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Author Topic: Yaesu FT 950 Tuning.  (Read 3223 times)
W9KDX
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Posts: 770




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« on: June 15, 2011, 05:50:23 AM »

I am not transmitting yet, but I wondered if this rig will allow me to measure the SWR when I hook up a 40 meter antenna?  I know I will need to shorten the antenna to get it right for the frequency and I am familiar with how to do this with an SWR meter, but I am wondering if the FT-950 will display the SWR so I can shorten the antenna accurately.  I think it will as one of the meter options is SWR, but, as I said, I am not transmitting yet so I am not sure if it will work.  I am hoping to avoid purchasing a separate SWR meter.

Also, I assume I will want to trim the antenna first to get the optimum length and then I will use the auto-tuning in the Yaesu.  Am I on the right track?

Thanks
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Sam
W9KDX
N4NYY
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Posts: 4758




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« Reply #1 on: June 15, 2011, 05:59:34 AM »

Yes, it will have an SWR meter on the display. The only time you need it is for transmitting. It is not urgent that you have a match while on receive.
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K1WJ
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Posts: 455




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« Reply #2 on: June 15, 2011, 10:42:00 AM »

Hook up 40m antenna - select swr on meter - then in cw mode - key radio - swr will be displayed - adjust antenna to get lowest swr. All set. K1WJ David
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AE4RV
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« Reply #3 on: June 15, 2011, 10:54:51 AM »

Hook up 40m antenna - select swr on meter - then in cw mode - key radio - swr will be displayed - adjust antenna to get lowest swr. All set. K1WJ David

Not strictly legal without a license and on air ID, just saying.
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WD8T
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Posts: 126




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« Reply #4 on: June 16, 2011, 09:05:10 AM »

Better yet Chas why not download the manual for free from Yaesu and read it while you study for your license. Look under the "files" tab.

http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=102&encProdID=292E02F4E4D00EC99887A63E7B8ECD1B&DivisionID=65&isArchived=0
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K2TL
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Posts: 40




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« Reply #5 on: June 17, 2011, 08:19:01 AM »

Keep in mind that the antenna tuner in the FT-950 only works for the transmitter.  The antenna goes straight through on receive and is not tuned at all.  This can actually be a problem, contrary to what anyone tells you.  You may find that the received signals are very low as compared to an antenna that is tuned...even if it is just a random wire.  Sure, you will hear signals and it might be good enough for your purposes.  The tuner in the 950 assumes you are already using a resonant antenna and touching it up on receive will not do a whole lot.  However, if you are using a non resonant antenna such as a twinlead fed multiband dipole or a random wire, or if you are using a resonant antenna on a band it is not designed for, you will notice a big drop in signal strength.
I know, I own one.  The solution when using a non resonant multiband antenna on the 950 is to use an outboard tuner.  That will work on transmit as well as receive, unless you purposely bypass the tuner for some reason.
Jim K2TL
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K5ZY
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Posts: 31


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« Reply #6 on: June 18, 2011, 02:53:56 AM »

Hey Jim.
Have you tried the FT-950 with a G5RV?
Does it suffer the diminished receive using a G5RV?
I've been looking at the FT-950 and the TS-2000 trying to decide which to try next.
This may help in that decision.

Thanks
John K5ZY



Keep in mind that the antenna tuner in the FT-950 only works for the transmitter.  The antenna goes straight through on receive and is not tuned at all.  This can actually be a problem, contrary to what anyone tells you.  You may find that the received signals are very low as compared to an antenna that is tuned...even if it is just a random wire.  Sure, you will hear signals and it might be good enough for your purposes.  The tuner in the 950 assumes you are already using a resonant antenna and touching it up on receive will not do a whole lot.  However, if you are using a non resonant antenna such as a twinlead fed multiband dipole or a random wire, or if you are using a resonant antenna on a band it is not designed for, you will notice a big drop in signal strength.
I know, I own one.  The solution when using a non resonant multiband antenna on the 950 is to use an outboard tuner.  That will work on transmit as well as receive, unless you purposely bypass the tuner for some reason.
Jim K2TL
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K2TL
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Posts: 40




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« Reply #7 on: June 18, 2011, 05:15:54 AM »

I would not recommend a G5RV to anyone under any circumstances.  That antenna is only moderately sensible on 20 meters.  It has a great deal of loss in the coax on every other band due to the high mismatch between the twinlead and the coax.  The FT-950 will not be able to disguise that mismatch on receive and that will further the reasons not to use it.  The TS-2000 is a fine radio but will do nothing to improve a bad antenna that persists in Ham Radio due to myth and commercial sellers making money.
Your real question should be regarding what rig to buy based on your personal needs, not based on which is a better choice when using a bad antenna.  Now there will be thousands of Hams who use the G5RV and swear by it.  That is always because they never bothered to learn even the most basic principles of antenna theory or transmission lines.
Anyway, this is an old and beat to death topic. Believe anything you like.   I use a twinlead fed doublet tuned through a 4:1 current balun and a MFJ-929 desktop tuner.  Works fine and is based on good antenna theory.
If you decide to buy the FT-950 ( an amazing radio ) and plan on using a non-resonant antenna you would do well to use an outboard tuner for the reasons I explained. 
Jim K2TL
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VE3FMC
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« Reply #8 on: June 18, 2011, 09:07:36 AM »

Remember this, the internal tuner in the FT-950 will not tune an antenna that has an SWR over 3:1.

My Ft-950 will tune my 40 meter dipole on 15 meters because the SWR at the radio is 3:1.

Any SWR much over 3:1 the internal tuner just won't handle it. In the manual it states that the tuner will tune antennas with an SWR under 3:1.

So if you plan on using a G5RV you might want to think about buying an external tuner.

BTW, I have had G5RV's up in the past. Mine did ok on 80, 40, and 20 but on the rest of the bands it was like trying to copy signals on the dummy load sitting under my operating desk.
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K5ZY
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« Reply #9 on: July 04, 2011, 10:18:19 PM »

I've had very good luck with my G5RV using the internal tuner on my ic-746 QRP to the South pole with this combination in one instance.
Now I have a TH7DX for 10/15/20 meters and don't use the G5RV unless I want to work on 40m. 
The reason I posted the question is I have a buddy with the Ft-950 that uses a G5RV and he truly don't hear what I hear with mine and the 746.
Your statement about the 950 not using the tuner on receive might explain why he don't hear what I hear.

I'm still leaning towards the TS2000 to replace my 746 because of it's double receiver capability.

I use a MFJ-989C external tuner when I use my collins amp.
I have a home brew external tuner I use when I use my 4-1000A home brew amp.
On field day I took a IC-718 with a LDG Z100 auto tuner and a slinky antenna to the park and work 10m and 15m with good results, even worked Hawaii.
I like trying different things to see what works for me.

I appreciate the information and hope you had a great 4th of July Smiley

Thanks
John
K5ZY
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AD6KA
Member

Posts: 2237




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« Reply #10 on: July 05, 2011, 01:42:28 PM »

@ CHAS0039:

If you do purchase a rig before you get your license and
want to have your antenna's "ready to go", I'd go to a local
club and seek out an Elmer to come over to your QTH and advise you.
Then HE can operate your rig's transmitter to measure SWR.

Who knows, he probably has even better gear for antenna
setup, such as an antenna analyzer. Anyway, it's a win-win
situation as he will give you LOTS of good startup advice
on you very first station.

I'd take your new Elmer out to a nice lunch or dinner as
a token of appreciation, especially if you guys are futzing with
wires in trees all afternoon. But that's just me.

Good luck es 73, Ken  AD6KA
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