XM radio

[Rickskymaster]

I need a device that can reduce 28 volts to 14, and that will plug into the XM Roady unit that I use in the car.

Several guys have told me someone has one for sale, but I cannot find it on any of the websites I have checked.

I have the Garmin audio panel setup to take the audio input, but I need this cord for the power.

Thanks in advance for any suggestions.

Rick

[Pete Somers]

Hi Rick

Have a look around for a King KA 39. There must be a few around used as owners are now upgrading the old KX 170/175 radio,s and these were used in the 28 volt installlations.

Peter

[Dave Underwood]

I had already thought the lighter put out 12 volts so you could plug it in directly. That is then legal as it is portable equipment. You might need a splitter if you want to power more items, but I think those are widely available.

Otherwise you might want to build something and get some form of approval. If that is the case, I can make two suggestions, 1) find a volage regulator that will handle the voltage/amperage requirements or 2) find a DC to DC converter. That would allow you to take 24 volts down to 12 volts off a fuse or breaker.

The DC to DC converter is more efficient and lower heat output.

Regards - Dave

[WebMaster]

The cigarette lighter is 24V.
Depending on the XM unit, most have a plug that will handle 12V or 24V.
If you need other, http://www.voltageconverters.com/inverters_110v.html
this place has 24V to 110V converters, then you would need a 110V to 12V adapter, which is pretty readily available.

BTW, which one do you have??

[Rickskymaster]

I have the first Roady that came out, I love the unit, but a friend who also has one in his plane told me that I need the voltage reduction.

Are you sure that it will handle and reduce the higher voltage?

Rick

[Pete Somers]

Hi All

DO NOT USE THE CIGAR LIGHTER!!
These are a 12 volt unit and uses a dropping resistor, which is mounted above the HYD power pack on the port side.
If you overload the lighter socket you will burn out the resistor.
It is meant to take the load of the heater element only.
BTW if you do not take the same current as the element in whatever you plug into the lighter socket you risk a higher than normal voltage being supplied.

Peter

[WebMaster]

DO NOT TRY THIS AT HOME

I did not read your post correctly. This is a Radio, intended to work in a car, right??

The adapter that goes with it will not deliver the correct voltage, and you will burn up the radio.

You need a seperate voltage dropping unit, not something you can plug into the cigarette lighter circuit.

[stackj]

http://shop.altenergystore.com/itemd...D2~eq~~Tp~.htm

Take a look at this unit. Appears to be exactly what you need.

[Peyton]

There was an article in CPA magazine with a full description of a Roady installation last year. It gives the part # and supplier of an adapter which I bought for approx $40. Alternately, it also tells how to modify the 12 VDC cigarette lighter plug which comes with the Roady. I also did that with $3 in parts from Radio shack...but you gotta be pretty good with a soldering iron. If you are a CPA member you should be able to go to their web page (www.cessna.org) and find that old issue and article. If you aren't a member email me and I will see if I can find a copy of my old instructions.

I installed a cigarette lighter aux recepticle from my fuse panel (with the work signed off by my mechanic in the log books) and plug the modified power plug into it. That makes the Roady a "temporary" installation so it doesn't have to be signed off.

Plug into your audio panel, throw the antenna on the glare shield and enjoy. I have no interference with my GPS430 or portable GPS295 with its antenna right beside the Roady antenna. Mine has worked great for a year!

If you want to discuss just call me at 864-419-9934.

Hope this helps

[Rickskymaster]

Peyton:

Any chance you could find where I can get the adaptor at.
I think I would prefer going this route.
I am not currently a CPA member, so I do not have the article you speak of, but I want to thank you for your assistance.
I will get the first round in Key West.

Rick

[Peyton]

Rick - Just got home from a weekend trip..Give me a day or so and I will get to the hanger and dig up that info for you.

[Peyton]

Rick - Source for the "SkyFi 10-30 VDC Power Adapter" is Aeromedix (www.aeromedix.com) phone 888-362-7123. Cost in Oct 2003 was $39.99 plus ship and hdlg.

CPA article was in Sept 2003 magazine if you can find a friend with the old mags or willing to download it from their web page members only area.

If you want to modify the existing 12 VDC cigarette lighter power plug supplied with the Roady just:
1.Open it and remove the 470mf capacitor rated 16 VDC and replace with PN:272-1030 rated 470mf at 35VDC from Radio Shack. Tight and tricky work with a soldering iron but simple enough.
2. Use a dremel tool or small hobby saw to cut cooling slots in the housing above the new capacitor.

A photo of my installation is attached.

[Peyton]

Rick - One caution....there is a small magnet to attach the antenna to your car top hidden in the base of the antenna (buried under the tape decal). Be sure to remove this magnet before using the antenna on your glare shield to prevent the obvious problems it would cause with your compass.

Mine has been working perfectly since Sept 2003. You will like this setup.

Enjoy

[J.T.Grant]

Dear Sirs,
Spoty's sells a simle plug in 24 to 12 volt dropping unit. Available in lower or higher current rating. Specifically designed to solve the problem of 12 volt accesories in a 24 volt aircraft.
Regards
James T Grant