FM Spectrum Replan - General Discussion

[dxnerd]

There was a Chinese language station on 77.43 MHz in Sydney a while back; from memory their audio was quite acceptable.

[ozbark]

@crankymedia

Why are the 152/173MHz narrowcasters allowed 25-30kHz bandwidth but 77MHz only 5kHz?

Thought it was the same. I’ve just looked at the licence on the ACMA website.
They are allowed 25kHz of bandwidth per licence spec.
Most likely Nathan is feeding the audio via twisted pair telephone line or something similar that is limited to around 3-5kHz.

@dxnerd

There was a Chinese language station on 77.43 MHz in Sydney a while back; from memory their audio was quite acceptable.

And if it’s the one I’m thinking of it was called "Muse FM’ or something similar & yes the audio/bandwidth was quite acceptable.

[tamago_otoko]

I thought the whole point of the 77MHz stations was for them to work like normal FM stations (i.e. wideband) on radios from Japan that tuned down to 76MHz? There’s a few floating around, I had an old portable that had a ‘Japan’ and ‘International’ setting which could receive the lower frequencies.

[TheStyles83]

Why the Heck does Gympie have 4GY and Zinc 96.1 and not a CHR Radio Station? Zinc and Hot shall swap Frequencies to Allow Zinc Broadcast in pro Northern Brisbane!

[ozbark]

@tamago_otoko

I thought the whole point of the 77MHz stations was for them to work like normal FM stations (i.e. wideband) on radios from Japan that tuned down to 76MHz?

This is only the 2nd such station I have heard on the 77MHz band. In both cases these stations used ‘Narrowband FM’ modulation, which can’t be demodulated (received) with standard Wideband FM demodulator in standard FM radio receivers.
It would be interesting to know how ACMA has allocated & classified the spectrum of 76 - 87.5MHz re usage & specs.
I also have a Japanese band radio that also receives 76 - 108MHz continuous but only with Wideband FM.

[robtog]

@ozbark

In both cases these stations used ‘Narrowband FM’ modulation, which can’t be demodulated (received) with standard Wideband FM demodulator in standard FM radio receivers.

I didn’t know analogue FM radio receivers were so limited they could only demodulate one form of FM. Otherwise I am sure we would start having more narrowband FM stations throughout the FM band, you know like what we get with the great versatility and flexibility of digital broadcasting (DAB)!

[Vidiot]

@ozbark

In both cases these stations used ‘Narrowband FM’ modulation, which can’t be demodulated (received) with standard Wideband FM demodulator in standard FM radio receivers.

That’s not quite right. A standard FM broadcast receiver will pick up the narrowband FM signal. But the audio level will be way down on normal.

[ozbark]

@Vidiot

That’s not quite right. A standard FM broadcast receiver will pick up the narrowband FM signal. But the audio level will be way down on normal.

Correct in practice (and I recall mentioning that to my lecturer years ago). And or but additional noise & maybe distortion maybe encountered on fixed (wide) bandwidth receivers & where the wide bandwidth of receiver doesn’t permit narrowing of bandwidth down to preclude interference from reception from narrowband stations 25kHz away from each other. Guess I’m opening a whole can of worms even mentioning these factors

[motosenokia]

@ozbark

Back to the subject of the former TV Band I spectrum. Nathan Rose has a new test station playing Classic Hits from Mt. Tomah (North/West Sydney) on 77.4MHz. Power is 50W, well heard but bandwidth is a deplorable 5kHz, audio quality being similar to listening to the radio over a landline. Compare with the foreign language broadcasters in the 152 & 173MHz bands who are using 25-30kHz of bandwidth. I wonder what Nathan’s plans are?

I’m flabbergasted by this. Broadcasting in an out of band frequency with limited audio bandwidth a genre which is already served by commercial radio???

[ozbark]

@motosenokia

I’m flabbergasted by this. Broadcasting in an out of band frequency with limited audio bandwidth a genre which is already served by commercial radio???

I was pondering whether Nathan might use this as some kind of future feed for his many River FM LPON unused licences? Even with a 25kHz NB FM signal the audio feed to his wideband FM LPON’s would sound crappy. That said it didn’t stop Radio Austral initially feeding their North Sydney FM LPON on 87.8 off air from their 151MHz band NBFM transmitter.

Nathan might have future plans for using the 77.4MHz transmitter as a broad area digital feed to his FM LPONs? However his Mt.Tomah 77.4MHz licence class says Broadcast Station, Sound.

I’m flabbergasted too.

[lovemusic]

@TheStyles83

Why the Heck does Gympie have 4GY and Zinc 96.1 and not a CHR Radio Station?

Gympie can receive Hot 91 and Sea FM. Zinc also has a repeater on 100.5 which covers most of the Sunshine Coast and it can be received in Caboolture.

[dxnerd]

@motosenokia

Broadcasting in an out of band frequency with limited audio bandwidth a genre which is already served by commercial radio???

Massages the ego.

[crankymedia]

@lovemusic

Gympie can receive Hot 91 and Sea FM.

Not the population centre of Gympie itself, signal reduces as you cross from Noosa to Gympie council on the freeway.

No Gympie business are buying on Sunshine Coast radio for locals to listen.

The FM 100.5 translator at Doonan stops short of Caboolture. Fades out towards the southern end of the pine forests, mostly gone by the Wild Horse Mountain service centres.

[Brianc68]

@crankymedia

@lovemusic

Gympie can receive Hot 91 and Sea FM.

Not the population centre of Gympie itself, signal reduces as you cross from Noosa to Gympie council on the freeway.

No Gympie business are buying on Sunshine Coast radio for locals to listen.

The FM 100.5 translator at Doonan stops short of Caboolture. Fades out towards the southern end of the pine forests, mostly gone by the Wild Horse Mountain service centres.

Yes agree. I drive through Gympie all the time and you cannot get Hot 91, Sea or Mix in Gympie.

[noisefm]

77.4 mhz is really just an experiment at this stage. Currently testing to determine what’s possible / what are the applications?

Personally and aside from the above, I’m very keen on DRM, longer term I think DRM will become the defacto digital radio standard worldwide. Unlike traditional AM and FM radio, DRM and DRM+ can be used across MW, HF and VHF, so opportunities exist to use parts of the spectrum that might be less congested.

[kycalling]

@noisefm

DRM and DRM+ can be used across MW, HF and VHF

That, and I understand the transmission reach is much greater. I think it would be a more economical way to run Radio National - less repeater stations, less electricity. If the audio quality is as good as DAB+ it could work for JJJ and Classic as well.

[lovemusic]

Fair enough. I thought there were FM translators at Tewantin for the 3 Sunshine coast FM stations. I’m assuming these signals are not received in Gympie?

[Brianc68]

@lovemusic

Fair enough. I thought there were FM translators at Tewantin for the 3 Sunshine coast FM stations. I’m assuming these signals are not received in Gympie?

I’m not sure any of these have ever been activated unfortunately.

[NRN11]

Hot FM has been on air since they started in 2003, Mix and Sea don’t feel they need translators for Noosa/Tewantin.

[lovemusic]

So it’s only Hot 91 that has a translator in Tewantin. Does this signal get received in Gympie?