[EMAIL PROTECTED] wrote: > If I could afford that equipment I would do that. However > the thought of spending as much on test equipment as a new > car is a little tough.
Totally understand. Although many good service monitors can be had for the price of a USED car, not a new one -- if that's helpful information. :-) (I hunted for three years and found an IFR 1500 for $2K in great condition, with a fairly recent calibration sticker.) > We do have a service monitor in the group I hang out with > but it does not have a tracking generator. A tracking generator is not necessary (or desired) for this test. Those are used for tuning duplexers, and sweeping antennas -- etc. Things that require a "sweep" of frequency. You don't need to sweep the receiver - you just need a variable strength signal on the receiver input for desense and receiver sensitivity tests. A service monitor is a signal generator by definition, so you have just about everything you need to do the tests already. Depending on what type it is, it may also be able to measure SINAD for you. If not, with a little practice you can learn to "hear" about where 12 dB SINAD is, and how it relates by ear to a full-quieting signal. Not as accurate at all, but you could get a ballpark idea of how well your receiver is working. The desense test only requires a known 12 dB SINAD measurement if you're trying to measure how MUCH desense is present. Any weak signal as long as it's consistent (even a friend with an HT on a fixed antenna far away or through a lot of attenuation and very low power) can be used as a weak signal source to check whether desense is present. What model/brand of service monitor is it? Perhaps we can help explain how to set the test up. I've played with a Cushman CE-5, a Motorola 2600 (?) a couple of older Motorolas, IFR 1200's and 1500's and HP 8920 series. I'm sure others here could explain how to set up other service monitors... Nate WY0X
