• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

New comm for J-3

I like to use my com to tune into fingers and talk with my buddies. I have not talked to a tower in more than 20 years. I will have to talk to tower at RDG for WW2 weekend unless my buddy just calls in from his Stearman for a flight of two. My buddy is a full time commercial pilot. When he is not working he avoids towers just like me. We flew from San Diego to WV59 in 3 days in a 48 C170 and never talked to a tower.
 
I am engaged with a very nice Garmin engineer - Jonathan - who seems willing to help. It may be that I will be able to use one of the two discrete buttons on the radio itself to go directly into the user memory. That would cure my memory problems, I think.

I have not yet fully ascertained that the memory can be programmed in my desired order, rather than numerically like the SL-40.

But it does sound like I will be able to use the internal intercom, so that saves $250 and some wing root space. I will report back when we figure all this out. Also, it could be that a dealer locally may have one to demo - we'll see.

i flew my first seven years without a radio. Often I am just as happy knowing where everybody is by listening to the radio. It is easy to cut somebody out in an uncontrolled pattern - even for the pros.
 
Have not yet given up and bought the fancy radio. I finally used the phone number so kindly provided on page one to contact the Pacific Operations Control Center. Their first reaction was "how did you get this number?"

They were really cautious - I think they figured I was just another terrorist trying to mess with the FAA. They ignored me. I called three days later, got a different guy, and he too was quite suspicious: " How do I know you are who you say you are?" But he ultimately routed me to a technician, who left me with the friendly impression that "it is what it is"

An ATC buddy whom I checked out in the J-3 before we started having these problems told me that what I am experiencing is indeed a problem, and that sometimes they really tighten the squelch down to avoid ATIS or Ground Control bleed-through.

I think the system is going to beat me.
 
Get all the guys you can together and each call often.

You have their number, keep calling and complaining. Have an avionics shop do a test and write up a work order saying all is working properly and offer to send that to the FAA guys to show your equipment is correct.

At some point they will get tired of the calls coming and look into what is up...

they might never say anything, but just fix it and you will not hear any more about troubles:lol:
 
I got a chance to use the GTR-200 - below is my letter to Garmin. As far as convincing the feds to do something to help hapless Cub drivers, I despair - but I did call the. Tower yesterday about an emitter off the west end. They said "not much we can do about extraneous transmitters" and I mumbled something about a federal law about interfering with flight . . ..

They are going to look into it. Maybe. Here is my note to Garmin:

A while back I asked about programmable memories in the GTR-200. I have since had the pleasurable opportunity to use and program a GTR-200 in a Great Lakes biplane - a noisy environment.

I was very pleased with the presentation, ease of entry, and ease of access to the memory banks. I will be purchasing this unit for our instructional Cub.

As a suggestion - perhaps it would be even better if, once in the USER memory mode, it stayed there after a frequency flip-flop? That would place this unit at the very top of comms with memory features. For our environment (seven towers in the local area, and airplanes not designed for cross-country) that would be optimum.

One thing I did not get a chance to check out was the internal intercom. The airplane I flew has a PM-1200 intercom, which worked flawlessly. I plan to have a PM-1200 ready, but will start out attempting to use your internal intercom. Most avionics techs advise against using an internal intercom, and I have avoided doing so so far, but by accident I got in to your menu functions and adjusting squelch and volume seems trivial.

I believe it was Kevin who helped me out with understanding this memory - I have lost the e-mail. Thanks for your help. This radio appears to be a quantum leap forward from the SL-40.

Regards - Bob Turner - San Diego

Sent from my iPad
 
Info on that intercom. The PS Engineering PM 1200 intercom is made for open cockpit aircraft. If it works in open air, it works well with a Cub with the doors open. Lots of volume with this unit. The only drawback I've run into is that it only runs two headsets. If you want more than two stations, you need to get the version that has outputs for an expansion unit. Not rocket science but it takes a little more wiring.

Web
 
Get all the guys you can together and each call often.

You have their number, keep calling and complaining. Have an avionics shop do a test and write up a work order saying all is working properly and offer to send that to the FAA guys to show your equipment is correct.

