Guide :Radio Communications : 19 DX 40-Channels Base CB Radio

Swr damage What transistors are typically damaged with SWR mismatching

Posted by henryjackson on Aug 13, 2007

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Solid State Guitar Amplifiers | Amplifier | Electronic Circuits

Solid-State Guitar Amplifiers ... Rabe founded SWR ... up” capacitor between emitters of driver transistors. Cross conduction typically begins at frequencies ...
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Failure Mechanisms and Reliability Issues in LEDs - Springer

... (currents typically near 20 mA), ... Mismatching coefficients of moisture expansion ... Lee SWR, Lau CH, Chan SP, Ma KY, NG MH, NG YW, ...
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Failure Mechanisms and Reliability Issues in LEDs | SpringerLink

Claims for damage caused by product failure can increase. ... Mismatching coefficients of moisture expansion ... Lee SWR, Lau CH, Chan SP, Ma KY, NG MH, NG YW, ...
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Solid State Guitar Amplifiers | Amplifier | Electronic Circuits

The case is even worse when it comes to solid-state guitar amplifiers. resistor ... Rabe founded SWR ... of driver transistors. Cross conduction typically begins ...
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Broadcast Engineering & Maintenance -

F rcadcast. EnUíneerinQ & Maintenance Nandbcck No.852 $19.95 . I rcadcast Eneineerine & Maintenance 1- landbcck f Uv !Patrick S. ìnneean '73933 . MTAB BOOKS Blue ...
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PE - 1973-05 | Loudspeaker | Equalization (Audio) -

PE - 1973-05. Uploaded by Anonymous kdqf49qb. ... typically draw between 12 and 15 times their ... SWR bridges, beam antennas, etc. There are many factors
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The Truth About HF Tuners -

Nov 21, 2008 · ... The Truth About HF Tuners ... to work properly and avoid damage. Much higher swr associated with multi band ... wires (typically ...
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Microwave Principles -

Microwave Principles ...
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Preface Solid state lighting (SSL) is recognized as the second revolution in the history of lighting. The primary reason is the annual global energy bill saving of ...
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Suggested Questions And Answer :

Swr damage What transistors are typically damaged with SWR mismatching

The transistors you are referring to are the rf power output transistors commonly called "finals". swr is the amount of your outgoing radio signal that is reflected back into your antenna ,through your coax(antenna Wire)and backs up in the radio circuitry. this backup will cause excessive heat to build up in the "Finals" therefore damaging the finals. this damage is serious but not major, just about any decent cb shop can resolve this problem. In a healthy antenna system the less swr you have the more efficent your cb radio is, this translates into more effective radiated signal therefore increasing the effective range of your radio. This information courtesy of Outlaw's CB Shop,Clinton SC.
Read More At : 19 DX 40-Channels Base CB Radio...

Matching c b antenna with c b radio

Here is some information that will help you test SWR with an inline watt meter. To get proper results you need to use an inline watt meter. Here is a really good site you can go to for help www.cbradiotalk.comEquipment needed: SWR meter, short jumper coax 3 foot. Procedure: The SWR meter needs to be placed in line between the antenna and the CB. Connect the antenna (normally connected to the back of the CB ) to the connector marked "Antenna" or "Ant" on your SWR Meter. Connect one end of the short jumper coax to the "transmit" or "Xmit" on the SWR meter. Connect the other end of your jumper coax to the CB. Assuming you have a standard SWR meter the switches should read as follows: REF or SWR, FWD, and there should be a slide switch marked "set" or "Adjust". If different consult your meter's owners manual. With the radio on the lowest channel (1 on CB) and the SWR meters switch in the Forward (FWD) position, depress the transmit switch (key up) located on the microphone. While holding the unit in this transmit mode, adjust the meter needle to the set position using the Set or Adjust knob on the meter. As soon as the needle is in alignment with the corresponding mark on the meter face, flip the switch to the Reference (REF) position. The meter is now showing your SWR on channel one. Note the value and quickly release the microphone switch. Record this reading. Repeat the previous step on channels 19 and 40. How to read your results: If SWR on channels 1, 19 & 40 is below 2.0, your radio can be operated safely. If SWR on all channels is above 2.0 but not in the "red zone" (normally over 3.0), you may be experiencing coaxial cable reaction (bad quality, wrong length, etc.), insufficient ground plane, or have an ungrounded antenna mount. If SWR is in the "red zone" on all channels, you probably have an electrical short in your coax connectors, or your mounting stud was installed incorrectly and is shorted. Do not operate your radio until the problem is found, serious damage can occur to your radio. If SWR on the lowest channel is higher than it is on the highest channel, your antenna system appears to be electrically short. Your antenna length may need to be increased. If the SWR on channel 40 is greater than that on channel 1, your antenna is considered to be "LONG" and reduction of physical height and/or conductor length will correct this situation.
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Connex 4600HP, recently added a bed cover to my truck and had to move my antenna, now that I moved it, I am getting a squeal on my cb when I key the mike, especially with the talkback on, which I have left on before with no problems. I turn the talk back off, and I can hear a slight noise inside the radio, but this is only with it completely quiet in the truck with the truck turned off. My SWR is lower on channels 1 thru saw 25 than 26 thru 40 and the squeal is not as bad on the higher swr channels. I did accidently key my radio without the antenna connected once while testing my swr. Hopefully I didn't hurt anything. Any ideas?

