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LP Pan versus P3 Panadapters

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Paul Maruna

LP Pan versus P3 Panadapters

To All,

Can you please provide comments on the LP Pan versus the P3 Panadapter on the K3.

The LP Pan seems to have a lot more features compared to the P3 and the cost is so much less.

I understand that the LP Pan requires a PC but you get a bigger screen when using a PC.

What makes the P3 better then the LP Pan for the K3, if it is ?

Thank you
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n7ws

Re: LP Pan versus P3 Panadapters

I don't yet have a P3, but I do use an SDR-IQ as a panadapter. I used an LP-Pan for a little bit before this.

If I had to state one advantage for either of these compared to the LP-Pan it would be this: Neither of them uses PowerSDR.

Wes N7WS

--- On Mon, 9/13/10, Paul Maruna <[hidden email]> wrote:

> To All,
>
> Can you please provide comments on the LP Pan versus the P3
> Panadapter on the K3.
>
> The LP Pan seems to have a lot more features compared to
> the P3 and the cost is so much less.
>
> I understand that the LP Pan requires a PC but you get a
> bigger screen when using a PC.
>
> What makes the P3 better then the LP Pan for the K3, if it
> is ?
>
> Thank you
>

Don Cunningham

Re: LP Pan versus P3 Panadapters

In reply to this post by Paul Maruna

Paul,
I don't see you getting a lot of comments, so I'll throw in a few cents
worth, hi. I bought the P3 for several reasons, but the main one is NOT for
what it is right now, but what I think it will be over time. It will have
VGA output at some time and allow the big screen, and I feel we, as
operators will have some input into what is on the display. It will add
features as we go that I can't even think of right now.

I didn't go the LP Pan or other SDR route as I didn't want to have to buy a
high dollar computer to do my hamming. Same reason, among others, that I
won't consider the Flex radios. I want a radio, with knobs, not a computer
program!! The cost of the computer needed to do SDR right was about the
same as the P3 was initially.

YMMV, but that's my take. Elecraft remains responsive to our wants/needs,
as long as they are reasonable. I have full confidence I won't regret the
initial price and price of add-ons as they come.
73,
Don, WB5HAK

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Bill Davis Jr

Re: LP Pan versus P3 Panadapters

In reply to this post by Paul Maruna

I too would like to see details of the improvement over LPan etc. I am a long time user of SDR/computer panadapters for use in detecting very weak signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got my K3 a year ago. I have yet to see one report regarding weak sig detection with the P3 after many requests to the initial testers of the P3. ANYONE out there looking for weak weak sigs with a P3??

73 Bill K0AWU EN37ed

---------------

> From: [hidden email]
> To: [hidden email]
> Date: Mon, 13 Sep 2010 20:00:52 -0400
> Subject: [Elecraft] LP Pan versus P3 Panadapters
>
>
> To All,
>
> Can you please provide comments on the LP Pan versus the P3 Panadapter on the K3.
>
> The LP Pan seems to have a lot more features compared to the P3 and the cost is so much less.
>
> I understand that the LP Pan requires a PC but you get a bigger screen when using a PC.
>
> What makes the P3 better then the LP Pan for the K3, if it is ?
>
> Thank you

Don Wilhelm-4

Re: LP Pan versus P3 Panadapters

Bill,

I cannot say anything about the comparison of weak signals on the
waterfall between the two,
but one great advantage of the P3 is the ability to adjust the span -
you can go from observing a 200 kHz chunk of the band (-100 kHz to +100
kHz) to a width that will allow you to examine a single signal in detail.

73,
Don W3FPR

On 9/14/2010 12:01 AM, Bill Davis Jr wrote:
> I too would like to see details of the improvement over LPan etc. I am a long time user of SDR/computer panadapters for use in detecting very weak signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got my K3 a year ago. I have yet to see one report regarding weak sig detection with the P3 after many requests to the initial testers of the P3. ANYONE out there looking for weak weak sigs with a P3??
>
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Rick Prather-2

Re: LP Pan versus P3 Panadapters

In reply to this post by Bill Davis Jr

Bill,

All I can tell you is if I can hear it I can see it!

Rick
K6LE

On 9/13/2010, at 9:01 , Bill Davis Jr wrote:

>
> I too would like to see details of the improvement over LPan etc. I am a long time user of SDR/computer panadapters for use in detecting very weak signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got my K3 a year ago. I have yet to see one report regarding weak sig detection with the P3 after many requests to the initial testers of the P3. ANYONE out there looking for weak weak sigs with a P3??
>
> 73 Bill K0AWU EN37ed
>
> ----
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GW0ETF

Re: LP Pan versus P3 Panadapters

In reply to this post by Don Cunningham

Don,

I'm using a Softrock IF kit (plus Z10000B buffer amp) as a panadapter with a ~£275 Samsung NC10 netbook. Initially I was surprised but it works well with the internal Realtek HD soundcard.

