I switched coax which one is better?

[vagrant]

Are you using an FM broadcast filter? Even if you have a nearby pager signal that is strong, you should use an FM broadcast filter as well. If you use the LNA again, which looks like it provides too much gain, you would put your filters inline "before" the LNA. Basically, filter the junk before you boost. Also, if you do use the LNA again, can you adjust it so that it provides 10dB or less gain? Perhaps just 5dB to make up for losses and not overload your receiver.

Start moving down in frequency, slowly, and watching your waterfall as you go. Basically, move it to a segment and wait. If you see a signal that is stronger than the others, that would be the frequency you want to attenuate. You need to identify that frequency first before buying a specific filter. Still, I would purchase an FM broadcast filter right now and at least get that RFI tamed down. I encourage you to always leave an FM filter inline.

 

[ArloG]

Don't exclude wall wart power supplies. A bad laptop battery causing the charging circuit to run full blast. Router Ethernet cable noise.
If you can start by killing the main breaker to see if noise drastically decreases and gradually connect things one by one. You may be surprised.
A repeating harmonic interference sure looks like a bad or noisy smps. Just a hint to try.

 

[Ubbe]

A RTL-SDR dongle are easily overloaded and adding a LNA will make it even more suspect to overload. You can use a LNA if you have a very low average RF interference level but you seem to to have a transmitter, or several, that overloads the RTL-SDR. With any LNA it is best to have it at the antenna to keep the impedance load to the antenna and to the coax at a constant level. Using a CATV splitter at the other end of the coax will also load the coax with a more constant impedance and to the receiver as well. Additional attenuation are always needed to keep the signal boost calculated from the antenna to the receiver at no more than 3-6dB.

To find what frequency it is that create the overload you reduce the gain gradually until you no longer see any overload issues and then start to look thru the frequency bands, at highest sampling rate to cover as much frequency range as possible, that's 3.2MSPS in my SDR#, for a high signal with that pattern in time cycle that you have when it overloads. It can be at any frequency from low-vhf to UHF as RTL-SDR do not use any band specific filters as scanners do.

/Ubbe

 

[AngWay]

If it is indeed interference, you will first need to identify what frequency is causing the interference. I would start by listening to the signal at 152.27 to see if you can identify it. Is there correlation between when this signal is active and the interference?

You have a challenging situation. You are trying to pull in weak signals in an environment that appears to have strong signals in the same area.

right now im trying to get my RSPdx device to scan a set of freqs like i do with the rtl-sdr devices i'm having a issue getting the squelch to work i read that maybe their isn't a squelch for the sdrplay on dsdplus fastlane. also for some reason when i'm parked on a CC it works i can hear the traffic but when i scan a set of freqs i only hear scrambled traffic. idk