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TSO Com?

The -225 is a better radio. Use good practices when installing it and the antenna and it will work well for years. Just make sure the owner/pilot is ok with working the buttons. You don't want to talk him into installing a radio that he hates changing frequencies on.

Web
 
Sorry. The Decathlon guy's question was "do I need TSO?" The answers I got in this thread were the best way to answer him. I was having conceptual difficulties linking him here, so I bumped it. Then I figured out that the link worked.
 
I did say, in post #1, that we have a number of these neat radios installed. Frequency selection is standard, with two knobs and a flip-flop button.

But you can program it for easily accessed memory frequencies - I have them all programmed for two different ways to access memory. Everybody loves it.

Best of all - even in the Stearman, the internal intercom is the best I have ever used. Voice actuated!

Only bad thing - RF Squelch is inadequate. We can hear approach control on our north runway frequency, and during the Covid lockdown (when a UHF and VHF frequency were combined with one controller keying both) it was almost intolerable.

This is an unusual situation - Garmin refuses to even listen to me any more. They say they did that so you can hear from way far away . . .
 
We have it maxed out. Our north freq. is 125.7. The offending frequencies are 132.2 and I think 257.875. Both need to be keyed simultaneously.

other radios, including my SL-40 and one of the older Garmin GPS- comms, do not have that problem.

The GTR also opens up over the departure end, where an auto dealership has a noisy emitter. It is so loud we find ourselves scrambling to turn the volume down.

The radio is otherwise spectacular. I am in love with the memory circuits and intercom.
 
Too bad they can't apparently address the issue via a firmware or software update. May be some intermodulation distortion and/or selectivity challenges going on as well. I'd inquire about this next time you have a conversation. From their Owner's Manual - typical jargon but should apply:

NOTE
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

Gary
 
First time I contacted them they seemed ready to help. About two years ago they stopped answering me, after explaining that the receiver was designed to listen to a tower from over a hundred miles out.

just what I want to do - call the tower an hour out!

I am living with it. During the height of Covid panic, Socal had a single controller on both frequencies. We were getting crystal-clear approach clearances to Palomar, Miramar, and Ramona. But the Great Lakes guys were going nuts - it was intolerable for about a month.

Now both controllers have to simultaneously key, and what we get is garbled stuff - not complete clearances.

No other comms have this problem.
 
Weird response from Garmin....maybe it's a faulty design soon to be replaced. Usually peaking receiver sensitivity has to be accompanied by dealing with increased signal to noise ratio problems. A variable RF gain plus variable digital filtering can help.

Not uncommon for east asian companies to deny issues exist then offer upgraded products and save face. Question: Does disabling the intercom function have any effect on receiver performance?

Gary
 
I had the GTR200 in my 18-95, worked awesome. I want another. Had no squelch issues, comm and intercom was excellent.


Sent from my iPhone using SuperCub.Org
 
There's been several product revisions and software updates for the GTR-200/200B. Maybe by now they're brothers from different mothers.

Gary
 
Well Bob you could have a Genave Alpha 200 which mine heard every RF source within gliding distance. Not sure what to do but put an RF pad on the coax and live with lowered expectations on transmit and receive.

Gary
 
Well, that's a thought! But isn't breaking squelch different from attenuation?

Again, I run an SL-40 in my personal Cub, and cannot hear SoCal interference. But the SL-40 memory system is so horrible I am tempted to pull it, sell it, and its PM-501, and install the 200. Getting quickly to the next local frequency is a big deal around here. I almost breathe a sigh of relief when I get into the 200-equipped J3s.
 
My understanding of variable squelch is it varies the tripping point at which the radio processes the signal through an audio chain so it can be heard. Signal strength from a transmitter varies over time as affected by terrain, atmospheric conditions, and distance but at a given instant is likely fixed. If you reduce the strength via resistance or attenuation it lowers the chance of it tripping the squelch. But unless there's a keyed switching process between transmit and receive both will be affected. Not easy to do.

With more complex radios there's many options for signal processing for both transmit and receive. It has to be experienced to appreciate the benefits.

I don't know your particular radio(s) series Bob but suspect Garmin would have evolved the radio's architecture over time as problems were reported from the field. I'd ask or test/swap to see if the current production models are subject to the problems you're experiencing.

Gary
 
My observation here, but if you insist on a Garmin radio, move up to the -225. Better quality unit.

Web
 
Probably the reason they haven't fixed the squelch is that I am the only complainer. After all, how many airports are within four miles of two high power transmitters, the difference of which is almost exactly the tower frequency?

And I am not at all convinced that the 225 circuitry is not identical; just TSO'd.
 
had icon in all 5 of my IFR aircraft.
backup garmin 430 ifs coupled
never had problems
all with radar altimeter for off shore use doing polar bear capture.
Built in Sat phones [OAS] required
 
The -A200 was an ok radio. The -A210 was a disaster. Noise and squelch setting issues. -A220 not much better. I'm not the only shop that won't install them anymore.

Web
 
I like menu driven radios that allow the user to personalize the features. But then I don't have to install and maintain them.

Gary
 
BC12D-4-85 said:
I like menu driven radios that allow the user to personalize the features. But then I don't have to install and maintain them.

Gary
Click to expand...

Nothing wrong with that. Some radios perform better than others, so make sure you get one that works and keep away from the ones that don't.

Web
 
In the amateur radio community user reviews and professional comparative testing of equipment is common and expected. Manufacturers know this and pay attention. Consumers can then follow the trends and avoid the issues.

I guess with aircraft it takes experienced folks like Web who offers support and advice based on technical training *plus* experience. We're fortunate to have this benefit.

Gary
 
So I guess you guys are saying replace my Icom A200 with a ky97 in instead of a Icom A220?

But the ability to monitor a frequency and talk on another is sooo tempting!
 
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