It runs LP Bridge, PowerSDR/IF and N1MM or Logger23 smoothly; with an extra LCD monitor this gives me an integrated panadapter/logging system with a low dollar computer. Maximum span is ~90KHz.

It's my normal mobile pc; I can take it to the shack, plug in a usb lead, vga lead (if I want to use the LCD monitor), a mic lead and bring it out of hibernate and I'm in business. Don't normally need the power supply unless I'm in for a long contest.

73,

Stewart, GW0ETF

Don Cunningham wrote

I didn't go the LP Pan or other SDR route as I didn't want to have to buy a
high dollar computer to do my hamming. Same reason, among others, that I
won't consider the Flex radios. I want a radio, with knobs, not a computer
program!! The cost of the computer needed to do SDR right was about the
same as the P3 was initially.
73,
Don, WB5HAK

ab2tc

Re: LP Pan versus P3 Panadapters

In reply to this post by Don Wilhelm-4

Hi,

I have been using LP-PAN for a couple of years. In spite of not owning a P3 I think I know enough about its capabilities to comment about the comparison. The P3 definitely has better sensitivity. LP-PAN is currently quite poor in that respect, but Larry is working (feverishly I hope) to bring out a preamp kit that should match the the P3 in sensitivity. P3 also has in edge in very small spans. I don't see this as very important since for in-band analysis I can get superior results by running a spectrum analysis program on the K3 line output. Lastly of course the P3 does not need a PC and PowerSDR software. The latest version of PowerSDR is much improved and installation instructions are also better. I don't even think about operating on the bands without a PC these days. I need it for logging, for cluster spots and yes, for LP-PAN. If I operate outside of my shack, like in the back yard on nice summer days or from Grandma's farm, I lug a laptop. I am not knocking the P3, but I don't feel a big urge to switch. Some people have both and that may make sense, too.

AB2TC - Knut

Don Wilhelm-4 wrote

Bill,

I cannot say anything about the comparison of weak signals on the
waterfall between the two,
but one great advantage of the P3 is the ability to adjust the span -
you can go from observing a 200 kHz chunk of the band (-100 kHz to +100
kHz) to a width that will allow you to examine a single signal in detail.

73,
Don W3FPR

<snip>

Larry K1UO

Re: LP Pan versus P3 Panadapters

In reply to this post by Bill Davis Jr

Bill,

I can tell you that just last night, on 160 meters, I copied 2 very weak stations perfectly Q5 that did not show on the P3 waterfall. Now, Its entirely possible its my adjustment skills but I dont think so. Yes..the K3 IF Mod was factory installed. This has happened more than once. For some reason I was expecting the P3 to show these very weak signals better than I could find them myself while tuning but no amount of adjustment so far will do this. I may be expecting too much?
Just so you know what anothers experience has been so far.
73

I too would like to see details of the improvement over LPan etc. I am a long time user of SDR/computer panadapters for use in detecting very weak signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got my K3 a year ago. I have yet to see one report regarding weak sig detection with the P3 after many requests to the initial testers of the P3. ANYONE out there looking for weak weak sigs with a P3??

73 Bill K0AWU EN37ed

shwhafen

Re: LP Pan versus P3 Panadapters

Hi Larry & all; I have not used Lp Pan so I cannot really make a comparison, but I have found that if the P3 ref level is set really low just at the noise level and if the span is set to narrow amounts that indeed very low level sigs can be seen. For example I hve been "seeing" the 20 meter beacon sigs that I can not read, but just barely hear. If I were scanning the ham bands, I don't think I would hear most of thse sigs...Of course, I was not noting on the P3 all the beacon sigs[this is at 14,000 Mhz]..My antenna is just a lowly screwdriver attached to my car port....I think my ears are fine, even after 61 yrs of ham radio...ok for weak sig detection...73 Steve, W6HPK

----- Original Message -----
From: Larry K1UO <[hidden email]>
To: [hidden email]
Sent: Tue, 14 Sep 2010 13:03:01 -0000 (UTC)
Subject: Re: [Elecraft] LP Pan versus P3 Panadapters

Bill,

I can tell you that just last night, on 160 meters, I copied 2 very weak
stations perfectly Q5 that did not show on the P3 waterfall. Now, Its
entirely possible its my adjustment skills but I dont think so. Yes..the K3
IF Mod was factory installed. This has happened more than once. For
some reason I was expecting the P3 to show these very weak signals better
than I could find them myself while tuning but no amount of adjustment so
far will do this. I may be expecting too much?
Just so you know what anothers experience has been so far.
73

I too would like to see details of the improvement over LPan etc. I am a
long time user of SDR/computer panadapters for use in detecting very weak
signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got
my K3 a year ago. I have yet to see one report regarding weak sig detection
with the P3 after many requests to the initial testers of the P3. ANYONE out
there looking for weak weak sigs with a P3??

