Transponder options

kevin · #1 07-07-02, 11:05 PM

Hello,

Your webmasters have returned from a fabulous four days in Nelson, BC, with a stop to clear customs on the way in Castlegar, BC. I recommend both to pilots who would like to fly to someplace with a bit of a challenge (but not overly). It is BEAUTIFUL country, very dramatically steep 6000' hills surrounding a river/lake with the airport and town right on the lake (description applies to both places, but Nelson is the prettier of the two).

Anyway, sadly my transponder died on the way back, and now only four days before Arlington, drat! I am going to try to get my avionics shop to look at it tomorrow through a combination of begging, tantrums and bribes, but if it does not work, does anyone other there have a 28v KT76 (not KT76A) that they could loan or sell me on short notice? I am inclined to replace the one I have with a Garmin GTX-327 if mine has lost the cavity tube, but if not, I hope to get mine repaired. I just might not be able to get it done in time. I'm also interested in shop suggestions in Oregon or Washington that I check with if my shop is too busy and the bribes don't work....

I need this fixed by Thursday afternoon. I need to be in Arlington Thursday night, then in Canada again on Saturday, and I need a transponder to cross the border...

I have no idea what is wrong with the transponder, only that it failed hard, and did not work for 3 sectors and approach control, so it is probably truly failed.

Any advice, suggestions, would be much appreciated.

Kevin

Kevin McDole · #2 07-08-02, 12:51 AM

Here are some sites that sell used equipment - and in particular KT76s. Looks like the price range is from $440 to $900:

http://www.wingsonline.com/avionics.html
http://www.avionics-wa.com/usedequipment.htm
http://www.avionix.com/xpndr.html

The first link is where I saw a KT76 for $440 (posted 6/1/02) - but you have to scan down quite a ways to see it.

Also, if your avionics shops is an AEA member, they have accessz to an online database of used equipment for sale - and that's maybe the best place to look.

Bob Cook · #3 07-08-02, 10:05 AM

Kevin

most of the time it is a voltage regulator inside that goes south when hot. replacement cost is about 5 dollars.

I had my transponder fail last year into Newark and cost 300 dollars to repair regulator. Now have dual transponders and extra blind encoder! Figured after 9/11 and with border crossings you are dead in the water without one.

Suggest you go for a backup. you can get factory refurbished KT76C for about 1K and blind encoder for 150$. Need a xfer switch.

Bob

SkyKing · #4 07-08-02, 03:14 PM

Kevin,

If you're unsuccessful at homebase, give Tom Leal a call at Olympia Avionics, Tel: (360) 357-3134. This guy knows his stuff... small mom & pop operation, very friendly. They're at the OLY airport. And they're a bona-fide King dealer. Occasionally he has some nice used equipment too in the glass case... so, it wouldn't hurt to ask if he's got another one you could swap out.

SkyKing

WebMaster · #5 07-08-02, 08:25 PM

I'll second Bob's note, we have 2 transponders and one blind encoder. Our primary transponder is coupled to the encoding altimeter. A couple of years ago, in a rented airplane, we lost transponder in the NE, where you got C & D airspace, and a couple of airbases all over the place. We are fortunate that our plane came with 2.

kevin · #6 07-08-02, 08:47 PM

Thank you all for your replies. Turns out the transponder is intermittant, and the problem cannot be reproduced on the ground. I just don't want to deal with a transponder that potentially dies on me when I am trying to cross the border twice over the next two weeks, or when I am making the trek to OSH, so I think I am going to bite the bullet and get a new unit (Garmin GTX 327). I have had problems with this transponder over the last couple of years, I think it is trying to tell me something.

Kevin

Bob Cook · #7 07-08-02, 09:17 PM

The 327 isn't any more reliable than a 76A or C. If you grab another 76 (cheap) then you can just swap it out on the fly if need be and carry it in the back. I did this for awhile until I had the other one installed. Mode S is coming soon and no doubt we are probably going to be forced to switch over. 9/11 is speeding things up!

You can get a real deal at OSH! Also you can get factory remans from Eastern or other places with a years warranty for under 1K.

just a thought.

bob

kevin · #8 07-08-02, 10:51 PM

Bob,

It would be silly of me to argue with *you* about electronics, so I'm just writing back to let you know my thinking, wrong as it may be.

I need one, absolutely as for sure as possible operating transponder for the next three weeks. Warranty will not help me, it has to work.

My thinking is that the best bet I have for getting that is to buy a new, current mfg transponder. I believe that the newer (i.e. 76C, G327, UPSAT equiv) transponders are more reliable than older technology, so I have a somewhat improved chance of reliable performance over next few weeks. (Of course, I could get a premie, nothing is certain in this life.) Of the current new models, I like the

Bringing my existing transponder along just uses up weight, as it is likely to fail again when it gets hot. I could buy another one for $500, but then I would be spending 1/3 of what my shop is charging me for the Garmin installed, and it could fail in a few months. The $1000 reman is an interesting idea, but remans are repaired factory returns, and from my time in the electronics biz, I don't want one of those. It could be a unit with an intermittant failure that has just been signed off as "cannot duplicate", and resold.

There is probably an emotional component, in that this transponder has failed twice in the last 12 months, and each time it was "tweak" to tune it again. I am tired of the additional stress that an inop transponder creates in IFR operations.

So, the cheapest, and probably smartest, way to go would be to buy TWO more KT76 transponders for $1000, and throw each one away when it fails, but that could be both in a short time, or not, who knows...

Sometimes, it just seems simplest to buy something new. Maybe not cheapest, maybe not smartest, and maybe it will fail after 3 hours of use. But it feels like the best long term use of the money.

I don't think mandatory Mode S is near enough to enter into this decision.

Who knows.

Kevin

Bob Cook · #9 07-11-02, 10:02 PM

Kevin

I can't disagree with logic like that, however, factory remans have full warranty. I bought a KT76-C at AOPA and is was NEVER used. It was bench tested and the klystron was putting out full power. 1k$, not bad! I am not convinced solid state is any more beneficial but I do totally agree that trying to get around with a defunct transponder is not very sensible.... that's why I opted for dual transponders and encoders.

So...... go with what makes you warm and fuzzy.....<G>. They all work fine.

ur right ... mode S is aways away. C U at OSH

Bob