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Post by libslayer on Dec 17, 2013 14:32:56 GMT -5
When I turn on amplifier my SWR's go crazy high. Which is the accurate reading? With amp on or off?
KATO808 #DeepInTheHeartOfTexas
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bluebird
Big Bucket Mouth
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Post by bluebird on Dec 17, 2013 15:58:59 GMT -5
When I turn on amplifier my SWR's go crazy high. Which is the accurate reading? With amp on or off? KATO808 #DeepInTheHeartOfTexas i check mine with the amp off they will climp with amp on ;D |
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Post by libslayer on Dec 17, 2013 16:09:05 GMT -5
So is it ok that they climb with amp on? Does it affect transmission?
KATO808 #DeepInTheHeartOfTexas
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Sandbagger
Administrator/The Boss 
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Post by Sandbagger on Dec 17, 2013 17:01:52 GMT -5
When I turn on amplifier my SWR's go crazy high. Which is the accurate reading? With amp on or off? KATO808 #DeepInTheHeartOfTexas No, this is NOT ok. What this most likely means is that your amp is outputting spurious emissions out of band where the SWR is high. Since an SWR meter is not frequency sensitive, it will report all reflected power back regardless of where it's coming from. Placing a low pass filter between the amp and the SWR meter will usually reduce the problem considerably. |
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Post by libslayer on Dec 17, 2013 18:24:53 GMT -5
Do I need to keep the filter on during normal operation as well or just during tuning?
KATO808 #DeepInTheHeartOfTexas
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Post by libslayer on Dec 17, 2013 18:45:35 GMT -5
#1 Attachments:
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Post by libslayer on Dec 17, 2013 18:46:57 GMT -5
Just stopped at cb shop. Don't know which one is suitable for my application KATO808 #DeepInTheHeartOfTexas Attachments:
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Post by spitfire441 on Dec 17, 2013 19:32:52 GMT -5
When I turn on amplifier my SWR's go crazy high. Which is the accurate reading? With amp on or off? KATO808 #DeepInTheHeartOfTexas No, this is NOT ok. What this most likely means is that your amp is outputting spurious emissions out of band where the SWR is high. Since an SWR meter is not frequency sensitive, it will report all reflected power back regardless of where it's coming from. Placing a low pass filter between the amp and the SWR meter will usually reduce the problem considerably. Just for clarification, are you using an external SWR meter? The kind that you need to calibrate? They need to be recalibrated at any changes in power output. If this is not your case disregard this message. |
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Sandbagger
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Post by Sandbagger on Dec 17, 2013 19:33:24 GMT -5
Just stopped at cb shop. Don't know which one is suitable for my application KATO808 #DeepInTheHeartOfTexas The one pictured in this post would be my choice. This one can handle 2 KW, while the other one is only good for 100 watts. |
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Post by spitfire441 on Dec 17, 2013 19:35:41 GMT -5
Just stopped at cb shop. Don't know which one is suitable for my application KATO808 #DeepInTheHeartOfTexas You can use either one. Just watch power rating, that seems to be the only real difference between them. On says 100 watts, the other says up to 5KW. Spitfire 441, County Wide Radio,LLC |
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Post by libslayer on Dec 17, 2013 23:06:44 GMT -5
Yes I'm swinging right at 230 watts.
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Post by libslayer on Dec 17, 2013 23:08:51 GMT -5
I'm using external meter. Didn't think about recalibrating once the amp is on....I'm going to go try that now.
