SDRTrunk RTL SDR V4 “channel start rejected tuner unavailable” error using SDRTrunk Software

[haydenm51300]

So I just purchased a RTL SDR v4 and I’m using it to listen to North Carolina Viper P25 using SDRTrunk software. I have everything set up; my control frequency for my tower and it works. I have a signal and it stays on CONTROL. It seems like most transmissions are coming through but I’m only able to hear a couple of them and for the majority that I can’t hear I’m getting an error message for “channel start rejected tuner unavailable - phase 1 channel grant PRI1 circuit”. What could be happening??

 

[mtindor]

So I just purchased a RTL SDR v4 and I’m using it to listen to North Carolina Viper P25 using SDRTrunk software. I have everything set up; my control frequency for my tower and it works. I have a signal and it stays on CONTROL. It seems like most transmissions are coming through but I’m only able to hear a couple of them and for the majority that I can’t hear I’m getting an error message for “channel start rejected tuner unavailable - phase 1 channel grant PRI1 circuit”. What could be happening??

Which NC Viper site are you monitoring? If you are using one dongle, that gives [typically] a max of 2.4 mhz of spectrum to work with. If the voice channels fall outside of that 2.4 mhz of spectrum, SDRTrunk won't tune to it because SDRTrunk doesn't want to lose the control channel.

 

[dave3825]

You most likely need another dongle or two. Go to the site and look at all the freqs listed for that site. Take the highest freq, and minus the lowest freq. The number you get will be the spread.

So for instance, Duke site, 858.8375 minus 852.450 equals 6.3875mhz. The average dongle yields around 2.4 mhz so for the Duke site, that 6.3875 divided by 2.4 equals 2.66, so 3 dongles would be needed.

1 (1)	007 (7)	Duke University	Durham, NC	852.450	853.5125	854.8375	855.2875	855.5875	856.8375	857.8625c
				858.8375c

The v4 dongle has up to 3.2 MHz of instantaneous bandwidth (2.4 MHz stable) as listed on Amazon

Amazon.com

On both the dongles release page, and its datasheet, it lists 2.56 max stable.

 

[haydenm51300]

i’m using Hibriten Mtn. Caldwell, NC

 

[haydenm51300]

You most likely need another dongle or two. Go to the site and look at all the freqs listed for that site. Take the highest freq, and minus the lowest freq. The number you get will be the spread.

So for instance, Duke site, 858.8375 minus 852.450 equals 6.3875mhz. The average dongle yields around 2.4 mhz so for the Duke site, that 6.3875 divided by 2.4 equals 2.66, so 3 dongles would be needed.

1 (1)	007 (7)	Duke University	Durham, NC	852.450	853.5125	854.8375	855.2875	855.5875	856.8375	857.8625c
				858.8375c

The v4 dongle has up to 3.2 MHz of instantaneous bandwidth (2.4 MHz stable) as listed on Amazon

Amazon.com

On both the dongles release page, and its datasheet, it lists 2.56 max stable.
View attachment 175294



View attachment 175296

could i possibly get by with 2 using a cable splitter to one antenna?

 

[mtindor]

could i possibly get by with 2 using a cable splitter to one antenna?

857.5875 - 851.175 = 6.4125 mhz. Even at 3.2 msps per dongle, you are likely going to run into issues. I'd say you probably need three dongles, or an Airspy mini and and the RTL dongle.

You can use a cable splitter, but you should only do that if you have ample signal to work with from the beginning, because any "splitting" of the signal is going to result in each split decreasing the signal by at least 3 db. But the splitter will do nothing to increase the mhz of coverage that you need. That can only be solved by an Airspy R2, or an Airspy mini and a dongle, 3 dongles, or an SDRPlay device. The Airspy R2 and SDRPlay devices can handle 10 msps (although figure on usable bandwidth of 8 mhz without performance loss). An Airspy mini will do 6 msps (about 4.8 mhz of usable spectrum without performance loss). Dongles, typically 2.4 - 3.x mhz ( 1.92 mhz - 2.56 mhz without loss of performance).

 

[dave3825]

could i possibly get by with 2 using a cable splitter to one antenna?

For that site you would need 2 more (3 dongles total) as it spans 6.4125 mhz

6.4125 / 2.4 = 2.67
6.4125 / 2.56 = 2.50
6.4125 / 3.2 = 2.003

If your close and getting a strong signal you could get by using one of those tv splitters but you would need one with 3 ports (4 total ports) which would give each dongle some signal. Each dongle would receive a reduced signal tho.

