http://elecraft.85.s1.nabble.com/K3-160M-Diversity-Users-tp3322951p3326381.html
This is particularly true if you are buying multiple filters.
the transceiver.
> I would get the 5-pole 200 Hz filters. Elecraft says they're
> narrower than the 250 Hz filters all the way down.
Close enough ... measurements of my 200 Hz filters "in circuit"
the 250 Hz filters: 370 Hz @ -6dB and 785 Hz @ -60dB.
... Joe, W4TV
> -----Original Message-----
> From:
[hidden email]
> [mailto:
[hidden email]] On Behalf Of Dick Green WC1M
> Sent: Saturday, July 25, 2009 1:30 PM
> To: 'Bill W4ZV';
[hidden email]
> Subject: Re: [Elecraft] K3 160M Diversity Users
>
>
> My experience pretty-much aligns with Bill's. I started out
> with matched pairs of 5-pole 500 Hz and 5-pole 200 Hz
> filters. The 500/200 combination makes a little more sense
> than the 400/250 combination because there's more difference
> between the filter widths.
>
> Like Bill, I rarely use the 200 Hz filters. Most of my use is
> contesting. If you spend too much time with BW cranked down
> to 200 Hz or less, you're going to miss a lot of callers. I
> only use narrow BW when someone plops down very close to my
> frequency when I'm in the middle of a QSO. That said, the
> narrow BW saves me every now and then, which for me is worth the cost.
>
> I was fairly satisfied with the 5-pole 500 Hz filters, but
> was sometimes bothered by thumping and clicking from loud
> stations (S9 and higher) just above my passband. This is
> likely caused by the hardware AGC activating at somewhat too
> low a level. Quite a while ago there was a fix to the RF
> board to raise the threshold, but some of us think it's still too low.
>
> At any rate, though the theory says that roofing filters
> aren't responsible for the ultimate selectivity (the DSP does
> that), I found that they do make a difference in the above
> situation. Switching off the 500 Hz filters and using the 200
> Hz filters produced audibly less interference, most likely by
> providing greater attenuation at the hardware AGC stage. That
> induced me to replace the 5-pole 500 Hz filters with 8-pole
> 400 Hz filters.
>
> The result was a minimal improvement, not easily detected by
> testing. The real test will come this fall when I'm squeezed
> into 40m or 20m with zillions of loud stations on either side.
>
> All that said, Bill is correct that, with the matching fee,
> the price difference between 5-pole and 8-pole filters is
> small enough that it makes sense to get the 8-pole filters. I
> should note that the 8-pole filters are not necessarily
> perfectly centered, but they're close enough that you
> probably won't need to use any offset for diversity.
>
> As far as the 200 Hz vs 250 Hz filters go, if you want to
> have them in reserve for those really tough QRM situations, I
> would get the 5-pole 200 Hz filters. Elecraft says they're
> narrower than the 250 Hz filters all the way down. Also,
> there's more BW difference between the 200s and the 400s/500s.
>
> I agree completely with Bill on the merits of diversity: with
> the right antennas, it's amazing.
>
> 73, Dick WC1M
>
> > -----Original Message-----
> > From: Bill W4ZV [mailto:
[hidden email]]
> > Sent: Friday, July 24, 2009 10:27 PM
> > To:
[hidden email]
> > Subject: Re: [Elecraft] K3 160M Diversity Users
> >
> >
> > W4UM wrote:
> >
> > > What are your recommendation if I were to get only
> > one pair of filters?
> >
> > I would go with either the 500 or 400 8-poles.
> >
> > > Is there any real value to getting a pair of narrow
> > (200Hz or 250Hz) filters as well as a pair of the wider (400Hz or
> > 500Hz)
> CW
> > filters, or am I just wasting money?
> >
> > I have a 200 Hz in my Main in addition to 500 Hz 8-poles in
> Main and
> > Sub. If you contest or are in huge simplex pileups, there are
> > definitely times when the 200 Hz may be useful. For some reason I
> > don't understand, I have no offset warbling when setting
> WIDTH to 200
> > (which enables the 200 Hz in Main and 500 Hz in Sub). Most of the
> > time when listening to weak signals,
> I
> > use 350-500 Hz WIDTH so a pair of 500 Hz filters is fine
> excluding the
> > extreme cases of simplex pileups or a strong station nearby
> (e.g. the
> > CQ
> 160
> > CW contest).
> >
> > > Is there a noticeable difference between the 5-pole and 8-pole
> > > filters?
> >
> > I used 5-pole 500s in my first K3 and have not noticed a
> significant
> > difference with the 8-poles, but I've not compared them
> > simultaneously.
> As
> > you stated, there's little cost difference (after the
> matching charge)
> > so
> I
> > went with the 8-pole 500 Hz when it became available. I personally
> > prefer
> a
> > slightly wider BW than the 400 Hz allows but that's another option
> > some choose.
> >
> > You'll love diversity on 160 and 80, especially if you have good RX
> > antennas. I use my TX antenna (similar to a 4-square) in
> one RX and
> > Beverages in the other, and I use diversity 99% of the time
> on the low
> > bands. I would never own any rig without diversity now
> that I've used
> > it.
> >
> > 73, Bill W4ZV
> > --
> > View this message in context:
>
http://n2.nabble.com/K3-160M-Diversity-Users-> > tp3322951p3323855.html
> > Sent from the Elecraft mailing list archive at Nabble.com.
>
>
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