[ICOM] Re: IC746 FL 52a filter

[Hans Remeeus]

I did a lot of changing with the x-tal filters in the IC-775DSP.

FL-222 (1.8 kHz), FL-44A (2.4 kHz) and finally the Inrad #314 (2.1 kHz).
This in combination with the FL-223 (1.9 kHz) gives me the bandwidth and 
sound I like.

I use this 9 MHz filters:
FL-102 (6 kHz)
FL-70 (2.8 kHz)
FL-223 (1.9 kHz)
FL-32A (500 Hz)
FL-232 (350 Hz)

And this 455 kHz filters:
FL-96 (2.8 kHz)
Inrad #314 (2.1 kHz)
FL-52A (500 Hz)
FL-53A (250 Hz)

Very nice feature of the IC-775DSP is the way how you can select the 
bandwidths.

E.g. the following front-controlled filter selections on SSB:
WIDE ON - 9 MHz NAR OFF - 455 kHz NAR OFF: 6 kHz bandwidth (very wide)
WIDE OFF - 9 MHz NAR OFF - 455 kHz NAR OFF: 2.8 kHz bandwidth (wide)
WIDE OFF - 9 MHz NAR OFF - 455 kHz NAR ON: 2.1 kHz bandwidth (medium)
WIDE OFF - 9 MHz NAR ON - 455 kHz NAR OFF: 1.9 kHz bandwidth (narrow)

Other combinations are possible too (e.g. on SSB):
WIDE ON - 9 MHz NAR OFF - 455 kHz NAR ON: cascaded 6 and 2.1 kHz 
bandwidth (wide/medium)
WIDE ON - 9 MHz NAR ON - 455 kHz NAR OFF: cascaded 6 and 1.9 kHz 
bandwidth (wide/medium)
WIDE ON - 9 MHz NAR ON - 455 kHz NAR ON: cascaded 6, 1.9 and 2.1 kHz 
bandwidth (medium)
WIDE OFF - 9 MHz NAR ON - 455 kHz NAR ON: cascaded 1.9 and 2.1 kHz 
bandwidth (medium/narrow)

Note: the above selections will give different results on CW/RTTY, AM 
and FM.

Together with the TWIN PBT and the built-in DSP gives you almost every 
combination you want!

On the IC-746 it is quite different, but I hope the above can help Perry 
in making a choice.


73,
Hans Remeeus (PA1HR)
http://www.remeeus.nl
Communication is about people, the rest is technology.



Adam Farson schreef:
> Hi Perry,
> 
> That sounds like a reasonable mix of filters, although I would have
> installed an FL-44A or Inrad 109 rather than the FL-222. Twin PBT works best
> when both filters are closely matched.
> 
> http://www.qsl.net/icom/xfilter.html
> 
> It is pointless to select the 15 kHz filter for wider transmitted occupied
> bandwidth in SSB mode. The balanced modulator is fed with carrier at 9 MHz,
> and the 2.4 kHz filter at 9 MHz does all the work of suppressing the
> unwanted sideband. (IC-746 service manual, p. 4-4.) The transmitted signal
> does not pass through the 15 kHz filter at all.
> 
> On SSB receive, however, the 15 kHz filter will really degrade receiver
> performance. Twin PBT will not work effectively, and adjacent-channel
> selectivity will suffer.
> 
> You can download the IC-746 service manual on mods.dk, Marcucci or here:
> http://www.qsl.net/icom/manuals.html
> 
> Cheers for now, 73,
> Adam VA7OJ/AB4OJ
> 
> -----Original Message-----
> 
> --- In IC746 at yahoogroups.com, "PERRY" <wa8thk at y...> wrote:
> 
> THANKS ADAM
> 
> I know I did not make it very clear on my removing of the ceramic filter '
> sorry.
> I replaced it with the FL 222 a 1.8 filter and I need the FL52A for the plug
> in on the 455 I tested the FL222 on tx and it sounds  good to everyone and
> its not bad on rx  for me, I can select 2.4 in the 9mhz and 15kc in the 455
> for wide then 2.4 and 2.4 for narrow ssb  (the second is realy 1.8 now)
> Then I will have several selections for the CW ..
> 1.9---1.8  and   500---500  
> 
> 73
> Perry WA8THK
> 
> 
> --- In IC746 at yahoogroups.com, Adam Farson <farson at s...> wrote:
>  >
>  > Hi Perry,
>  >
>  > The ceramic SSB filter should be replaced with an FL-44A, FL-96 or
> Inrad 109
>  > 455 kHz SSB filter (mounted on the board, with pins soldered in
> place). The
>  > FL-52A (and a matching FL-100 for 9 MHz) can be plugged into the
> option
>  > slots.
>  >
>  > If you install an FL-52A on the board, SSB transmit and receive
> will not
>  > work.
>  >
>  > Cheers for now, 73,
>  > Adam VA7OJ/AB4OJ
>  >
>  >
>  > -----Original Message-----
>  > From: IC746 at yahoogroups.com [mailto:IC746 at yahoogroups.com] On
> Behalf Of
>  > PERRY
>  > Sent: 30 December 2005 08:20
>  > To: IC746 at yahoogroups.com
>  > Subject: IC746 FL 52a filter
>  >
>  > Hello Group
>  >
>  >  I am looking for a Bargin Priced
>  >  Filter for my 746 non pro
>  >  I would like  a 455 if Icom FL52A  500 hz filter
>  >    or Inrad brand....
>  >
>  >  I have removed the stock ceramic from the board and installed a
> 1.8 kc
>  > filter and with the FL52A  I will have better  selections of the
> SSB and CW
>  > modes  Perry  wa8thk at yahoo . com
>  >