SDR Console transmit audio bandwidth limited to around 5 kHz
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Hello Simon, I'm thoroughly enjoying SDR Console 3.2 with one notable exception. The transmit audio bandwidth is limited to around 5 kHz no matter what wider transmit filter I create to allow for higher bandwidth. I am an avid AM and ESSB fan and I had the expectation that TX filter bandwidth upper limit would be the similar to Thetis 2.9.0.6 which is 9.9 kHz. I would prefer to use SDR Console as my all around SDR interface, as it is outstanding software, but the transmit audio restriction is moving me to use Thetis more often for ESSB and AM modes. Is it possible to remove this 5 kHz restriction on transmit in a future release so SDR Console mirrors the transmit bandwidth available in Thetis?
Thank you for your efforts in the development of SDR Console! Carmine K1VL
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Max
On Tue, Dec 6, 2022 at 05:12 PM, Carmine Iannace (K1VL) wrote:
Hello Simon, I'm thoroughly enjoying SDR Console 3.2 with one notable exception. The transmit audio bandwidth is limited to around 5 kHz no matter what wider transmit filter I create to allow for higher bandwidth.Carmine. Unless I missed something you can make your own TX filter up to 24kHz? See attached picture. This is latest build from Simon's download link. Have you got the latest? https://www.sdr-radio.com/download#Release 73 Max
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Siegfried Jackstien
see picture dg9bfc
Am 06.12.2022 um 18:34 schrieb Max:
On Tue, Dec 6, 2022 at 05:12 PM, Carmine Iannace (K1VL) wrote:
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There's another filter in the TX chain which is ~5kHz, will investigate.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Max via groups.io <radiomax@...>
Sent: 06 December 2022 17:34 To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> Subject: Re: [SDR-Radio] SDR Console transmit audio bandwidth limited to around 5 kHz On Tue, Dec 6, 2022 at 05:12 PM, Carmine Iannace (K1VL) wrote:
Hello Simon, I'm thoroughly enjoying SDR Console 3.2 with one notable exception. The transmit audio bandwidth is limited to around 5 kHz no matter what wider transmit filter I create to allow for higher bandwidth.Carmine. Unless I missed something you can make your own TX filter up to 24kHz? See attached picture. This is latest build from Simon's download link. Have you got the latest? https://www.sdr-radio.com/download#Release 73 Max -- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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Yes,
For AM and SSB there's a fixed 6kHz cut-off, I can increase this. I'll have to make sure
it doesn't affect any other part of the transmission chain.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Simon Brown via groups.io <simon@...>
Sent: 06 December 2022 18:16 To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> Subject: Re: [SDR-Radio] SDR Console transmit audio bandwidth limited to around 5 kHz There's another filter in the TX chain which is ~5kHz, will investigate.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Max via groups.io <radiomax@...>
Sent: 06 December 2022 17:34 To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> Subject: Re: [SDR-Radio] SDR Console transmit audio bandwidth limited to around 5 kHz On Tue, Dec 6, 2022 at 05:12 PM, Carmine Iannace (K1VL) wrote:
Hello Simon, I'm thoroughly enjoying SDR Console 3.2 with one notable exception. The transmit audio bandwidth is limited to around 5 kHz no matter what wider transmit filter I create to allow for higher bandwidth.Carmine. Unless I missed something you can make your own TX filter up to 24kHz? See attached picture. This is latest build from Simon's download link. Have you got the latest? https://www.sdr-radio.com/download#Release 73 Max -- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
-- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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jdow
Well, a fairly unbiased reading of the FCC rules suggest 3kHz would be more appropriate for "communications quality" bandwidth considerations. Wider than 5 kHz suggests you want to broadcast rather than communicate. The restriction is annoying in the abstract. But, it does avoid a communication from the FCC due to complaints from people who read the rules and ALL the rules. That said, at 0300 local on 75 meters a transmitter 100 kHz wide would probably not annoy anybody. For that, though, build your own transmitter and SDR. That way any "blame" that gets assigned goes to the user-designer-coder-constructor. {o.o} On 20221206 09:12:17, Carmine Iannace
(K1VL) wrote:
Hello Simon, I'm thoroughly enjoying SDR Console 3.2 with one notable exception. The transmit audio bandwidth is limited to around 5 kHz no matter what wider transmit filter I create to allow for higher bandwidth. I am an avid AM and ESSB fan and I had the expectation that TX filter bandwidth upper limit would be the similar to Thetis 2.9.0.6 which is 9.9 kHz. I would prefer to use SDR Console as my all around SDR interface, as it is outstanding software, but the transmit audio restriction is moving me to use Thetis more often for ESSB and AM modes. Is it possible to remove this 5 kHz restriction on transmit in a future release so SDR Console mirrors the transmit bandwidth available in Thetis?
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jdow
In the US if enough operators get annoyed enough to complain to the FCC bad things could happen rather globally within the US. The rules and regulations are generally regarded to limit bandwidth to 3 kHz for the demodulated audio for SSS, AM, and FM. Now, an AM signal on 75 meters, for example, occupies about 6 kHz if the audio is not wider than 3 kHz. That suggests one could weasel through a justification for 6 kHz SSB. But, any more than that is likely to annoy other ops if the band is busy. I'd leave it hard coded to 6 kHz unless a very serious use case is given. I might code up 100 kHz for my own use. But, I'd not contribute to delinquency on the part of people of any age by releasing the code to others. Let them dig their own graves.
