Re: [IRCA] Sync Detection Question

["Steve Ratzlaff" <steveratz@xxxxxxxx>]

Here are some of my comments, as an R8B owner.
During the good TA conditions of October, I wanted to find which of my
various radios might be better at initially detecting the faint AM modulated
signals. I put my radios in a stack at my operating position and rigged up
antenna and audio output
switching such that I could select any of the radios, using the same
antenna, and listen to the audio in the headphones. In my stack (still) are
the AOR AR-7030, Drake R8B, Icom 746Pro, Icom R-75 (no AM mods).
I've found that the AR7030 hears a faint AM-modulated signal first, in AM or
SSB/ECSS mode;
followed immediately or perhaps at the same time, by the R75 in SSB/ECSS
mode. The signal needs to be stronger before the R8B and the 746P (both in
either SSB/ECSS or AM mode) receive it. And with a little stronger signal
the R8B can have the AM Sync Detector mode activated and it will
hold the signal quite well as long as the level stays up.
Thus, I do most of my listening for AM signals with the AR7030, for the very
weak TAs we've all been trying for; but if the signal gets strong enough,
then I find it's more pleasant listening on the R8B in AM Sync Det mode. I
do
not particularly care for the sound of the 746P on AM signals, and rarely
try it anymore, and it does not hear the weakest signals as well as the
AR7030 anyway, despite the stellar reviews some have given it for AM
signals--it has not proven to be my best AM-mode radio in my own particular
tests.
For initially finding the signals, I use the R75 set to CW mode; with its
250Hz CW filters it will hear a faint TA het very well, even if a strong
station is on the frequency. I can gauge fairly well now what level het is
needed before the AR7030 will get audio, then when that happens I switch to
the AR7030 and try for the audio.
Obviously my setup is fairly unique to me, but in general I find that with
the R8B I never try to hunt for a weak AM signal in AM Sync Detector mode,
and that if you have another radio, you might want to try it--it may hear a
very weak AM signal initially better than the Drake.
Steve
NE Oregon
----- Original Message ----- 
From: "Nick Hall-Patch" <nhp@xxxxxxxx>
To: "Mailing list for the International Radio Club of America"
<irca@xxxxxxxxxxxxxxxx>
Sent: Monday, January 16, 2006 12:37 PM
Subject: Re: [IRCA] Sync Detection Question


> Quoting "J.D. Stephens" <jdstephens_99@xxxxxxxxx>:
>
>> I have noticed during my recent chase for
>> Trans-Atlantic Mediumwave stations, that when I use
>> the Synchronous Detector on my Drake R-8, instead of
>> enhancing the intelligibility of the transmissions, it
>> has the opposite effect.
>>
>>
>
> I'm not sure that the R8's synchronous detector is of any use at all in
> DXing
> situations; does anybody have experience to the contrary?  And if R8A and
> B
> owners could check in with their opinions, as I seem to recall that one of
> the
> versions upgraded the sync detector in some way?  (Can't get to my notes
> as I'm
> on my lunch break at work)
>
> Certainly, not nearly as effective as the selectable sideband sync of the
> ICF-2010.
>
> best wishes,
>
> Nick
>
>
>
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