I haven't been able to do any hands on work for a while so thought I would contribute a frequency dial scale for the AWA Radiola 429-MA which was made some time ago.

The AWA Radiola 429-MA does not have frequency marked on the dial. In order to make alignment easier I have prepared a frequency scale that can be attached to the front of the dial that makes locating the dial pointer to the positions required by AWA's alignment procedure easier.

The frequency for IF peaking 540kHz, and the upper and lower alignment frequencies 1500 and 600kHz are marked with a cross.

The scale is scanned backed by a ruler. The length of the scale is the distance in mm between 2LG and 4QL, 144mm.

It is up to you to produce a print the correct length. This can be done by manipulating the print size in print software, and by trial and error matching the ruler scale to an actual ruler.

Then cut out the scale and stick it on, lining up the dashed lines at each end with 2LG and 4QL.


The preparation was done by plotting frequency against distance for a dozen or so stations across the dial in Excel (looking up the old frequencies in Wikipedia) , and producing a polynomial equation describing the resulting curve. The polynomial was then used to calculate distance from frequency at 10kHz intervals. This was in turn plotted which results in a scale with 104 gradation marks at 10kHz intervals. This scale could be manipulated in a graphical software package to produce a final schmick dial scale, but I simply used a pencil, ruler and set square to produce the final dial scale from this final plotted scale.

Photo uploaded.

For rough dial calibration 2AY went from 1500 to 1495 and 3SR 1260 being devisable by 9 stayed put, up the top & middle.

Quite handy as the actual stations are close.

If 2AY was 1500, it doesn'r agree with my scale where it is 1480-1490. What to make of that? I suppose as long as it was close that was good enough, or the draftsman made an error.

I used the main Sydney city stations, plus country stations at the end of the dial for my plot against frequency, that is

2LG 2WL 2LF 2SM 2CH 2UW 2KY 2UE 2GB 2BL 2FC 2CR 4QL

The plot was quite smooth so I figured the dial must be pretty accurate for station locations as were. Just as well I didn't choose to use 2AY! But it would have produced a bump in the plot which would have made me wonder.

Somebody with a Victoria dial may be able to comment on 3SR.

The problem was for some bizarre excuse, possibly related to revenue. somewhere about the late 70's they changed from a separation of tens to apparently a European separation of nine, then to make it even more crazy, like rendering all TV's obsolete. They reallocated the frequencies.

That meant that 3NE locally went from 1600kHz to 1566 and as said 2AY to 1495 and so it went on so that every radio from that point backwards, has pretty much all of its marked stations in the wrong place.

That means as you have realised, is to know the frequency high to low, and unless there is a bar in frequency that can be marked with a generator, you could be all at sea.

There is a list of the current allocations. I think on the ACMA site I have archived somewhere a list I made comparing 1937 to some but it will be a bit dated.

I will have a search in the sub folders of the main folder it should be in. Currently there is an audit of duplication and junk on the mobile HDD's and 1/3 of a 2Gb drive has been cleared out.

I used List of Australian AM radio stations in Wikipedia because it has old and new frequencies side by side. Wavelengths are there also for those interested.

This doc says that the 1978 change was according to The Geneva Frequency Plan and does mention that freeing up about 10% of the band was a motivation.

2AY is on 1494, not 1495.

Also in post#1 it says 629-MA which of course should be 429-MA.

That rather runs with my comment more room more revenue.

Did not last long by way of space, as some stations are now beyond 1600 and in 1937 most stopped at 1500, before that was moved to 1600.

Should have noticed that the numbers in 1495 don't add up to 9, 18 or 27.

Thanks Robbert, 629 changed to 429 in Post#1.

Marcc, Wiki also says that the change to FM really started then too because of better sound and cheaper transmitting equipment, which shut down some AM stations. Others though became community stations of one sort or another.

AM may have worse sound quality and be more subject to interference, like it can pick up lightning from a substantial distance. Anderson actually discovered both AM and FM where the frequency wobbles with the audio.

It was very much realised in the early days, just which frequencies traveled the greatest distance and it was from radio experiments, the hole in the Ozone layer was found.

It looks like it has been discovered just what a seemingly crazy idea it was to move some stations. I believe the original concept was to keep stations that had to cover the largest area low. Also space them apart so that they did not cross modulate & trample on each other.

There are two strong stations here ABC Radio National,(575?) that Rodney Chamness felt was a waste of a transmitter as it probably had a bout 13 listener's & 3NE 1566 Commercial, which also broadcasts in AM. I often wonder if they are concerned about cost, why the same programming is not sent out simultaneously on both?

2CO Corowa was I think the first rural transmitter 1925. Some goose was responsible for having it only broadcast Riverina stuff when, before they stuffed up the antenna could be heard at Broadford Vic. on a car radio in daytime. I am not sure what decision was made other than the historically wrong one. To not replace its Alexanderson Antenna with the same.

I did find the excel file, thought it was old 1932 compared to 2005. However, should there be a desire. It can be updated.