 

[haydenm51300]

For that site you would need 2 more (3 dongles total) as it spans 6.4125 mhz

6.4125 / 2.4 = 2.67
6.4125 / 2.56 = 2.50
6.4125 / 3.2 = 2.003

If your close and getting a strong signal you could get by using one of those tv splitters but you would need one with 3 ports (4 total ports) which would give each dongle some signal. Each dongle would receive a reduced signal tho.

so buying 2 antennas with the 2 new dongles would probably be the best option?

857.5875 - 851.175 = 6.4125 mhz. Even at 3.2 msps per dongle, you are likely going to run into issues. I'd say you probably need three dongles, or an Airspy mini and and the RTL dongle.

You can use a cable splitter, but you should only do that if you have ample signal to work with from the beginning, because any "splitting" of the signal is going to result in each split decreasing the signal by at least 3 db. But the splitter will do nothing to increase the mhz of coverage that you need. That can only be solved by an Airspy R2, or an Airspy mini and a dongle, 3 dongles, or an SDRPlay device. The Airspy R2 and SDRPlay devices can handle 10 msps (although figure on usable bandwidth of 8 mhz without performance loss). An Airspy mini will do 6 msps (about 4.8 mhz of usable spectrum without performance loss). Dongles, typically 2.4 - 3.x mhz ( 1.92 mhz - 2.56 mhz without loss of performance).

another thing i had a question about. do i need to change the serial numbers on the dongles?

 

[dave3825]

so buying 2 antennas with the 2 new dongles would probably be the best option?

Depends on your endgame. Tough question to answer.


If your using the antenna that come with the dongles and your receiving what you want, and If the signal is very strong by you, a 3 way tv splitter could work with one antenna. But it might not. That's the beauty of Amazon and free returns.

If you ever plan to broaden your reach and or listening choices, meaning try scanning stuff not that close to you, or puts out a weaker signal, then an outdoor antenna and a multicoupler would be the way to go.

another thing i had a question about. do i need to change the serial numbers on the dongles?

Some say you have to but I have not changed any of mine and had 4 NooElec dongles going in SDRTrunk without issue. Maybe the Rtl Sdr Blog's act differently.

 

[haydenm51300]

Depends on your endgame. Tough question to answer.


If your using the antenna that come with the dongles and your receiving what you want, and If the signal is very strong by you, a 3 way tv splitter could work with one antenna. But it might not. That's the beauty of Amazon and free returns.

If you ever plan to broaden your reach and or listening choices, meaning try scanning stuff not that close to you, or puts out a weaker signal, then an outdoor antenna and a multicoupler would be the way to go.



Some say you have to but I have not changed any of mine and had 4 NooElec dongles going in SDRTrunk without issue.

Okay. So say I buy 2 more dongles, adding 2 more antennas. Will it work right if I just use all individual antennas for each dongle or would i have to only use one antenna with the splitter?

 

[dave3825]

If the antenna your using now is keeping control yellow, it means your getting a decent signal. Decent enough to decode the control channel. If all the voice channels are putting out the same power, and not experiencing any interference, it should work fine with separate antennas. I could also work fine with a splitter and one antenna. Not sure how much signal your getting and what each dongle would get after splitting.


You could also receive the system using DSDPLus FastLane, and using just one dongle. Only drawback is you would only be receiving one tg at a time where SDRTrunk can receive many tg's in use simultaneously.

 

[haydenm51300]

okay. could i use DSDPLus FastLane until i receive my dongles or would that software interfere with SDRTrunk when i receive them?

 

[haydenm51300]

If the antenna your using now is keeping control yellow, it means your getting a decent signal. Decent enough to decode the control channel. If all the voice channels are putting out the same power, and not experiencing any interference, it should work fine with separate antennas. I could also work fine with a splitter and one antenna. Not sure how much signal your getting and what each dongle would get after splitting.


You could also receive the system using DSDPLus FastLane, and using just one dongle. Only drawback is you would only be receiving one tg at a time where SDRTrunk can receive many tg's in use simultaneously.

okay. it is receiving enough to have consistent control but It’s not insanely strong.

 

[morfis]

could i use DSDPLus FastLane until i receive my dongles?

Yes

would that software interfere with SDRTrunk when i receive them?

You can't use two pieces of software to control the same rtl device at one time. When you have your new rtl devices you'd probably want to use SDRTrunk for your original use scenario.

So get a fourth rtl device so you can play with DSD+FL with that whilst the other three are in use by SDRTrunk