This one is both dongles connected via the USB hub, also on the outside antenna.
SDRTrunk - How to Import MCSO
- Thread starter kingshootr
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It's not the program. I'd lower the gain a bit more if you want to use the outside antenna - the waterfall is indicating exceptionally strong received signals. When receiving simulcast systems, one solution to simulcast distortion / garbling is to eliminate / attenuate the signal to a point where the receiver is only using the signal from a single tower. Better receivers can deal with signalling from 2 or more subsites, but RTL-based SDRs are not optimized for this use. Even public safety grade radios can suffer with extremely strong signals from multiple subsites.
RTL based dongles (as well as Airspy, SDRplay, etc.), are in fact well suited for this very thing. They simply receive whatever signal is out there without destroying any of the components of it. The software then does the demodulating of the full, unmolested signal.
Oh and public safety grade radios don't have issues with strong signals from multiple subsites, otherwise they'd be unusable in some overlap areas. 🤦♂️
It's best to have it outside, but it can work inside the attic if the smaller antenna or attenuator doesn't work. I would recommend the Yagi. It will eliminate the Distortions, and you can also Null out any unwanted signals.
Public safety grade radios can have issues with "simulcast distortion." We just reconfigured antennas at one of our simulcast subsites to fix a coverage issue, and had to verify that we would not introducing distortion. So yea, they can be affected, according to the Motorola engineer in charge of that project.
It looks to me like you're monitoring at least two separate systems and three sites, with two being very strong and the other not so much. If that is the case, then introducing attenuation is going to hurt the weaker system, not help.
So you're monitoring two RWC sites and the Maricopa system simulcast, correct? The two RWC sites are very strong, the county site, not so much?
Oh and by the way, you'll want to enable the "Ignore Data Calls" for all channels; it just wastes tuner bandwidth and CPU resources when enabled and doesn't show you anything of value.
So you're monitoring two RWC sites and the Maricopa system simulcast, correct? The two RWC sites are very strong, the county site, not so much?
Oh and by the way, you'll want to enable the "Ignore Data Calls" for all channels; it just wastes tuner bandwidth and CPU resources when enabled and doesn't show you anything of value.
PS - Forget about the posts stating that the other spikes are "interference", as that doesn't look like it to me. Looks like you simply have some very strong/nearby transmitters which is perfectly reasonable, and one of the sites you're trying to monitor is just weak at your location. Unfortunate, but introducing attenuation is just going to make everything weaker. If you're barely able to decode the county simulcast now, it'll be even worse after you attenuate.
SDRTrunk is pretty forgiving, and so unless the strong/nearby transmitters are immediately adjacent frequencies to the county's channels, it's not going to be a big issue. Of course if you crank the gain way too high, you're going to have issues, but it looks like you have the gain at a pretty reasonable level now.
The bottom line is that you may not be able to achieve satisfactory results decoding the county cell on the same antenna as the RWC sites.
SDRTrunk is pretty forgiving, and so unless the strong/nearby transmitters are immediately adjacent frequencies to the county's channels, it's not going to be a big issue. Of course if you crank the gain way too high, you're going to have issues, but it looks like you have the gain at a pretty reasonable level now.
The bottom line is that you may not be able to achieve satisfactory results decoding the county cell on the same antenna as the RWC sites.
Everything is working pretty well now. Thanks.
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