Assuming that you meant 8600 Mark II. I own one and it is a fine general purpose receiver IF you understand its limitations and are willing to live with them.
The first question that you need to ask yourself is what do you want to listen to and what limitations will affect the antenna(s) that you will be using.There are a lot of challenges with indoor antennas that you will need to consider. You're always going to have some trade-offs between performance and practicality, which almost always outweighs performance. So the next questions that you should ask yourself are more about practicality than whether you're going to be able to hear a VHF station 200 miles away.
I assume that the loft is within the confines of your apartment and any antenna would be visible to visitors. (that causes additional issues) Is the model XYZ antenna wife or girl friend approved for appearance etc? Don't let anyone else fool you, this can be a serious concern. There's little sense to plunking done $100-$200 or more only to have her say she doesn't like looking at it; you will eventually get rid of it. Can you use safely use this without kids running into it, swinging on it or playing with it? Can you install it and not worry about running into it in the middle of the night? Don't overlook the other issues if installing indoors; how much vertical space will you need and how much clearance will you need with the radials? How will you run your coax to the radio?
On to some recommendations:
I'd use a Terk Advantage loop for AM broadcast. It is a significant improvement over the AOR loop that comes with the receiver. I use one and can hear can hear several AM stations 200 plus miles away in the daytime from inside an office building.
For HF, shortwave broadcast, ham etc. I would start with a simple wire 10-15 foot long. There are a variety of lower cost, active antennas available. If you want to spend more serious money, AOR and others make different types of HF loop antennas. You may need to look at a noise canceller like a Timewave ANC-4. Google Universal Radio and download their catalog.
For VHF/UHF, I'd start with a short telescoping whip. That may will work just fine to hear the local ham repeaters, FM broadcast etc. If you want better performacne, I would say that any of the wide varieties of wideband antennas would work for general purpose, omni-directional reception; some with and some without radials. I listen to milcom action so I use vertical antennas tuned to the VHF aviation bands; it works satifactorily on the UHF aviation band. If you want a directional VHF/UHF antenna then you may want to consider a log periodic type. Google DPD Productions.
Regards
Dan
