[Elecraft] Sub RX Filters choice

[Don Wilhelm]

Gordon,

I am going to give you a slightly different answer than I have seen 
posted on the reflector.

If diversity mode is your main consideration, then ideally, you need to 
have matched filters
The 5 pole filters  can be matched at extra cost from Elecraft, but the 
9 pole Inrad filters supposedly have zero offset and do not have to be 
matched.

The matching problem becomes less important at wider filter bandwidths, 
so since you have the 2.7 kHz filter in the main already, you can get 
another 2.7 for the subRX and average the offsets.  It is not the ideal, 
but it will work fine for diversity reception.

73,
Don W3FPR

On 12/18/2012 6:28 AM, mm0gpz wrote:
> Hi.
>
> My K3 has a standard 2.7 Khz ssb filter, a narrow 2.1 Khz ssb filter and a
> 400 hz cw filter.
>
>
> I am planning to purchase the sub RX KRX3 and would like some filter advice
> please. I am much more interested in CW.
>
> Do I have to match up all these filters on the Sub RX for diversity? I know
> the 2.7 Khz is standard but for diversity I seem to remember reading the
> same filters should be in place? I also seem to recall that the filters are
> not cascaded so in essence, only one filter is in line at a time. So if I
> purchase only the 400 hz filter for the sub RX, it diversity reception will
> work fine as long as the 400 hz filter is selected for CW or SSB will be
> fine between > 2100 and 2700?
>
> What would happen if I engaged the 2.1 SSB filter in main RX and I don't
> have same filter in Sub RX.
>
> Thanks for your time.
>
>