one mike for all HF rigs

[N5YPJ]

I'm doing some remodeling on my corner shack and at this point wouldn't mind buying a boom mike. My space has always been limited. Just a stab in the dark, is there a low impedance mike(s) that can be used on Icom, Kenwood and Yaesu HF rigs or is one brand dependent as to which mike they use? I'm thinking of a mike switch to switch between rigs and realize that there are different connectors.

[WB2WIK]

Sure you can do that. But the earlier Icom rigs, I think before the IC-756 or so, had no mike preamp in the rig (it was in the mike) so a standard mike for Kenwood and Yaesu might not work with many of the earlier Icom models. The later models are compatible.

They all vary a lot in "gain," but of course they all have mike gain controls so this shouldn't be an issue.

I use one single PR-40 (Heil) mike on three rigs here, with a switch. And yep, the three cables all have different connectors! But I run the PTT lines all in parallel through a simple diode OR gate and use one footswitch for everything. So to change rigs I just rotate my chair and everything else remains the same.

The PR-40 is dynamic and has rather low output compared with some mikes, but it does work with all the modern gear as well as my old Drake TR-7 and sounds better on all of them than any other mike I've ever used.

[K9STH]

Actually, you don't want a "low impedance" microphone! What you want is what is generally called a "medium" impedance microphone with an impedance around 600 ohms. "Low impedance" microphones generally have an impedance around 20 ohms and are usually carbon, or carbon compatible.

I use the same microphone on just about all of my transmitters. Instead of a switch for the microphone audio I have a mini-box with RCA phono jacks, each of which goes to a separate radio. The microphone cord has an RCA plug and I just plug it into the desired transmitter. For PTT, I use a foot switch and that does go through a rotary switch.

Glen, K9STH

[N5YPJ]

Actually, you don't want a "low impedance" microphone! What you want is what is generally called a "medium" impedance microphone with an impedance around 600 ohms. "Low impedance" microphones generally have an impedance around 20 ohms and are usually carbon, or carbon compatible.

I use the same microphone on just about all of my transmitters. Instead of a switch for the microphone audio I have a mini-box with RCA phono jacks, each of which goes to a separate radio. The microphone cord has an RCA plug and I just plug it into the desired transmitter. For PTT, I use a foot switch and that does go through a rotary switch.

Glen, K9STH

Hmm thanks for that. My bad. I figured that gear from the past 20 - 30 yrs would be more requiring the low impedance mikes, TS-830S excepted.

[K9STH]

YPJ:

Actually, most transmitters until the early 1950s and most commercial FM transmitters up until the early 1980s required low impedance microphones (carbon or carbon compatible). High impedance microphones were used on most amateur radio transmitters up until the early 1970s.

Glen, K9STH

[WB2WIK]

Hmm thanks for that. My bad. I figured that gear from the past 20 - 30 yrs would be more requiring the low impedance mikes, TS-830S excepted.

It's not a matter of "requiring" any particular mike; the rating is generally just what the input impedance of the mike preamp stage happens to be.

I had a TS-830S with a Kenwood desk mike many years ago, and the mike could be "switched" from "LO" impedance (500 Ohms or so) to "HI" impedance (50K Ohms or something) and I tried it both ways many times (you'd just unplug the connector on the back end of the mike body, twist it 180 degrees, and plug it back in to change impedance). Made virtually no difference.

A low-Z mike can drive a high-Z mike preamp just fine. The other way around may not work.

[WA6TKD]

It's not a matter of "requiring" any particular mike; the rating is generally just what the input impedance of the mike preamp stage happens to be.

I had a TS-830S with a Kenwood desk mike many years ago, and the mike could be "switched" from "LO" impedance (500 Ohms or so) to "HI" impedance (50K Ohms or something) and I tried it both ways many times (you'd just unplug the connector on the back end of the mike body, twist it 180 degrees, and plug it back in to change impedance). Made virtually no difference.

A low-Z mike can drive a high-Z mike preamp just fine. The other way around may not work.

That is my understanding also. However with normal non-amplified mics don't the lower impedance element types tend to have a lower output voltage then the the high impedance element mics given the same sound level input, requiring different mic gain settings on one's rig?

[WB2WIK]

It might, and so what?

[WA6TKD]

It might, and so what?

No so what, just asking, if as a generalization, if high impedance mics tend to have higher output then low impedance elements for the same sound pressure.

I read in the Kenwood manual for their MC-50 (which has switchable impedance option) mic sensitivity rating:

-56db +/- 3db at 50K ohms
-76db +/- 3db at 600 ohms

So is that typical sensitivity ratings for low and high mic elements? A 20db difference in output is pretty significant and possibly not all mic gain controls have enough extra range to work with a low impedance only mic if they were designed for the levels of a typical high impedance mics?

Perhaps there is no such thing as 'typical'?

[WB2WIK]

I really don't know.

But I haven't had a problem adjusting the mike gain to accommodate a wide range of mikes on just about any rig I've ever used, so I don't think this is much of a problem.

I usually use a Heil PR40 for most stuff, it's dynamic and 600 Ohms; rated -53.9 dB at 1 kHz. Seems perfectly adequate for every rig I have. I note the much less expensive Heil Gold Line mikes are -55 dB (wide) or -58 dB (narrow) at 1000 Ohms.

So I suspect most dynamic mikes we'd be using are somewhere in that range.