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Author Topic: FT-2000 CW sounds and 'looks' terrible...  (Read 1400 times)
NR0U
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Posts: 28




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« on: October 06, 2012, 01:31:09 PM »

Long story short...trying to help my elmer with digital.  FT-2000 and HRD(DM780). He can decode PSK, although looking at his waterfall, signals are not as clear and concise as my station(FT-450 and HRD).  He cannot decode RTTY or CW.  So I go over there and start poking around.  I confirm PSK decodes OK and decide to look at some CW signals just to investigate a bit...

The CW signals on the water fall are horrid and have tons of NOISE and appear distorted.  Looks nothing like on my waterfall where CW is simply a clean line of dits and dahs.  It also sounds like shit.  I operate CW, he does not.  You could hardly copy this.  Sounds like a woodpecker on a 2x4 and like it is overwhelming the speaker or the receiver with distortion.  S-meter is not pegged, volume is not too high, so I am a bit stumped.  I am not too familiar with his rig, but it is similar to mine and I cannot figure out why it sounds like crap(this is with all digital software shut down, just pure radio cw...)...

Not sure how else to describe this to you.. I have a DM780 screenshot showing the signal, but not sure how to attach in this forum...

Any thoughts from the FT-2000 guru's?

Thanks,
NR0U


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N4CR
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Posts: 1694




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« Reply #1 on: October 06, 2012, 01:34:32 PM »

What is the sound card and interface?
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73 de N4CR, Phil

Never believe an atom. They make up everything.
NR0U
Member

Posts: 28




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« Reply #2 on: October 06, 2012, 01:38:09 PM »

Signalink USB.  However, when I shut all that down, the rig sounds like crap...I now suspect that something is set wrong on the rig and that is the source of the problem.
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TANAKASAN
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Posts: 933




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« Reply #3 on: October 07, 2012, 12:45:20 AM »

I don't have an FT-2000 in front of me but this sounds like an interesting problem so I did some digging on your behalf.

Please check menu setting "092 rdSP CNTR LV". This alters the gain or loss of the Contour function with -15dB being the default value. One site I found highlights the following problem:

The rig's output remains clean up to the +15 dB point. However, at +16 and above, the onset of clipping is observed.  Notice in the graph above the +20 point does not peak with the expected +5db level over the +15 setting due to compression clipping at some point in the AF/DSP chain.

From this, we can see that using the contour in the peak mode, levels of +15 dB and less are needed to avoid distortion products unless the signal is low enough to be below the AGC action threshold.


http://ac0c.com/main/page_ft2k_roofing_filters_ft2000_dsp_filters.html

Tanakasan
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NR0U
Member

Posts: 28




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« Reply #4 on: October 07, 2012, 09:43:00 AM »

Thanks Tanakasan,

I will check this out.

Lance
NR0U
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VA7CPC
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Posts: 2406




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« Reply #5 on: October 07, 2012, 05:45:45 PM »

FWIW --

Yes, it sounds like a problem with the rig settings.

Try finding a MW AM broadcast station (540 - 1600 kHz), and tuning it in in CW or SSB mode.  In either case, set the IF filter fairly wide.   

If _that_ sounds bad, you will have a stable signal to use for adjusting things until it sounds good.

First check that the noise blanker is OFF.  A noise blanker (on any rig) wreaks havoc with any strong signal coming in.

And make sure that the AGC is turned on, and the RF preamp is off.

           Charles
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NR0U
Member

Posts: 28




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« Reply #6 on: October 10, 2012, 05:00:00 PM »

Thanks Gang,

I got it.  AM reception was great, so I just keep staring at the rig.  Remember it is my elmers FT-2000 not my FT-450...but
close enough that I suddenly noticed the notch filter!!!  It was on and cranked down.  So, I turn it off and BAM, CW and
RTTY signals decode and all is right in the world. 

Whew, back to normal. 

73
Lance
NR0U
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TANAKASAN
Member

Posts: 933




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« Reply #7 on: October 11, 2012, 06:22:33 AM »

When you have a rig with a front panel like the flight deck of Concorde then pilot error is a possibility  Smiley

Tanakasan
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