73 Bill K0AWU EN37ed

--
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shwhafen

Re: LP Pan versus P3 Panadapters

Corrections: beacons at 14100 Mhz, not 14000 Mhz,,,Steve W6HPK

----- Original Message -----
From: [hidden email]
To: Larry K1UO <[hidden email]>
Cc: [hidden email]
Sent: Tue, 14 Sep 2010 16:22:46 -0000 (UTC)
Subject: Re: [Elecraft] LP Pan versus P3 Panadapters

Hi Larry & all; I have not used Lp Pan so I cannot really make a comparison, but I have found that if the P3 ref level is set really low just at the noise level and if the span is set to narrow amounts that indeed very low level sigs can be seen. For example I hve been "seeing" the 20 meter beacon sigs that I can not read, but just barely hear. If I were scanning the ham bands, I don't think I would hear most of thse sigs...Of course, I was not noting on the P3 all the beacon sigs[this is at 14,000 Mhz]..My antenna is just a lowly screwdriver attached to my car port....I think my ears are fine, even after 61 yrs of ham radio...ok for weak sig detection...73 Steve, W6HPK

----- Original Message -----
From: Larry K1UO
To: [hidden email]
Sent: Tue, 14 Sep 2010 13:03:01 -0000 (UTC)
Subject: Re: [Elecraft] LP Pan versus P3 Panadapters

Bill,

I can tell you that just last night, on 160 meters, I copied 2 very weak
stations perfectly Q5 that did not show on the P3 waterfall. Now, Its
entirely possible its my adjustment skills but I dont think so. Yes..the K3
IF Mod was factory installed. This has happened more than once. For
some reason I was expecting the P3 to show these very weak signals better
than I could find them myself while tuning but no amount of adjustment so
far will do this. I may be expecting too much?
Just so you know what anothers experience has been so far.
73

I too would like to see details of the improvement over LPan etc. I am a
long time user of SDR/computer panadapters for use in detecting very weak
signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got
my K3 a year ago. I have yet to see one report regarding weak sig detection
with the P3 after many requests to the initial testers of the P3. ANYONE out
there looking for weak weak sigs with a P3??

73 Bill K0AWU EN37ed

--
View this message in context: http://elecraft.365791.n2.nabble.com/LP-Pan-versus-P3-Panadapters-tp5528469p5530182.html
Sent from the Elecraft mailing list archive at Nabble.com.
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Bill Davis Jr

Re: LP Pan versus P3 Panadapters

In reply to this post by shwhafen

Hello all -- K0AWU here

I am reading this thread with great interest. I apologize to those that have seen similar messages from me on this subject in the past. I had SO HOPED that with such a large number of P3s now in the field I would have seen reports on weak sig detection from some of the EME or weak sig VHF/UHF/Microwave operators.

I use the Softrock SDR based panadapter (with buffer amp) for detection of weak microwave signals. Seeing sigs too weak to work allows optimizing beam/dish headings and elevations often enough to allow communications. Power SDR here does NOT allow that but VE3NA's Rocky slow waterfall does exceptionally well with "beaconing" CW signal detection and display. Rocky however requires more CPU time than PSDR.

Normal operations here will be with the displayed bandwidth to me around 40Khz or more. (96Khz sample rate)

Rocky allows me to see 2 or 3 db below what I can hear and 5db or so too weak to work, plus I don't have to be concerned about having the K3 on frequency. As you can imagine, at 10,368.100 MHz or even 1296.100 MHz we aren't always starting within 500Hz of ON frequency. The ability to read the sig strength relative to the noise floor is of great value in that it allows real sig levels to be recorded and exchanged.

Google my call for links to my SDR/K3 webpages if you are interested in more info.

I too have a shack computer, 5yr old Dell DIM4700 Pentium 4 at 2.8GHz with 3GB of RAM. I can run the SDR1000, Rocky or PSDR for K3 panadapter and logging programs plus several other applications with few issues. So I had a shack computer already. (M Audio Delta 44 sound card)

I am not promoting an SDR based panadapter over a P3. I just am VERY interested if the P3 can see deeper.... Somewhere someone knows or is finding out .... RIGHT??

