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#2
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you might be using cheap coax
(never use foam! foam diaelectric is actually the better coax. it's velocity factor is higher, less loss. ron |
#3
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On Mon, 19 Jul 2004 14:30:11 GMT,
wrote in : you might be using cheap coax (never use foam! foam diaelectric is actually the better coax. it's velocity factor is higher, less loss. ron The velocity factor has nothing to do with performance, and the difference in loss is insignificant unless you plan on running several hundred feet. What -is- significant is that foam is easily ruined by mild heat, moderate bending or crimping, and humidity that gets trapped inside. Foam is a poor choice for mobile installations. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#4
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Wow, there is alot more to this than I thought. I have alot to learn but now I
know where to start. Thanks |
#5
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Ok im going to ground the radio and the amp tonight. starting with the antenna,
what should I replace the wilson mag mount with. I went with the mag mount due to parking in a car port. that way i could pop it off and set it in the bed of my truck. I wont lose any sleep over dumping the wilson but what shoud I get. I plan on upgrading every thing now but I would like to start with tha anyenna and then move on to radio. one thing at a time $$. It looks like I wasted money the first time around I would like to get it right this time. thank agan Rock by the way I was stationed in Miomar San Deigo and 29 palms. |
#6
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On 19 Jul 2004 21:52:47 GMT, (ROCH USMC) wrote in
: Ok im going to ground the radio and the amp tonight. starting with the antenna, what should I replace the wilson mag mount with. I went with the mag mount due to parking in a car port. that way i could pop it off and set it in the bed of my truck. I wont lose any sleep over dumping the wilson but what shoud I get. I plan on upgrading every thing now but I would like to start with tha anyenna and then move on to radio. one thing at a time $$. If you have a roll-bar or utility rack you can weld a bracket at the top, then use just about any type of whip with a quick-disconnect mount. For top-mounted antennas I prefer center-loaded whips, but others like fiberglass and they work fine, too. Or, if you really want top-notch performance (in -both- Tx and Rx) you might try a full-sized 9' whip on the rear bumper and tie it down when not in use. I have a 9' whip mounted on the center of my roo-guard in the front and tied back so it doesn't catch on the brush. Anywayz, the 9' whip shouldn't cost you much more than $20-$30 for both the whip and mount. On the places where the antenna mount contacts the metal of the vehicle, make sure it's contacting clean, bare metal and makes a GOOD connection. For coax, get some RG-8 or better and avoid crimp connectors. If you have a soldering gun, learn to solder them yourself. It's ok to use up some coax to practice soldering these connectors because the results are worth the effort. It looks like I wasted money the first time around I would like to get it right this time. Nothing was wasted. It's always good to have a backup. Keep the old mag-mount for emergencies. thank agan Rock by the way I was stationed in Miomar San Deigo and 29 palms. Far out! I was in Stumps for C&E from late '81 to early '83! -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#8
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HAHHA,,,absolutely amazing,,this dude posts via aol early in the morning
wee hours when there are no other posts being made via AOL, but bypasses AOL and goes out of his way to sign up with google to make his post....and before the post can show up on most servers, Gilliland answers. Add to that the guy is getting rid of his Wilson because the first person he came across on usenet told him it was no good? The dude can change out and solder a coax connection but doesn't know how to set his swr and needed Frank to instruct him? HAHHAHAHHAHAHAHAHAHHAHHA! Frank's self-esteem is the only thing taking a "beating". |
#9
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#10
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On Tue, 20 Jul 2004 10:21:32 -0400,
