www.mgef.org - home of W2SZ/1 not to be confused with W2SZ

www.hamtronics.com - a supplier of amateur VHF gear, particularly repeater oriented stuff

www.downeastmicrowave.com - a supplier of Microwave goodies to amateurs

www.frontiernet.net/~gmills- Greg, K2LDT's page

www.barenys.com - A site that John setup.

www.deathbike.net - a site by Jason

www.2ub.org - a site by Tom, N1MU

www.joelglickman.com - (pretty obvious)

www.accuratecnc.com - The company that I bought my PCB milling machine from. (see the results of a prototype here). 

www.precisebits.com - a source for milling bits and other supplies

www.shars.com - they sell some affordable measurement tools

- a very good site for RF and general engineering info, you can find many tidbits here faster than you can walk over to the shelf and leaf through your books!

www.radio-labs.com - a good resource for PLL design software, consulting, and more!

www.sonnetsoftware.com - one of my favorite planar EM tool vendors.  In 2010 we've upgraded to Sonnet Professional for some of the more challenging work we've taken on and it is a nice complement to Genesys/Momentum (both stand alone and with direct interfaces between tools).

www.modelithics.com -- This is our go-to source for quality third party simulation models (we use the Complete  library here at RFdude.com for board level design work up through 30 GHz).  We've had good success with both the nonlinear (transistors, diodes) and passive (R, L, C) models for commercial and aerospace designs spanning DC to 30 GHz.  We've designed attenuators, mixers, filters, diplexers, amplifiers, VCO's, couplers and combiners using these models.

www.orcad.com - I also use Orcad Capture

www.ieee.org - I am (or was at one time) a member of the following societies

• www.mtt.org - Microwave Theory and Techniques Society (MTT-S)
• www.ieee-uffc.org - Ultrasonics, Ferroelectrics, and Frequency Control Society (UFFC)
• www.ieeeaps.org - Antennas and Propagation Society (AP-S)
• www.comsoc.org - Communications Society