[Elecraft] P3 vs SDR-IQ

[Phil Wheeler]

I agree with Joe. My usage of the P3 and the PX3 
is 100% fixed-tune mode, and I find both the P3 
and PX3 to work very well for me. They do differ 
in amplitude scale in A-B comparisons, but this is 
compensated for by scale adjustments.

I've never really found a situation where Tracking 
mode is helpful, but maybe I'm missing something.

73, Phil W7OX

On 7/31/15 8:03 AM, Joe Subich, W4TV wrote:
>
>> It’s difficult to see a station, and find where 
>> you are trying to
>> tune to, when the display loses itsaveraging.
>
> As a long time user of the P3, I strenuously 
> disagree with that
> assessment.
>
> 73,
>
>   ... Joe, W4TV
>
>
> On 2015-07-31 9:57 AM, John Kramer wrote:
>> Wayne
>>
>> Apologies, I have never seen a P3 in action 
>> before, I live too far away from locations
>> that have regular hamfests. Maybe I should go 
>> and watch some youtube clips.
>> I just thought the basic architecture in the P3 
>> would be the same as my
>> PX3.
>> But, reading your last two paragraphs, tells me 
>> the issue I have with my PX3
>> also happens on the P3 - In tracking mode 
>> averaging info is reset the moment
>> you tune. I find this loss of averaging when 
>> tuning, to be totally counter
>> intuitive when trying to home in on a signal. 
>> It’s difficult to see a station,
>> and find where you are trying to tune to, when 
>> the display loses its averaging.
>>
>> Thanks for the good work at Elecraft, and your 
>> quick response
>>
>> 73
>> John, ZS5J  C91J  A25J
>>
>>
>>
>>
>>
>>
>>
>> On 31 Jul 2015, at 3:42 PM, Wayne Burdick 
>> <n6kr at elecraft.com> wrote:
>>
>> John,
>>
>> The P3 and PX3 use entirely different 
>> interfaces to the radio. The P3 taps into the 
>> K3/K3S 8.2 MHz I.F., while the PX3 uses a 
>> baseband I/Q signal from the KX3. While both 
>> methods provide the basic benefits of a 
>> panadapter, the P3's implementation provides 
>> higher performance, using more expensive 
>> hardware, and is priced accordingly.
>>
>> The P3 is incredibly smooth in its tuning and 
>> presentation, and the unit is widely regarded 
>> as one of best panadapters available. 
>> Averaging, fixed-tune mode, noise blanking, 
>> peak detection and its many other features are 
>> all free of any sort of tuning noise or artifacts.
>>
>> If you're in "fixed-tune" mode, where the 
>> VFO/filter cursor moves across the screen, 
>> averaging information is preserved. There is no 
>> increase in the noise floor, no matter how fast 
>> you tune.
>>
>> In "tracking" mode, where the VFO/filter cursor 
>> stays fixed at the center of the screen, 
>> averaging information is reset when you tune. 
>> This has always been the case, but I'll mention 
>> this to our panadapter design staff and see if 
>> it might be possible to preserve the averaging 
>> data in tracking mode.
>>
>> In any case, I hope you can observe a P3 in 
>> action sometime.
>>
>> 73,
>> Wayne
>> N6KR
>>
>>
>> On Jul 31, 2015, at 1:13 AM, John Kramer 
>> <jkramer at iafrica.com> wrote:
>>
>>> I think I know what Joe is getting at….and I 
>>> agree with him, if I understand him correctly. 
>>> When he refers to “noise floor”
>>> he means that he loses averaging when he 
>>> tunes, resulting in the crazy spectrum display 
>>> (what Joe refers to as noise).
>>>
>>> I haven’t seen or used a P3, but I bought my 
>>> first Elecraft products 3 weeks ago - a KX3 
>>> and PX3. If the P3 behaves in the
>>> same manner as the PX3 then I can see what Joe 
>>> is complaining about. Right out the box my PX3 
>>> had this frustrating
>>> feature of losing averaging the moment you 
>>> spun the VFO on the KX3. I pointed this out to 
>>> a local KX3/PX3 owner, and
>>> he told me to download the latest firmware 
>>> which allows you to select “fixed mode” or 
>>> “fixed track”. I downloaded the
>>> firmware. YES, it kinda fixes the problem….you 
>>> can now tune the radio and KEEP the 
>>> averaging….but the problem is
>>> that now your receive filter goes down the 
>>> display as you tune. This is better than the 
>>> previous method, however
>>> you now have your receive filter heavily 
>>> offset from the centre of the display. You 
>>> might tune down the band, with your
>>> RX filter at the bottom of the scale, and you 
>>> are now unable to see much below, but you can 
>>> see a huge chunk of
>>> the band above you.
>>>
>>> I bought the KX3 and PX3 for portable ops. My 
>>> main rigs for the past 5 years are Flex rigs. 
>>> I have the 5000/3000/1500
>>> and will be getting a 6500 soon as my shack 
>>> rigs. With these rigs and PSDR, your RX filter 
>>> REMAINS CENTRED and when
>>> you tune around the band, you DON’T LOSE your 
>>> averaging. This is how I like it to be, and if 
>>> Elecraft can achieve this
>>> in a firmware update, I would be very happy.
>>>
>>> 73
>>> John, ZS5J