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Author Topic: Antenna Tuner Question?  (Read 2076 times)
K1JWJ
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Posts: 20




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« on: September 20, 2017, 03:31:44 PM »

New to the HF world. Running an Icom IC-735 into a ZS6BKW/G5RV antenna at 44' inverted V and 24' at the ends.
I just bought a used MFJ-949E antenna tuner from a eHam member.

My question: when I am running through the tuner, my receive volume is noticibly lower than when I run the antenna coax directly into the transceiver.

Is this normal?

73, Jeff
K1JWJ
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WB6BYU
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Posts: 17070




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« Reply #1 on: September 20, 2017, 03:52:35 PM »

Have you adjusted the tuner to match the antenna?

When properly adjusted, the received signal through the tuner should NOT be weaker than it is direct.

Are you connecting the twinlead directly to the balanced terminals on the back of the tuner, or using
coax between them?  If you are using the balanced output, make sure you have the jumper connected
from one of the balanced terminals to the "single wire" terminal post.

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K1JWJ
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Posts: 20




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« Reply #2 on: September 20, 2017, 04:34:51 PM »

Have you adjusted the tuner to match the antenna?

When properly adjusted, the received signal through the tuner should NOT be weaker than it is direct.

Are you connecting the twinlead directly to the balanced terminals on the back of the tuner, or using
coax between them?  If you are using the balanced output, make sure you have the jumper connected
from one of the balanced terminals to the "single wire" terminal post.



No, I have coax into the shack and into the tuner.
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KE6EE
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Posts: 1855




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« Reply #3 on: September 20, 2017, 04:36:53 PM »

If you put the tuner's coax selection switch in "bypass" you should
experience no reduction in signal level.

Otherwise, as already suggested, best reception using your tuner in the "tuned"
switch position will be with the tuner tuned as for transmitting.

This should suggest to you that tuning your tuner for best reception will get you close
to where you should be for transmitting.

The problem with getting a new piece of gear is that you have to learn how it works. Or take
advantage of that opportunity. Sometimes there is a manual that is worth reading.
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K1JWJ
Member

Posts: 20




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« Reply #4 on: September 20, 2017, 04:51:55 PM »

If you put the tuner's coax selection switch in "bypass" you should
experience no reduction in signal level.

Otherwise, as already suggested, best reception using your tuner in the "tuned"
switch position will be with the tuner tuned as for transmitting.

This should suggest to you that tuning your tuner for best reception will get you close
to where you should be for transmitting.

The problem with getting a new piece of gear is that you have to learn how it works. Or take
advantage of that opportunity. Sometimes there is a manual that is worth reading.

Yup, read the manual. Also, cannot tune yet as I am awaiting delivery of a new mic. And, you are correct: in "by-pass" my reception is equal to no tuner in place.

So, I am assuming all is good until I get that mic and can actually tune as for transmitting.

Thanks
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K2OWK
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Posts: 1273




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« Reply #5 on: September 20, 2017, 05:21:00 PM »

I had one of these for a while. The best way to tune this is in the receive position as someone has stated. Tune for best receive signal on the frequency you plan to use, before tuning your transmitter. This will give you a close antenna match and transmitter tuning will only take a few seconds. When you get used to adjusting the tuner for the frequency you plan to use, mark down the settings for the next time you operate and after a time, it will only take a second or two to tune it.

73s

K2OWK
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WB6BYU
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Posts: 17070




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« Reply #6 on: September 20, 2017, 05:31:52 PM »

Quote from: FRJEFF

...Also, cannot tune yet as I am awaiting delivery of a new mic..



You can adjust the controls to try to maximize the received signal, which will give you some experience
with the unit.

If you want to get the feel for adjusting a tuner without actually transmitting you can use W9CF's
online tuner simulator.

And there are several different ways to generate RF from your radio that don't necessarily require
a mic.  I'm not familiar enough with the IC-735, but typically if you put it in FM or AM (or possibly
RTTY) mode and flip the big TX/RX switch manually, it should generate a carrier.  (Best to reduce the
output power to 5 - 10W for adjusting a tuner, just use enough to get an indication on your meter.)
You can also plug in a key, or a shorted plug that simulates a key, or a couple wires connected to
a plug that you can touch together to key the radio.

Actually running SSB is not a good way to measure the SWR, because your output power
jumps all around with modulation.  Just keying the mic in SSB mode shouldn't generate any output
power - you have to talk into the mic to generate output.  Only on AM or FM will the rig generate
output power when you just key the mic.  That's a problem that many newcomers find when they
first get on SSB - it doesn't work the way they are used to like AM or FM.
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AC2EU
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Posts: 1208


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« Reply #7 on: September 20, 2017, 05:34:09 PM »

It sounds like the tuner is not dialed in.
You can get pretty close to where it should be tuned in Tx by adjusting for maximum noise or signal.
An external tuner should enhance both rx and tx performance.
It should be BETTER in tuner mode.
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AC2EU
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« Reply #8 on: September 20, 2017, 05:41:01 PM »

Quote
...Also, cannot tune yet as I am awaiting delivery of a new mic..

This a bad idea too. there is NO CARRIER on SSB and it's hopeless trying to adjust SWR in SSB mode.
You should ideally use "key down' low power cw or AM (with no modulation) or FM with no modulation, All of these produce a carrier so you don't need a mike to tune at all, in fact, using a modulated signal just complicates the process.
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K1JWJ
Member

Posts: 20




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« Reply #9 on: September 21, 2017, 12:35:44 PM »

Got it figured out.
Stupid me!
Had radio in SPLIT, so she was switching to and transmitting in VFO B, when I was in VFO A.
Workers perfectly now.
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KC4ZGP
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Posts: 1637




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« Reply #10 on: September 21, 2017, 01:01:46 PM »


Yes st....silly you, silly you.

Next, get on 160 and lets dit dit it.

Kraus
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KC3RN
Member

Posts: 200




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« Reply #11 on: September 21, 2017, 04:05:27 PM »

Also, cannot tune yet as I am awaiting delivery of a new mic. And, you are correct: in "by-pass" my reception is equal to no tuner in place.

So, I am assuming all is good until I get that mic and can actually tune as for transmitting.

Thanks

FYI, you should tune using the CW mode, not SSB......  Also, reduce your power to 10 watts or so.
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