Top Ten Tuners of all Time??

sean...Your comment about unit-to-unit differences was very true in the days of analog tuners, where exact alignment of multiple stages of tuning circuits was as much art as science. With today's digital tuners and phase lock loop chips I had the impression that unit-to-unit differences were small, although I must admit that I never had a bunch of the same models on hand to compare. I did have a tuner where the biFet front end RF amplifier transistor was blown, (so the RF gain was 1) and the tuner still worked fairly well. I suppose that RF gain variations could occur and produce the effect you remark upon.

sean

yer comments about tuna wariabliity are spot-on - even for todays current "school" of digital tuna. that's why getting a highly-regarded species serviced and aligned, right from the get-go, is a great idea. i'd recommend ed hanlon of antenna performance specialties, bill ammons, from the fmtunerinfo.com site, or stephen sank, owner of talking dog transducers...

re: the sherwood micro cpu, there's a li'l info about this on the fmtunerinfo site, or ya can post a question to the yahoo tuna forum...

regards,

doug s.

El: Even with "modern digital circuitry", there are still PLENTY of unit to unit variations that one has to deal with. I work on mass produced PLL based transceivers on a daily basis and see identical units that perform from one extreme to another.

Doug: I hear ya and agree. I've got a $15K signal generator at work and can do this myself but i've never gotten around to it. While part of the problem would be that i would like to have a service manual for each tuner that i have, the other part is that working on this stuff would be too much like work for me. The carpenter doesn't want to come home to a leaky roof and i don't want to have to take my tuners to work : )

As to the Sherwood, i've seen the info on the tuner website and even have an original review of it. I've talked to a few shops about these and their opinions are typically that they are VERY hard to keep running. I would imagine that this is like any other product though. That is, once you get it into the hands of someone that knows the in's and out's of it, it becomes a lot more manageable. Sean
>

sean...Is it fair to say that the many PLL transcevers that you work on are all in the shop because they aren't working well? After you fix them, don't they all work great?

I work on brand new units right out of the box and notice these problems even more than on used units in for repair.

Having said that, i can align a brand new unit after the manufacturer's recommended period of warm up and when it comes back in after a few weeks or months of use, many of the parameters of operation have changed due to break-in. As such, i always recommend a "follow up visit" after an alignment to bring things back into spec once everything has fully settled in. This goes for new or used units as they all drift slightly after prolonged operation. As i've mentioned before, the effects of "component break-in" ARE measurable and this is not debatable as far as i'm concerned. Sean
>