First Flight! and a little radio problem

Papa · #1 12-12-2008, 07:20 PM

Well, yesterday was the big day. N558RV took to the skies for the first time, and with the exception of a few minor issues flew great! I'm breaking in a new engine (Superior XP-IO-360), so I just did laps above the airport for a half hour or so, but I was pretty happy with how everything worked. The issues I had were:

1. Round analog ASI and Dynon D180 airspeed differed at low speed by about 10 knots.

2. Oil temperature readings were erratic, and when they worked a little low (160 F)

3. Radio transmit is reported as very broken. The radio is a ICOM A200.

Two of those items are already fixed when I took the airplane up for another 1.6 today. I did a pressure reset on the Dynon unit, and now the airspeeds agree within about 2 knots all the way down to stall speed. I removed the wire to the oil temperature sender, scuffed the terminal end up a bit and reattached it. That fixed the erratic readings, and they are now very steady. And I blocked the oil cooler (baffle mounted) and had oil temps in the 200 F range.

My remaining problem is this: I did a quick check of the radio, coax, and antenna on the ground and everything seemed in order. I did a radio transmit check between a handheld and the aircraft radio and it seemed okay. (The handheld was only about 30 ft from the aircraft, however) The radio is receiving great. Everything sounds clear, and the range is at least 40 miles when airborne, probably much more. When I went flying this afternoon, however, the transmit problem was not fixed, and I was very nearly NORDO when I got back to the pattern as nobody could understand my transmissions. Does anyone have some suggestions on where to start trouble shooting? The Headset is fine and was used in a different aircraft two days ago without issue.

Thanks in advance the help!

Mark

frankh · #2 12-12-2008, 07:56 PM

And what he said!..

Rockyjs · #3 12-12-2008, 08:01 PM

Congratulations on your first flight Mark!

You still may want to try a different headset even though yours worked fine in a different aircraft.

Bob Axsom · #4 12-12-2008, 08:38 PM

The manufactured hardware is most likely OK. I would look at the Mic jack wiring as well as the audio input to the transeiver. Since the other people of frequency were offended by your garbled transmission you are producing RF radiation. I am not familiar with the connector interface but if there is an obstruction built into your installation the radio pins may not be engaging the tray connector properly. Look at the pull-in-and-lock device on your radio. If it is not in the proper orientation when you install it in the tray/airplane it may appear to install properly but the "lug" may actually be blocking the full insertion. Another possibility is interference from other systems in the aircraft. If the short range ground test was made with power supplied by the aircraft battery, try the same test with the engine running and see if the reception by the handheld is still 5x5 (loud and clear). If the transmitter outputs clearly the transmissions are not going to get garbled by distance.

Bob Axsom

PaigeHoffart · #5 12-13-2008, 05:02 AM

A friend of mine had a similar issue with the A200. It ended up being cabin noise over modulating the radio, which caused clipping and distortion. The solution was pulling the radio and adjusting the mic gain pot on the back. He also installed an Oregon Aero mic muff, which helped considerably. You can search the archives and probably find some other posts on the issue.

Paige

Geico266 · #6 12-13-2008, 06:11 AM

Congrats Mark. Sounds like you have most everything under control due to a good built.

sprucemoose · #7 12-13-2008, 08:44 AM

Congrats on your first flight!

As for your radio issue, Paige is right. This is a very common issue with the A200, which is a great, low cost radio, but the factory default settings for mic gain and sidetone are way too low for our noisy airplanes. Information on how to change the settings is in the manual, and there is plenty about this issue in the archives. Do a search on A200.

Troubleshooting Rule #1- always try the cheap, easy fixes first!

L.Adamson · #8 12-13-2008, 09:21 AM

Quote:

Originally Posted by sprucemoose

Congrats of you first flight!

As for your radio issue, Paige is right. This is a very common issue with the A200, which is a great, low cost radio, but the factory default settings for mic gain and sidetone are way too low for our noisy airplanes. Information on how to change the settings is in the manual, and there is plenty about this issue in the archives. Do a search on A200.

Troubleshooting Rule #1- always try the cheap, easy fixes first!

Interesting! My A200 would squeal at high throttle settings; but I once connected reverse polarity to it (before the plane was finished), which smoked it a bit and blew it's internal fuse. An A210 has replaced it, but I sometimes suffer the noise problem with the intercom, as I have no insulation yet. Maybe I'll just adjust the mic gain, and find that I still have a good radio.

edit: the intercom is a seperate unit

L.Adamson

cyrilmclavin · #9 12-13-2008, 10:26 AM

Well done as for the radio noise i have the same setup i tried the gail etc hepled a bit but it turned out to be un-sheilded wire so i rewired with sheilded but most of all check that the mag wire sheilding is grounded thst is where 90% of my problem lay. Hope this helps.

cyril

Papa · #10 12-13-2008, 04:58 PM

Thanks everyone for the kind words, and the radio advice. I think Paige is probably on to something with the mic gain suggestion. I'm always up for trying the cheap and easy things first! There is a fair amount of noise in the cockpit, and given that my reception is good, the idea that the radio is over-modulating when I transmit makes a lot of sense. I'll give it a try and report back.

Mark