[Elecraft] K3 panadapter choices

Fri Nov 14 14:50:47 EST 2008

Hi Dave,

The Perseus certainly seems impressive. As a second receiver it would cost only $151 more than the KRX3, if the latter is stuffed with all the filters I have now added to my K3. I will be very interested in your experience with it in the CQ WW CW. Please report the average and peak number of strength of the strongest signals at your location, across the whole HF spectrum, if that is practical. 

When you say "click and go" I assume the Perseus software is tuning the K3. Are you saying that *no* adjustment is needed to get the right pitch for SSB or CW? 

I have the kits for SoftRock Lite and the isolation amplifier sitting here, just waiting to be put together, so I will definitely give that a go first. I too don't much like the idea of getting an outboard soundcard, so if the soundcard is the weakest link (in desktop and/or laptop) I don't know if I will take that step or go to something not requiring a soundcard. There is no doubt that a receiver for the full HF range is worth more than just a panadapter. One slight count against the Perseus might be that it requires a power connection. Is it tolerant enough as to voltages to be run from either the typical home station 13.8V supply, or a car battery being discharged to 11 V or so?

73,
Erik K7TV
  ----- Original Message ----- 
  From: G4AON (via Nabble) 
  To: K7TV 
  Sent: Friday, November 14, 2008 11:07 AM
  Subject: Re: [Elecraft] K3 panadapter choices

  Erik (and Julian) 

  I'm posting only on Nabble as the Mailman Reflector seems to be broken at my end today... 

  I was looking for a low cost panadapter for my K3 and kept finding issues, there was the IF leakage/spurious injection issue, "low sensitivity" when using the K3 IF out, "my soundcard isn't good enough" so I might need an outboard soundcard, will 192 KHz span be enough? And so I kept having doubts. A friend recently bought a Perseus that he found outperformed his TS480. The Perseus at that time covered an 800 KHz span and was a direct connection to USB2 and was available for next day delivery from a UK source... Span is now up to 1600 KHz. 

  Having a high specification panoramic receiver has been an eye opener for me, maybe next weekend the CQ WW CW contest will cause the Perseus to struggle compared to the K3 but we will see, it's certainly holding it's own so far. The screen resolution is good enough to "click and go" on pretty much all CW and SSB signals at 100 KHz resolution without needing fine tuning, wider spans usually need a tweak but this could easily improve if/when the screen display is increased in size from it's present 1024 pixels wide. 

  I don't connect my Perseus to the K3 IF, it connects in parallel via a ferrite splitter using the RX RF IN/OUT sockets on the KXV3. 

  For my money the Perseus makes a good 2nd receiver, certainly it compares favourably on cost against the K3 second receiver (with a 2.8 KHz and 400 Hz filter installed) when you include shipping and tax. 

  I haven't used any of the low cost alternatives, but the Perseus certainly impresses me. 

  73 Dave, G4AON 
  K3/100 #80 
  -------------------------- 

    K7TV wrote:
    Researching my options for a K3 panadapter (Softrock, LP-PAN, SDR-IQ, Perseus, Mercury...) I want to thank Paul W9AC for sharing his experience with the SDR-IQ on the list: 

    "When observing signal strength on the display, there's ample resolution for 
    signal comparisons.  SDR-IQ is powered from the PC's USB port, so only two 
    connections are made (I.F. and USB).  SpectraVue supports the K3 and using 
    the "point 'n click" feature has been great.  Click on the display and the 
    K3 instantly moves to that frequency.  The only shortcoming I've found is 
    that SpectraVue needs to poll the K3's mode offset data so that changing 
    modes does not require an offset change in SpectraVue.  Not sure if that's 
    handled automatically when using LP-PAN and PowerSDR." 

    I would be very interested to read similar detail about the other possible hardware and software choices. An overview table showing which spectrum analysis software packages work with which hardware choices would be very helpful. 

    As long as a the hardware is used for spectrum display (not as a receiver to be listened to) it seems to me that hardware in the low to middle price range is good enough. The issue then is the software choice first and then finding hardware compatible with the software. When choosing software I would really like to know if there is any package available today that already adjusts for the mode offset, or is planned to do so in the near future. A wide and narrow spectrum display window may also be a positive feature in comparing one software package to another, especially if one is going to run other software at the same time. 

    If one contemplates actually listening to the outboard SDR, it seems that more money does buy better performance, although probably none of the reasonable hardware choices will be as good in some contests as the second receiver option of the K3, which has roofing filters. On the other hand, it would hardly be practical for an assistant operator to reach the K3 controls to make use of the second receiver, while the computer controlling an outboard SDR could easily be used by an assistant operator. (Of course depending on the contest, this may or may not be legal for a given entry class.) Maybe the second RX in a K3 could be run from a computer while the rig is otherwise run from the front panel? Maybe two computers (one per operator) could be used to control the K3 with second RX. I don't have experience with the various rig control software available, so I hope someone can enlighten me. 

    73, 
    Erik K7TV 

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