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[Yaesu] Re: Synchronous Hf AM mode issue - Feedback wanted.

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Subject: [Yaesu] Re: Synchronous Hf AM mode issue - Feedback wanted.
From: WD8ARZ" <wd8arz@null.net (WD8ARZ)
Date: Wed, 27 May 1998 15:12:00 -0400
Hello Dennis, and thank you for the excellent reply about the hum on AM

Between the ground loop, several touch lamps and one floresent light on this
end, you may have made a direct score on this one. It makes sense with the
symptoms I have, the changes from one antenna to another, and the external
hand held rx test. I will pass on my testing results to the various
reflectors I posted the original message to.

Qsl about the FT-102. I had the FT-301 and except for the annoying red leds
of the display, I loved the receiver. I may keep my eye out for a FT-102 as
a back up. My IC-720 and IC-745 are showing signs of their age and have high
phase noise in them to boot.... hi hi

73 from Bill - WD8ARZ

-----Original Message-----
From: Dennis O'Brien <pegasus@mho.net>
To: WD8ARZ <wd8arz@null.net>
To: <yaesu@contesting.com>
Date: Wednesday, May 27, 1998 2:46 PM
Subject: Re: [Fox_Tango] Synchronous Hf AM mode issue - Feedback wanted.
:WD8ARZ wrote:
:> Never before have I had AM synchronous Tuning (page 29 in the user
:> and I was really looking forward to what it would bring to my listening
:> pleasure. Per the manual, synchronous tuning reduces the distortion
:> by carrier fading by receiving the signal in LSB while reinjecting a
:> unfading carrier. In the past I would simply use sideband to tune in the
:> station and choose the side that was the cleanest. Synchronous tuning
:> lock onto the carrier and allows tuning around the signal abit with out
:> losing zero beat.... Okay, well and good, but I simply dont find fading
:> issues to be that improved in synchronous mode much more if at all over
:> synchronous mode...even with different filter selections ( I normally
:> in the widest filter). I have running many comparasions with the both
:> receivers tuned to the same station, same AM mode, same filters, but one
:> receiver non synchronous and the other synchronous.
:Hi..    Well, one thing for sure.. there are synchronous detectors.. and
:synchronous detectors.. Some are excellent (as in the Sony ICF-2010) and
:are lousy.. (as in Grundig Satelite 700)  I don't know it's implementation
:the MP, but from the sounds of it, it may not be a good one.  I've heard
:that completely remove all but the smallest hint of selective sideband
:> Part of the problem with the above is aggravated by a second AM mode
:> and the bigger one in my experience. Hum in the AM mode audio that
:> with the the signal strength and is particularly an issue with rapid
:> fading.... enough to destroy the received audio intelligibility. The hum
:> 90 plus percent of the cases is not in the audio when listening to a AM
:> signal in sideband mode, so it is not a station sourced hum.
:> 73 from Bill - WD8ARZ
:> wd8arz@null.net
:   Bill, I've heard this kind of hum several times.. it's not usually a
:problem but likely a groundloop of some sort.  But the noise is generated
in the
:receiver from some outside influences... some of these you touched on in
:letter.  I've encountered it very severe in some instances and even going
:battery power didn't remove the hum.  I HAVE found that these "touch lamps"
:emit this same hum VERY loud sometimes.. even when the lamp is off.. but
:the hum gets stronger when the lamp is on.  Disconnecting your house A.C.
:will tell you a lot about it.  Doorbell xfmrs have been a source of similar
:noise.Good luck with it anyway!
:   I'm still plodding along with the mid-80s FT-102.. Still, I think, the
:amateur receiver ever made.. No synthesizer (phase-noise) Direct feed
:WONDERFUL AGC implementation, bullet-proof front end, receiver
:(remember those?) no noisy diode-switched circuits, extremely sensitive
:(-144dbm) and very quiet receiver.  When "DSP" receivers begin to handle
:and interference BEFORE the AGC loop, then I'll be interested.  Until then,
:thanks.  A while back I had my 102 right next to a 1000MP on the same
:switching back and forth.. My 102 heard weak signals that were not even
:in the MP.. specially on 10 meters.  A cw beacon in TX was Q5  (about S-1
:lots of audio) and not detectable on the MP.  Yea, we did have to search a
:to find signals weak enough for the that, but it happened.  The MP is a fun
:though.. LOTS of things you can do with it to customize it's interface with
:  73..
:     Dennis,
:         N0SP

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