[Elecraft] K3 - P3 or LP-PAN comparison

[Dick Green WC1M]

Some comments that may be helpful for both threads about the P3:

I have two K3s in an SO2R contest configuration. The K3 I use mostly for
running has an LP-Pan and NaP3. I just installed the pre-amp option in my
LP-PAN, and it works well, but I haven't done a contest with it yet. The run
K3 also has a SubRX that I use almost exclusively for Diversity reception.
The radio I use mostly for S&P has a P3 (no SVGA card) and no SubRX.

Both panadapter solutions work well, but I have a preference for the P3,
especially for S&P. The main reason is that the P3 display seems sharper and
more responsive to me. This will sound odd, but the signals on LP-PAN/NaP3
seem slightly "fat" and "slow", and the screen display seems more chaotic
that it does on the P3. It could be that the display is just that much
bigger, but I don't know. I've not been able to make the NaP3 display look
as good or respond as well as the P3 display.

The main reason I use LP-PAN/NaP3 on the run radio is to check the band
activity (i.e., is the band open enough to run?) I've tried to use it to
find an empty space to run, but haven't had a lot of success with that. For
some reason, that's easier to do with the P3. 

Another issue is screen real-estate. I happen to have a 24" main monitor
that I use for the contest logger, a 20" second monitor that I use for NaP3
and a bunch of other utility programs and a 7" touch screen I use for a
program I wrote called AntennaMaster that I use to select antennas, tune
SteppIRs, tune my Acom amp, etc. If you have just one monitor, it's hard to
find enough room on it for NaP3 and all the other things you might want to
see during a contest.

As for CPU usage, when I had a core2-Duo system, LP-PAN/PowerSDR-IF used a
lot of CPU and the system fans would be humping it all contest. I worried
about the heat stress that was putting on the system, especially the CPU.
Now I have an i7-based system with an NVIDIA 570 graphics card and the CPU
usage is much lower. CPU usage with LP-PAN/NaP3 is so low I barely notice
that the fans are running a little faster. FWIW, I use LP-Bridge with
Writelog and NaP3, and it works flawlessly.

All in all, if the P3 was a little less expensive, I would use one on the
run radio instead of LP-PAN/NaP3 (anybody want to sell me a used P3?) 

Now, I hasten to add that there are some advantages to the LP-PAN/NaP3 or
LP-PAN/PowerSDR-IF solutions. For one thing, it can provide a sub receiver
if you don't have one. Second, it can produce excellent filtering and audio
for AM B/C stations without having to buy a 6 KHz filter for the K3. For
another thing, PowerSDR-IF has some monitor modes that transform it into a
very useful receive monitor scope (like being able to see the other
station's transmit envelope.) LP-PAN is also a lot cheaper than a P3. Even
if I had a P3 for the run K3, I wouldn't sell my LP-PAN. I would hook them
up together (more feasible with the $25 LP-PAN pre-amp option installed
because the pre-amp helps to compensate for the 3dB IF splitter loss in the
P3.)

On the SubRX, whether money should be spent on that over a P3 depends very
much on what you do with the radio. I would probably go for the sub because
it makes the K3 a much more powerful radio. If you're a DX-er, it's
indispensable because it allows dual-watch. If you're a contester with the
right kind of antennas (ideally, opposite polarity), Diversity reception can
be an unbelievable upgrade to your station -- it was for mine. That said, I
use a full-size 2-el 40m beam at 110' and a full-size 40m 4-square with 60
radials per element. That combo had better be good! As has been noted,
Diversity does require purchasing identical filters for all bandwidths with
which you want to do Diversity reception. If you aren't a DX-er or a serious
contester, then a sub might be less important and a P3 might make more sense
for the dollars you have to spend.

Hope this is helpful.

73, Dick WC1M

> -----Original Message-----
> From: Wes Stewart [mailto:n7ws at yahoo.com]
> Sent: Tuesday, July 03, 2012 11:59 AM
> To: Elecraft; Robert G. Strickland
> Subject: Re: [Elecraft] K3 - P3 or LP-PAN comparison
> 
> I use an SDR-IQ on the i-f output of my K3.  I use LP-Bridge to share
> data between the K3, SpectraVue, DXBase logging and/or N1MM.
> 
> Additionally, with a laptop/SDR-IQ combination I have a nice little
> standalone receiver for travel use, although the sensitivity is poor
> without something like an active antenna.
> 
> Disclaimer: I once owned an LP-PAN but sold it, I've never owned a P3
> although I played with a preproduction one once.
> 
> Wes Stewart N7WS
> 
> --- On Mon, 7/2/12, Robert G. Strickland <rcrgs at verizon.net> wrote:
> 
> 
> 
> In another post I ask about sub-receiver versus panadapter. Here, a
> question about type of panadapter. My station occupies a very small
> space, and adding the P3 would strain the real estate. So, I've been
> looking at other panadapter possibilities that use the computer screen
> for display. What sort of useful comparisons can be made between the P3
> and the LP-Pan box/software? Are there any other panadapter options that
> I should consider? Thanks for any and all opinions.
> 
> ...robert
> --
> Robert G. Strickland, PhD, ABPH - KE2WY
> rcrgs at verizon.net
> Syracuse, New York, USA
>