[ICOM] IC-781 - was IC7800

[Anders Janis SM4RNA]

This is not regarding the IC-781 but may be of general intrest anyway.

For the IC-775DSP version when the TX-DSP is enabeld the TX-audio is 
filtered thru the 6kHz filters(and ofcourse also fildtered by the DSP at the 
selected bandwith) This mean that TX-audio will not be limited if the FL-96 
is changed to a FL44A or Inrad 109.

If the TX-DSP is switched off or you have the rare non DSP-version of 775 
the TX-audio is sent thru the 2,4 - 2.7kHz filter combo.

Changing the FL-96 to the Inrad 109 in my 775DSP really made the radio 
better. I also modified my IC-746 non pro and changed both the 9MHz to a 
FL-80 and the 455kHz to a Inrad 109. That was even a more noticeable 
improvement.

de Anders SM4RNA

----- Original Message ----- 
From: "Adam Farson" <farson at shaw.ca>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Wednesday, March 19, 2008 5:51 PM
Subject: Re: RE: [ICOM] IC-781 - was IC7800


Hi Tim,

Yes, the IF filters are also in the transmit signal path. The 2.4 kHz pair 
will provide the same 3dB occupied bandwidth as in the IC-751A, which uses 
the FL-80/FL-44A pair, but the FL-223 will degrade transmitted audio 
fidelity. I found that the 2.4 kHz filter pair offered the best compromise 
between adjacent-channel selectivity and transmitted audio articulation.

I used to get around this (when required) by setting up Split with the 
FL-223 on receive (WIDE button pressed) but the FL-80 on transmit. TX and RX 
frequencies were equal.

It is so much easier with the IC-7800, IC-7700 etc.

Cheers for now, 73,
Adam, VA7OJ/AB4OJ

----- Original Message -----
From: Tim Duffy K3LR <k3lr at k3lr.com>
Date: Wednesday, March 19, 2008 8:51 am
Subject: RE: [ICOM] IC-781 - was IC7800
To: 'ICOM Reflector' <icom at mailman.qth.net>

> When using these narrow filters, are they also part of the
> transmitter chain
> (i.e. they might reduce the transmitted bandwidth and fidelity)?
>
> 73,
> Tim K3LR
>
> -----Original Message-----
> From: icom-bounces at mailman.qth.net [mailto:icom-
> bounces at mailman.qth.net] On
> Behalf Of Adam Farson
> Sent: Wednesday, March 19, 2008 1:08 AM
> To: 'ICOM Reflector'
> Subject: RE: [ICOM] IC-781 - was IC7800
>
> Hi Mike,
>
> Glad you were able to snag a 109. It, and the FL-223, will make
> quite a
> difference to your IC-781 on SSB.
>
> Cheers for now, 73,
> Adam VA7OJ/AB4OJ
>
>
----
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