scanSydney

A possible test transmission popped up this morning on 420.2125Mhz - that control channel type sound.

Still going at 3:45PM. At one stage an RFS transmission broke in.

Very strong signal in Sydney South West. I suspect off Horsley Park. Not listed on any Sydney site.

Mike

It sounds a lot like one of the standard test patterns - I'll compare a few and report back!

EDIT:-

OK, so the noise is the "Standard Tx Test Pattern (formerly CCITT V.52)". You need a service monitor to read the resulting BER but it shows that they're doing coverage testing. At my location I get the signal with a 0% BER.

I think it's a RFS PMR test. That frequency appears as belonging to the RFS on other country sites. Might be the same as what they use on 420.200Mhz off Kurrajong Height - hence the test.

With the BER you're getting Citabria, do you think it's coming off Kurrajong Hts or Horsley?

Mike

Initially thought it was Kurrjong because of the strength (it's very high), but then I checked and it turns out that I have line of sight to the licensed allocation at Narrow Neck, even though I am definitely in the Sydney Basin!!!

It seems like it's at Hosley Park for me. I'm receiving it on a portable indoors and fairly strong mobile near Bankstown Airport.

Mike

Don't underestimate just how high that site is - here is the path from Narrow Neck to Bankstown Aerodrome:-

Yes, it's LOS too..

Hmmm. You may be right.

There was an RFS weather report broadcast on 420.200Mhz this arvo and with 20 dB attenuation, the 100% signal from Kurrajong dropped to about 80%, but the test transmission on 420.2125 dropped from 100% to about 30% with attenuation.

20dB attenuation on anything from Horsley Park barely makes a difference.

Mike

It was coming up with a NAC 211 last night with Blue Mountains RFS traffic, and NAC211 belongs to the Blue Mountains Digital PMR Vote. However doesnt appear to be a channel assignment in the codeplug for it, ill have a closer a look.