Craig, I think I am correct in saying that the various bandpass filters available, eg ICE, Dunestar were created to reduce tx phase noise from adjacent current design radios in MO and SO2R setups. I have a pair of the Dunestar 600s here and they do just that, although antenna separation plays a big part also. We used them for several years in our GU8D operation in the IOTA Contest and they were very effective.
toggle quoted messageShow quoted text
One of the things that has impressed me in the K3 discussions was the in-band close-in figures. A couple of years ago we did some in-band checks here using 2 FT1kMPs with roofing filters and tx amps. I haven't got the actual data to hand but with mono band antennas on 20m separated by 70m, we were able to operate SSB and CW to within about 100KHz. I wouldn't have thought the Dunestars would have made any difference but I honestly cannot remember.
I'm looking forward to getting my K3 shortly to do some more tests. In particular at the beginning of October we have the RSGB 21/28MHz Contest which I won last year using just the MP. This year I am intending to run SO2R with the MP and K3 and will be looking to do in-band dual mode as well as dual band. That should be interesting.
73 Chris G3SJJ
It will be interesting to see if the Elecraft K3 needs external
bandpass filters when used in a multi multi contest environment.
Considering what the cost is for a full set of W3NQN filters, it
certainly make the K3 a popular if you dont have this additional cost
or weight to carry around on an expedition or in contest station.
I also wonder if a Tracking Preselector will become a future option
for the K3. The Yaesu U tune preselector is a great feature although
old hat! However if the K3's front end is bullet proof it would be
hard to justify the additional expense and marginal performance gain
from a preselector. When bad IMD, Keyclicks and phase noise dominate
the value of such filters is questionable. However it might be handy
in places like Europe. Its going to be torturous operating a perfect
receiver like the K3 and hearing the good, the bad and the ugly
knowing very well its not your receiver when you hear the bad!
Such is the price of perfection!
--- In Elecraft_K3@yahoogroups.com <mailto:Elecraft_K3%40yahoogroups.com>, "Jon Pellant" <w1jp@...> wrote:
<mailto:Elecraft_K3%40yahoogroups.com>, Rick <mrfarm@> wrote:
Thanks for your feedback. I trust my gut instincts sometimes and my gut
made me blindly order a K3. I trust I won't be dissappointed.
--- In Elecraft_K3@yahoogroups.com
Assuming you like the ergonomics of a given rig, the one parameter
I look at the most is the close-in IMD3 (Third Order Intermodulation