice guy. I just have no patience or respect for liars and bull**** artists, on or off the net. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
Frank:
You might be a nice guy, I see idiots who are nice guys, ma'roons too... John "Frank Gilliland" wrote in message ... On Mon, 01 Aug 2005 22:04:01 -0400, jim wrote in : snip I have to agree with you Frank. This 'John' comes on this board denigrating CBer's and is now a know all see all. He'll either leave, lurk, or start posting under another alias. It's too bad that some people have to be like that because I'm sure they could make positive contributions to the group. Even Dave had a lot of helpful advice; he just couldn't accept that sometimes he was wrong, which doesn't make a lot of sense to me since it's so easy to verify your facts -before- you post your opinions. But I'm sure he will be back..... when he's finished sulking. You definitely aren't a people person yourself but at least you are honest in your beliefs. I'll take that as a compliment. I really am a nice guy. I just have no patience or respect for liars and bull**** artists, on or off the net. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
On Mon, 1 Aug 2005 19:55:10 -0700, "John Smith"
wrote in : Frank: You might be a nice guy, I see idiots who are nice guys, ma'roons too... I'll try this one more time. You will need to focus -REALLY- hard because this is probably going to be explained on a temporal level with which you are unfamiliar: logic. Are you ready? Ok, here we go..... Fact: Somebody already installed the antennas and coax in the trucks. Fact: Most people who install antenna systems adjust them for the best impedance match to their radios. Now just in case you are worried about the word "most", here are a couple things to consider: If the antennas and coax are -not- adjusted for a very good match then the other drivers of these trucks would have blown -their- finals already (according to your "truth") and would have either complained or fixed the problem. And since a company owns the trucks, the antennas and the coax, and apparently wants the drivers to use CB radios while driving, it's very likely that the company checked the antenna systems so as to make sure they actually work and not blow up the drivers' radios. This seems plausible because if company equipment is defective they could be liable for the cost to repair or replace the driver's CB radio. Even in a worst-case scenario where the antenna systems were defective and blew up CB radios all the time, not only is there something fundamentally wrong with the antenna systems that no matchbox is going to fix, but someone is bound to warn him that he should -not- plug his radio into the truck's antenna. So in all probability..... Conclusion: The antenna systems on these trucks have been adjusted for the best impedance match to a CB radio. Now hold on tight because this is where it all comes together..... Fact: All CB radios are designed for a load impedance of 50 ohms. From this fact you can draw two conclusions: Conclusion #1: A CB radio with a load impedance of 50 ohms was used to adjust the antenna systems in the trucks for the best impedance match. Conclusion #2: Any CB radio the original poster uses is going to have a load impedance of 50 ohms. And those two conclusions lead to one FINAL conclusion: The antennas and coax are -already- adjusted for the best impedance match to -any- CB radio the original poster might use. Bottom line: He's not going to blow up his radio if he doesn't use a matchbox. Now feel free to go back to your troll routine of calling me a "fool", an "idiot", a "ma'roon" and a "brain-dead whacko", because you just earned your place in the killfile. =-PLONK!-= ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
Frank Gilliand Is Right !!!!
Finally we got the correct and right answer. Right On Frank !!!! Brian - Las Vegas , NV |
Frank... the point you're missing is that although it's like you say
"All CB radios are designed for a load impedance of 50 ohms."... there are certainly different reactances (j factor) from radio to radio. No radio or antenna is exactly 50 +j0. This is where the matchbox can help to supply the conjugate needed for maximum performance. Professor www.telstar-electronics.com |
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"Frank Gilliland" wrote in message ... On Mon, 1 Aug 2005 19:55:10 -0700, "John Smith" wrote in : Frank: You might be a nice guy, I see idiots who are nice guys, ma'roons too... I'll try this one more time. You will need to focus -REALLY- hard because this is probably going to be explained on a temporal level with which you are unfamiliar: logic. Are you ready? Ok, here we go..... Fact: Somebody already installed the antennas and coax in the trucks. Fact: Most people who install antenna systems adjust them for the best impedance match to their radios. Now just in case you are worried about the word "most", here are a couple things to consider: If the antennas and coax are -not- adjusted for a very good match then the other drivers of these trucks would have blown -their- finals already (according to your "truth") and would have either complained or fixed the problem. And since a company owns the trucks, the antennas and the coax, and apparently wants the drivers to use CB radios while driving, it's very likely that the company checked the antenna systems so as to make sure they actually work and not blow up the drivers' radios. This seems plausible because if company equipment is defective they could be liable for the cost to repair or replace the driver's CB radio. Even in a worst-case scenario where the antenna systems were defective and blew up CB radios all the time, not only is there something fundamentally wrong with the antenna systems that no matchbox is going to fix, but someone is bound to warn him that he should -not- plug his radio into the truck's antenna. So in all probability..... Conclusion: The antenna systems on these trucks have been adjusted for the best impedance match to a CB radio. Now hold on tight because this is where it all comes together..... Fact: All CB radios are designed for a load impedance of 50 ohms. From this fact you can draw two conclusions: Conclusion #1: A CB radio with a load impedance of 50 ohms was used to adjust the antenna systems in the trucks for the best impedance match. Conclusion #2: Any CB radio the original poster uses is going to have a load impedance of 50 ohms. And those two conclusions lead to one FINAL conclusion: The antennas and coax are -already- adjusted for the best impedance match to -any- CB radio the original poster might use. Bottom line: He's not going to blow up his radio if he doesn't use a matchbox. Now feel free to go back to your troll routine of calling me a "fool", an "idiot", a "ma'roon" and a "brain-dead whacko", because you just earned your place in the killfile. =-PLONK!-= Man, it takes a lot for Frank to killfile someone ;). I plonked him months ago when he insisted on top posting, after many people asked him not too. Landshark -- The internet is fun but it's no substitute for books, people, nature, or direct experiences. But you think that you can get everything you need from your computer, you are a fool. Frank Gililland |
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