73 Bill K0AWU En37ed

>
> Bill,
>
> I can tell you that just last night, on 160 meters, I copied 2 very weak
> stations perfectly Q5 that did not show on the P3 waterfall. Now, Its
> entirely possible its my adjustment skills but I dont think so. Yes..the K3
> IF Mod was factory installed. This has happened more than once. For
> some reason I was expecting the P3 to show these very weak signals better
> than I could find them myself while tuning but no amount of adjustment so
> far will do this. I may be expecting too much?
> Just so you know what anothers experience has been so far.
> 73
>
> (K0AWU email follows)
>
>
> I too would like to see details of the improvement over LPan etc. I am a
> long time user of SDR/computer panadapters for use in detecting very weak
> signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got
> my K3 a year ago. I have yet to see one report regarding weak sig detection
> with the P3 after many requests to the initial testers of the P3. ANYONE out
> there looking for weak weak sigs with a P3??
>
> 73 Bill K0AWU EN37ed
>

Alan Bloom

Re: LP Pan versus P3 Panadapters

In reply to this post by Larry K1UO

Hi Larry,

It depends on the span. Unlike some other panadapters, the P3
automatically reduces the sample rate as you narrow the span, which
improves the sensitivity.

For example, I have my HP8656B signal generator set to 3640 kHz with the
amplitude as low as it will go (-127 dBm). The K3 has the preamp off,
the attenuator on, and default CW shift and width. Under those
conditions I can just barely hear the carrier. It's weak enough that if
it were a modulated CW signal I don't think I could copy it.

However the carrier is clearly visible on the waterfall if I set the P3
span to 2 kHz. As I increase the span the signal gradually gets harder
and harder to see. Above about 30 kHz or so the signal disappears into
the noise.

So that's the trick. Narrow the span to make those signals pop out of
the noise.

73,

Alan N1AL

On Tue, 2010-09-14 at 06:03 -0700, Larry K1UO wrote:

> Bill,
>
> I can tell you that just last night, on 160 meters, I copied 2 very weak
> stations perfectly Q5 that did not show on the P3 waterfall. Now, Its
> entirely possible its my adjustment skills but I dont think so. Yes..the K3
> IF Mod was factory installed. This has happened more than once. For
> some reason I was expecting the P3 to show these very weak signals better
> than I could find them myself while tuning but no amount of adjustment so
> far will do this. I may be expecting too much?
> Just so you know what anothers experience has been so far.
> 73
>
>
>
>
> I too would like to see details of the improvement over LPan etc. I am a
> long time user of SDR/computer panadapters for use in detecting very weak
> signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got
> my K3 a year ago. I have yet to see one report regarding weak sig detection
> with the P3 after many requests to the initial testers of the P3. ANYONE out
> there looking for weak weak sigs with a P3??
>
> 73 Bill K0AWU EN37ed
>
>

samuel ernst-fortin

Re: LP Pan versus P3 Panadapters

It strikes me, when implementing algorithms to compute Periodograms using
DFT/FFTs, there are tradeoffs in variance and spectral resolution. There are a
number of factors, including window/FFT length, window function, amount of
window overlap, degree of zero-padding, number of estimates to average, choice
of normalization factors, etc. Then you've got a lot of considerations with
respect to how that spectrogram is displayed on screen that can influence the
visual detection problem. We haven't even addressed computational complexity /
speed of computation.

I do not know how much flexibility the P3 allows for changing a number of
these parameters, the manual indicates spectral resolution is changed with
"span", so if everything is automatically selected for the end-user at this
release of the software, perhaps some configuration options might be placed
back into the hands of the user in a subsequent release, including a guide
provided to help one understand these tradeoffs in PSD estimation and
presentation and how to configure the display for optimal results depending on
what you want to do. The manual is not very verbose in this regard.

With sampling rate known, and these other parameters chosen, conceptually, the
software can report an estimate of the spectral resolution which could be
theoretically expected on a popup information window or other.

This is one argument for having an "external", potentially more "open to
adjustment" system for analysis of the IF information, rather than say a P3.

KJ4VPI

________________________________
From: Alan Bloom <[hidden email]>
To: Larry K1UO <[hidden email]>
Cc: [hidden email]
Sent: Tue, September 14, 2010 1:00:30 PM
Subject: Re: [Elecraft] LP Pan versus P3 Panadapters

Hi Larry,

It depends on the span. Unlike some other panadapters, the P3
automatically reduces the sample rate as you narrow the span, which
improves the sensitivity.