At some point they will get tired of the calls coming and look into what is up...

they might never say anything, but just fix it and you will not hear any more about troubles:lol:


Maybe? Good idea but I bet you they will change their phone number.
 
Yeah. I called the number a poster above suggested - Pacific Operations Center - they asked me how I got the number, and how would they know I wasn't a terrorist?

Nope - I am losing the incentive to fight these guys. We have been asking for a wind sock at the approach end for years. Answer is always " too expensive - and the environmentalists won't let us"

I don't need it - but the students do. Today the tower was calling the wind 240/10G20, the runway was 28, and the windsock was sticking out due north. It is laughable - the tower says "wind 240/16" and immediately the student says "wind check" and nobody is looking at that wind sock. The only time the tower report and the actual wind are the same is when it is not important - like 280/6.
 
I did call the. Tower yesterday about an emitter off the west end. They said "not much we can do about extraneous transmitters" and I mumbled something about a federal law about interfering with flight . . ..

True as far as the controllers being able to do something, but, if the transmissions are someone acting as a controller or obviously attempting to disrupt air traffic, the FBI gets involved. Otherwise it's up to the FAA's district frequency management office.

Frequency problems are the most frustrating ones to deal with because the controllers usually cannot hear the interference or it doesn't impact them directly. They usually take a LONG time to find the source and correct because airborne equipment and operators are required to track it down and identify the cause. Those resources are few and far between.

In your case of the unheard transmissions, resolution could take months or perhaps longer. It takes dedication and cooperation from the specialists at the Operations control center, the field technicians, the users and support staff to resolve. First step is to identify the problem to get the gears turning. That's where you are at right now.

Wish I could do more to help.....

Wayne
 
If, as you say they claim, they tightened the squelch down because of 'extraneous transmitters' the ruling body for this is the FCC. The FCC licenses operators with transmission capability to control just such issues. You'll need to verify that this is the issue or is that tower guy puffin' smoke up your shorts. If that is actually the reason they changed their squelch settings, the FCC is the group that needs to be contacted to enforce transmission rules for the operations causing interference.

Web
 
They tell me that squelch is not tightened, and that it is adjusted to preset numbers not related to ambient noise. My ATC spy (a participant here and a Cub driver, but not named for obvious reasons) tells me that indeed they do tighten the squelch up, and part of it is their own antenna farms. The ATIS and Ground antennae are often very close, and can bleed through.
 
We finally bit the bullet. The Stearman got a GTR-200 and the PM500 intercom. Web is correct - if you want to use a PS Engineering intercom in an open cockpit, you must use the 1200 in ptt mode. We are now pulling out the PM-500 and replacing it with a Sigtronics unit with ptt capability.

I am using ptt incorrectly, but you get the idea - you have one button for radio transmit and another button for intercom. No voice activated PS Engineering intercom in an open cockpit. The PM1200 has the ptt feature and a voice activated feature, but no squelch knob. We were able to use a Sigtronics portable in the Stearman as a voice actuated intercom without monkeying with squelch for every power setting - the PM-500 works, but needs a squelch adjustment for each power setting.

The reason I chose the PM-500 for the intercom is that I have had such spectacular results in the 85 hp J-3 with door open - I figured it would work. We will be putting the same setup in the Cub we now have the Icom in, and I expect it to work fine.

The thing that disturbs me about the Sigtronics unit is that none of the wires are shielded. We always shield all audio wires, even the return wires. I did not do the Stearman installation - it took 22 hours at the local avionics shop - but I am half done with the Cub installation, and will probably be done with another report in a month - I work slow. Mechanical is all done - I just have to wire it and test it.
 
If you insist on using a Sigtronics (I'm always against that) fabricate up a wire harness using shielded wires and isolation washers on ALL jacks. It doesn't cure all the problems but it helps.

Web
 
Sigtronics (I'm always against that)
What issues do you encounter? I've had two different Sigtronics intercoms in my 12 (over about 40 years), and they've worked very well - at least I am pleased with the performance??
 
What issues do you encounter? I've had two different Sigtronics intercoms in my 12 (over about 40 years), and they've worked very well - at least I am pleased with the performance??