{o.o}
On 20221206 10:29:39, Simon Brown
wrote:
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Yes, the interface on SDR Console does allow you create very wide TX filters but even when they are created there seems to be a hard limit at around 5 kHz. When I test transmit audio response on another SDR receiver the hard limit is apparent.
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Simon, Outside of ESSB and AM there may be some digital modes that may need this bandwidth in the future particularly on VHF frequencies and above.
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Hi,
Send me a direct email, I'll get you in the test team group, a kit awaits you.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Carmine Iannace (K1VL) via groups.io <Carmine@...>
Sent: 07 December 2022 11:50 To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> Subject: Re: [SDR-Radio] SDR Console transmit audio bandwidth limited to around 5 kHz Simon, Outside of ESSB and AM there may be some digital modes that may need this bandwidth in the future particularly on VHF frequencies and above. -- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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Siegfried Jackstien
i would not hardcode a limit .. not at 6 and not at 10 kc ... the software should not look for the limits in us / from fcc .. in other countries the limits may be more or less restrictive its on the users end to stay inside the rules/limitations .. not the programmers problem if a user wants 24kc .. he should be able to (but needs to make his own rx and tx filters) what i miss is a deviation and max frequency setting for wide fm (similar to what we have for nfm) dg9bfc sigi
Am 07.12.2022 um 06:22 schrieb jdow:
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Hi,
I have a bandpass filter in the modulation DLL which must have an upper value, I just never
expected someone would want more than 6kHz!
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Siegfried Jackstien via groups.io <siegfried.jackstien@...>
Sent: 07 December 2022 17:54 To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> Subject: Re: [SDR-Radio] SDR Console transmit audio bandwidth limited to around 5 kHz i would not hardcode a limit .. not at 6 and not at 10 kc ... the software should not look for the limits in us / from fcc .. in other countries the limits may be more or less restrictive its on the users end to stay inside the rules/limitations .. not the programmers problem if a user wants 24kc .. he should be able to (but needs to make his own rx and tx filters) what i miss is a deviation and max frequency setting for wide fm (similar to what we have for nfm) dg9bfc sigi
Am 07.12.2022 um 06:22 schrieb jdow:
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jdow
Going wider also upsets the inverse decimation (whatever it is called) required to generate the signal efficiently while ultimately driving the full transmit D/A bandwidth.
{^_^}
On 20221207 11:48:31, Simon Brown
wrote:
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Well, if you use a 3kHz transmit filter then it'll not make any difference. My 6kHz (now
9.9kHz) filter is to remove up-sampling artifacts. I generate audio at 48kHz, apply the 9.9 kHz filter, up-sample to 192khz (48 x 4) and run through a Hilbert filter. Actually, there's more to it (a lot more to it) but that's the rough outline.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of jdow via groups.io <jdow@...>
Sent: 07 December 2022 20:40 To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> Subject: Re: [SDR-Radio] SDR Console transmit audio bandwidth limited to around 5 kHz Going wider also upsets the inverse decimation (whatever it is called) required to generate the signal efficiently while ultimately driving the full transmit D/A bandwidth.
{^_^}
On 20221207 11:48:31, Simon Brown wrote:
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Siegfried Jackstien
where my overnight tests helpful? good enough for your needs? dg9bfc sigi ps hopefully you and george are well?? Am 07.12.2022 um 20:48 schrieb Simon
Brown:
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Brian Morrison
On Wed, 7 Dec 2022 19:48:31 +0000
"Simon Brown" <simon@...> wrote: Hi,Please don't encourage the Hi-Fi BW SSB people ;-) -- Brian G8SEZ
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Well,
It can sound very good. I listen to some stateside AM using ~20kHz bandwidth and the quality
is excellent.
From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Brian Morrison via groups.io <bdm@...>
Sent: 07 December 2022 23:42 To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> Subject: Re: [SDR-Radio] SDR Console transmit audio bandwidth limited to around 5 kHz On Wed, 7 Dec 2022 19:48:31 +0000
"Simon Brown" <simon@...> wrote: > Hi, > > I have a bandpass filter in the modulation DLL which must have an > upper value, I just never expected someone would want more than 6kHz! Please don't encourage the Hi-Fi BW SSB people ;-) -- Brian G8SEZ -- - + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.
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Brian Morrison
On Thu, 8 Dec 2022 06:12:45 +0000
"Simon Brown" <simon@...> wrote: Well,For broadcast AM I suppose it's acceptable, but I thought the 9kHz spacing would put paid to that. On SSB it's just unnecessary, and probably violates various bandplans etc. I suppose I should have added a :-p -- Brian G8SEZ
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Siegfried Jackstien
As far as i remember 9 kc is in mediumwave while 10((5) is used in shortwave
toggle quoted messageShow quoted text
and we have an experimental hobby .. why not try those wide band things out ?? (if not on shortwave then on vhf uhf or whatever) locally i received dab and retransmitted that in stereo to my kitchen radio (with pilot tone and with rds subcarrier showing station name, title and artist) before you ask: no ... not with sdr console .. grin dg9bfc sigi ps .. it was done with pluto and no amplifier so no harm to others ;-) Am 08.12.2022 um 09:19 schrieb Brian Morrison:
On Thu, 8 Dec 2022 06:12:45 +0000
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jdow
MW in the US is 10 kHz. So there is no legal 20 kHz AM
transmission in the US. There are job-lots of people doing it with
very questionable legality. But, the FCC in practice does very
VERY little to deal with people who violate regulations and
vigilante actions are frowned upon by the authorities. {o,o} On 20221208 00:36:22, Siegfried
Jackstien wrote:
As far as i remember 9 kc is in mediumwave while 10((5) is used in shortwave
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