Basic git-archive --remote question

I'm trying to create a tarball from a git tag and I can't get the
syntax right.  The documentation is not very clear.

Can someone help me?

== details

git v1.8.1.4

The upstream git repo is at: https://github.com/dkovar/analyzeMFT

Here's a few attempts using git as the protocol:

git archive --format=tar --remote=github.com:dkovar/analyzeMFT.git v2.0.4

Permission denied (publickey).
fatal: The remote end hung up unexpectedly

git archive --format=tar --remote=git://github.com/dkovar/analyzeMFT v2.0.4

fatal: remote error
   Your Git client has made an invalid request:
   003agit-upload-archive /dkovar/analyzeMFT

git archive --format=tar --remote=//github.com/dkovar/analyzeMFT v2.0.4

remote: fatal: '//github.com/dkovar/analyzeMFT.git' does not appear to
be a git repository
fatal: sent error to the client: git upload-archive: archiver died with error
remote: git upload-archive: archiver died with error

The github page also says I can use ssh with git as the user, but that
complains I don't have the private key (which I don't):

git archive --format=tar
--remote=ssh://git@github/com/dkovar/analyzeMFT.git v2.0.4


Thanks
Greg