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RE: Bamboozled by bandwidth

Hi Ron,

> Just getting going here and have read all the QEX articles with great 
> interest. I am bewitched, bothered and bewildered over the question 
> of bandwidth requirements.
> It would be useful to see a display of activity taking place in the 
> frequency spectrum of interest for example my operation is almost 
> exclusively in the low 25 kHz of the HF CW bands.  When in QSO I only 
> need a 100 Hz or so and I note that Leif states that  large 
> bandwidths are primarily required for noise reduction functions but 
> that increases the problems of dealing with large in-band signals.
Absolutely. If you do not have local QRN at your QTH, then you should
use an ordinary SSB transceiver and run Linrad without the second fft.

> Given a high performance HF radio (mine is a Ten-tec Omni pro) with 
> 100 Hz  Xtal filtering, linrad DSP and a 16 bit sound card what's to 
> be gained by more elaborate hardware measures that increase bandwidth 
> ? What am I missing ?
You will miss what happens 10kHz away. The pattern on the waterfall 
display when something interesting occurs (pileup) is very characteristic.
If you do not care - and if you do not need the blanker, use some 486
computer from the junk yard and run Linrad only for baseband processing. 
(If you can figure out how to get Linux running on an old computer)


Leif  /  SM5BSZ