(Nicolai Carpathia) tried desperately to walk and chew gum at the same time (post on-topic while trying to discredit me) by writing in : On 19 Jul 2004 05:01:36 GMT, (ROCH USMC) wrote in : *Hi *Here is what I just got, Cobra 29 LTD Classic that was bumped up a bit, a new Palomar Elite 300 amp (ebay) , Diesel (?) noise canceling mic and a Wilsom 5000 mag mount ant. I cant get the SWR down below 2.5. I ran a new 18' cable and a ground wire to the frame of the truck but ever time i key up the ANT light lights up on the radio. My questions a 1. How can I get the SWR down? Just three words: Grounding, grounding, and grounding. You need to ground the radio AND the amp AND the antenna. The antenna is already grounded. A Wilson mag mount needs no additional ground. A magnet isn't a any type of electrical connection at all. Some have been duped into thinking there's a capacitive coupling between the magnet and body through the paint, but fail to realize that the magnet itself prevents any capacitive coupling. That's why most mag-mounts come with 18' of coax yet frequently show high SWR. And unless the antenna is a dummy load, you can move the cable around and watch the SWR needle wander. Fact: Mag-mount antennas have ****-poor ground connections. By "grounding" I mean an "RF ground". At 27MHz, this means mounting the radio and amp directly to the chassis and/or using grounding straps that are no more than a few inches long. Only after your system is properly grounded can you address any other issues. Nonsense. One can mount the radio in a slide mount and to make it temporary or it can be mounted in a permanent manner. Nobody said it couldn't. A slide mount is fine if the receiver half is mounted to the chassis (or with a very short grounding strap). It can be mounted to the dash and a myriad of other places. Strip the plastic and vinyl from the dash, and behold... the chassis! The chassis also exists in a "myriad of other places". The radio does not need directly mounted to the chassis in order to provide proper grounding. In fact, this is less practical and not the manner of which the majority of cb installs are complete. It's very practical. It just takes a little extra effort. And those other issues can be many. Almost as many as there are ways in which to mount the radio other than mounted directly to the chassis. For example, your 'bumped' Cobra may have been 'bumped' by a moron; your Palomar may have a detuned input or output, a bad power transistor, or even worse it might be self-oscillating; you might be using cheap coax (never use foam!); you might have a bad antenna; etc. But regardless of the problem, it's always easier to troubleshoot if the system is properly grounded. *2. Is this a good combo? Not really. Sure it is. Palomar amps work quite well. When fed with the correct input levels. A radio that has been 'bumped' (which I assume to mean it has been tweaked for more power) may easily exceed the maximum input levels for the amp. Even 4 legal watts will overdrive most of the smaller amps. The makers of these cheap linears (that usually aren't very linear at all) don't tell you that the power rating is for -peak- power. LOL,,umm,,that's how amps are rated. You used the term linear, he called it an amp. Unless his Cobra is capable of FM, your point is moot. One that is familiar enough to add new coax to a Wilson is more than likely already aware of this. IOW, a 300-watt amp will do 300 watts PEP, which translates to a maximum of 75 watts RMS (AM carrier power). Push it any harder and you will get a bigger carrier, but you start clipping well below 100% modulation, splattering your signal across the spectrum. Watts are watts, regardless of how they are measured. Refer to them as RMS, PEP, or BIRD, as you have in the past...watts are watts. With many radios, the blue faced palomar 250 are will sing 100 watts all day long without bleeding and they are very cheap. A common misconception, hence the frequent and continuing occurances of RFI, and the increasing popularity of LP filters. You also appear to be incorrect pertaining to modulation, as there are many instances pertaining to cb, when one wishes to achieve loudest optimum modulation, a power mic is required. Many times, this can cause the bleed over to begin. Remove the power mic in many applications, and the bleed can often be removed. I don't expect you to follow, Frank, you're still smarting after having your head handed to you after making the stupid comment that fiberglass antennas can have nothing to do with bleed issues. CB radios have modulation limiters which prevent modulation from exceeding 100% (usually set for 90-97%). A power mic may clip and distort the audio, and if that happens just turn down the mic. But if the limiter has been disabled (as some monkey-techs like to do, one of their stupid "CB tricks"), the result is that the RF will start clipping and/or become unsymmetrical, both of which cause harmonics and 'splatter'. And overdriving an amp is ALSO a cause of harmonics, as I described before. Cheap CB amps like the Palomar are rated in watts PEP, even though they don't specify them as such. The way to tell is to look at the spec sheet of the power devices (transistors) and find out how those are rated, which is usually for PEP. That is the case for the Palomar in question. The difference is that AM is measured in RMS. With an