Good 'ole ADF

inav8r

inav8r

Line Up and Wait
Joined
Feb 14, 2005
Messages
600
Location
Indiana, US
Display Name
Display name:
Mike B.
I see a lot of posts suggesting that the ADF is obsolete and not used very much. As a student planning and flying my solo XC's almost every one of my flights has used my ADF as a primary mode of navigation (mostly because almost all of the airport's I'm flying to has an NDB on the field). As for navigation equipment the C172 I fly only has dual (basic) VOR, ADF and a yoke mounted Garmin 195 GPS.

My instructor has taught me how to navigate VFR using all 3 systems - as well as the finger on the chart method. For my XC's I have been using either the VOR or ADF as primary (where appropriate) and the GPS only as backup to my finger on the chart. To help facilitate this I keep the GPS off of the moving map display.

What other gear do you usually expect to see in an aircraft when you say the ADF can be obsolete'd?
 
IMO, GPS serves as an adequate replacement for ADF because the GPS is more precise, more reliable, and offers more info than just an arrow pointing off somewhere.

But you can't get the local news/talk station on the GPS, so I think ADFs still have a place. :D
 
ACK! ADF!? NDB? Run!

Your training probably will pay dividends when you work on your instrument rating. Otherwise, if you've got GPS you're going to use it. I never had one until after I got my private. The cheapest of cheap aviation GPS handhelds are going to be worth their weight.

But it is nice hearing the ball game when you travel. Even if it is an expensive AM radio. :)
 
Older is better; I just wish I could find an old AN range receiver (and transmitter). Those pilots from the past were real aviators!
 
Dave,

I've never been able to document it, but my understanding is that the last AN radio range was a Lunken Airport in Cincy. I'd be interested to know if that's true.

I've seen some AN stuff in display cases at local airports. I suspect that it shows up on EBay from time to time.

bill
 
AirBaker said:
ACK! ADF!? NDB? Run!
Click to expand...

I know many folks feel this way, but I think they were just taught wrong.

Yes the NDB signal can be a little unstable during precip and t-storms, but I spent many years reliably gettin into my home airport with only an NDB approach that was worth anything and that got me to 400 and 3/4.

Don't get me wrong, I love GPS, especially the new moving map displays, but when flown properly, and it isn't that hard to fly them properly, the NDB approach is often better than the VOR and always better than no approach.

Just one pilot's opinion.
 
I still have Olivers station guide for the ADF. I When I was a student intrument pilot I did a number of Low Frequency range appoaches with those old head sets. The radio was a Hallicrafters. Doing those range approaches was interesting and fun. Just stay "on the beam" and use your timer as you cross your fixes. The ADF really helped out for it would tell where the station was. I was instructed to find the station without the ADF and that was always entertaining to say the least. You never now when the ADF may fail so we did a lot of range approaches without it. WE use to do this at what is now KBWI. The Airport then was Friendship and the id was BAL. They had a low Freq range and on trips up to the NY area, we would use Newark and Hempstead ranges.

As I look back on it I feel very lucky to have learned from pilots who were around in the early days of instrument flying. I cannot thank them enough.

John J
 
Greebo said:
IMO, GPS serves as an adequate replacement for ADF because the GPS is more precise, more reliable, and offers more info than just an arrow pointing off somewhere.

But you can't get the local news/talk station on the GPS, so I think ADFs still have a place. :D
Click to expand...

I'm surprised that Garmin or somebody hasn't come out with a GPS/XM radio combination using a single antenna. The extra cost would be almost trivial. The next step would be downlinked wx to boot, and the ultimate would be uplinked DB updates (all for a fee of course).
 
Let'sgoflying! said:
Older is better; I just wish I could find an old AN range receiver (and transmitter). Those pilots from the past were real aviators!
Click to expand...

An ADF will do fine as a four course receiver, just set the mode to "Receive". Finding a suitable course may be more problematic.
 
Arnold said:
Don't get me wrong, I love GPS, especially the new moving map displays, but when flown properly, and it isn't that hard to fly them properly, the NDB approach is often better than the VOR and always better than no approach.

Just one pilot's opinion.
Click to expand...

Well, I don't know if I agree that this 'often' better than a VOR approach. If it was all that I had to get into my airport, then I would feel better about it. :) I think I would rather fly a GPS approach with a hand held GPS than an NDB approach in a pinch. Besides, I don't even have an ADF installed anymore.
 
Arnold said:
I know many folks feel this way, but I think they were just taught wrong.

Yes the NDB signal can be a little unstable during precip and t-storms, but I spent many years reliably gettin into my home airport with only an NDB approach that was worth anything and that got me to 400 and 3/4.

