ADF

[Andrew Conroy]

Hello Everyone,

The unit is a KR 86 ADF. I have yet to see this thing work properly. I can tune into and find any AM radio station just fine. When I tune a local NDB, I can identify the station fine but when I select "ADF," the signal becomes very staticky and the pointer turns steadily to a direction other than the beacon. The pointer seems to be pointing in a specific direction, just not the correct one.

Please don't let this turn into a comment about gps.

Any advice or recommendations to troubleshoot?

[N3322G]

Hi Andrew,

You are a man after my heart. I loved my ADF. We ran out of space in the panel and had to give it up ... I still miss it.

The ONLY time our ADF failed is when there was an antenna problem - only twice in nearly 40 years. So my suggestion would be to look hard at connections and the antenna itself. For us it was the connections that failed. I did notice when it was removed that there was some corrosion back there (on the bottom aft of the fuel drain area around the cut for the antenna). We keep the airplane clean and dry so we were surprised at that. I mention because this may also be an area to inspect.

Memory is hazy but IIRC there is a sensing antenna and a tuning antenna so again, guessing, I'd go after the sensing antenna. Don't know if any manuals are out there but you might try Googling the device. Ours ran down the belly under the floor.

[Andrew Conroy]

Thanks for the advice. I am going to pull up the deck in the baggage compartment to get gain acess today. We shal see if I can get this thing to work. Who knows.

[Andrew Conroy]

Well I finally got the baggage compartment deck up. Checked all connections to no avail. Finally I pulled the loop antenna connection apart and found that one of e board mounting screws inside connector had punctured one of the wires and it was grounding out. I went to test fly and I am able to pick up ndb's reliably to about 25 to 30 miles. I can pick up adf marker beacons up to 15 miles or so.

The only problem with what I have now is that the needle does not point straight up when the beacon is directly ahead. I placed the compas card where the needle points when the beacon is directly ahead and tracked the ndb using relative bearing from where I had set the card.

Can a kr86 needle be calibrated/zerod?

[N3322G]

Hurray for progress.

Haven't had that problem so no advice.

[Andrew Conroy]

Well after son research on the internet I found a tch tip article that had some kr86 adf information. The instructions for my symptoms were to simply remove th face plate and turn the needle by hand until it lined up. I flew to Bowie and pointed the plane at the antenna a few hundred feet away. After I manipulated the needle, the adf worked perfectly. Praise The Lord. Took off and shot a practice ndb approach at Bowie then Denton muni. Worked great the whole way with good range. The adf marker beacon at denton started working 20 -25 miles out. The ndb at Bowie works about 30 miles out.

To recap, the problem was the screw that dug into the loop antenna wire and then a miscalibrated needle. Thanks for the support.

[N3322G]

Way to go Andrew!

It really is amazing what can be found on the Internet.

[Fred Horne]

If you’re interested, I have a NARCO ADF841 with tray and antenna for sale CHEEP. Rebuilt in 2010. Fhorne@cox.net