[Icom] IC-775DSP: an undocumented feature ???

Wed, 31 Mar 2004 00:20:23 +0200

Have you got any respons in this issue?

I will try it next weekend.

73 de Anders

----- Original Message -----=20
From: "Vladimir V. Sidorov" <[email protected]>
To: <[email protected]>
Sent: Sunday, March 28, 2004 10:22 AM
Subject: [Icom] IC-775DSP: an undocumented feature ???

> Hi all,
>=20
> Playing with the radio some time ago I've noticed something new for me =
at
> the 775. Supposingly the APF is only working for CW. But apparently if =
the
> button is pressed in SSB mode, it also works. The effect is not as =
drastic
> as in CW, but certainly the overall sound changes itself. It is =
noticeable
> for rather weak signals, only.
> It looks like there comes a resonant frequency within the bandpass, =
and the
> resonant is around 1200 Hz what makes the incoming signal more ringing =
and
> more readable. At some weak signals the button works like a switch,
> illigible - non-illigible.
> The only explanation I can imagine is the fact that switches in the
> transceiver are made on pin-diodes. Accordingly there might come =
leakage of
> an incoming signal through the non-fully unswitched diode and the APF
> circuit partially remains working.
>=20
> Before posting this message I have made several checks to be sure, I =
am
> quite far from gallucinating... and for sure there is an effect on =
weak
> signals, as described.
>=20
> Did anybody else notice the same?
>=20
> And if somebody wants to repeat my experience, let me remind you once =
again,
> it is only working for weak signals, there is no any difference in =
receipt
> of strong ones.
>=20
> Thanks and 73,
> Vladimir EU1SA
>=20
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