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Re: [IRCA] Elad FDM-S2 and a Phaser [Latency Issues]



I too guessed that Les must mean audio latency.A delay of 100 - 200 mS in the audio processing of Windows (as measured by many) with MME drivers is the cause of most of the latency, not the Perseus or other SDR. With some SDR programs (SDR Radio, Linrad) you can choose WASAPI or ASIO drivers to get latency of a few ms, but not Perseus.No amount of CPU or memory will change things much.Perseus can contribute a bit of latency depending on delay and filter taps that are chosen in the SW settings, but normal settings don't add a lot of delay.But I've not heard or known of anyone having a phasing problem due to the delay. It is a problem for hams switching between TX and RX modes but thats a different story.
Chuck

> Date: Wed, 25 Feb 2015 12:11:09 -0600
> From: swl.tn.usa@xxxxxxxxx
> To: irca@xxxxxxxxxxxxxxxx
> Subject: Re: [IRCA] Elad FDM-S2 and a Phaser [Latency Issues]
> 
> I think Les may be saying he is having an issue with the audio latency of
> the SDR hampering his efforts to get a perfect null during live listening..
> I've not had this issue myself, but one solution could be to use an antenna
> splitter so you could use a separate analogue receiver strictly for setting
> nulls.
> 
> On Wed, Feb 25, 2015 at 10:55 AM, neilkaz <neilkaz@xxxxxxxxxxxxx> wrote:
> 
> > Les, forgive me as I don't quite understand exactly what you mean by
> > latency. I will state that I have used both the Quantum Phaser and the
> > Wellbrook Array Controller with my Perseus and the audio recorded and
> > played back is EXACTLY the same as what I heard when listening to it live
> > while phase adjusting a deep null.
> >
> > You refer issues getting deep nulls when playing back the audio? Again, I
> > don't understand. You have to do your nulling prior to playback.
> >
> > 73 KAZ
> >
> > -----Original Message-----
> > >From: Tim Tromp <kilokat7@xxxxxxxxx>
> > >Sent: Feb 25, 2015 4:20 AM
> > >To: IRCA Mailing list for the International Radio Club of America <
> > irca@xxxxxxxxxxxxxxxx>
> > >Subject: Re: [IRCA] Elad FDM-S2 and a Phaser [Latency Issues]
> > >
> > >Les, I use a quantum phaser with my Perseus and have never noticed a
> > >latency issue when making phaser adjustments, and I'm still using my old
> > >MSI Wind netbook.  I'm curious to hear from others now.
> > >
> > >73,
> > >-Tim
> > > On Feb 25, 2015 4:13 AM, "Les Rayburn" <les@xxxxxxxxxxxxxxxx> wrote:
> > >
> > >> I'd like to pair my Elad FDM-S2 SDR receiver with my Quantum Phaser,
> > >> allowing me to null out local stations using two antennas. The problem
> > that
> > >> I'm having is that there is a certain amount of latency present in the
> > >> playback of audio from the SDR, making it difficult to do the subtle
> > >> adjustments that result in the deepest nulls.
> > >>
> > >> This problem isn't unique to the Elad. Had the same issues with my
> > SDR-IQ,
> > >> FunCube Pro, and Perseus SDR's as well. Despite running a very modern
> > >> computer, with quad processors, plenty of RAM, etc. The latency just
> > seems
> > >> to be impossible to remove.
> > >>
> > >> For real-time listening or recording, it makes little difference...but
> > >> it's a stumbling block when using a phaser. Just wondering if anyone has
> > >> figured out how to work around this issue, or another solution.
> > >>
> > >> Advice more than welcome.
> > >>
> > >>
> > >> --
> > >> 73,
> > >>
> > >>
> > >> Les Rayburn, N1LF
> > >> Maylene, AL
> > >> EM63
> > >>
> > >> Member NRC, IRCA, & Medium Wave DX Circle
> > >> Former CPC Chairman for NRC/IRCA
> > >>
> > >> Perseus SDR, SDR-IQ,Funcube Pro, Wellbrooke ALA-1530+ loop, LF
> > Engineering
> > >> Active Whips,
> > >> Quantum Phaser, Kiwa Loop, Palstar MW Pre-Selector
> > >>
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> 
> 
> -- 
> 73,
> Brandon Jordan, WA4230SWL
> Fayette County, TN EM55gc
> http://www.swldx.us
> 
> WinRadio G33DDC G313-e | RFSpace SDR-IQ NetSDR | Elad FDM-S2 | Icom R75
> IC-7200
> Array Solutions SAL-30 Shared Apex Loop
> DX Engineering NCC-1 Phased ARAV3 Active Whips
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