Radio History


It’s possible, however there was (and still is) a difference between 4BC and 4AK; While both were 5kw at the time, 4BC used a twin-mast directional antenna that may have had a null towards the south. 4AK by contrast is omni-directional.

According to an announcement on-air at the time 4AK could be heard clearly in Melbourne at night.


This is still true with 18kw daytime and 6.3kw nighttime power.
There current towers are fairly short so at night SEN 1116 sometimes over powers it on the Sunny Coast and Western Brisbane.


In Sydney, it went something like this:

2FC 610 to 576
2BL 740 to 702
2EA 800 to 801 (later to 1386 & then 1107)
2GB 870 to 873
2UE 950 to 954
2KY 1020 to 1017
2UW 1110 to 1107
2SM 1270 to 1269
2JJ 1540 to 1539

In nearby centres close to Sydney:

2KA 780 to 783
2KA (Penrith translator) 1480 to 1476
2CT (Campbelltown) 1390 to 1602
2GO 1310 to 1323 (later to 801)
2WL 1430 to 1314
2WN 1580 to 1431
2HD 1140 to 1143
2NC 1230 to 1233
2NX 1360 to 1341
2KO 1410 to 1413
2NA 1510 to 1512

Sources: ABT Annual Reports 1977-78 & 1978-79


…and then to 1107 sometime after 2UW converted to FM and relaunched as Mix 106.5? Or were 2EA and SBS Radio completely different entities?


No, they were the same, as the callsign for SBS Radio’s AM service in Sydney & Melbourne is still 2EA & 3EA respectively.


What happened to 2CT?


It shut down in 1981 due to financial troubles.

More about the station below.


Do you mean that 4AK was once on 1224?

If so, that may have also caused issues for 2WS in Sydney as well as 3EA.


“Friendly” 4AK was on 1220 and had to move to 1240 because of 3EA.


4WK also made a frequency move around that time from 880 (very close to 4GR) to 960. That later let 4BH move from 1390 to 880.


Can vouch for that still today, 4BC in western Brisbane is surprisingly weak here in the west and cops a fair bit of interference, especially once they switch to the lower night power and the skip kicks in

I’m sure it’s been talked about here a few times before, they had a much better site years ago in Fig Tree Pocket but sold the land and moved to Nudgee as they could make a fortune from the prime real estate the transmitter site was on. The old site from my understanding served the whole city much better


It was better in some places worse in others.

From what ive heard there was 2 choices for transmitter sites… Nudgee or Cornubia

Cornubia with a big DA would of been my choice considering how close the road is getting…only a matter of time before we see it move

here is a picture before the TX was installed


Wow. Such a big change for those ABC stations.

Pity it had to happen. I know it’s purely co-incidental but the change to 9kHz spacing was about the time AM radio started on a downward trajectory. Truly wideband transmission on AM began to disappear as stations inserted audio filtering (often because of what was built into the audio processor) to restrict audio to 9kHz. As is mostly the case still today.

And that 10kHz heterodyne whistle came down to a more annoying and obvious 9kHz on wideband AM radios. Sigh.


Drone photo from my miserable time working there as a tech

Always set the processors to 9khz if they are set lower and bandwidth of the tower allowing… Gotta have good audio :wink:


4BC always seemed to be located towards the west and that’s where the coverage was best - Western Suburbs, across Ipswich to the range. The rest of the metro area also had good coverage. The disadvantage was that the nulls seemed to line up towards both the north and south coasts and the growth suburbs in those corridors.


And from memory, 4BC was the weakest of the Brisbane commercial AM stations on the Gold Coast.


Was it about 2001 4BC moved from Fig tree Pocket to Nudgee?

I remember in the early 2000’s, until they moved into the Cannon Hill studios, they had horrible audio being transmitted. Not sure if that was studio or transmitter related.


Yeah the Nudgee site is hard up against the motorway and trapped by expanding residential development on the western side. Plus it suffers the disadvantage that the CBD is to the south where the null to Melbourne is

A site south or east would have made more sense for mine, given the limitations placed on it by the co-channel in Melbourne. Lets you fully blast the CBD area with a good signal. Works for all the other AM stations being based out Tingalpa way


I’ve long thought a site out in the Redlands or Logan would be great to throw the signal north, back to the co channeled stations to the south. Close to the coast in the Redlands or good conductivity on a flood plain in Logan. Rich red soil in Redlands.


They do have DAB to help cover for any inadequacies in the AM signal.