[aprssig] Automatic omni DF query

[Chuck Gooden]

If I am not mistaken, AM is used on 121.5 and Doppler systems will not 
be effective on AM signals.

Rick Green wrote:
> On Mon, 9 Feb 2009, Scott Miller wrote:
>
>   
>> Before anyone asks, these particular units won't work for 121.5 - I've
>> only been able to get them to receive as low as 127 MHz.
>>     
>    That's a moot point anyway - I just read on another site that the 
> government has announced the discontinuance of satellite monitoring of 
> 121.5 and 223.0, obsoleting a huge 'fleet' of ELTs., so all the boaters, 
> aviators, and hikers will be forced to upgrade to the new standard.
>
>