Electrical Systems and Avionics

[GAD]

I am looking at used radios for there plane that I want to buy and wonder what is the normal voltage as some of the radios are 14 verse 28. Electrical systems have always been a bit of a mystery to me!

Thanks, Greg

[hilltop170]

Greg-
I'm no expert either but all of the 170s I have ever seen were 12 volt systems. 24 volt radios will not work in a 12 volt system. Look long and hard before buying used radios, they should be "yellow tagged" meaning they have at least been checked out by a certified shop and deemed good to return to service. What kinds of radios have you been looking at?
Richard

[sphillips]

170's are 12volt only, and I agree, only buy yellow tagged.

[4stripes]

The price of a new certified VHF has become more reasonable, and the reliability will be worth the extra investment. There is nothing more wasteful than having to not fly, while you wait for repairs. Avionics shop rates are higher than you might expect.
I was fortunate to have a good King KX170B, but it has been in the shop twice in the past 18 years.

[Bruce Fenstermacher]

Greg

It's good to look around at what is available and what they cost in the used market.

Before I bought anything I'd talk to the avionics shop you are going to have to the work. They might not like your choices meaning they would have a difficult time installing them or they just don't want to get involved with the installation. Avionics shops frequently have used radios to sell themselves and of course your transaction will go smoother if you buy the whole thing from their shop.

24 volt systems are found for the most part in slightly larger singles, twins and turbine powered aircraft.

Avionics are generally either 12-14volt, 24-28 volt or are switchable between them depending on the aircraft needs. Some of the new avionics like at least the hand held Garmins have a voltage range like 5-30 volts which means the unit will automatically adjust in the range.

You will never be upset with a quality communications system. A system includes the antenna and wiring to the audio. You can be frugal but don't be cheap.

[blueldr]

If you're looking for a comm radio, I strongly recommend the VAL 760 TSO. It's the least expensive flip flop on the market and , for me has been, by far, the best and most powerful and reliable I've ever owned.

I previously had a King KX170. Two trips through the shop cost more than the VAL did brand new, and then it still would not operate reliably. The VAL has never had any kind of a problem in sixteen years and works perfectly all the time.

[blueldr]

Another great feature of the VAL radio is ,for some unknown reason , never touted by the manufacturer.

It is an excellent conservator of aircraft locks and doors. I've never heard of any airplane being broken into to steal the avionics, not to mention hangar doors and panels.

[jrenwick]

If you're looking for a comm radio, I strongly recommend the VAL 760 TSO. It's the least expensive flip flop on the market and , for me has been, by far, the best and most powerful and reliable I've ever owned.

There may be some differences of opinion on this. I have a VAL 760 in my Swift, and I'm not fond of it. The toggle switches that set the freqs are tiny and uncomfortable to use, and they get flaky over time, so that you never know whether a press of a switch is going to change the frequency or not. The LED display is supposed to dim automatically at night, but mine dims unpredictably in full daylight. VAL will make the whole thing like new for a couple hundred, give or take, but while that's going on, I'll have no radio. And I don't regard it as a true flip-flop, because you can only set the active frequency -- never the standby.

But it's the cheapest thing on the market, and I guess when they're working right, they are loud and clear.

Best Regards,

John