MicroP25RX

[btt]

..
BTW look what came in late last night

Looking good! That is a strong signal you have there! The AUTO VGA will handle that in the ROAM-OFF mode, but you will probably need an adjustable fixed gain setting when scanning with that site in the list. I have this on the list of things to do soon.

 

[btt]

Ok i'll try the new firmware this afternoon. You can import Dsdplus files now?

It should import the DSD+ '.groups' files now.

 

[ScannerDude244]

Yeah it helps when the site 2 miles away and VHF yagi on 30ft pole it's not the main site I listen to. The system has a VHF and 700mhz simulcast sites that I listen to the most.

As you can see the LSM site is far from me

 

[btt]

I haven't seen VHF simulcast before. Cool! Good EVM.

 

[ScannerDude244]

It should import the DSD+ '.groups' files now.

OK what about RID,SItes?

 

[btt]

OK what about RID,SItes?

The .sites import should still work from the files I've seen. I don't have the '.radios' RID import for DSD done yet.

 

[ScannerDude244]

Not doing so great on my 700mhz even the yagi vs SDS,OP25,DSDplus. I know you are working on gain and other stuff when you get to it.

 

[btt]

Not doing so great on my 700mhz even the yagi vs SDS,OP25,DSDplus. I know you are working on gain and other stuff when you get to it.

Not sure what the issue might be with that site. Try setting the roaming mode to OFF. Does that help?

 

[ScannerDude244]

Nope still the same it's having a hard time locking on the SDS RSSI reading of -60 -80 at the highest

 

[btt]

Nope still the same it's having a hard time locking on the SDS RSSI reading of -60 -80 at the highest

Ok, it actually is a very strong signal then. The gain before the ADC is too high. With roaming set to off, the AGC should take care of this, but sounds like it isn't. I will work on the VGA settings next.

 

[ScannerDude244]

Here is quick side by side with the SDS.

 

[btt]

Here is quick side by side with the SDS.

Thanks. It will take me a bit to get gain related changes added to the interface. In the meantime, would you mind loading up this firmware and see how it does on your 770 MHz system?

 

[ScannerDude244]

It will be awhile, but I will

 

[KevinC]

Here is quick side by side with the SDS.

Are those both on site 20? Looks like the SDS has RSSI in the 60 dBm range and the BTT in the 100’s.

I know the SDS will show false high RSSI if it sees other extremely strong signals in the band. Maybe you have Band 14 causing the high SDS RSSI and bad decode on the BTT. Just a guess as don’t know how sharp the BTT filter is.

 

[ScannerDude244]

Are those both on site 20? Looks like the SDS has RSSI in the 60 dBm range and the BTT in the 100’s.

I know the SDS will show false high RSSI if it sees other extremely strong signals in the band. Maybe you have Band 14 causing the high SDS RSSI and bad decode on the BTT. Just a guess as don’t know how sharp the BTT filter is.

Yup same site and I do hav a 700mhz filter from scanner master works ok. but doesn't go high enough in the band to knock down lte.

 

[btt]

I think we can get it working with gain changes.

 

[KevinC]

Yup same site and I do hav a 700mhz filter from scanner master works ok. but doesn't go high enough in the band to knock down lte.

How far are you from the closest 700 subsite?

 

[ScannerDude244]

25miles, but yagi pulls them with no problem

 

[KevinC]

25miles, but yagi pulls them with no problem

Ok. I suspect the BTT RSSI reading is more close to being correct and the high SDS is due to strong OOBE, probably Band 14.

Oh yeah, I hate Band 14. You can have sites licensed at 1,000 watts. If you happen to be in the fresnel zone of one of those 1 kW antennas you’re screwed.

 

[mtindor]

Are those both on site 20? Looks like the SDS has RSSI in the 60 dBm range and the BTT in the 100’s.

I know the SDS will show false high RSSI if it sees other extremely strong signals in the band. Maybe you have Band 14 causing the high SDS RSSI and bad decode on the BTT. Just a guess as don’t know how sharp the BTT filter is.

I could be totally wrong, but didn't Todd say the P25RX had a sensitivity of something like 0.35uv while the microP25RX has something like 0.80uv ? That and the fact that he is probably using a 700/800 ducky on the SDS and then using the antenna provided with the MicroP25RX on the MicroP25RX. Either of those factors is going to make a difference in signal strength, and if both are true then that really would have an effect. I don't know what the sensitivity is on the SDS, but I know that if I put my 800 mhz antenna on either one, sitting at the same location in the basement shack, the SDS picks up the local site (not very strong but no issues decoding) and the MicroP25RX is barely detecting it down here. And I have nothing stronger to work with, signalwise, where I am located. So it isn't overload or anything like that.

Of course, I'm not complaining. I was aware of the sensitivty of the MicroP25RX before I bought it and don't plan on having it in the basement.