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high SWR readings

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moondawg
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high SWR readings

Post by moondawg » Wednesday, 06 May 2009, 14:45 PM

When operating barefoot, the SWR needle hardly moves. When I add an amp (I've tried 3 with the same results) the SWRs go up to nearly 2, and swing backwards a little when modulation is added. I think the jumpers are fine. Do you think I can get this down by retuning my antenna (solarcon a99) or am I way off base looking for a solution?


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Re: high SWR readings

Post by Red Warrior » Wednesday, 06 May 2009, 14:52 PM

Your amplifier looks like an antenna to your radio. Backwards swing is usually from too much modulation. Turn your deadkey down and reduce the mike gain.
What one person receives without working for, another person must work for without receiving.



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Re: high SWR readings

Post by moondawg » Wednesday, 06 May 2009, 15:58 PM

Sorry, I may have worded that wrong. It is the SWR meter that swings downward when modulation is introduced, not the RF swing. The RF swing looks normal. One of the amps I have has the dial a watt feature and the higher I set it the higher the SWRs go. The SWR meter on the radio indicates normal SWR, it is the inline meter between the amp and feedline that reads high. Thanks in advance for any tips or hints of a solution.

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Re: high SWR readings

Post by Red Warrior » Wednesday, 06 May 2009, 16:18 PM

You cannot measure SWR while modulating the carrier. The reading only means something during dead key. The indications during modulation are meaningless.
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moondawg
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Re: high SWR readings

Post by moondawg » Friday, 22 May 2009, 14:44 PM

I finally solved the problem by putting a low pass filter behind the amp. It stopped all the harmonics and settled down the SWRs to normal. The lack of filtering on the amp was the root cause.


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Re: high SWR readings

Post by 127 » Saturday, 23 May 2009, 4:10 AM

Red Warrior wrote:You cannot measure SWR while modulating the carrier. The reading only means something during dead key. The indications during modulation are meaningless.
If you can't read swr while modulating then maybe I need to get my money back for the Bird dual sampler/meter I just bought. The "reading" means just as much when modulating as it does when dead keying.

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Re: high SWR readings

Post by 'Doc » Saturday, 23 May 2009, 5:39 AM

If you are talking about power, watts, yes, it's doing what it's supposed to do. If you are talking about SWR, then it's not. That 'Bird' isn't going to give you a direct reading of SWR anyway. That 'Bird' will 'swing' backwards too, in the right circumstances. It's still reading correctly, but what it's reading isn't being done correctly. Any and all watt meters will do that.
If you're happy with that 'Bird' meter then keep it. Personally, I have no use for a 'Bird', it's over-kill for most hobby radio. There are others at a much lower price that will do the exact same thing.
- 'Doc

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Re: high SWR readings

Post by De_Wildfire » Saturday, 11 July 2009, 22:02 PM

Don't spend the money on the bird meter. Get a WM1 Computing meter that measures true PEP for about $149. I've seen the Bird meter run side by side to the WM1 and it works well at 1.5kw. Just as accurate. It even has a remote head. Check it out.

Here's the information:
Autek Research, PO Box 7556, Wesley Chapel, FL 33545 USA.
(813) 994-2199
http://www.autekresearch.com" onclick="window.open(this.href);return false;

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Re: high SWR readings

Post by 'Doc » Sunday, 12 July 2009, 6:02 AM

And while I'm thinking about it, it is possible to read SWR while speaking or modulating. But there's only one way that I am aware of, and that's with a 'forward'/'reverse' reading dual meter that has the SWR scale where the two needles cross. Personally, I don't see all that much advantage with doing that, but if it makes you happy...
- 'Doc

Another interesting thing is that there's only one straight line in that whole SWR scale.

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Re: high SWR readings

Post by PYRO-736 » Saturday, 18 July 2009, 17:17 PM

Birds are expensive yes but if your runnin big power theyre the way to go for an honest reading. Am in the midst of setting up a DAVEMADE 16 pill system in my jeep and I want a true number not a bragging number. Am looking for the readings of my forward as well as reflected power at all times I have a 43 dual line section to put in line so I will have both readings all the time. With Birds you are also not limited to any power range just by a new slug. For the average setup yes its overkill but for a big setup is worth its weight in gold. Take care and enjoy DXing and I hope to catch you guys out there.


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