AR2500 report, parts 2 and 3 by KB1MZ The second unit arrived in about 10 days. It also had the non-continuous coverage, though it was about 50 MHz "better". THe 45 MHz bleed through and the lack of image rejection on the 800-1300 MHz band were about the same. Sensitivity on the 800-1300 MHz band was much better. The tuning knob also exhibited the same erratic performance in the counter-clockwise direction. (apparently this is a "feature" common to the AR2500) At this point the radio did everything that I wanted. Then about three weeks, the < 550 MHz band went "deaf" by about 40 dB, but the 800-1300 was still fine. My SWAG was that the MC5800 front end chip died. This unit went back to ACE, and at this time is languishing away, waiting to be repaired (ACE person said 4 to 6 weeks, and that there were currently no more 2500's available for replacement). I tried to pin them down on particulars, but the lady on the other end of the phone was polite, but vague, promising that their repair tech would call me the next day (he hasn't yet). I get the impression that there is a serious design problem with the 2500 and they are trying to fix it without calling too much attention to the fact. I'll gently nudge them about once a week until I get either the radio or my money back. Maybe I should have saved up some more dough and gone for the AR3000. -< round three... >- I finally got the AR2500 back from ACE. THe deaf <550 MHz problem was fixed (new 5800 IC, and they did some real tacky ECO's in a feeble attempt to solve the squelch and 45.03 MHz IF bleedthrough problems. They hung a couple transistors, resistors and some wires around the inside, and as a result, the squelch action is a little better. Then they stuck a wad of aluminum sticky tape over part of the VCO/Loop filter area, ostensibly as a shield. But there was NO contact with the ground foil, and, in fact this "tent" was loose, rolling around the inside of the scanner like the proverbial loose cannon. Did I mention that the radio was dead on arrival? When I plugged it into the power pack, and turned it on, *NOTHING* happened. As dead as a rock. Nil. Nada. After calming down, and rejecting the idea of asking the USAF to "nuke" ACE, I opened up the radio, and found that one of the plugs going to the front panel/control boards was not plugged in. I don't know if the ACE "tech" was in a hurry that day and overlooked this minor detail, or perhaps the UPS delivery crew had a little game of hackey-sack with my unit. Anyway, I put the plug back in, removed that deadly little aluminum tape "time bomb" and tried again. This time, it worked. Better than before, but still far from perfect. In another feeble attempt to fix the hole between 550 and 800 MHz, they replaced the VCO assembly. This was apparent by the soldering iron burns and globs of flux around the area, that wasn't there before (I admit, I peeked). Now this gap is 600 to 790 MHz. Better, but still not to spec. The tuning knob is still erratic at best in the CCW direction, giving random results. It works fine as long as I tune upwards in frequency. The 45 MHz bleedthru was still there, and the local NHSP Troop B on 45.020 comes thru loud and clear. No matter what frequency the 2500 just happens to be tuned to. I figured this out: It's not a bug, its a feature! Just like having a free priority channel! How clever of those AOR folks! Wow! Another feature that I discovered was that the antenna didn't have to be actually connected securely to the BNC connector on the back. Just touching it to the outer shell of the BNC, or to the attenuator switch handle did the trick just fine. How clever! Further examination of this phenomenon disclosed that the outer shell of the BNC was not even connected to ground. Anywhere. Cold solder joint. Anyway, I decided to bite the bullet, and see if I could solve some of these problems. First, I grounded the BNC shell. Better. I took a real plunge, and removed the cheap BNC and put in a mil-spec Amphenol BNC, and removed that pesky little attenuator switch and board, and wired the antenna jack directly to where it should go. Better yet! Next, I took some sticky-back copper foil and stuck it in the inside of the upper-half of the plastic cabinet, and made a good solid contact to the BNC outer shell. This provided a bit of shielding, and kept the internally generated signals inside, and kept out most of the 45 MHz NHSP out of my IF strip. I know, the warranty's blown, but now it almost works as it should. Besides, I accomplished in an evening what ACE couldn't do in 10 weeks. It does what I want it to do, in the main bands of interest (118-137 and 225-400 MHz). I can live with the hole in the UHF TV spectrum, and the very marginal HF/shortwave performance. Would I do this again? No way, man.