The only thing that comes to mind is to make sure the antenna is well grounded and to make sure that where it's been re routed that there are no power wires next or close to the antenna wire which can cause interference which will be more noticeable once you turn on the truck.
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I got this midland 77-092 CB radio it first happened when i putted the antenna with has magnet base on the radio, the radio has metal casing, and it began to make a weird noise, after that got quite but smoke started to come out, so i got it off, then opened it to check it, and seems to be a 3 pinned transistor that is also welded to the casing(guess is the ground terminal or transistor)that got fried, so i don't know if was the magnet of the antenna that cause it. radio still powers up but like for 30 seconds it will start to smoke again from that piece. i will like to know if this piece can be found somewhere so i can replace it, and will appreciate, link or at least pics so i can look for it in local market. thanks

Hi, I would assume that the magnetic antenna has bas SWR( Standing Wave Ratio, mismatch of antenna to radio Frequency). Normally the reason this would happen is that the antenna requires a larger metal base ( on cb radios a min or 3 foot X 3 foot). The transistor that smoked was probably the final output transistor ( The number of this transistor may be a C-1969 ). The transisor you are needing to replace needs to be the same number as the old one due to the chararistics of the transistor. You may also have a bad resistor or two leading to that same transistor. Check them also. After you replace the seemingle bad parts, make certain your antenna SWR's are correct by using a SWR Meter ( sold at CB Shops or Radio Shack. Good Luck on your problem. Ed " Original Radio Man"
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How to set swr for galaxy dx44 - Galaxy Radios DX-44V 40-Channels Base CB Radio

The same way you set it for any other radio. Your antenna should have an adjustment tip on it , but that's still not a problem . Get an external SWR meter and put it inline with your radio the the meter.Put you radio on channel 40 and the meter on set and key the mic. you should set the needle on the set reading.Now put the meter in the opposite setting and key the mic. Write this number down on paper.Put you radio on channel 1 and do the same thing ,write this number down.Now out the radio on 19 and do the same thing. If your reading on 40 is higher than on 1 your antenna is long and you must shorten it. If it is higher on 1 than on 40 you must shorten it.After each time you do this you should write down the numbers to see how close to 1.5 you are getting. Anything under a 2.0 is good but a 1.5 is what you want. Now you could be lazy like me and just get a matchbox that will do it for you but then you are loosing power to the radio. A 1.5 reading with the box is a 20% loss in power compared to normal output without it.
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SWR high on SSB - Galaxy Radios DX-959 40-Channels Base CB Radio

Reset your swr on am then go to ssb and set it there.Keep going back and forth until your swr is set.
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How to set swr galaxy dx 949 - Galaxy Radios DX-949 40-Channels Base CB Radio

You do not "set" cannot set it on the radio. the radio can tell you what yourswr is. it can take an swr measurement. swr has to do with the antenna system. in order for the radio waves to radiate from the antenna properly, the physical length of the antenna must match the length of the radio waves. if the antenna is too long or too short you will have a higher swr ratio. the higher the ratio the less energy will leave the antenna. but that energy needs to go somewhere, so it goes back into the radio which causes damage and can ruin a radio.first turn the channel to 20. then switch the meter switch to CAL. then key the radio. while keyed, turn the CAL knob up until the needle in the meter gets right to the CAL Mark. next flip the meter switch and key the radio. where ever he needle is, is what your swr is.if it is more the 1.5 that's getting high. if its over 2 you are in the danger zone. if its over 3 you are damaging your radio. you must repeat the calibration proceedure for every figure out weather your antenna is too long or short, you compare the swr readings from channel 1 and ch 40. if the swr is higher in 1 then on 40 the entenna is too short. if its higher on 40 then 1 its to long.
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I have a Midland 1001Z 40-Channels Base CB Radio and a Magnetic-mount CB antenna. 29" stainless steel whip and 6" spring. About 46" high overall. All bought from / in Alberta canada. I hooked up a SWR meter to it to match them up. The end problem i had was when i was adjusting the antenna to get it at 2 or below. I cant get it to come down from 3. Not sure what I should do from this point. Can i cut down the antenna or replace it ? should i change it to a single antenna that is a Heavy-duty dual trucker kit with 1.2m (4') 1/4" wave helically-wound antenna, 20-gauge copper wire, factory-tuned ?

Try Grounding it better. Its supposed to equal 8.5 ft.(102 inches) but the coil may make that in all.You can clip like 1/8 inch off at time until it goes 2.1 Swr. Thats a good standard. 1.5 SWR is desired. If it don't have a coil with it that may be the problem. You could turn it into a 8.5 ft. antenna by buying a 102" inch whip to screw into the base of your antenna, it depends if it holds or not. You could build you a matcher like this with a solder gun+solder and 2 resistors. Get you a box with 2 female cb antenna inputs. Drill a hole for both Cb antenna inputs into box. Place them into holes screw nuts down snug. Run a copper wire inside to both grounds or a plate somewhat. Run a thick gauge copper wire from center cb ANT INPUT(2) to other input of ANT INPUT(1). Solder 2 100 ohms in parallel from input to Ground. If you could take apart your radio(eliminating the box idea). Just Solder 2 (100 ohm) resistors to your Antenna output then put it back together. 50 OHM MATCH HERE Is the main idea. I've used 75 OHM Tv coax and reduced SWR.
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Fresh install SWR will not come down

I try to use the center channel of where I'm going to be talking the most to get my swr the lowest ( ch.20 for all 40),but sometimes you can't so try to remember this; if it's low on 1 and high on 40 it needs to be shortened if it's high on 1 and low on 40 it needs to be lenghthened.
Read More At : 3300 240-Channels Base CB Radio...

How do i set the swr - Galaxy Radios DX-949 40-Channels Base CB Radio

Http:// Go to that web site above, it has everything you will ever want to know, manuals, service manuals, check it out.
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