I think the best choice, and pretty close to the only choice for an after market desk mic that will work for the
FT-2800M is the Heil Handi-Mic.....
HandiMic - Amateur Radio - Heil Sound
The Heil Handi-Mic Pro is designed for a full range voice that works well with VHF -
FM rigs, however because of the way Yaesu wires their VHF -
FM radios, you have to buy the Microphone, either the CH-1-YM coil cord, or the CC-1-YM microphone adapter & connecting cable.....(this one includes the connector for a separate foot or hand switch)....then you also have to get the AD-100 adapter so it all works with the bastard wiring configuration these Yaesu radios use.
Follow this link to CheapHam.com, scroll down til you find the handi-Mic's listed. This is the cheapest prices I know of for Heil Sound equipment.....
http://www.cheapham.com/page4.html
Refer to the first link for all the spec's and information right from Heil.....
I use an Icom
Ic-2200H for my base radio, and I put the Heil Handi-Mic Ic on it with the coil cord, that way I can sit back in my camping chair and rag chew. I have the Heil GM-5 with the regular mic cord and a foot switch on my Kenwood
TS-130S
HF rig, both mic's have received nothing but flowers as far as my transmit audio goes, I have no doubt the Handi-Mic Pro will sound every bit as good on your
FT-2800M.......