How ironic.
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What inner city relays? Weāre talking FM here not DAB+
Fox and Triple M have relays on the Rialto building - https://web.acma.gov.au/rrl/site_search.site_lookup?pSITE_ID=11599&pSORT_BY=frequency&pSORT_DIR=asc
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They are āBackupā relays.
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AS Melbourne Fan says these are back-up sites in case Mt Dandenong is wiped out.
They are not normally on air in any capacity
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Itās not possible to have FM relays on the same frequency (other than road tunnels where relays work well as the original signal is completely unavailable). It would cause all sorts of issues with echo and signal cancellation.
You notice it driving into the City Link tunnels that there is sometimes quite an audible echo or brief loss of signal as you enter the tunnels and the FM relay kicks in.
Thatās not true, there are some FM SFNās in Europe. I think thereās at least 1 in Australia (but I canāt remember where).
Thereās a broadcast engineer in Brisbane that I sometimes work with, who knows how to do it properly, & through my processor, I have the ability to run 2 identical feeds out with different timings to suit an FM SFN.
There will be an echo/signal cancelation spot, but you engineer it to be in an area of little significance.
In the cities, thereās reflected signals bouncing around off tall buildings everywhere anyway, giving the same effect as an SFN.
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Which is also used for tunnel announcements:
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In addition to FM SFNs, AM SFNs are also possible ā for example, BBC Radio 4 on 198 kHz has multiple overlapping transmitters on the same frequency.
Probably not a proper SFN by design, but the Islamic LPONs on 87.6 and the Spanish LPONs on 87.8 in Sydney essential act as SFNs as they have numerous overlapping transmitters in Sydney all on the same frequency.
ABC Wide Bay and Eidsvold are a SFN on 855.
In Victoria, the āsouthernā frequency for 3SUN - Hit Shepparton/Goulburn Valley. It broadcasts on 93.7 from Mansfield, Alexandra and Yea.
It was largely implemented to provide a single frequency for travelers to Mount Buller once you get out of range of the Melbourne stations.
EDIT: The Alexandra license is no longer listed in the ACMA database.
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KCSN Los Angeles and KSBR Orange County are both on 88.5 and had for many years suffered terrible interference with each other. A couple of weeks ago they solved the issue by effectively merging and creating a SFN of three transmitters on 88.5 which continues with the KCSN altenative rock programs. The KSBR jazz programs continue on the HD2 channels. They also have a three transmitter SFN on 89.9 to the north west of LA.
Thanks for the info. Didnāt realise it was commonly done despite the technical limitations.
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Is ABC News on 94.5 covering all of the Sunshine Coast and Gympie areas using 2 Tx sites be the one youāre thinking of?
Also there is a SFN for Victoria Police that is used as a Voting network for their analog comms.
V/Line also used to have a SFN for their Train To Centrol comms.
RDS from some stations carrying the hit program in SEQ tonight
90.9
91.9
93.1
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For a minute there, I thought I was seeing some Dxāing.
Gladstone RDS from tonight
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Youāve done well to get those from Brissy with RDS since they are only 1kw!
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