Gerry: The HP-8562A can measure directly up to 18 GHz, and with external harmonic mixers, you can extend that range out to 26 GHz, 40 GHz, 50 GHz, well, just add money. Actually, you can find HP-11970 series mixers for about $500 each if you search hard. HP would like to sell them to you at about $2300 each.
I assume that you are happy with your equipment up to 3 GHz. You can get effective coverage from 1 GHz to 12 GHz from a horn antenna such as the EMCO 3115 (a double ridged horn). It's actually rated to go to 18 GHz, but I find the antenna factor gets too high above 12 GHz, so I switch to a pyramidal horn for the 12 GHz to 18 GHz range. Pyramidal horns will be much more efficient in the 1-2 GHz, 2-4GHz, 4-8GHz and 8-12 GHz ranges, but that would involve 4 antennas, with attendant additional labor costs to do a sweep of that range. You will need very low loss coax. Gore makes great stuff, but you can dole out $2000 for 20 feet. Then there's Storm, which will sell you another goo cable for $1,000. My favorite is United Microwave, where I buy a twenty foot length, with a male SMA at each end, for under $200. (Great low loss stuff, but not armored, can't handle more than about 10 watts, and has factory installed connectors.) For horn antennas, I watch the surplus market, build my own, or buy from Raven Industries in Valley Center, CA. Raven is also an excellent antenna cal lab. You can build your own, or straighten out the dents in a surplus horn, then get it calibrated. Good as buying new! I prove my system's performance by injecting a CW signal into the head end of the coax. Yes, this does mean several sig gens, and this is not a low budget solution. I use a Rohde and Schwarz SMG up to 1 GHz, then an HP-8350A from 1 GHz to 18 GHz. The R&S goes for about $6000, but the HP mainframe and plug-in cost about $3000 and >$12,000 on the used market. Maybe you can find an impulse generator from surplus. The very old Empire and Stoddart companies had models for both up to, and above, 1 GHz. They were good in their day, but such old stuff might be more unstable than you can tolerate. You can also find many of the HP 600 series signal generators in surplus, often for $50. But, unless you are prepared to do a good bit of repair or restoration, I don't advise this route. If your proof of performance demands a check of the receiving antenna, and the site, then you will need a remote located emitter. This raises the complication level way up. There are some range calibration emitters available, but I'll have to leave comments on them to someone else in our group. Ed ------------------------ From: Gerry McMahon <[email protected]> Subject: Antenna and Cable Calibration Query (30 - 3000 MHz) Date: Wed, 22 Jul 1998 22:31:21 +0000 To: [email protected] > We use a Bilog antenna, Horn antenna, cables, and a HP 8562A > Spectrum Analyser to measure signals at frequencies between 30MHz > and 3GHz. > > We need a set up to verify the operation of our > measurement system (antenna, cables and spectrum analyser) before > and after every job. We would be interested in receiving any > information about possible cost effective methods (the HP 85640A > tracking generator for this SA is beyond our budget) for testing > our cables and antennas between 30MHz and at least 3GHz. > > Ideally we would like to be able to plot the transfer function of > the antennas and cables, but measurements at a number of spot > frequencies (e.g. using a comb generator) may be adequate. We > would like to be able to test up to 14GHz, but realise that > this may be prohibitively expensive. > > Thanks for any advice. > > Gerry McMahon > [email protected] > ---------------End of Original Message----------------- -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 07/22/1998 Time: 16:37:58 --------------------------
