"Pete KE9OA" wrote in message
I can't comment on some of these receivers, but I can comment on the
AOR7030. Meets its specs? Maybe, but after 1 year of use, some unadvertised
"bonuses" were thrown in. The mode switches have developed bounce problems
which could have easily been addressed in software. The mechanical tuning
encoder has been noisy since day one, sometimes "scanning" the frequencies
on its own. The sensitivity is definitely not on a par with the R75. I don't
care what the unit is specified as; the MDS on the R75 is better. According
to Dave Zantos, the 7030 Plus isn't much better. On his sample unit, the
optical encoder shaft developed a wobble after about one year. His 7030 Plus
had a low level background noise on signals that wasn't present with the
7030. It is suspected that the removal of the shielding from the synthesizer
might be causing the problem.
I do have both the R75 and the AOR7030, and after two years, the R75 has not
had any problems surface.
If the 7030 wasn't a Christmas gift from my wife, I would have sold this
unit a long time ago.
On the subject of the R75, I know, the sync detector isn't the best in the
world, and the "large front mounted speaker" is a joke, but in terms of RF
handling, selectivity, etc, the R75 is a very good receiver.
Normally, I don't step into this kind of discussion, but sometimes, there is
more than meets the eye in this situation.
If anybody doesn't like the R75, that's fine...................still, it is
a fairly good receiver, especially for the 450 dollar price tag that this
unit is being sold for. Okay, the sync detector doesn't work. Hi Pete nice review.About the R75 sync det,Kiwa CO have a fix for it: Synchronous Detector Upgrade
Kiwa provides two major upgrades to the Synchronous Detector. Together
they provide enhanced performance where the PLL stays "locked" under
the most difficult signal conditions.The first upgrade is best
described as a "dual speed control voltage". The control voltage for
the PLL filter is tuned within an optimum window that is determined by
signal conditions.The response is slow to maintain a "centered"
condition. A second circuit provides the control accuracy to react to
fast flutter fading and noisey conditions. These two circuits provide
a dual speed control for the PLL.
The second major upgrade is to the Synchronous AM AGC. The dual speed
technique is used again to first center the AGC but still allow for
quick short changes in AGC characteristics as required by signal
conditions.In the yahoo R-75 group we have two other sync det mod
projects,one of this mods use a comparator[339]and work very good and
the cost is less than $7.00 for the total mod.I'm using your Pete's
[sensitivity mod] and now this receiver shine in the MW band.After did
your mod I tested it with a drake R8B and for hard core dxing the Icon
won hands down,thanks for the R75 exceptional quit circuitry,the help
of its nice DSP and your well designed sensitivity mod.