SDRTrunk Control Channel Fine, Voice Fades

[lukestaker]

I have been having trouble with my voice channel fading out. it doesn’t light up as a call at all. but my control is getting a great waterfall and lights up as control. i have tried multiple antennas with and without lna.

currently using this antenna
High Gain 10dBi SMA Male Wide... Amazon.com: High Gain 10dBi SMA Male Wide Band 3G/4G LTE Modems, Routers, & Cell Boosters Omni-Directional Outdoor Fixed Mount Antenna for Verizon, AT&T, T-Mobile Mobile Cell Phone 4G LTE Router, Eifagur : Electronics

with an lna (this combination was recommended to me by another feed provider)



i get no errors in the sdrtrunk console

 

[Whiskey3JMC]

Please provide the RRDB link to the system you're trying to monitor as well as make & model dongle(s) you are using & quantity. You may be short a dongle or more for what you're trying to monitor

 

[lukestaker]

Please provide the RRDB link to the system you're trying to monitor as well as make & model dongle(s) you are using & quantity. You may be short a dongle or more for what you're trying to monitor

https://www.radioreference.com/db/sid/6643

currently have 3, it was working for a while when i ran it on the old machine, but when that machine died i swapped to a laptop and have had issues. the laptop worked ok for a while but i get nothing. my scanner still works fine and it can events enough to see that the traffic isn’t encrypted.

 

[Whiskey3JMC]

https://www.radioreference.com/db/sid/6643

Assuming this site?

770.95625

773.28125c

774.45625c

851.7125

851.975

859.5625

currently have 3

RTL-SDRs or something else? You'd need a 4th to cover the entire spectrum

iCAD TR Config Generator

tr.icarey.net

Dongle 1​

2.4MS/s (Covered Frequencies: 2)

Frequency (MHz)	Comment
770.916000000	Lowest Edge
770.956250000	Voice Channel
772.116000000	Center Frequency
773.281250000	Control Channel
773.316000000	Highest Edge

Dongle 2​

2.4MS/s (Covered Frequencies: 1)

Frequency (MHz)	Comment
773.263000000	Lowest Edge
774.456250000	Control Channel
774.463000000	Center Frequency
775.663000000	Highest Edge

Dongle 3​

2.4MS/s (Covered Frequencies: 2)

Frequency (MHz)	Comment
850.641000000	Lowest Edge
851.712500000	Voice Channel
851.841000000	Center Frequency
851.975000000	Voice Channel
853.041000000	Highest Edge

Dongle 4​

2.4MS/s (Covered Frequencies: 1)

Frequency (MHz)	Comment
858.369000000	Lowest Edge
859.562500000	Voice Channel
859.569000000	Center Frequency
860.769000000	Highest Edge

 

[lukestaker]

rtlsdr, i’ll order a 4th now, thank you

 

[Whiskey3JMC]

Alternatively you could consider using DSDPlus FastLane as it tunes to each voice channel more like a scanner. There are advantages and disadvantages better explained in this post

 

[mtindor]

This post is important to read before calculating how many dongles you need.

Here....we......go

https://forums.radioreference.com/threads/dsd-2-523-released-friday-january-24-2025.484091/#:~:text=Berkeley%20Co%20WV-,Jan%2024%2C%202025,-Add%20bookmark LRRP.EXE V 1.27 https://forums.radioreference.com/threads/lrrp-tiles.492828/page-2#post-4218772 So 2/523 is the latest, gotcha. Thanks...

forums.radioreference.com

Airspys, SDRPlays, RTL dongles all suffer from this. The upper and lower 10% of the available bandwidth is going to be down quite a bit on performance. If you set something for 2.4 msps, the best performance is going to be within the 1.92 mhz portion, 960 khz above and below center. For an Airspy R2 at 10 msps, you've got 8 mhz of usable bandwidth, 4 mhz on either side of center.

If you are monitoring a very strong site, then you are still going to be able to make use of all 2.4 mhz or 10 mhz, but if the site(s) you are monitoring aren't super strong, you are going to notice problems with any transmissions that occur in the top/bottom 10% of the avaiable spectrum of the device.

 

[lukestaker]

got it working again. went away from auto ppm found that -1.8 seems to be the sweet spot for me