Rip wrote in
t:

VOR test points certainly do still exist. Check the Airport and
Facilities Directory for one near you. Keep in mind that up to a 6
degree error is permissible between units when doing an airborn check
(as it sounds like you have been doing).

Rip

It is 6 degrees for an airborne checkpoint. It is only 4 degrees when you
are checking one VOR against the other, which is basically what is going on
in this case.

There are many ways to check which one is correct. You can use a VOT
(available at some airports), an approved ground checkpoint, or an approved
airborne checkpoint. These are all listed in the AFD. You can also make
your own airborne checkpoint, or do the dual VOR check (which doesn't
really tell you if the receiver is incorrect, only that the two receivers
agree). If you are not going to take it to a shop, I would recommend the
VOT first, the the ground checkpoint, then the approved airborne. Jim Weir
has also been working on a navigational tester in Kitplanes for the last
few months.