Fillet Question

[rwanttaja]

Almost looks like the headset jack couldn't be assembled if the housing was all one part......

Was preying on my mind, too. :-)

Rotating the jack to put the contact stanchions on top seems to leave clearance for the jack to lever into place. It can then be turned to the desired angle. The printer doesn't generate the transformer-bay bulkheads very well (they're more crescent-shape) and that leaves more room.

I'm not that fired about this design because it cantilevers off the instrument panel; don't like the way loads are going to go. I'm working on a more-squat design.

Ron Wanttaja

[flyboy2160]

...I'd been selecting the aft face of the oval area, AND the side of the table area, or the vertical line AND the aft face of the oval area. Never considered just clicking the vertical line only...

Sometimes using the standard 'edge fillet' method of picking the edge in the crotch won't work. You can then try a 'face' fillet, which is closer in practice to your original pick scheme. You pick the faces between which you want the fillet.

[rwanttaja]

Assembled...but not wired...unit, both open, and with the outer shell in place.

I'm thinking about making one 1/8"=1/4" longer, to make wiring a bit easier.

For those wondering, when you are using an aircraft headset on a handheld radio, this adaptor increases the headphone sound level by 6 dB (doubling the volume).

Ron Wanttaja

[Kyle Boatright]

I'm not that fired about this design because it cantilevers off the instrument panel; don't like the way loads are going to go. I'm working on a more-squat design.

Ron Wanttaja

Can you mount it behind the panel, with only the jack protruding?

[rwanttaja]

Can you mount it behind the panel, with only the jack protruding?

I've considered that... in fact, just mounting a second jack in the panel with the matching transformer. Then I could plug in to the "aircraft headset" or "ear bud" jack as appropriate. A bit more work than I want to do, unless I have to peel open the behind-panel area for another reason.

Ron Wanttaja

[flyrgreen]

[QUOTE=rwanttaja;79194Ron Wanttaja[/QUOTE]I'm not that fired about this design because it cantilevers off the instrument panel; don't like the way loads are going to go. I'm working on a more-squat design


I have worked with all things audio for many years and saw this problem right away. You are correct to be concerned about the moment-arm weight from all this hanging on the 1/4" jack. By the time the actual headset cable and plug are connected there is considerable force. I don't have a guess about this force making for actual breakage, but it will make for internal connection problems. You likely know that there are factory-made transformer adapters just like this, for sale at any audio outlet (including Radio Shack if you can find one). But they are made of metal and much heavier than your SW design. I'm guessing that's why you are bothering to do this work. But the cantilever and significant moment arm seems dicey to me. I would try to design something that is a 90 degree plug.

[rwanttaja]

I'm not that fired about this design because it cantilevers off the instrument panel; don't like the way loads are going to go. I'm working on a more-squat design

I have worked with all things audio for many years and saw this problem right away. You are correct to be concerned about the moment-arm weight from all this hanging on the 1/4" jack. By the time the actual headset cable and plug are connected there is considerable force. I don't have a guess about this force making for actual breakage, but it will make for internal connection problems. You likely know that there are factory-made transformer adapters just like this, for sale at any audio outlet (including Radio Shack if you can find one). But they are made of metal and much heavier than your SW design. I'm guessing that's why you are bothering to do this work. But the cantilever and significant moment arm seems dicey to me. I would try to design something that is a 90 degree plug.

Yes, and the problem here is actually worse than it might first appear. I'm building this adaptor to get good volume from a Flightworks Denali ANL headset; as an ANL headset, it has a battery box on the cord about ~6 inches from the plugs. So the cantilevered design, if I just plug in the headset, is even worse with the weight of the battery box added.

As you can see from the aircraft installation, I do have options. There's a small shelf below the headset jacks; it's where I used to clamp the battery box from the Denalis before I decided I needed more volume.

I might actually build a little clip to attach the headset's battery box to the GPS mount (the disk-shaped thing just above the ferrite cores on the headset cable). That would take most of the load off a plug-type adaptor.

I actually made a "long" version of an adaptor cable; ~3' of cable terminating in a box with the jacks. This works, but there's too much cable. Might do a short version that attaches to the Denali battery box.

This is a nice casual project. In the summer, I use 8-ohm ear buds, and in the winter, I wear a Rugged Radios headset where I've swapped out the 300-ohm speakers for 8-ohm units. No rush, no impact if it takes me a while to solve.

Closest Radio Shack to Seattle that I know of is in Skagway, Alaska...that's a fur piece to drive. I know they had some transformer adaptors before, but never saw a 300-ohm to 8-ohm version. I used a lot of Rat Shack audio transformers in my own adaptors, though.

Ron Wanttaja

[rwanttaja]

And...test fit went pretty well. Was able to fit the ANL battery box across the strap below the radio, and the adaptor actually rests on it a bit.

I'll probably remove the ferrite cores; believe my feedback problem has another source.

One of these days, hopefully, it'll stop raining long enough to take it out for a test....

Ron Wanttaja

[flyrgreen]

Yep, that looks like good support. I had a 'feedback' sounding radio problem when I bought my (used) plane. After much poking and cursing, turns out it was a weak ground on the BNC antennae connector on the tray. I see you are handheld so no tray, but mentioning this to say that a working but very weak ground on the antennae side will choke the signal and make it cram back into the radio's output. Imagine if that were you--- you'd be be squealing too!

[rwanttaja]

Yep, that looks like good support. I had a 'feedback' sounding radio problem when I bought my (used) plane. After much poking and cursing, turns out it was a weak ground on the BNC antennae connector on the tray. I see you are handheld so no tray, but mentioning this to say that a working but very weak ground on the antennae side will choke the signal and make it cram back into the radio's output. Imagine if that were you--- you'd be be squealing too!

Yeah, I had a squealing (audio feedback) problem that was driving me nuts. No problem plugging in the headsets directly, no problem when using 8-ohm headsets. Problem ONLY occurred when an impedance matching transformer was used. Used another handheld at home for testing, but could never reproduce the issue. Thought it might have been some leakage on the antenna coupled with the windings of the transformer, but even with the adaptors wrapped in copper tape, still had the feedback.

Finally figured it out: Sidetone volume level was too high. "Sidetone" is hearing your voice in the headphones when you transmit. Adding the adaptor increased all audio in the headset by 6 db...which is *four times* the audio power. I cranked down the sidetone volume (keypad adjustment on the Icom) and the squeal went away. And I did still have sidetone at a decent volume level.

Ron Wanttaja