# Radio Data System (RDS)

**URL:** <https://forums.mediaspy.org/t/radio-data-system-rds/237>\
**Category:** General Radio and Digital\
**Created:** [December 28, 2015, 7:43am UTC](https://forums.mediaspy.org/t/radio-data-system-rds/237 "2015-12-28T07:43:12Z")\
**Posts on this page:** 1\
**Showing post:** 393

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**Author:** ![anon71206228](https://forums.mediaspy.org/letter_avatar_proxy/v4/letter/a/e9a140/32.png) [@anon71206228](https://forums.mediaspy.org/u/anon71206228)\
**Post date:** [September 25, 2017, 5:33am UTC](https://forums.mediaspy.org/t/radio-data-system-rds/237/393 "2017-09-25T05:33:15Z")

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> [@tonks8526](#):
>
> It’s 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.

That’s not true, there are some FM SFN’s in Europe. I think there’s at least 1 in Australia (but I can’t remember where).

There’s 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, there’s reflected signals bouncing around off tall buildings everywhere anyway, giving the same effect as an SFN.

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