View Full Version : NDB frequency decimals
pholooh
8th Nov 2002, 15:44
I will just like to know how one tunes to an NDB that has a decmal point in it(e.g. coventry's CT 363.5) as the ADF frequency selector has only three digits.
I'm not YET a licensed pilot, justa curious wannabee.
Thanks in advance for all info.
Stan Evil
8th Nov 2002, 17:26
The bandwidth of these ADF receivers is wide enough to cope with being 0.5 KHz off frequency. Conventionally people tune to the frequency minus 0.5 (ie 363 KHz at CT) but, if I had reception problems on that then I'd tune 364 and expect to get a result.
To be honest, I've never seen a digital ADF that turnes to 0.5 KHz.
fireflybob
8th Nov 2002, 17:34
ADFs on most large public transport aircraft can tune to 0.5 kHz and some can select narrow or broad bandwidth.
This issue was covered on another thread at:-
NDB (http://www.pprune.org/forums/showthread.php?s=&threadid=69833&highlight=ndb)
Hope this helps
I recall on my IRT I tuned in an NDB incorrectly (by 0.5) but idented it and used it correctly. I passed so that has to be the acid test really.
One really has to wonder....just WHY would a decimal frequency be necessary with an NDB anyway?
Any airways tech guys here have a clue?:confused: :confused:
OzExpat
11th Nov 2002, 06:58
I've never found anything that I'd call a convincing reason for it 411A. It was once suggested to me that it happened because all the whole frequencies in that particular part of the spectrum had been used up. It seems that this may have been because the authority involved (US FAA??) didn't want to go to higher frequencies - or maybe the receivers couldn't tune those higher frequencies... or some such.
Anyway, like I said, I'm still waiting for a convincing reason. I've only been involved in procedure design since 1985, so there's probably still time to learn the truth? :D
pholooh
11th Nov 2002, 14:52
Thanks for all your replies, they've been really helpful;) :o