AM radio that does 4 watts RMS (which is also the carrier power), it outputs 16 watts PEP at 100% modulation. So if your AM radio is driving your 300-watt amp to 300 watts carrier -without- modulation, the result is some big-time distortion because the amp is incapable of meeting the 1200 watts PEP requirement for an AM signal at 100% modulation. You should have had your Cobra 'dumped' instead of 'bumped'. That's a personal opinion coming from one who doesn't know any better and bases his technical advice on nothing but personal emotion. Slight peaking and tuning is perfectly acceptable when done by a competent technician. In fact, Many cb radios can use a tune-up alignment after being shipped. Most experienced ampheads have their radios 'detuned' for -lower- output power to prevent overdriving the amp. That's a fact, not my personal opinion. As for a mag-mount, personally, I wouldn't waste my money. Again, you don't know any better. Many of us have talked around the world on mag mounts, barefoot, on a regular basis. Mag-mounts are great solutions for temporary mounts, rental cars, quick disconnects, etc. Money spent on a Wilson is not wasted. It is to me because I don't need temporary mounts. If I want to remove the antenna I just unscrew it. And I don't rent vehicles, I buy them. But you have, Again, a perjorative personal opinion of yours. Lockheed Martin proved the efficiency of the Wilson in independent tests. You should check their test data and you may grasp why they are so popular and have legions of loyal customers,,,they make a tight product that delivers what they claim. Phen-fen had the support of independent tests and legions of loyal customers.... Firestone had the support of independent tests and legions of loyal customers.... Asbestos had the support of independent tests and legions of loyal customers.... DDT had the support of independent tests and legions of loyal customers....etc, etc, etc. so you should know that 18' of coax isn't a reliable substitute for the terrible grounding characteristics of mag-mount antennas. If you want real power you need a real antenna, not a glorified refrigerator magnet. "Real" is a relevant term. The Wilson will have no problem with the amplifier he is using. _ *3. on my amp it has a ON/OFF , HIGH, MED, LOW and a PRE-AMP on and off. * What is with the PRE- AMP. The pre-amp is used to amplify the received signal. They are mostly worthless because the usually much better than the S/N ratio of the pre-amps. IOW, they will just make the noise louder. However, they work great for older and low-end transceivers, and simple homebrew receivers. The pre-amps are worthless by no means. They work absolute wonders when the needle is flat with no noise for those extreme fringe stations. I've used a cheap pre-amp on a regular basis to talk to the east coast of Fl late at night,,,BAREFOOT. That's because you run a Tentec. Oh, and up North we have come up with a really cool invention that has been adopted by the vast majority of civilized society. It's called the "shoe". *Ok I know I will take a beating from some of you and that is part of the game but any help or any suggestions would be great. Here's your beating: If you want to play 'hammie', get a license. Running an amp isn't "playing hammie" to all, just to those anal retentive status starved individuals. If you can't afford a license (about the price of a happy-meal), or if the test is too difficult (even when you are allowed to memorize the questions and answers before the test), then at least get yourself a book on the subject and learn what you are doing. Seeing as he can solder and change out a coax on a Wilson, He never claimed to have done anything of the sort. Your communication deficit is acting up again, Twist. it appears he is learing what he is doing quite fine. If one wanted a hammie license, I am certain one would find that information if that is what they were seeking. With all the bull**** you have given this dude, he may run like hell from anything hammie related, merely because someone like yourself is advocating it, and he wouldn't be blamed for doing so. It's just the manner in which you come across to all those you can't understand. You're just jealous because I haven't given you a good beating for a while. Now go back to trollville and behave yourself until you are summoned for your next beating. ============= http://tinyurl.com/ytcah http://tinyurl.com/2yor7 http://tinyurl.com/2sapq (Twisty cast the first stone) ============= "...but I admitted I was wrong, Like a man! Something you and QRM have a problem with. You guys are wrong and you both know it and are both too small to admit it." "...but as usual, your best simpl isn;t good enough." "Athis is how proper communication wroks..." ---- Twistedhed ---- ============= -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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