Wiring up a new PTT switch

[Old Koreelah]

I purchased an aftermarket PTT but find the switch unreliable and too klunky to fit on my stick. In order to feed the cable up through the stick (where I plan to install a smaller switch) I had to cut the original switch off. Now to wire in the new one...

 

My new, smaller switch only has provision for connecting two wires, but the tester says that the original switch connects two pairs of wires (red to green and black to white). Is a double switch necessary for this application, or is it just that the manufacturer happened to use this sort? I don't want to cut the connectors apart to trace the wiring.

 

Any advice?

 

Regards,

 

Lyle

 

 

[fly_tornado]

try joining one pair and put the other pair through the ptt switch

 

 

[Old Koreelah]

Thanks for the quick reply, FT! That may work, but having no understanding how it is wired up, I fear the radio may be damaged if wired incorrectly.

 

 

[fly_tornado]

part of the fun of home building is learning....

 

 

[Wayne T Mathews]

Thanks for the quick reply, FT! That may work, but having no understanding how it is wired up, I fear the radio may be damaged if wired incorrectly.

Huullooo,,, Lyle, your brother used to be, and even though he's retired from the RAAF now, I'm guessing he still is, one of the best rad techs this country has. When you've got those sort of brains in the family, man, why would you be asking us? Unless of course, you're just teasing...

 

 

[Old Koreelah]

Huullooo,,, Lyle, your brother used to be, and even though he's retired from the RAAF now, I'm guessing he still is, one of the best rad techs this country has. When you've got those sort of brains in the family, man, why would you be asking us? Unless of course, you're just teasing...

Not teasing, Wayne. The things you learn on this forum. Brother has moved far away from that trade in recent decades. I hoped that someone on this forum had experience of wiring up their own PTT switch. As FT says, it's part of the fun of home building, but I've had just a little too much fun... most jobs I've ended up doing re-doing until I arrive at the ideal set-up. Expensive and time consuming. My shed is full of cast-off bits and pieces; I'd rather not add a cooked radio to the mix!

 

Lyle

 

 

[Kyle Communications]

Lyle

 

Normally the PTT is just 2 wires that get shorted together by the switch the second set could be a parallel set going to another ptt switch somewhere do all 4 wire go to the same place?

 

Mark

 

 

[sain]

what radio is it? that may help us somewhat.

 

 

[matto]

If you can post a wiring diagram from the radio manufacturer i should be able to assist

 

 

[fly_tornado]

from what I understand with the PTT switch the mic is open all the time and the PTT just completes the circuit. not sure why there are 2 wires, maybe its a backup to a secondary switch?

 

 

[Old Koreelah]

If you can post a wiring diagram from the radio manufacturer i should be able to assist

what radio is it? that may help us somewhat.

Sorry, it's a Vertex Standard VXA-150 hand-held.

I have located a useful site http://www.brenorbrophy.com/HG/head_set_ptt.htm but the resistors in the PTT circuit made my eyes glaze over...

 

Can I do any damage if I don't add resistors?

 

 

[Old Koreelah]

LyleNormally the PTT is just 2 wires that get shorted together by the switch the second set could be a parallel set going to another ptt switch somewhere do all 4 wire go to the same place?

 

Mark

Thanks for the reply, Mark, but short of cutting open the connectors I don't know where the wires go.

 

 

[Virago]

Is this PTT switch the type that has two plugs (oh well, a plug and a socket) If so, refer to fig 9 of the attached link. It tells you which wires have to be joined to allow the "mic audio" to go through to the radio when only the PTT is being switched. http://flightcom.net/pdf/403mcManual.pdf John.

 

 

[matto]

Do you have a mulitmeter? Set it on resistance(test by touching the leads together, 0 ohms means you have a short circuir or the right wire when testing the following) by holding one lead on a section of the plug and trying the other lead on the cut wires you will be able to work out which one goes where. Also if you break open your old switch you can see what colour goes where and replicate this on your new one.

 

The resistor will prevent an open circuit and help eliminate initial transmission noise (click or pop when the button is pushed) but it will work without it. You should only need 2 wires

 

 

[Old Koreelah]

Thanks Virago and matto! The link should give me enough to go on. You learn lots when you design and build houses, bikes, planes... but electronic is one area I have always shied away from. It's time I learned a little.

 

 

[Kyle Communications]

This should help just note what yaesu version you are using the 2 plug or single plug

 

Mark

 

Headset and PTT circuits for popular handheld transcievers.doc

 

Headset and PTT circuits for popular handheld transcievers.doc

 

Headset and PTT circuits for popular handheld transcievers.doc

[sain]

Sorry, it's a Vertex Standard VXA-150 hand-held.I have located a useful site http://www.brenorbrophy.com/HG/head_set_ptt.htm but the resistors in the PTT circuit made my eyes glaze over...

Can I do any damage if I don't add resistors?

looks like it. Have a look at the manual for the Vertex VXA-150 (available on the Yaesu site here). The circuit in that that include an external ptt include the resistor (see pg 30).

