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Author Topic: amatuer newbie question: location of SWR meter ...  (Read 5832 times)
BPONG
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Posts: 24




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« on: October 19, 2009, 10:07:13 AM »

i have put all my electronics in an enclosure.

basic equipment list:
IC-7200, LDGtuner, Daiwa CN-801HP SWR Meter, MFJ300W dummy load, antenna switch.

i will use the antenna switch to go between dummy load and operating antenna.

the question is...
where do i put the SWR meter ?

the sales guy says the order is:

transceiver -> SWR meter -> antenna tuner -> ant. switch

is this correct ?
i thought the SWR meter comes after the antenna tuner.

feedback would be greatly appreciated before i go building all my connecting cables and such ...

thnx in advance,
bp
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AA4PB
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« Reply #1 on: October 19, 2009, 10:20:29 AM »

The SWR meter goes between the Tx and the tuner. It tells you when the tuner is adjusted to present a 50 ohm load for the transmitter.

If it were placed between the tuner and the antenna it would tell you the SWR on the feed line out to the antenna but there is nothing you can do inside the shack to change that SWR. The tuner can ONLY change the SWR on the coax between the tuner and the transmitter.
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AA4PB
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« Reply #2 on: October 19, 2009, 10:28:46 AM »

You could also go:
Tx >> Switch >> Tuner >> Antenna
....................>> Dummy Load

The switch then switches between the tuner and the dummy load. There is normally no need to have the tuner in line when the dummy load is selected.
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BPONG
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« Reply #3 on: October 19, 2009, 11:04:11 AM »

AA4BP;

is the SWR meter located between the switch and the tuner ?
if so, then the sequence is:

tx - switch - a) SWRmeter - tuner - antenna
..............b) dummy load
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AA4PB
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« Reply #4 on: October 19, 2009, 01:01:14 PM »

I'd put the SWR meter between the Tx and the switch so that it reads the SWR to the dummy load when the dummy load is selected and the SWR to the tuner when the tuner is selected.
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BPONG
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« Reply #5 on: October 19, 2009, 02:06:49 PM »

AA4BP;
thnx.
va3bpo
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KB1OOX
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« Reply #6 on: April 23, 2010, 07:23:26 PM »

were dose it go if you are useing a amp also?right now i have rig>swr>amp>tuner.. is that right?
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K7GLM
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« Reply #7 on: April 23, 2010, 09:42:02 PM »

If the meter has the required watt rating, put it between the amp and the tuner. Assuming that the input tuning on the amp is correct, you don't need to check the SWR between the radio and the amp, as it should be 1.4:1 or less. Instead, you should be monitoring the conjugate impedance of the antenna system (tuner, cable, antenna) against the output side of the amp.

OTOH, most modern tuners that can handle QRO power have the SWR meter built in.
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KE7HLR
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« Reply #8 on: May 21, 2010, 12:44:51 PM »

Read these two eHam articles,

    http://www.eham.net/articles/23375
    http://www.eham.net/articles/23317

and then put the SWR meter away in your closet...  Grin

73 & GL,
Dan, KE7HLR
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W3LK
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« Reply #9 on: May 21, 2010, 05:19:25 PM »

The Icom 7200 should have a built in SWR meter so an external one really isn't needed.

73s John AA5JG

Internal SWR meters are notoriously inaccurate. They are no substitute for a GOOD, external power/SWR meter.
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A smoking section in a restaurant makes as much sense as a peeing section in a swimming pool.
N3OX
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« Reply #10 on: May 22, 2010, 08:33:55 AM »

Internal SWR meters are notoriously inaccurate. They are no substitute for a GOOD, external power/SWR meter.

Especially if you already own the meter...  Smiley

VA3BPO, there are actually things you can learn by putting certain SWR/power meters in between the tuner and antenna, but the things you can learn there are a bit academic. In other words, not anything that's going to help you get on the air, just things that can help you learn about transmission line theory.  So you maybe want to save such experimentation for later.  Plus, putting it between tuner and antenna, aside from not quite telling you what you want to know without some subtle interpretation, puts some significant stress on the meter because the voltages and currents are higher than what it would see in normal service in a matched feedline. 

So when you want to make sure your tuner is adjusting itself to present a good match to your radio, the salesman gave you the right advice: SWR/power meter goes between the rig and the tuner.

Don't put it in the closet  Grin

« Last Edit: May 22, 2010, 08:45:41 AM by Dan » Logged

73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
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