Downward Expander 2.8.11

N9VX
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Downward Expander 2.8.11

Postby N9VX » Mon Nov 30, 2020 6:18 pm

Could some tell me how to set the DEXP in Thetis 2.8.11 to get the same results as found in mRX? In mRX I set the Threshold at -30 to -40 and the Attenuate to 100% and it instantly shuts down the audio between words. If I do not set Attenuate to 100%, I get a rushing noise between words that is heard while recording my audio.

Thanks,

Joe N9VX
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w-u-2-o
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Mon Nov 30, 2020 7:14 pm

The VOX and downward expander changed dramatically in Thetis 2.6.4. It is the most advanced VOX available in the hobby, including any external processors you might find available.

Instructions for its use can be found here:

https://apache-labs.com/community/viewtopic.php?f=9&t=3049&p=7168
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Re: Downward Expander 2.8.11

Postby Jim » Sun Apr 18, 2021 6:10 pm

Joe, I notice if I have the downward expander ON with 2.8.11 either 32 or 64 bit I get a keyup spike or burst. When running the Amp the spike can be 150 - 200 watts so I have discontinued using DEXP.
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Sun Apr 18, 2021 6:39 pm

Jim,

Post your DE settings. Perhaps there is something that can be fixed. Because I can't think of anyone else with this problem.

Also, are you using VAC?

73,

Scott
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Re: Downward Expander 2.8.11

Postby Jim » Sun Apr 18, 2021 7:06 pm

Scott I tried different settings but we have the settings back to default. Any help or settings would be appreciated.

I did read the instructions for it's use.

tnxs & 73 de KE4WY Jim
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Sun Apr 18, 2021 8:58 pm

If you are only using DEXP and not VOX it probably shouldn't matter, but try setting your Anti-VOX gain to -20 and enabling Anti-VOX.

You did not say if you are using VAC for TX, RX or both. Are you?
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Re: Downward Expander 2.8.11

Postby Jim » Mon Apr 19, 2021 1:17 am

Scott, lowering Anti-Vox gain and enabling Anti-Vox
did not make any difference.

I hope it won’t cause some other issue but we just
found that unchecking Auto look Ahead and lowering the release ms from 100 to 1 may has just eliminated
The key up burst/spike.

We have VAC setup but have not been using it.

Thanks de KE4WY Jim
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Mon Apr 19, 2021 10:48 am

That's very strange. I cannot duplicate that problem. I normally run vox with the look-ahead and a 250ms release time, too.
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Re: Downward Expander 2.8.11

Postby Jim » Mon Apr 19, 2021 11:19 am

Scott, I was reading another discussion "Noise Burst on initial Transmit' which mentions going to general/options and changing RF DELAY from 10 to 200. I changed mine to 200ms, went back to DSP/VOX/DE and reset release time from 1 back to 100 and re-enabled LOOK AHEAD and with DEXP on all appears Normal. With DEXP on I now have my normal working downward expander that operates smoother than my 1st solution.
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Mon Apr 19, 2021 11:24 am

That's not a solution. That's merely a part of the same mystery. There should be absolutely no reason to run such an obnoxiously high delay. It would drive me crazy if I had to. My delays are set to minimum and, again, no problems here.

Are you running Protocol 1 or 2 firmware?
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Mon Apr 19, 2021 11:30 am

And what version firmware, specifically?
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Re: Downward Expander 2.8.11

Postby Jim » Mon Apr 19, 2021 12:03 pm

Scott, P2.....2.0 and software version 2.8.11(10/20/20)
64 bit.

Scott, also have The 32 bit version of 2.8.11 (10/20/20)
installed which suffers from same DEXP issue.

Both were downloaded off the Github Taper site and not modified.

Thanks for the sanity check. I just set my RF Delay to 200
as the station mentioned on the Noise burst on initial transmit.

I checked my 64 bit v. And found the burst just goes away
at an RF Delay of 35..........the 32 bit version at an RF Delay of 45.

KE4WY Jim
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Mon Apr 19, 2021 2:21 pm

I don't know if you can do this experiment, but if you can: does this also happen to you when you source audio via VAC?

Unfortunately I can't do the opposite experiment and not use VAC because my station is remotely operated.
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Re: Downward Expander 2.8.11

Postby Jim » Mon Apr 19, 2021 4:55 pm

Scott, this is strange. With VAC enabled with and DEXP enabled no spike. Now with DEXP off I see the spike which is just the opposite of what I see
with VAC off. Now using VAC, I moved the RF DELAY from 35 to 150 and still see the spike with the DEXP OFF. Thats with 64 BIT 2.8.11. Just checked the 32 Bit and it's the same.

KE4WY Jim
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Mon Apr 19, 2021 5:31 pm

Jim wrote:Scott, this is strange. With VAC enabled with and DEXP enabled no spike.

That's what I was afraid of. That somehow the audio look ahead delay line has garbage data in it when the TX audio source is the ANAN hardware CODEC, but with VAC it is fine. While this is by no means proof of that, it implies this might be the case.

Now with DEXP off I see the spike which is just the opposite of what I see with VAC off. Now using VAC, I moved the RF DELAY from 35 to 150 and still see the spike with the DEXP OFF. Thats with 64 BIT 2.8.11.

