V is for VOR

[Gone Flyin]

Was having issues with my C150's VOR, recently. Could barely hear the morse code identifier and the indicator flag kept flipping from OFF to TO / FROM.

I had helped my friend fix the VOR antenna on his 150 last year when the nylon insulator block at the top of the vertical fin cracked and one side of the antenna was handing down.

I knew the wiring inside there was somewhat precarious, so I headed there, first.

Sure enough, one side of the coax shield had broken off from the antenna terminal.

It was clear this had been worked on before as there were two different terminals used for the connection to the #10 X 32 threaded ends of the antennas. I removed all the wiring, made two new connections and installed new self-locking stainless steel nuts.

I also noticed there was considerable weight pulling on the coax cable from below. I assume there is some kind of termination block for the open circuit end of the coax. Why it is so heavy, I cannot say, but it may have had something to do with the connection breaking.

So that it does not happen again, I installed two large cable ties to the top of the coax loop preventing it from falling into the hole. Basically, a simple strain relief.

Now, there is no longer any tension on the connection to the antennas.

Put it all back together and flew the plane. The VOR is back in business.

 

[geezer]

Good fix, I think that I have not done that on a couple of Cessna's that I have flown. One, the cable was too short to reconnect, and we took it to the avionics shop for a proper repair, and log book entry.

Caution, though, the reason the cable is pulling down hard may be that it is making a 90 turn at the base of the stabilizer, and you have pulled it tight and sharper radius than it was. Previous repairs may have "lost" some length, and now there may be a serious chafe problem. Inspect down there to see what is happening, and adjust as needed. There may be some extra slack in the cable running forward.

 

[Joe Pilot]

Don't know why original installers don't add a little loop for slack and future repairs. $0.50 of wire makes someones future life much easier.

 

[Gone Flyin]

Don't know why original installers don't add a little loop for slack and future repairs. $0.50 of wire makes someones future life much easier.

The loop was not the issue. There was no strain relief.

It is all hanging on the braid and there is weight of some kind on that cable constantly pulling it down. Every time you land, it bounces up and down and breaks off a few more strands of wire. Just a matter of time and then you lose your VOR... maybe when you need it most.

Get your AP to check it... or do it yourself.

Not that complicated.

 

[sourdough44]

I’ll sometimes dial in a VOR for a reason or two, mostly novelty. The GPS is working fine.

I can see reason to want or need a VOR, I’d rather not spend to much $$ doing so.

 

[Der Fliegermeister]

AC 43.13-2B Fig. 3-6.

Go buy some RG58 and make yourself a new balun loop. It's not expensive and it's the proper fix you'll be proud of. Usually there's a BNC connector near the tail cone or such that connects the balun loop from the antenna to the coax running to the nav receiver or splitter up front. Each one of those unions is good for around 2dB loss so make sure there aren't several in the line from "maintenance" over the years.

Electrical tape + zip ties is just janky...

 

[pfarber]

AC 43.13-2B Fig. 3-6.

Go buy some RG58 and make yourself a new balun loop. It's not expensive and it's the proper fix you'll be proud of. Usually there's a BNC connector near the tail cone or such that connects the balun loop from the antenna to the coax running to the nav receiver or splitter up front. Each one of those unions is good for around 2dB loss so make sure there aren't several in the line from "maintenance" over the years.

Electrical tape + zip ties is just janky...

Something that no one will ever see ?

If you think zip ties and electric tape is not a thing in GA then you must not work in GA.

 

[Der Fliegermeister]

Something that no one will ever see ?

If you think zip ties and electric tape is not a thing in GA then you must not work in GA.

Really? That's your standard of workmanship? "No one will see it."

I have been in GA long enough to make money cleaning up after "mechanics" that figured no one would see their fix.

When the fix is literally spelled out for you and drawn in a nice little picture, what possible excuse could someone have for not doing it right?