KMA 20 Audio Selector & COM radio 3 Decimal Place Tuning

DavidT

Hi,
I need help with the above, which is probably due to my inexperience with the Warrior. I'm trying to listen to ATIS at Humberside airport in UK (124.13) according to MSFS ATC;

No problem if I use ATC's preset to tune ATIS on COM1, provided microphone dial is also on COM1 or EXT, except frequency changes to 124.10 & not 124.13
If I manually tune either COM1 or COM2 to 124.10 (or even the available 124.12 & 124.15), no ATIS through the speaker
Tried a couple of other locations with the aircraft at the appropriate airport without success
It seems ATIS frequencies are often 3 decimal places, whereas the COM radios display only 2. Is there a way in any configuration files to alter that, to ensure the correct manual frequency is inserted?

I've attached screenprint of my KMA 20 setup. Can anyone see any problems with this or give me a clue to anything else I should check. Ihave tried to search this forum and the wider internet, but to no avail.

Thanks,
DavidT WarriorKMA 20.jpg

N293WK

@davidt 124.13 only exists in the realm of 8.33kHz channel spacing, something that these radios do not support. These radios are older, and only support 25kHz spacing, hence why it skips from 124.12 to 124.15. (The 124.12 is actually 124.125, but only two decimal places are required to remain unambiguous).

If you want to fly in the UK (or anywhere that uses 8.33kHz spacing), you'll either need to tune using the MSFS ATC window or use a newer radio (GNS or GTN options).

Here's a short PDF explaining the reason and how it works: https://www.ofcom.org.uk/__data/assets/pdf_file/0023/144590/Understanding-8.33kHz-frequencies-and-their-specific-channel-number.pdf

DavidT

@n293wk Thank you so much for your speedy response along with your enclosure. Very helpful. I wasn't losing my insanity after all!
I was quite enjoying the relative simplicity of the GPS100, but now I shall follow your 2nd suggestion and explore the other two options, which I had not previously tried, but was aware of.

DavidT

jmarkows

I think they might be capable of 8.33kHz spacing, but it's bugged.

See here: https://community.justflight.com/topic/2963/com1-tune-in-problem

@N293WK given that you've posted in both threads saying that the radios don't support 8.33kHz spacing, what's the bug that JF is referring to? I have the files from support but haven't done any real flying recently to know whether or not I can tune certain frequencies now.

N293WK

@jmarkows That bug was slightly different.

Normally, 119.22 is really 119.225, but it's unnecessary to show the third digit because anytime you have .22, it will be followed by a 5. There was a bug where 119.22 was being converted internally to 119.220, which is incorrect. That's the bug they were referring to.

Note that it's impossible to represent all 8.33-separated frequencies with only two decimal places. To show this, consider that there would be 12 frequencies from 118.00 up to but not including 118.10, but only 1 digit to play with, which means there are 2 that we can't represent in that range alone.