Microphone recommendations for FT-901DM?

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Microphone recommendations for FT-901DM?

Postby KF6PBP » Tue Jan 12, 2010 11:52 pm

Can anyone recommend a decent hand or desk microphone for the FT-901DM?

I recently picked up a mostly-working FT-901DM shortly after upgrading my license. Then I bought a cheap Astatic 636L hand mic to get on the air. The Astatic works, but I have to talk with my mouth practically touching the mic to get any audio. No surprise that I have gotten reports of muffled audio on the air!

Any suggestions are welcome.

73,
Jeff, KF6PBP
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Postby Ghostwriter » Fri Jan 22, 2010 9:08 am

Hello Jeff,

Your Astatic 636L is a Low Impedance 600-Ohm Noise Canceling Handheld Microphone. Your Yaesu FT-901DM H.F. Transceiver has a High Impedance 40~50 K Ohm Microphone Input. This presents a very large Impedance Mismatch at Audio Frequencies. This is very similar to a High VSWR between a RF Transmitter and a Mismatched Antenna.

What you need is either a Shure 450 Series II Desk Top Dual Impedance Microphone or an Astatic 878HL Omnidirectional Dynamic Desk Microphone with the proper microphone connector depending on your financial budget.

You could also look for a second hand / used Astatic D104 High Impedance 50 K Ohm or a Shure 440 / 444 High Impedance 50 K Ohm Desk Microphone at a local Hamfest / Swapmeet or on eBay but Buyer Beware when using eBay. Buying these two different Desk microphones on the used market can vary between $25.00 ~ $75.00.

Congratulations on your recent upgrade to General!

73,

Dan
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Postby KF6PBP » Sat Jan 30, 2010 12:36 am

Ghostwriter,

I'm pretty sure that the FT-901DM has a low impedance microphone input. It is listed as 600 ohms in the manual.

I recently picked up a Shure 444D on eBay, hopefully it will improve my setup. It has hi/lo impedance so it should work regardless.

73,
Jeff KF6PBP
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Postby KF6PBP » Mon Feb 08, 2010 7:34 am

I wanted to post an update, the Shure 444D arrived and I am getting good audio reports from everyone I have worked with it. I highly recommend this mic (in the low impedance setting) with the FT-901.
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Postby K7ZRZ » Mon Feb 08, 2010 4:00 pm

Jeff,

For a great microphone setup... take a look at my entry on QRZ.com (entering my K7ZRZ call sign) and click on my little picture up in the left. If you are interested in how I made the mic boom - and if you have enough room to set up such a thing - let me know, and I'll post some more picture links, and tell you all about it.

I made that boom from a common desk lamp quite a few years ago, and now it holds up my Heil Goldline mic. It's just the best way I can imagine to mount a mic for a great range of adjustments and operating postures.

Continued good luck with the rig and station. Get on 75, you'll enjoy that band for morning and afternoon/evening operating, and we might find each other there sometime. I do get on 20 meters occasionally, but not regularly. I like to check into the Maritime Mobile net mid-day on 14.3 and will often try for some kind of data or cw contact down below 14.1.

73,
Brian K7ZRZ
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Postby Ghostwriter » Wed Feb 10, 2010 11:45 pm

Hi Jeff,

I stand corrected on the FT-901DM High / Low Microphone Impedance issue. As I recall the Astatic 636L is a Noise Canceling microphone which is normally used in aircraft, heavy equipment and big semi - trucks that can produce vast amounts of noise. On a typical noise canceling microphone it's normal to practically eat the microphone to get audio output. I'm glad to hear that the Shure 444D Desk Microphone is working so well for your station application.

73,

Dan
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Postby N8YX » Mon Mar 22, 2010 2:45 pm

I'm currently using a Telex 752 paging mic with my FT-901. It gets very good reports.

Might rewire the 4p mic connector to allow the use of a Kenwood MC-50, as I have a few of those kicking around the shack.
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Postby KD6KWZ » Mon Jun 07, 2010 7:38 am

While we're talking about FT microphones, what's a good one for a FT-301? I'm looking into a low cost one, but it has no mic.

Buyer Beware when using eBay


X2. I now have a Vertex VX-10 UHF hand held, thanks to ebay (my bad for not studying it more), that needs a 486 computer (or 386) with a USB port to program, good luck to me! That, or spend $75+ to pay for programming!

-Mike
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