For example, I have my HP8656B signal generator set to 3640 kHz with the
amplitude as low as it will go (-127 dBm). The K3 has the preamp off,
the attenuator on, and default CW shift and width. Under those
conditions I can just barely hear the carrier. It's weak enough that if
it were a modulated CW signal I don't think I could copy it.

However the carrier is clearly visible on the waterfall if I set the P3
span to 2 kHz. As I increase the span the signal gradually gets harder
and harder to see. Above about 30 kHz or so the signal disappears into
the noise.

So that's the trick. Narrow the span to make those signals pop out of
the noise.

73,

Alan N1AL

On Tue, 2010-09-14 at 06:03 -0700, Larry K1UO wrote:

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Merv Schweigert

Re: LP Pan versus P3 Panadapters

In reply to this post by Alan Bloom

For some reason that goes against what I think many are looking for in the
P3, if one has to narrow the span to 2khz, then I see no use for the P3
at all, I need
to see what is on the band at -127DBm at 30 to 50khz or more span. If
the signal is
only seen at 2KHZ, I can hear that by ear and dont need the P3. I
think VHF
operators are saying the same thing, they need to look over a larger
portion of the
band and spot weak signals and move to them, not narrow to 2KHZ and sit
there
and tune the radio hoping to find a weak signal, thats what you do
without a P3.
Does the LP Pan also work that poorly that you cannot see weak signals
30KHZ
away?
I do notice that with all the P3 sales, you do not see many LP Pans for
sale, so either
people who buy the P3 are just buying it to have another Elecraft
product, or they are
keeping both and not sure yet which is the best?
Most of my operation will be low band, 160 meters, and if I cannot see
the weak
signals on the band and cover at least 30 KHZ then the P3 is of no use
at all.
Bill W4ZV are you seeing the weak signals on 160 that are 20 or 30KHZ away?
Or do you have to narrow the span down to see a signal that is barely
audible?
160 ops would like to know.
73 Merv K9FD / KH7C

> Hi Larry,
>
> It depends on the span. Unlike some other panadapters, the P3
> automatically reduces the sample rate as you narrow the span, which
> improves the sensitivity.
>
> For example, I have my HP8656B signal generator set to 3640 kHz with the
> amplitude as low as it will go (-127 dBm). The K3 has the preamp off,
> the attenuator on, and default CW shift and width. Under those
> conditions I can just barely hear the carrier. It's weak enough that if
> it were a modulated CW signal I don't think I could copy it.
>
> However the carrier is clearly visible on the waterfall if I set the P3
> span to 2 kHz. As I increase the span the signal gradually gets harder
> and harder to see. Above about 30 kHz or so the signal disappears into
> the noise.
>
> So that's the trick. Narrow the span to make those signals pop out of
> the noise.
>
> 73,
>
> Alan N1AL
>
>
> On Tue, 2010-09-14 at 06:03 -0700, Larry K1UO wrote:
>
>> Bill,
>>
>> I can tell you that just last night, on 160 meters, I copied 2 very weak
>> stations perfectly Q5 that did not show on the P3 waterfall. Now, Its
>> entirely possible its my adjustment skills but I dont think so. Yes..the K3
>> IF Mod was factory installed. This has happened more than once. For
>> some reason I was expecting the P3 to show these very weak signals better
>> than I could find them myself while tuning but no amount of adjustment so
>> far will do this. I may be expecting too much?
>> Just so you know what anothers experience has been so far.
>> 73
>>
>>
>>
>>
>> I too would like to see details of the improvement over LPan etc. I am a
>> long time user of SDR/computer panadapters for use in detecting very weak
>> signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got
>> my K3 a year ago. I have yet to see one report regarding weak sig detection
>> with the P3 after many requests to the initial testers of the P3. ANYONE out
>> there looking for weak weak sigs with a P3??
>>
>> 73 Bill K0AWU EN37ed
>>
>>
>>
>
>
> ______________________________________________________________
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Alan Bloom-2

Re: LP Pan versus P3 Panadapters

No I didn't have to narrow the span to 2 kHz to see the -127 dBm signal.
Anything less than about 30 kHz was sufficient.

Also, remember I had the K3 preamp off and the attenuator on. With the
attenuator off, the -127 dBm signal is visible all the way up to 200 kHz
span.

With the K3 preamp turned on I can see a -135 dB signal, even at 200 kHz
span. (I had to use a 10 dB attenuator to get the signal generator to
go that low.)

