M7300 Mic question

[LowderK]

OK here is the question I have.... does Harris have a MIC that will connect to the Rear of the Head and a cover for the front mic port...? and if so does anyone have the Harris part numbers for these...... thanks in advance

 

[BMDaug]

I’ve ever seen that before! Which radio exactly? You could go BT if you have a 100M w/CH100 or a 200M, and I suppose if you run a CH721, they are cheap enough that you could run dual head and use a head just for your mic in.

Or, there is a mic in and assignable PTT on the 25pin accessory port on the back of the head and at the 40pin on the back of the brick, so you could make something up, but you would likely need to abandon the Harris style semicircular mic connector and go with something more universal.

-B

 

[LowderK]

sorry i should have said CH721 on a m7300 i’m wanting a cleaner install in my console like you can do with a motorola XTL or Apx and have the mic connected to the rear of the head it’s helps keep cords organized with a clean look…… i found at one time a cover for the ch721 mic port awhile back but lost the info……. and i’m sure they make a microphone that is available to use the rear ports but it’s just finding the odd stuff i’m sure

 

[BMDaug]

sorry i should have said CH721 on a m7300 i’m wanting a cleaner install in my console like you can do with a motorola XTL or Apx and have the mic connected to the rear of the head it’s helps keep cords organized with a clean look…… i found at one time a cover for the ch721 mic port awhile back but lost the info……. and i’m sure they make a microphone that is available to use the rear ports but it’s just finding the odd stuff i’m sure

I’ve seen that mic connector cap somewhere too, but I haven’t remembered where yet either!!!

Perhaps they did make something, but it isn’t published in any of the docs I have. There are even diagrams showing all the places you plug stuff in and the only diagram with the Conxall mic connectors show them plugging into the front panel.

It really would be easy to make one, and if you found a dual PTT hand mic, you could wire up both aux inputs… one as PTT and the other as ALT PTT. Then you can have an alternate PTT set up for each system.

Part of the reason I’m not sure this exists is because Harris has been a bit lazy in the past with audio accessories… I have an HHC731 and there is a section in the manual about how to set up a headset and it involves adding resistors to a custom made wiring harness… So if something exists, it’s likely a custom job. I’d just find your favorite hand mic, and buy a mating pair of lemo connectors and either a 25 pin or 40 pin accessory connector and DIY.

-Brian

 

[LowderK]

that’s kinda what i’ve been looking at….. i’m needing this for 2 radios both M7300’s. one is 7/800 and the other is VHF and i honestly only need the HF mic the other is just basically a scanner at this time….. when you said dual PTT are you saying they have 2 PTT buttons like some of the motorolas…? i have a motorola that looks normal but the PTT moves up for A and down for B do you have the Harris part number?

 

[LowderK]

also if you find that mic port cap again ever would you pass along..? i’ve looked everywhere…. i even think i bought one but can’t find lol

 

[redbeard]

I’ve seen that mic connector cap somewhere too, but I haven’t remembered where yet either!!!

I posted here looking for the cover as well and either myself or someone else added the part number to the post. I called NLT about it and it's $80+ each. I wanted them for my consoles since they have two mic connectors.

I have seen a rear mic too, perhaps for motorcycle use with a DE-9 connector.

 

[redbeard]

Ok I was close, but probably thinking of the Motorola motorcycle mic. Here's pics and part numbers.

 

[LowderK]

you guys Rock…… thanks and y’all have a great weekend

 

[BMDaug]

@LowderK I just meant that the 100M supports an alternate PTT function, which you could wire up to a custom solution.

I use mine to beacon APRS on the correct channel no matter what. So I use the line output, the mic input, and alt PTT on aux input 1. It all works flawlessly so making a mic should be easy. You can likely have your pick and just use whatever mic is comfortable. The Harris manual publishes audio levels for full rated deviation so you can find something suitable.

@redbeard that’s cool to know there was an official part!!! Thanks for that! That said, I’d probably still build something. I could get something made up for $10 plus the cost of the mic.

-B

 

[redbeard]

I use mine to beacon APRS on the correct channel no matter what. So I use the line output, the mic input, and alt PTT on aux input 1. It all works flawlessly so making a mic should be easy. You can likely have your pick and just use whatever mic is comfortable. The Harris manual publishes audio levels for full rated deviation so you can find something suitable.

Would like to see a write up on how you made that all work and maybe a screenshot or two from RPM. Lots of these in the hands of hams now that would appreciate it.

 

[BMDaug]

Would like to see a write up on how you made that all work and maybe a screenshot or two from RPM. Lots of these in the hands of hams now that would appreciate it.

I’m working toward something with images etc., but the basics are pretty simple. RPM allows the user to set an “alt PTT” channel on a per system basis. I just set that to my APRS channel.

I then wired audio from FDISC output on the RF brick 44pin to my sound card interface input (masterscommunications.com) and the audio out from the sound card interface to the external mic input on the 44pin. PTT GPIO sound card output then wired to either aux input of 100M set to alt PTT.

That’s all. I use APRSISCE and SoundModem by UZ7HO on a Panasonic Toughpad FZ-M1 for ultimate flexibility, but any properly calibrated audio interface will work fine for APRS. Other audio I/O options on 44pin may allow for increased bandwidth (VARA FM), but I have not tested other 44pin I/O options at time of posting.

I tried DireWolf but couldn’t create a reliable solution, so UZ7HO SoundModem for the win!!!

-B

 

[merlin]

There is no 'MIC' connector on the rear of the CH-721. The accessory connector does have mic connections on the 44 pin connector.
P1 pins 27 (hot) pin 8 common ground. (12, 13)
What I don't know is if this connection is on the option cable (P4-24, 1 ?)
I have the desktop, and the mic is really little problem. (seems upside down to me)