RTL bandwidth dongle issue

[N8DAD]

I have 2 RTL v3 dongle's, on sdr trunk.
Michigan MPSCS system. I have a site that has freq on 774mhz and control and other voice channels are up to 853,855mhz.
Question is how do I keep getting getting
"tuner unavailable" bulls*** from coming up. I need help understanding how to get this to get all freqs

If anyway can get expense hair to deep setup right. My email is also on QRZ , shoot me a eval if you wish so we can take it off here.
My callsign is N8DAD or, respond here... Thanks.
Barry

 

[N8DAD]

I have 2 RTL v3 dongle's, on sdr trunk.
Michigan MPSCS system. I have a site that has freq on 774mhz and control and other voice channels are up to 853,855mhz.
Question is how do I keep getting getting
"tuner unavailable" bulls*** from coming up. I need help understanding how to get this to get all freqs

If anyway can get expense hair to deep setup right. My email is also on QRZ , shoot me a eval if you wish so we can take it off here.
My callsign is N8DAD or, respond here... Thanks.
Barry

Looks like I need to learn to proofread. Sorry

 

[dave3825]

It would help if you link the site for others to determine the best approach. Basically your using one dongle to cover the 774mhz and another dongle to cover the 853 to 855 mhz. You need to determine the total bandwidth in each range. 853 to 855 is 3 mhz alone. Each dongle is good for 2.4mhz though I am running NooElec dongles at 2.56. You do not say how far the 774 spans. You may need another dongle or you may get by using a different site.

 

[N8DAD]

It would help if you link the site for others to determine the best approach. Basically your using one dongle to cover the 774mhz and another dongle to cover the 853 to 855 mhz. You need to determine the total bandwidth in each range. 853 to 855 is 3 mhz alone. Each dongle is good for 2.4mhz though I am running NooElec dongles at 2.56. You do not say who far the 774 spans. You may need another dongle or you may get by using a different site.

Ya sorry bout the post, new kinda to even posting here on RR.
Yes I have no figured that all out, it seems the one dongle is catching it all but the few on 774 and that's a voice ch. So what would I set the Freq to on the one to cover that area. I know I'm just missing something here, sorry.
U seem each dongle to a cc freq , but I guess I am not to sure how to set the 2nd one up..
Thks

 

[dave3825]

Which site are you trying?

4 (4)	033 (21)	Gaylord 1	Otsego	851.3875	851.8875	852.3875	853.275c	853.8875c	854.2875	854.9875
				855.2125
4 (4)	034 (22)	Waters	Otsego	851.600	851.975	852.1625	852.975	853.475	853.725c	853.975c
				854.2625	855.2875	856.1875
4 (4)	047 (2F)	Gaylord 2	Otsego	774.58125	851.0375	851.575	851.8375c	852.2375c	852.550c	853.3375c
3 (3)	045 (2D)	Ottawa County Simulcast	Ottawa	769.20625	769.65625	770.18125	771.00625	771.63125	772.15625	772.75625
				851.325	853.575c	854.1875	854.3875	854.6875c	856.0375c

 

[N8DAD]

Gaylord 2 , sorry thank you for your time. Just dumb I guess. Just now setting this up correctly.. Thanks for the help

 

[N8DAD]

just confused on how to properly set up software i think to resolve this issue

 

[dave3825]

Good news is the 851 0375 to 853 3375 works out to 2.3 Mhz, so one dongle will work fine in that range if set for 2.4. And the other dongle can handle the control 774.

774.58125

851.0375

851.575

851.8375c

852.2375c

852.550c

853.3375c

Bad news is I have never set up a system like that, so I am not sure exactly how to keep the second dongle in the 853 range. I am confident someone will be along with the procedure.

 

[N8DAD]

Ok, so it's not all me going nuts on this, ok.
As a newbie with a setup line this I was like what..

Thanks u did help.....73

 

[dave3825]

I am in the car right now and realized did I miss read what you posted. That 774 freq is just a voice freq and not a control channel. I am pretty sure there is a way to start the first dongle and five the second to stay at 774.

Though the Gaylord 1 site only spans 3.825mhz and might be easier to do. I have been lucky with my systems all fitting in each dongles bandwidth.

 

[N8DAD]

Yes, the 774 is just voice stream, I keep missing a lot from that freq, I guess I don't no how to get what ever dongle to just watch on it near there so it will get that traffic, so use just 1 RTL only but the 774 area..

 

[N8DAD]

Gaylord 1 site , to far from me to get

 

[dave3825]

Try this

Go in your alias editor and set up a dummy p25 channel for 774.58250. Set max traffic channels to 0 and tell it to ignore data. Assign it to one of the 2 tuners. Set it for auto start.

Then click on your system and assign the other dongle to the system. Set that to auto start also. Then set the start order with the single p25 as 1, and the second dongle with the 800 freqs to 2. Save and exit. Then restart Sdrtrunk.

When it starts up, it should tell the 1st dongle to go to 700mhz, and the second dongle should start on the 800mhz.

 

[N8DAD]

Ok I'll try now, I'll b bag y to see what happens and let u know, I really need to thank you.

 

[N8DAD]

Ok I'll try now, I'll b bag y to see what happens and let u know, I really need to thank you.

Yup that's the trick, u saved me from tossing it threw the window. Your a good man.. I'll take notes.. hagd. 73, Barry - N8DAD

 

[wgbecks]

There is a common misconception that an SDR's "Sample Rate" is the same as it's "Bandwidth". This is unfortunately not the case
in that all SDR's exhibit a definite roll off in frequency response as your approach its lower and upper limits.

The spectrum (FFT) graphic shown below is of an RTL SDR with who's sample rate set at 2.4 MSPS @ 855 MHz with the antenna
intentionally disconnected to place a focus on the noise floor across the entire spectrum. Observe the points where the usable sensitivity
begins to decline or roll off. These points more or less represent the maximum usable bandwidth.

An SDR will continue to receive (decode) beyond the roll off points but with at an ever-increasing decay in sensitivity. How much
depends upon available signal levels present for the system that you're monitoring. A good rule of thumb for RTL SDR's is to assume
a working bandwidth of approximately 85% of the sample rate.