Alan N1AL

On Tue, 2010-09-14 at 07:51 -1000, Merv Schweigert wrote:

> For some reason that goes against what I think many are looking for in the
> P3, if one has to narrow the span to 2khz, then I see no use for the P3
> at all, I need
> to see what is on the band at -127DBm at 30 to 50khz or more span. If
> the signal is
> only seen at 2KHZ, I can hear that by ear and dont need the P3. I
> think VHF
> operators are saying the same thing, they need to look over a larger
> portion of the
> band and spot weak signals and move to them, not narrow to 2KHZ and sit
> there
> and tune the radio hoping to find a weak signal, thats what you do
> without a P3.
> Does the LP Pan also work that poorly that you cannot see weak signals
> 30KHZ
> away?
> I do notice that with all the P3 sales, you do not see many LP Pans for
> sale, so either
> people who buy the P3 are just buying it to have another Elecraft
> product, or they are
> keeping both and not sure yet which is the best?
> Most of my operation will be low band, 160 meters, and if I cannot see
> the weak
> signals on the band and cover at least 30 KHZ then the P3 is of no use
> at all.
> Bill W4ZV are you seeing the weak signals on 160 that are 20 or 30KHZ away?
> Or do you have to narrow the span down to see a signal that is barely
> audible?
> 160 ops would like to know.
> 73 Merv K9FD / KH7C
>
>
> > Hi Larry,
> >
> > It depends on the span. Unlike some other panadapters, the P3
> > automatically reduces the sample rate as you narrow the span, which
> > improves the sensitivity.
> >
> > For example, I have my HP8656B signal generator set to 3640 kHz with the
> > amplitude as low as it will go (-127 dBm). The K3 has the preamp off,
> > the attenuator on, and default CW shift and width. Under those
> > conditions I can just barely hear the carrier. It's weak enough that if
> > it were a modulated CW signal I don't think I could copy it.
> >
> > However the carrier is clearly visible on the waterfall if I set the P3
> > span to 2 kHz. As I increase the span the signal gradually gets harder
> > and harder to see. Above about 30 kHz or so the signal disappears into
> > the noise.
> >
> > So that's the trick. Narrow the span to make those signals pop out of
> > the noise.
> >
> > 73,
> >
> > Alan N1AL
> >
> >
> > On Tue, 2010-09-14 at 06:03 -0700, Larry K1UO wrote:
> >
> >> Bill,
> >>
> >> I can tell you that just last night, on 160 meters, I copied 2 very weak
> >> stations perfectly Q5 that did not show on the P3 waterfall. Now, Its
> >> entirely possible its my adjustment skills but I dont think so. Yes..the K3
> >> IF Mod was factory installed. This has happened more than once. For
> >> some reason I was expecting the P3 to show these very weak signals better
> >> than I could find them myself while tuning but no amount of adjustment so
> >> far will do this. I may be expecting too much?
> >> Just so you know what anothers experience has been so far.
> >> 73
> >>
> >>
> >>
> >>
> >> I too would like to see details of the improvement over LPan etc. I am a
> >> long time user of SDR/computer panadapters for use in detecting very weak
> >> signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got
> >> my K3 a year ago. I have yet to see one report regarding weak sig detection
> >> with the P3 after many requests to the initial testers of the P3. ANYONE out
> >> there looking for weak weak sigs with a P3??
> >>
> >> 73 Bill K0AWU EN37ed
> >>
> >>
> >>
> >
> >
> > ______________________________________________________________
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> >
> >
>
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Larry K1UO

Re: LP Pan versus P3 Panadapters

In reply to this post by Alan Bloom

Hi Alan,

Ill admit I didnt try a narrower span and I normally use the +-15Khz setting (30Khz span) on the 160 meter cw band. Ill try narrowing it up and see if it picks up the very weak signals but I dont want to operate on a too narrow span or, as they say, it becomes much less useful to me.

73 Larry

"However the carrier is clearly visible on the waterfall if I set the P3
span to 2 kHz. As I increase the span the signal gradually gets harder
and harder to see. Above about 30 kHz or so the signal disappears into
the noise.