KATO808 #DeepInTheHeartOfTexas
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Sandbagger
Administrator/The Boss
Posts: 6,250
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Post by Sandbagger on Dec 18, 2013 8:07:39 GMT -5
I'm using external meter. Didn't think about recalibrating once the amp is on....I'm going to go try that now. KATO808 #DeepInTheHeartOfTexas Oh snap! Yes, your forward power calibration will change when you kick on the amp, so it needs to be reset in order to get an accurate SWR reflected power reading. Typically SWR will rise slightly with higher power, but it should not be drastic. |
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Post by libslayer on Dec 18, 2013 8:51:37 GMT -5
LOL I never thought to recalibrate either..just tried and BAM all is well. Who'd a thunk it eh? You guys are the best.  KATO808 #DeepInTheHeartOfTexas |
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Post by spitfire441 on Dec 18, 2013 14:00:06 GMT -5
LOL I never thought to recalibrate either..just tried and BAM all is well. Who'd a thunk it eh? You guys are the best. KATO808 #DeepInTheHeartOfTexas  I thunk it  Glad it was an easy one. Sandbagger has a tendency to "nuke" the question. ;D Nuke = an ability to take something easy and make it complex. |
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Sandbagger
Administrator/The Boss
Posts: 6,250
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Post by Sandbagger on Dec 18, 2013 14:52:20 GMT -5
LOL I never thought to recalibrate either..just tried and BAM all is well. Who'd a thunk it eh? You guys are the best. KATO808 #DeepInTheHeartOfTexas I thunk it Glad it was an easy one. Sandbagger has a tendency to "nuke" the question. ;D Nuke = an ability to take something easy and make it complex. Radio is naturally complex. It's the operators who are simple.... ;D |
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Post by libslayer on Dec 18, 2013 18:45:20 GMT -5
All you guys have been a huge help as I delve into this new hobby. Now the question remains....I'm bleeding through folks radios (car and home...some radios that aren't even turned on). Now of course as a guy I find this exceptionally cool. But I know I need to fix this problem. Would the low pass filter take care of this issue? KATO808 #DeepInTheHeartOfTexas |
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Sandbagger
Administrator/The Boss
Posts: 6,250
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Post by Sandbagger on Dec 18, 2013 19:33:23 GMT -5
All you guys have been a huge help as I delve into this new hobby. Now the question remains....I'm bleeding through folks radios (car and home...some radios that aren't even turned on). Now of course as a guy I find this exceptionally cool. But I know I need to fix this problem. Would the low pass filter take care of this issue? KATO808 #DeepInTheHeartOfTexas Maybe. But what kind of antenna are you running and how high up is it? |
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Post by libslayer on Dec 18, 2013 19:52:40 GMT -5
I just upgraded yesterday to this antenna...I have the coil at 18" above the cab. Was running a K-40 trucker and was doing the same thing (bleeding over into FM radios) KATO808 #DeepInTheHeartOfTexas Attachments:
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Sandbagger
Administrator/The Boss
Posts: 6,250
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Post by Sandbagger on Dec 19, 2013 7:26:25 GMT -5
I just upgraded yesterday to this antenna...I have the coil at 18" above the cab. Was running a K-40 trucker and was doing the same thing (bleeding over into FM radios) KATO808 #DeepInTheHeartOfTexas Oh, so you're running mobile. Usually dealing with bleeding into TV's and radios is a headache for base station operators. Running mobile you always have the luxury of driving somewhere where there aren't other people to annoy when you want to play radio. As for your own FM radio, there is only so much you can do. Tight grounding of the radio, amp and antenna (no mag mounts), and antenna placement, and making sure the output of the amp is clean, is about all you can do. Once you get above a certain power level, you just can't keep the signal from getting into the electrical wiring of the vehicle, and it becomes frustrating trying to, with all those little wires running around the vehicle acting like small antennas. |
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Post by cbrown on Dec 19, 2013 9:58:43 GMT -5
Radio is naturally complex. It's the operators who are simple.... ;D So true! ;D ;D |
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Post by libslayer on Dec 19, 2013 16:25:32 GMT -5
So just be polite and use etiquette...which I'm already doing since I discovered the issue. thanks for all the help. |
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Post by Trapper John on Apr 16, 2014 12:42:50 GMT -5
I think I will put up a sign in my shop/shack that says that! I will credit you with it Sandbagger.
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I thunk it 
Glad it was an easy one. Sandbagger has a tendency to "nuke" the question. ;D
