Physical PTT for Remote SmartSDR

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  • Updated 7 months ago
I want to have a physical PTT switch and run my radio via SmartSDR remotely from the physical radio (actually just downstairs from radio location in a telecom rack in a closet).

Yes I know how to MOX and VOX and the wonderful space bar trick.  I still want physical PTT.

Given the following:
* Flex Radio 6xxx
* SmartSDR 2.4.9
* Windows PC with USB and Audio in but NO Serial port
* Open to using other software to assist (like FRStack)
* Open to building interfacee
* Fine with configuring CAT

How would I do this:
Have a physical microphone (Could be be USB or traditional - don't have this yet) and a PTT button

Driving PTT via CAT is my presumption and use something like FRStack to translate to MOX for SmartSDR

I've seen other threads here like putting an Arduino Nano ($30) into a Footswitch and running a Serial to USB Cable ($10-20) but that seems overcomplicated and expensive and was a solve 4 years ago.

Could it now be just as simple as wiring a switch (shorting pins 8 & 9) to a DB9 and then into a Serial To USB Cable and enabling CAT with PTT and running FRStack?

Or is there something a bit more elegant that I'm missing?

Have ya done it?  Help me out with your learnings please!
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Dave - N6XVZ

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Posted 1 year ago

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Michael Walker, Employee

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Would this work for you?  Not very complicated and very clean.

Mike va3mw

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Dave - N6XVZ

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I ended up following along with the tip Michael provided and it served me well.
This push switch is a bit stiff for use so may have to swap it out. I wanted to post this for newbies since much has changed with the advent of the 6xxx series and SmartSDR 2.4.9.  

I built a dual RCA based cable so I can swap in different setups if I want and have both Foot and Hand PTT.


Parts I used:

RCA Speaker Y - gauge is a bit too large so you could really just use an old RCA cable and strip out one of them and save some $.  This however lets my tie two RCA jacks into same ports on Serial cable and not have to swap out.

This is the breakout Serial end that I connected RCA Female (above) to.  Notice I chose the male with NUTS that I could screw/bond the cable below too.  They have many options so choose carefully!

This is the USB to Serial cable I use to go into the computer and Cat/PTT configured for the USB.  I chose this one because it had FTDI chip - important.  Connected to Windows10 seamlessly and drivers already there.

Finally the switch.  It's a bit stiff for such a small button so you might shop around.  Use your multi meter to determine which contacts close when it closes BEFORE you solder up.

There is just no good way to photograph the end product.  Butt ugly but functional!

73's and thanks!

Dave N6XVZ
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The response from Michael works great for PTT using a FTDI RS-232 cable and is what I have used for the past 11 months.
as far as the Microphone it is also very easy and I have tried many different USB sound card interfaces and have settled on the Shure X2U USB XLR Microphone adapter. 
I run this with my Heil PR-40 and audio is superb.

Don't waist your money on the purple Heil USB XLR (not enough audio out) or other USB XLR cable adapter they are very poor audio quality compared to the SHURE X2U adapter and a waist of Money.
Here is a link on Amazon, 

Then you can do as I did and just run your SHURE X2U and Heil PR-40 (or what ever XLR MIC your running) MIC profile using the PC Mic selection, sounds almost as good as running on the Balanced audio connection.

You pay a bit more for this quality device but it is well worth it.

This will give you OUTSTANDING TX Audio on the FLEX6700 or FLEX6600 radio's and I'm sure the other 6xxx radio's running Remote. 

Hope this helps.

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John - K3MA

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You can get the parts on ebay for a few dollars or from retailer Quicksiler for a few more dollars.  Works up to 300ft away from the radio.

I would recommend you get it from Quicksilver.

John K3MA
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Lee, N2LC

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The index finger button on the Flex Control set to MOX is close enough to PTT for me.