So that's the trick. Narrow the span to make those signals pop out of
the noise. "

73,

Alan N1AL

Merv Schweigert

Re: LP Pan versus P3 Panadapters

In reply to this post by Alan Bloom-2

Alan, thanks for the explanation, sounds like there is some other
problem then
if people are not seeing the weak signals that they can hear.
Will hook up the P3 here shortly and see what mine does. If you can see
-127DBm
at 30 KHZ it sounds fine to me.
73 Merv K9FD / KH7C

> No I didn't have to narrow the span to 2 kHz to see the -127 dBm signal.
> Anything less than about 30 kHz was sufficient.
>
> Also, remember I had the K3 preamp off and the attenuator on. With the
> attenuator off, the -127 dBm signal is visible all the way up to 200 kHz
> span.
>
> With the K3 preamp turned on I can see a -135 dB signal, even at 200 kHz
> span. (I had to use a 10 dB attenuator to get the signal generator to
> go that low.)
>
> Alan N1AL
>
>
>
>
> On Tue, 2010-09-14 at 07:51 -1000, Merv Schweigert wrote:
>
>> For some reason that goes against what I think many are looking for in the
>> P3, if one has to narrow the span to 2khz, then I see no use for the P3
>> at all, I need
>> to see what is on the band at -127DBm at 30 to 50khz or more span. If
>> the signal is
>> only seen at 2KHZ, I can hear that by ear and dont need the P3. I
>> think VHF
>> operators are saying the same thing, they need to look over a larger
>> portion of the
>> band and spot weak signals and move to them, not narrow to 2KHZ and sit
>> there
>> and tune the radio hoping to find a weak signal, thats what you do
>> without a P3.
>> Does the LP Pan also work that poorly that you cannot see weak signals
>> 30KHZ
>> away?
>> I do notice that with all the P3 sales, you do not see many LP Pans for
>> sale, so either
>> people who buy the P3 are just buying it to have another Elecraft
>> product, or they are
>> keeping both and not sure yet which is the best?
>> Most of my operation will be low band, 160 meters, and if I cannot see
>> the weak
>> signals on the band and cover at least 30 KHZ then the P3 is of no use
>> at all.
>> Bill W4ZV are you seeing the weak signals on 160 that are 20 or 30KHZ away?
>> Or do you have to narrow the span down to see a signal that is barely
>> audible?
>> 160 ops would like to know.
>> 73 Merv K9FD / KH7C
>>
>>
>>
>>> Hi Larry,
>>>
>>> It depends on the span. Unlike some other panadapters, the P3
>>> automatically reduces the sample rate as you narrow the span, which
>>> improves the sensitivity.
>>>
>>> For example, I have my HP8656B signal generator set to 3640 kHz with the
>>> amplitude as low as it will go (-127 dBm). The K3 has the preamp off,
>>> the attenuator on, and default CW shift and width. Under those
>>> conditions I can just barely hear the carrier. It's weak enough that if
>>> it were a modulated CW signal I don't think I could copy it.
>>>
>>> However the carrier is clearly visible on the waterfall if I set the P3
>>> span to 2 kHz. As I increase the span the signal gradually gets harder
>>> and harder to see. Above about 30 kHz or so the signal disappears into
>>> the noise.
>>>
>>> So that's the trick. Narrow the span to make those signals pop out of
>>> the noise.
>>>
>>> 73,
>>>
>>> Alan N1AL
>>>
>>>
>>> On Tue, 2010-09-14 at 06:03 -0700, Larry K1UO wrote:
>>>
>>>
>>>> Bill,
>>>>
>>>> I can tell you that just last night, on 160 meters, I copied 2 very weak
>>>> stations perfectly Q5 that did not show on the P3 waterfall. Now, Its
>>>> entirely possible its my adjustment skills but I dont think so. Yes..the K3
>>>> IF Mod was factory installed. This has happened more than once. For
>>>> some reason I was expecting the P3 to show these very weak signals better
>>>> than I could find them myself while tuning but no amount of adjustment so
>>>> far will do this. I may be expecting too much?
>>>> Just so you know what anothers experience has been so far.
>>>> 73
>>>>
>>>>
>>>>
>>>>
>>>> I too would like to see details of the improvement over LPan etc. I am a
>>>> long time user of SDR/computer panadapters for use in detecting very weak
>>>> signals at UHF/VHF/microwave. I use a Softrock on the K3 IF port since I got
>>>> my K3 a year ago. I have yet to see one report regarding weak sig detection
>>>> with the P3 after many requests to the initial testers of the P3. ANYONE out
>>>> there looking for weak weak sigs with a P3??
>>>>
>>>> 73 Bill K0AWU EN37ed
>>>>
>>>>
>>>>
>>>>
>>> ______________________________________________________________
>>> 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
>>>
>>>
>>>
>> ______________________________________________________________
>> 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
>>
>
>
>
>

N8LP

Re: LP Pan versus P3 Panadapters

In reply to this post by Alan Bloom-2

That's useful info for comparison, Alan.

