some interference during transmission

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can anyone explain this, during call then this extra signal cuts in then goes quiet during this cycle. Then after its done I hear the call... So I hear a call then then blank then resumes. It sometimes starts at the begining of a call or middle or at the end...
 

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Steve2003

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Are you using the demo version of Virtual Audio Cable? The demo version will play a message over your virtual audio line every few seconds....
 
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sdr direct from RTL usb dongle

Yeah I thought that might be, but SDR gets its feed direct from the usb dongel. My VAC is ver.410 and with no water mark. That I know of.......But it doesn't explain the marks on the frequency causing dsd to stop decoding.
Could it be, that they found a way to deter us from tuning in?
 
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Nope, still there.

Wow, this is really annoying, there must be a filter to get rid of this... this tone walks over the whole transmission. I even switched the dongles around to see if it comes from them, control to voice viceversa...nothing
 

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interference 100mhz away?

Could I be getting bumped by paging channels 100mhz up? I'm in the 866mhz band. If I was getting hit by it, what would I do? I tried the RF gain low to high. and antenna placement. bandwidth etc...
I'll do some more digging...

thank-you Unitrunker
 

mtindor

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Could I be getting bumped by paging channels 100mhz up? I'm in the 866mhz band. If I was getting hit by it, what would I do? I tried the RF gain low to high. and antenna placement. bandwidth etc...
I'll do some more digging...

thank-you Unitrunker
That's interference. Either an image from somewhere else that just so happens to show up on the frequency you are monitoring, or perhaps you have two different entities using that same frequency and you happen to be between both of them. For instance, agency A using that frequency in town A, and agency B using that frequency in town B. And then you in town C, right between the two of them. So you end up hearing traffic from both agencies on the same frequency, interfering with each other.

Mike
 
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That might be it.

Yes , might be it...I've noticed that when the CC switches to this one frequency, Unitrunker signal strength bar jumps low to high(green to red) a lot, and I see in sdr that a anolog voice is being broadcasted over with very wide bandwidth. But this does not look like a voice or data, And it happens on all 15 trunked frequencies. I think its a tone overlay. I have a suspicion, I will buy a scanner with a dtap and get Unitrunker to control it for Provoice. And see if its the quality of audio coming from the RTL stick...Maybe it won't pick it up, and it will work better with dsd
 
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SCPD

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To expand on Mike's comments - "A" could be broadcast FM while "B" is something like a two-way conventional or paging transmission - where you only see the problem while both A and B transmit. Just speculation at this point.
 
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I found it.

So as I might add that i'm following a edac system with the Harsh beeps. They seem to be posted over the PV transmissions. Causing me to lose the transmissions with DSD. There are fourms out there about this and they were causing trunk tracking scanners to stall and stop tracking...

My problem is, they are buging DSD. So this thread is to be placed elsewhere as I have found others. But if anyone can help would be great.

What I need is a virtual filter between second instance of SDR to block these tones from reaching DSD

ie............SDR1->Unitruncker->SDR2->**filter**->DSD
something to phase out The bad beeps have the normal 4800 Hz tone mixed with its ninth subharmonic, 534 Hz. The spectral plot shows high harmonic content and the odd harmonics of 534 Hz give the tone its edgy sound.
 
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tylerwatt12

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There are programs that let you route VST plugins through an audio device in windows. Try that. You would need an audio filtering VST
 
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wow VST..

Wow , talk about a big hurdle to jump over. I'll have to learn about music production aswell?!
There are so many to choose from. I'll try some and post back.
 
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Thank-you tylerwatt

There are programs that let you route VST plugins through an audio device in windows. Try that. You would need an audio filtering VST
Your tutorial explained a lot of good info..Turns out I was using a low sampling rate, like it said could cause interference. I set it higher and BAM, perfect decode, the only downside is higher cpu usage. But now no problem with a quad core dual...Like I've been reading everywhere when everything is just fine tuned correctly, but so many variables with everything.

regards
 
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