Nothing but noise issues. Metal skin, fabric, steel frame, wood frame, doesn't seem to matter. Besides being an old design, they tell you to install with unshielded wires and ground jacks to airframe (taboo for any avionics guy). Another problem is that most of their models use a single amplifier to power all headsets. So as you plug in more headsets your volume decreases.

Web
 
Thanks Web. My Sigtronics installation instructions specifically stated to NOT ground the jacks to the airframe, but to run ground wires to the common ground buss. I called and asked the tech guys why, and they said I might have noise issues by grounding jacks directly to the airframe, and they strongly recommended against that. I followed the instructions carefully, including the non-shielded wire, and have no noise problems. But then, my one example does not mean that's always true. I will say that I paid a lot of attention to a good single-location ground buss, largely based on advice received here on 'da org'. Thanks again for your contributions - -
 
Smoke test today!

At first, semi-success. I turned it on, but no audio. A quick check with an ohmmeter assured me I had hooked it up correctly, so I went in to the radio's "system setup" page and enabled the intercom. Then, success! Everything worked, including the internal intercom.

Of course, I only got one time around the pattern - we are not allowed to do more than that when there is a football game at the stadium.

One possible "down" might be the LCD screen - I put the radio in the wing root, and viewing at an angle is not as good as I had hoped. I may also have the internal lighting not set up properly.

More as I wring it out with a student. I did hook up the intercom "key" leads (that's apparently what they call intercom ptt). I am so far convinced that I did not need them - I did not mess with the intercom squelch, and had noise-free intercom at all power settings and flight conditions, door open.
 
I think the "wring out" phase is complete. Everybody, including the tower, is pleased. I set it up with two different ways to access memory, and showed everybody how to set the squelch on the intercom. The "monitor" feature is not well understood yet, but as folks get used to it I think they will like it. Its only real use is ATIS, but once in a while it is nice to listen to two tower frequencies.

The book says it draws six tenths of an amp - I think they made an error; we have over six hours on the first battery, which says this thing is not power hungryl.

The intercom is not perfect, but it is good enough that we are going to try it in the Stearman. I will let you know how that works.

In short, so far we are delighted! I even put a ptt in the stick, which everybody really likes.
 
Oops. I thought I had said - we bought two Garmin GTR-200 comms. I made the mistake of thinking that the PM-501 would be a good intercom in the Stearman - it has worked great in the Cub. Garmin encouraged me to try the internal intercom, and I am glad they did.

Wiring this thing was trivial - I have four twin-lead shielded cables, four PTT signal lines, a ground and a power line. Took about two hours to get the plug ready, and another two to solder stuff in situ to avoid extra wire lengths.

We will now convert the Stearman to use the internal intercom. I shall report back.
 
Last edited:
Peter just asked, in a PM, for more info. We have been operating flawlessly for over three months - more or less daily flights. I love to demo this thing.

The internal Garmin intecom is the best I have flown in a door-open airplane. We still have not hooked the Stearman directly to the internal Garmin intercom, but that is imminent. The Garmin seems to know when wind noise is present, and mutes it slightly if it cannot automatically squelch it out. I do have it set up for ptt intercom, but have not used that feature except for demo.

The Cub is a battery- only aircraft. We are getting eight tach hours between battery charges. Running on battery voltage is considerably below the stated 14 1/2 volts the radio "requires", but we have full power and no complaints. The battery low indication is you cannot transmit. It is obvious the minute the finger hits the button. Then we change batteries for another eight hours, and charge the low one.

Setup is semi-involved. I programmed the bottom soft key to cycle through my memory, and the top soft key to do the same with the little knob on the right. Both are extremely useful in our frequency-saturated area. I mounted the radio in the wing root ahead of the rear spar, and can operate it from either seat. Much, much better than my SL-40 and PM-501. A joy to use.

If you use "monitor" I recommend going in to the factory settings, and making it shut off when you change frequencies.

We do have an RF problem locally - I expect to find a pair of antennae within five miles broadcasting on two frequencies, the difference of which is 125.7 Mhz. This radio is pretty sensitive, and may be picking up something on that frequency due to heterodyning. It has not been an operational problem, but it is peculiar to these radios.
 
Back
Top