To satisfy my curiosity and answer the original question, I just ran a similar test with my LP-PAN, with and w/o the upcoming preamp mod kit. First, I should mention a couple differences in PowerSDR/IF and the P3. With PowerSDR/IF the sampling rate is fixed to one of three values... 48kHz, 96kHz or 192 kHz. The sensitivity of the display is the same at any span for any given sample rate. The sensitivity is proportional to sampling rate, so it is 3dB better at 48kHz than it is at 96 kHz, and 3dB better at 96kHz than it is at 192 kHz. My tests were run with the popular E-MU 0202 sound card (the E-MU 1212m is a few dB quieter).

With the K3 preamp ON, the stock LP-PAN at 96kHz sampling rate (and 96kHz span) produces a blip on the pan display 10dB above the noise floor with an input signal of -128dBm (noise floor of -138dBm). With the LP-PAN preamp kit installed, the sensitivity improves by 7dB (noise floor of -145dBm). Dynamic range remains the same. Remember, the noise floor will be 3dB better if 48kHz sampling rate is selected, and 3dB worse if 192kHz sampling rate is selected.

For any weak signal work, the K3 preamp should be ON to overcome the loss of the K3 buffer. Also, the waterfall (or Panafall) display should be used to take advantage of the averaging, which reduces random noise. With PowerSDR/IF waterfall, I am able to clearly see signals within a couple dB of the noise floor, and which I can barely detect in the K3 by ear.

Also, remember that if you feed LP-PAN from the P3, there is an additional 3dB loss in the splitter. I have designed the LP-PAN preamp to provide a noise figure a few dB better than would normally be necessary, in order to compensate for the loss of the P3 splitter. The NF of LP-PAN w/preamp kit is about 6-7dB.

Larry N8LP

<quote author="Alan Bloom-2">

With the K3 preamp turned on I can see a -135 dB signal, even at 200 kHz
span. (I had to use a 10 dB attenuator to get the signal generator to
go that low.)

Alan N1AL

Alan Bloom

Re: LP Pan versus P3 Panadapters

> Also, the waterfall (or Panafall) display should be used to
> take advantage of the averaging, which reduces random noise.

That's a point I forgot to mention. If you turn on averaging in the
waterfall you can see farther down into the noise. It works best on
steady carriers. With CW signals you have to keep the averaging time
less than a dit.

On the P3, you turn on waterfall averaging with the "Wfall Avg" menu
selection.

Alan N1AL

On Tue, 2010-09-14 at 23:03 -0700, N8LP wrote:

> That's useful info for comparison, Alan.
>
> To satisfy my curiosity and answer the original question, I just ran a
> similar test with my LP-PAN, with and w/o the upcoming preamp mod kit.
> First, I should mention a couple differences in PowerSDR/IF and the P3. With
> PowerSDR/IF the sampling rate is fixed to one of three values... 48kHz,
> 96kHz or 192 kHz. The sensitivity of the display is the same at any span for
> any given sample rate. The sensitivity is proportional to sampling rate, so
> it is 3dB better at 48kHz than it is at 96 kHz, and 3dB better at 96kHz than
> it is at 192 kHz. My tests were run with the popular E-MU 0202 sound card
> (the E-MU 1212m is a few dB quieter).
>
> With the K3 preamp ON, the stock LP-PAN at 96kHz sampling rate (and 96kHz
> span) produces a blip on the pan display 10dB above the noise floor with an
> input signal of -128dBm (noise floor of -138dBm). With the LP-PAN preamp kit
> installed, the sensitivity improves by 7dB (noise floor of -145dBm). Dynamic
> range remains the same. Remember, the noise floor will be 3dB better if
> 48kHz sampling rate is selected, and 3dB worse if 192kHz sampling rate is
> selected.
>
> For any weak signal work, the K3 preamp should be ON to overcome the loss of
> the K3 buffer. Also, the waterfall (or Panafall) display should be used to
> take advantage of the averaging, which reduces random noise. With
> PowerSDR/IF waterfall, I am able to clearly see signals within a couple dB
> of the noise floor, and which I can barely detect in the K3 by ear.
>
> Also, remember that if you feed LP-PAN from the P3, there is an additional
> 3dB loss in the splitter. I have designed the LP-PAN preamp to provide a
> noise figure a few dB better than would normally be necessary, in order to
> compensate for the loss of the P3 splitter. The NF of LP-PAN w/preamp kit is
> about 6-7dB.
>
> Larry N8LP
>
>
>
>
>
> With the K3 preamp turned on I can see a -135 dB signal, even at 200 kHz
> span. (I had to use a 10 dB attenuator to get the signal generator to
> go that low.)
>
> Alan N1AL
>