Second receiver options ??

[callen1155]

Hello guys.

I've been using my K3 about a month now and really enjoying it. Since I have a keen interest in DXing and pulling out weak signals (DXing cw & ragchewing cw) I'm starting to think about adding the KRX3 second receiver although I understand that LP-PAN also provides second receiver capability.

I also understand that true K3 'diversity reception' greatly aids weak sig copy and would only be available with the KRX3 receiver but not with LP-PAN.

Additionally, I use an older, slower desktop for playing radio and would probably need to a better pc if i go the LP-PAN route, plus the soundcard, and then the unit itself.

So if you had enough funds for either the KRX3 second receiver or the LPAN which would you choose. I'm leaning toward the KRX3 but wanted to get the experts' take on this as well.

Seems that the visual aspect of LP-PAN, while appealing, would be less beneficial basd on my operating  than the diversity reception.

Is that making sense?

thanks and 73.
chuck
af4xk

[W8JI]

Chuck,

LP Pan mostly is a spot and click assist to operating, it
really will not be a better or different second signal
channel than the K3's audio. There is, of course, no weak
signal diversity improvement from running LP Pan in one ear
and the K3 in the other.

Stereo diversity reception that allows significantly
enhanced weak signals requires significantly different
antennas for each receiver input and also requires nearly
exact duplicates of phase, signal processing time delay, and
bandwidth in both receiver channels for maximum effect.
Average signal-to-noise of the desired signal on both
antennas also has to be about the same for maximum effect.
It does no good to combine mostly noise from one ear with
signal and some noise from the other.

There is a little improvement from antennas on each channel
being different in polarization when spacing is close, but
by far the most significant improvement occurs when the
receiving antennas are a fairly large distance apart in
wavelengths. Keep in mind "polarization" does not mean the
physical layout of the antenna, but rather the actual
response. For example my Beverages, although long horizontal
wires, have only vertical polarization in the front lobes.
If I diversity pair a Beverage with a vertical array, they
must have large spatial separation (over 1 wavelength) or
enhancement is far from optimum.

Another use of stereo is filling in holes in receiving
directional patterns, like listen west and northeast at the
same time using two different directional patterns.

73 Tom

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[callen1155]

Thank you for the info Tom. I appreciate it.

chuck
73

[Richard Zwirko]

Chuck,
    In his response to your KRX3 vs LP-PAN question, Tom, W8JI, mentioned
the advantages of diversity reception by adding the KRX3 to your K3.  I use
this feature very often of the lower 3 HF bands and strongly second this
recommendation . Using the KRX3 sub receiver in my K3  with a second receive
antenna, it's amazing to hear audio fading down and out in one ear while
fading up in the other ear with the result being perfect copy.

But another plus from installing the KRX3 sub receiver module is being able
to simultaneously monitor a second frequency. If you chase DX stations, you
know that many of them run split operation, listening to a known range of
frequencies. By monitoring your transmit frequency, if a loud competing
signal is heard on it, you can quickly and easily move the 'B' VFO to a
better TX frequency. Transmitting on a clearer frequency will often improve
chances of working the DX station.

If I had to make the exclusive choice between the KRX3 and LP-PAN I would
choose the sub receiver module. I believe it improves chances of working DX
over what the LP-PAN could do. That's not to say that the LP-PAN features
won't soon be added to my K3.

73,
Rich - K1HTV

= = =

From: callen1155 <[hidden email]>
Subject: [Elecraft] Second receiver options ??
To: [hidden email]
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Hello guys.

I've been using my K3 about a month now and really enjoying it. Since I have
a keen interest in DXing and pulling out weak signals (DXing cw & ragchewing
cw) I'm starting to think about adding the KRX3 second receiver although I
understand that LP-PAN also provides second receiver capability.

I also understand that true K3 'diversity reception' greatly aids weak sig
copy and would only be available with the KRX3 receiver but not with LP-PAN.

Additionally, I use an older, slower desktop for playing radio and would
probably need to a better pc if i go the LP-PAN route, plus the soundcard,
and then the unit itself.

So if you had enough funds for either the KRX3 second receiver or the LPAN
which would you choose. I'm leaning toward the KRX3 but wanted to get the
experts' take on this as well.

Seems that the visual aspect of LP-PAN, while appealing, would be less
beneficial basd on my operating  than the diversity reception.

Is that making sense?

thanks and 73.
chuck
af4xk
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html