I cannot duplicate that problem with VAC.

What happens if you duplicate my General > Options > Options-1 settings with VAC as follows: RX Delay 0, MOX Delay 0, RF Delay 2, PTT Delay 0?

Just checked the 32 Bit and it's the same.

No need to waste your time. Bugs generally track the same in both versions.
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Re: Downward Expander 2.8.11

Postby Jim » Mon Apr 19, 2021 7:03 pm

Scott,

RX DELAY 0
MOX DELAY 0
RF DELAY 2
PTT DELAY 0

VAC ENABLED works with no spike DEXP on or off

VAC OFF listening through my powered speakers .....DEXP off no spike DEXP ON 900 WATT spike...changing only RF DELAY to 30 no spike
DEXP on or off

73 de KE4WY Jim
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Mon Apr 19, 2021 7:44 pm

What amp are you using?

I'm using an Elecraft KPA500.

I wonder if it is somehow amp-dependent.
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Re: Downward Expander 2.8.11

Postby Jim » Mon Apr 19, 2021 9:28 pm

Elecraft KPA-1500.

I did not notice this issue with Thetis 2.69.
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Tue Apr 20, 2021 12:22 pm

So probably not amp dependent, then.

Still can't duplicate your problem :(
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Re: Downward Expander 2.8.11

Postby Jim » Tue Apr 20, 2021 1:25 pm

Scott, I have not run VOX in years. I tend to pause too often but setup my VOX for a long delay and it appears I don’t see this burst with VOX. I will see if I can live with my VOX setup with a group I meet with every weekday afternoon.
So today will be my test run. Been a foot switch man for years.
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Tue Apr 20, 2021 2:07 pm

Jim,

You will love the VOX. It is the crown jewel of the audio suite. It is the only VOX available with the look-ahead feature so that you don't lose the first syllable. The side-chain trigger lets you pick the dominant tones of your voice so that nothing else in the shack triggers it.

Since every possible adjustment is available you can really tune it up good. Most people won't even know you are using VOX. I also prefer a longish hold and release time. Here are my settings. Be sure to crank that anti-vox gain down a ways, -20 is a good starting point.

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Re: Downward Expander 2.8.11

Postby Jim » Tue Apr 20, 2021 2:26 pm

Scott, thanks so much.

KE4WY Jim
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Re: Downward Expander 2.8.11

Postby rdwing » Tue Jul 26, 2022 9:07 am

I'm pretty sure I'm seeing this issue. I use a mic directly connected to the radio, but VAC for RX audio.
With DEXP enabled, I sometimes get a pretty good noise burst after keying up. DEXP disabled the problem goes away. The issue seems to occur even with VAC disabled. This is primarily noticed on Phone.

Seperately, actually I also get noise bursts at the end of a transmission in CW, and those are transmitted over the air. They show up especially when using TUN or 2TON.

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Re: Downward Expander 2.8.11

Postby w-u-2-o » Tue Jul 26, 2022 12:30 pm

The CW part of your problem should be covered in a separate topic.

What happens if you disable the VOX Audio Lookahead feature but leave DEXP enabled?
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Re: Downward Expander 2.8.11

Postby rdwing » Tue Jul 26, 2022 8:52 pm

w-u-2-o wrote:What happens if you disable the VOX Audio Lookahead feature but leave DEXP enabled?

Disabling the VOX look ahead helps a lot but does not 100% resolve, nice work around. I'd say its a 90% fix. I think now its just the small hang time before the DEXP engages. I will have to play with the timing there.

I seemingly can't use vox if I want to use VAC for RX audio, so I guess that's an OK for now. But eventually I would like to run VOX with this.
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Wed Jul 27, 2022 12:36 am

rdwing wrote:
w-u-2-o wrote:What happens if you disable the VOX Audio Lookahead feature but leave DEXP enabled?

Disabling the VOX look ahead helps a lot but does not 100% resolve, nice work around. I'd say its a 90% fix. I think now its just the small hang time before the DEXP engages. I will have to play with the timing there.

I seemingly can't use vox if I want to use VAC for RX audio, so I guess that's an OK for now. But eventually I would like to run VOX with this.

That doesn't follow. If you review this entire thread, you'll find that VAC audio seems to work fine for VOX. It's only those who choose to use the built-in CODEC of the hardware (plug the mic into the ANAN) that have a problem. And even then it's only 2 or 3 people who have had this problem. It seems to operate fine for nearly everyone.

Also, I corresponded with the developer of this part of the code. It picks up the audio stream after the CODEC and VAC inputs, i.e. it is the same stream at that point. An inspection of the code reveals no way in which it should behave differently one way or the other.
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Re: Downward Expander 2.8.11

Postby rdwing » Wed Jul 27, 2022 1:04 am

I only use VAC for RX audio. TX audio is from a mic connected to the front MIC jack. VOX doesn't seem capable of functioning in this config.

Disabling the Audio LookAhead mostly solved the problem of a noise burst upon keying up.
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Re: Downward Expander 2.8.11

Postby w-u-2-o » Wed Jul 27, 2022 1:38 am

Why not use VAC for transmit as well?

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