As David above points out, you can do what is called the "Alton Brown Good Eats" dryer using a box fan and filters. works well actually.
On the convection oven: I recently got one, but I haven't used it to dry anything!
Thanks for reminding me I need to add more to the site about drying with an oven. Lazy me!
Ok, on drying veggies:
If you use frozen vegetables, all you have to do is spread them out frozen, and let them dry. Frozen is precooked also, so great for backpacking! All you need is to add boiling water and let sit for 10-15 minutes and they come back.
Mushrooms and very thinly shredded items like carrots: I don't precook them, as I cut them very, very thin. They seem to do their thing when combined with boiling water.
If you buy veggies such as Just Veggies, the freeze dried ones, they are precooked.
And yep, cooking and drying vegetable blends is really good! Comes back tasty! And really good with pasta.
Which, if you precook at home, and then dry, becomes basically instant pasta. Just cut short the cooking by a couple minutes, as the sit in boiling water finishes it up.
And hey, don't worry about your oven, fancy or not, it'll get your job done!
Einstein, not to advertise myself, but I do take checks and money orders by mail also :-)