Rio Rancho Simulcast switch today

[Fowler]

Ive been listening to SCSO on 151.415 Im hearing a hetrodyne (sounds like two units talking at the same time) with units in the field. Dispatch sounds fine. Anyone else hearing this?

 

[ChrisABQ]

I'm getting garble too, because of simulcast? I do hear the dispatch saying that another unit was covered on occasion, but not always.

 

[Fowler]

I think the 2 transmitters are coming up on repeat, the base is coming up on one (remote base)
Were hearing both sites hense the hetrodyne

Any other thoughts?

 

[ChrisABQ]

After doing a little research, I came across this old post discussing phase distortion on simulcast systems. http://forums.radioreference.com/922682-post7.html

As an experiment, I'm removing the CTCSS tones associated with the new SCSO, SCFD, RRPD and RRFD frequencies (I've heard the same thing on both systems). I currently monitor these with Uniden BCT15X.

My Baofeng UV-5R is also scanning these systems but does not seem to suffer the phase distortion issue.

 

[Fowler]

Im listening with my Uniden here in the east mts CSQ still have the hetrodyne on the mobiles..

 

[ChrisABQ]

I tested last night, both the BCT15X and BCD436HP have the distortion issue, the Baofeng does not. However, this morning, there has been much distortion in comms and the dispatcher for SCSO is telling units they are horrible in reception.

 

[Fowler]

Agreed Listened today the dispatchers on both SCSO and RRPD were complaining about some of the units transmissions....bugs to be worked out

 

[ChrisABQ]

I'm just posting a little update as to what is happening. As Rio Rancho, Sandoval County and now Bernalillo have all upgraded to simulcast systems, the distortion is definitely due to multipath distortion. According to tower locations, I sit in a terrible area to receive these systems (as the tower locations are slightly offset). However, after building a 1/2 wave dipole (aluminum tube) that's resonant at 150 mhz and creating an air choke for elimination of EMI, I have eliminated about 95% of the distortion issues from all three systems. The discone I was using was horrible. Also, setting the systems to FM rather than NFM, the distortion that does get through sounds more like static than the irritating noise of distortion.

I still receive 50% (or more) distortion issues on my 436 (rubberduck) and old Realistic Pro 2011, but cleaned up the receive issues on my exterior antenna system and 15X.