VHF mics

mogmog2

mogmog2

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I've always thought that having another mic in the cockpit was a good idea. Now I see some newer/better (than my Garmin 100i) can have a remote mic which has a shedload of controls and costs a fair bit.

So, does anyone know why you can't connect 2 mics to one set? They're hard-wired, but that's not a big deal & plenty of pukka connector options available and you couldn't use them both at once. I was thinking of a passive DI box (normally used to input 2 musical instruments into 1 amp input). From my (lightweight research sampling) mic impedance may be 600Ohms, which works with a DI box.
Obviously it wouldn't be all-singing & dancing like the remote handset, but would be a useful addition for only a few ££
Thoughts?
Cheers
 
I guess if you've got an old VHF that you don't mind hacking about it wouldn't be too difficult to do. Maybe you could get around the problem of sound from two mics by sensing the PTT switch on the remote mic so only one mic would cause anything to be transmitted if only one PTT switch is pressed. Otherwise you could end up being overspoken by your crew next to the chart table discussing gawd knows what.

Is the Garmin remote mic expensive enough to justify the trouble?
 
The mics tend to use electrostatic elements that use a small voltage to work, it is quite easy to wire up two via a relay and switch them, using the PTT would not be that easy as the mic switch is an output from the radio. Easy to do with Ham radio gear as the mic is on a 5 pin plug but most marine have hard wired so getting a second mic may need to butcher a radio. The mics have to be the same as mic gains are not adjustable on marine radios.
 
And can't change channel, tweak volume / squelch. So you are stuck not being able to do things that you may want to do do improve your use in the cockpit and presumably the reason you wanted to have a remote mike was so you didn't need to go below...

Of course - it is no co-incidence that the Ram Mike price is around the same as a HH VHF... which would be your alternative...
 
I have ram mike and wouldn’t be without it, full remote function of whole radio, built in speaker and full display, also different radio volume above and below, keeps admiral happy when she’s rest below.
 
Daverw said:
I have ram mike and wouldn’t be without it, full remote function of whole radio, built in speaker and full display, also different radio volume above and below, keeps admiral happy when she’s rest below.
Click to expand...
Plus one, Ive just fitted a ram mike for my Standard Horizon ais gps equipped vhf. Best £120 ive spent in a long time
Stu
 
Thanks,
I wasn't sure about the PTT bit particularly.
lpdsn the Garmin RAM is about £180, but it doesn't go in the 100i which came with the boat, so I'd need to upgrade the lot.: Not in the foreseeable future.
Daverw
I'll research the cable/pinouts. Assuming there is a voltage signal wire, the DI box is out (unless maybe just route the voice signal through there and bypass the PTT signal?).
The radio is out of warranty, so I'm a free agent if I want to be adventurous! Would it not be possible to cut the mic cable to leave a short tail & put a suitable inline connector(5 pin XLR springs to mind) and use this to connect to whatever arrangement?
I can see that gain would be an issue - this info might not be available.
Shinyshoe & Daverw
Yes, it would lack those functions, but I've not had to adjust the squelch a lot, but with an active cockpit speaker, output volume can be takn care of.
As you say, RAMs cost a bit (and my radio doesn't have provision anyway). I have a handheld so this isn't vital - just wondering about the feasibility of it. Thought it might make an interesting winter project.
Thanks for your input.
 
I don't need convincing that a RAM is a good piece of kit :) We've just bought the boat & there are a lot of demands on our funds - buying a whole new VHF setup isn't that high on the list unfortunately. If it was just a matter of adding the RAM, I might be able to get away with it.
 
mogmog2 said:
lpdsn the Garmin RAM is about £180, but it doesn't go in the 100i which came with the boat, so I'd need to upgrade the lot.: Not in the foreseeable future.
Click to expand...

That's 50% more than the SH equivalent, which even comes with its own mini (or micro) AIS display, so it does sound overpriced.

I'm currently at a halfway house of having a cockpit speaker but the fixed VHF down below. The SH speaker cost £39 at the time and is handy for monitoring, but obviously I do need to go below to use the VHF. 90% of the time a HH is good enough if I want to transmit from the cockpit (albeit I do need to switch the cockpit speaker off first).
 
The mic element is powered by DC bias on the AC so your di box would filter this out. It’s similar to a phantom powered condenser mic but not 48v. As said the second mic would have to be the same so you would have to locate another 100i to take the mic off, you are extremely unlikely to get the element spec to convert one, this is hard in Ham gear where the manufactures are very open about design and even issue circuit drawings. You could of course cut the existing mic, put a socket on it and with an extension cable fit another socket in the cockpit and then you could use the mic in both places.
 
Lpdsn,
if the Garmin price is not representative, then maybe upgrade day isn't quite so far away.
I would have thought that a cockpit speaker would give better sound than the necessarily small one in a RAM, so it seems like a worthwhile improvement regardless of whether I upgrade in the future.

Daverw,
Thanks for that info. Seems like matching the mic gain is the thing that would sink this. It was only an idea for an.evening or two's tinkering.
Extending the mic cable is an option providing the extra cable wouldn't be a right pain. I need to make a nav station anyway, starting from scratch, so have some scope there.
 
mogmog2 said:
I would have thought that a cockpit speaker would give better sound than the necessarily small one in a RAM, so it seems like a worthwhile improvement regardless of whether I upgrade in the future.
Click to expand...

The remote station on my Standard Horizon gives perfectly good sound without a dedicated speaker.

I don't think a simple mic in the cockpit would be worth the effort. Adjusting volume, squelch, and channel while receiving is a big part of how I use my remote, which a simple mic wouldn't help with. And when you do come to transmit, the only call you'll be able to make without going below is an emergency one, because otherwise you're going to have to change channel away from 16 during it, or at best (calling a station that listens on its working channel like a marina) go below to change channel before starting to transmit.

It's not totally useless, but it's a lot more inconvenient than it at first appears.

Pete
 
PRV,
Thanks, all good real life info.
Sometimes, but not always, when you think "why hasn't this been done before?" there's a good reason.
Does rather sound like it's not worth the effort then, especially as it'll be a while before I sail solom
I've got more than enough stuff to be doing anyway really.
 
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