My best stab at switcher noise would be to try a "brute-force" AC line filter. Radio Shack catalog 15-1111 may help. 73, Ed Hare, W1RFI ARRL Lab 225 Main St Newington, CT 06111 Tel: 860-594-0318 Inte
Hi, Jim, The article in question is available for download at: http://www.arrl.org/tis/info/pdf/020708qex046.pdf I suggest that people read it, especially my sidebar, before reading this post. The me
Thanks, Tom. I must admit, I was a bit surprised to see some of the assumptions, but I thought back to the mental image I had of ARRL HQ before I started working there, and I can understand. The bes
Thanks, Tom. That is why I join in these discussions. I agree that ARRL can and should do as thorough a job as possible telling members how we do things. Of course, in one sense, we did, because the
Here is a bit of info on the process ARRL uses to obtain and test equipment. The details of the test procedures are fully documented at: http://www.arrl.org/members-only/prodrev/testproc.pdf A number
Correct to: This fixture has been tested to at least +40 dBm IP3 and +85 dBm IP2, with an independent verification using the Lab's 2nd receive test fixture, which uses 1 W ultra-linear amplifiers do
Most of the time, we leave one of the W1AW castoff rigs in there. Staff can bring their own rigs in if they want. We also use that station as a test bed if we need to do any on-the-air testing, on "
The appear to be mostly a cal lab. We used to use someone else -- and I do forget who. The time that other company sent back my Bird wattmeter elements as calibrated and indicated that they werflat v
Well, I do own a Ten Tec and like it, so I belong here. :-) Glad to offer any info I can on the ARRL Lab! I do know it pretty well. :-) Yes, the testing is rather extensive. It was also a daunting t
If memory serves, the Argo V IP3 was improved at greater spacings than the 20 kHz standard used in the ARRL Lab tests. The Lab actually tests dynamic range at a number of test-tone spacings and puts
Hi, Jim, An important nit -- the spec for the RX-340 IP3 is +30 dBm typical, +25 dBm min. Those negative numbers would be bad. 73, Ed Hare, W1RFI ARRL Lab 225 Main St Newington, CT 06111 Tel: 860-59
Just a quick check of an unspecified receiver I just tested in the screen room: Reference level IP3 -120 dBm 3 dBm -100 dBm 5 dBm -80 dBm 2.5 dBm -75 dBm 3 dBm -70 dBm 3.5 dBm -65 dBm 8.5 dBm -60 dB
AGC "on" is the ONLY way to make receiver measurments with a receiver output that would be more than about 30 or 40 dB above the noise floor. But the effect is not quite what you are thinking. In ma
Alas, to my knowledge, no one doing testing looks at more than a sample of one. The ARRL Lab ends up spending about 20-30 test hours on a major rig and it really isn't possible to do complete testin
There are a lot of factors that would go into what makes a rig "sound good." Probably the most important is the intermod that takes place within the receiver's passband. In recent rigs, the expanded
We all hope we never are the most ignorant on the reflector. It is easy enough to make a faux pas. The REAL measure of our humanity is found in how we react when we are wrong -- or wronged! Actually
I didn't check your math, Jim, but that all looks about right to me. I know that Ulrich Rohde has been recommending using such high-level tones for IP3 testing. This may be quite appropriate to test
Dynamic range expressed in dB does normalize for sensitivity. It is the difference between the sensitivity and the measured degradation. In theory, a rig with a 100 dB IMDDR of 100 dB should still ha
Almost no digital equipment other than personal computers are going to be certificated (FCC's word) or authorized under a Declaration of Conformity. Most digital equipment is "verified," meaning that