Don't get me wrong, I love GPS, especially the new moving map displays, but when flown properly, and it isn't that hard to fly them properly, the NDB approach is often better than the VOR and always better than no approach.

Just one pilot's opinion.
Click to expand...

Agreed.

I'm just VFR for now but I learned clock-compass-sectional, then NDB, then VOR, then DME. My first instructor said "You're going to learn to navigate properly first then you'll learn how to make it stupid simple later." I'm not flying in the seeproof stuff yet but if you can fly NDB's properly, following a line on a tv screen is a big yawn. (To this day I've only flown with a handheld GPS exactly once for about 30 minutes...I was bored to tears in 5 minutes flat) Don't get me wrong though. If the chips are down and I'm between the rocks and the blower is acting funny and I have only onc shot at the runway, I wouldn't turn down the tv if it was in the middle of the panel and I knew how to use it properly but you can bet the familiar toys will be on too. I may be obsolete and come from the school of hard knocks but I'm not dumb either.

NDB's aren't all that hard at all. It's all about situational awareness. IMHO: They're actually a lot of fun especially under the hood because they make you think.

Learn hard, stay very proficient hard, operate simple.
 
lancefisher said:
An ADF will do fine as a four course receiver, just set the mode to "Receive". Finding a suitable course may be more problematic.
Click to expand...

Really Lance? I thought they transmitted one letter when on one side 'A'? and 'N' on t'other. Well actually there were 4 courses centered on a beacon.

So on the A side you get .-
On the N side you get -.
And if you ever get on the convergence you get a solid tone?
Maybe I heard it wrong.
 
Let'sgoflying! said:
Really Lance? I thought they transmitted one letter when on one side 'A'? and 'N' on t'other. Well actually there were 4 courses centered on a beacon.

So on the A side you get .-
On the N side you get -.
And if you ever get on the convergence you get a solid tone?
Maybe I heard it wrong.
Click to expand...

Dave,

Lance is correct. They used a phased transmitting array to send the "A" in one direction and "N" in the other. All you needed was a straightforward radio receiver as the "electronics" (such as they were) were on the ground.

By designing the tower placement properly, you could get sharp changes in the change from "A" to "N", resulting in the solid on-course tone.

The same phased-array antenna technique is used today for AM (ancient modulation) radio stations.

I can get a lot more technical if you want (I used to design phased-array AM antennas for a living).
 
Let'sgoflying! said:
Really Lance? I thought they transmitted one letter when on one side 'A'? and 'N' on t'other. Well actually there were 4 courses centered on a beacon.

So on the A side you get .-
On the N side you get -.
And if you ever get on the convergence you get a solid tone?
Maybe I heard it wrong.
Click to expand...

You're right, and I'm right. All you need is a basic AM receiver on the right bandwith audio output and that's exactly what your ADF is when you put the mode switch on receive. The ground station transmits the A modulated signal with a beam pattern that's 90 degrees from the N pattern. When you're "on the beam" you hear both signals at equal levels which equates to a constant tone (at least theoretically. According to my dad you usually heard one side louder than the other briefly even if you tracked perfectly). If you were off center one side would be louder than the other with the difference in level between the A and N somewhat proportional to your angular off course error. Flying directly over the station put you in the "cone of silence" (remember Maxwell Smart?) which was used to indicate station passage and as a timing reference for an approach. The trickiest concept was figuing out where you were once you got lost by flying an intercept heading and then tracking to/from the station. You had to figure out which of the four courses you were on by determining which side was the A side, and whether the signal was getting stronger or weaker. Then I think there was some trick to guesstimate how far you were from the station.

Now picture doing this in mountainous terrain with a bunch of thunderstorms around. Best not to get lost in the first place I think.
 
lancefisher said:
I'm surprised that Garmin or somebody hasn't come out with a GPS/XM radio combination using a single antenna. The extra cost would be almost trivial. The next step would be downlinked wx to boot, and the ultimate would be uplinked DB updates (all for a fee of course).
Click to expand...

Garmin has come out with XM radio in combination with its new XM weather receiver. The weather is displayed on the Garmin 430-530. :dance:
 
Gary Sortor said:
Garmin has come out with XM radio in combination with its new XM weather receiver. The weather is displayed on the Garmin 430-530. :dance:
Click to expand...

Yeah, and PS-Engineering has a satellite radio option on the PS 8000 audio panel, but I was thinking that a GPS-com would be a natural for the inclusion of an entertainment radio since the display and knobs would be useful and the audio output is already there (needs to be upgraded to stereo though).
 
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