[Kenwood] RE: ssb filters for my 850

Mon Feb 13 16:48:46 EST 2006

NP on the questions!
Basically, there are four filter positions in each IF on the '850. From
the factory, two of the 8.83MHz IF slots and three of the 455KHz slots
are occupied. So, from the factory, the setup is:
 8.83MHz 455KHz
 ------- ------
 6K 12K
 2.7K 6K
 open 2.7K
 open open
You can add any filter you want to any of the open slots - the radio
doesn't care. Don't think of the filters in terms of mode of operation
- think of them purely as bandpass filters. Just get filters with the
bandwidth(s) you want to use.
For example, you can put an 2.1KHz Inrad and a 400Hz Inrad in slots 3
and 4 of the 8.83MHz IF (the way one of my 850's is setup). If you
really wanted to, you could even put the 400Hz filter in slot 3 and the
2.1K in slot 4 - it doesn't matter as long as *you* know which filter is
where and ignore the labels on the front panel. You can also add any
bandwidth filter in the 455KHz IF slot. BTW, there's no need to follow
any order and you can skip slots if you really wanted to (e.g. skip slot
3 and put a filter in slot 4). For the more daring (such as Mr. C.S.
Turner), you can even replace the "stock" filters in both IF's by
opening up the radio and doing some minor surgery to remove and replace
the existing ceramic filters.
You can use any filter bandwidth in any mode on the '850. Yes, this
means you can select a 400Hz filter while in USB or LSB mode...just
don't expect to understand much! That's one of the beauties of the
'850...flexible filter selection (aka any filter for any mode). Yes,
there are such things as "RTTY" filters, but, if you think about it,
these are just filters for SSB use - just on a different center
frequency.
In your case, I would stick with "drop-in" filters. Since you're
interested primarily in SSB, then get a matched pair of InRad 2.1K
filters - one for each IF. If you engage both 2.1K filters at the same
time (aka "cascade the filters"), the ultimate bandwidth will seem lower
than 2.1K. And, if you really wanted to, you could narrow the BW
further by using the slope tuning controls (best done with cascaded
filters of the same bandwidth).
With the last remaining plug-in slot (in the 8.83MHz IF), I would
suggest a 1.8KHz filter for SSB, or, a 400Hz filter for CW. I have an
InRad 400Hz filter in my SSB '850 as I can get as narrow as I need for
SSB using cascaded 2.1k's (plus slope tuning) and the 400Hz helps those
times I need to do CW on that rig.
NOTE: The InRad filters may require you to cut some pins in your rig to
fit. No problem here though as these are redundant ground pins for the
filter and easily done.
GL & 73,
 - Aaron Hsu, NN6O
-----Original Message-----
Sent: Monday, February 13, 2006 12:04 PM
Subject: Re: [Kenwood] RE: ssb filters for my 850
Aaron
 thanks for the info. I planned to use inrad filters,I guess Iam 
confused about the filter layout on the 850. not much detail in the 
manual. I will use the 850 for ssb only,have a proII that lives in the 
ritty,psk and cw world only. I guess the 850 has a factory ssb filter 
installed in the 455 IF? leaving a open slot in the 8830 IF for a 
second ssb filter? the remaining slots are for cw filters if you want. 
I can use the 2 remaining slots for ssb if I want ??
sorry to be a pain ,
thanks dale