All you really need to do is solder the resistor onto one leg of the switch, then the wire for that leg to the other end of the resistor.

 

You can get 8 of the resistors from jaycar (here) for about 46 cents.

 

 

[eastmeg2]

That reminds me of a PTT I canibalised (from a radio set I bought from Aldi's years ago) for my Buzzard trike which I'd installed a 2nd hand Microair M760 in.

 

It took a little while to figure out why the PTT didn't work until I measured its impedance which coincidently was 2.2k-ohm.

 

It did work after I opened up the switch to solder in a wire to bypass the 2.2k resistor and fitted a 3.5mm mono audio plug to the other end to match the socket I'd installed in the dash board.

 

Cheers,

 

Glen

 

 

[Old Koreelah]

looks like it. Have a look at the manual for the Vertex VXA-150 (available on the Yaesu site here). The circuit in that that include an external ptt include the resistor (see pg 30).All you really need to do is solder the resistor onto one leg of the switch, then the wire for that leg to the other end of the resistor.

You can get 8 of the resistors from jaycar (here) for about 46 cents.

Thanks sain. Your efforts are appreciated. I have downloaded all relevant info (after negotiating some unwanted good luck-I won an iPhone 4s and they wouldn't take no for an answer; I had to quit Safari to get the persistent buggers off my computer.)

 

I have manuals, both paper and pdf, related sites, multimeter, headset, PTT assembly and radio all laid out on the desk. I have used the tester to find which wires are connected to which part of the plug and jack. Now I have to concentrate and figure all this out!

 

 

[Old Koreelah]

Sorry to bug you again, people, but I really need a hand with my radio...

 

You may remember I recently asked for advice re wiring up a PTT switch on the stick.

 

 

 

After reading all the advice offered, and testing the cut-off original PTT switch, I tested my plan by carefully touching together the two pairs of wires that the original switch connected. The radio worked OK so I joined one pair of wires and soldered the other through the switch.

 

 

 

I now get a loud tone whenever the PTT switch was pressed. This happens even when the PTT circuit is removed from the radio and only the headset is connected via the 3.5mm plug.

 

Just to complicate the issue, the tone does not occur when the radio is operated without the headset.

 

 

 

What have I damaged and how can I fix it?

 

 

 

Regards,

 

Lyle

 

 

[Tex]

Sounds like EMI or RF interference: I would add ferrite rings to everything

 

http://www.jaycar.com.au/productView.asp?ID=LF1250&keywords=ferrite+suppression&form=KEYWORD

 

and use a noise filter on the power line

 

http://www.biasboating.com.au/product_p/4844.htm

 

 

[J170 Owner]

I purchased an aftermarket PTT but find the switch unreliable and too klunky to fit on my stick. In order to feed the cable up through the stick (where I plan to install a smaller switch) I had to cut the original switch off. Now to wire in the new one...My new, smaller switch only has provision for connecting two wires, but the tester says that the original switch connects two pairs of wires (red to green and black to white). Is a double switch necessary for this application, or is it just that the manufacturer happened to use this sort? I don't want to cut the connectors apart to trace the wiring.

 

Any advice?

 

Regards,

 

Lyle

Is there not a wiring diagram for the plane? Either with the plane or on the manufacturers website?

 

 

[Old Koreelah]

Is there not a wiring diagram for the plane? Either with the plane or on the manufacturers website?

The aircraft is owner-built and heavily modified. The PTT has nothing to do with the airframe design, which dates from the 1940's when a radio was an unnecessary complication.

The problem is how to replace a 4-terminal switch with a tiny 2- terminal PTT switch. Neither the Vertex radio or the after-market PTT has a wiring diagram which can help.

 

After doing my best with the info I could obtain, it appears I may have damaged the radio. (The noise sounds like feedback, but only happens when the headset is connected. Fitting a different headset does not remove the noise, no does adjusting the volume or removing the headset from proximity to the radio.

 

Thanks for the suggestion and links, Tex. Is it possible to install ferrite rings without having to cut off and reattach plugs?

 

 

[Tex]

You can get clip on ones http://www.jaycar.com.au/productView.asp?ID=LF1294&keywords=ferrite&form=KEYWORD

 

they are a lot bigger generally but you can put a wrap in the line and run the wire through twice.

 

Beyond the noise is the head set working... can you hear and talk with it?

 

Photos might help us resolve the issue

 

 

[Old Koreelah]

You can get clip on ones http://www.jaycar.com.au/productView.asp?ID=LF1294&keywords=ferrite&form=KEYWORDthey are a lot bigger generally but you can put a wrap in the line and run the wire through twice.

Beyond the noise is the head set working... can you hear and talk with it?

 

Photos might help us resolve the issue

Thanks Tex. That sounds like a workable solution. I don't have a nearly radio to test my reception against, but it appears that despite the noise while transmitting, it still works OK.

 

Have you any ideas what exactly would have caused the noise?

 

Two pix: original PTT, and the current setup, with new PTT at top of pic.