View Single Post
  #7   Report Post  
Old November 3rd 07, 05:51 PM posted to rec.radio.shortwave
Telamon Telamon is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 4,494
Default options when upgrading to a serious tabletop

In article . com,
bm wrote:

On 2 Nov, 19:12, wrote:
On Nov 2, 10:54 am, wrote:

There are drawbacks though - you need a decent PC/laptop plus a
massive 500Gb hardisk as the recordings are huge.


The biggest drawback, I think, is its use of a 14-bit A/D, which will
severely limit dynamic range. As a point of reference, 1st gen DSP
receivers, such as the WJ HF-1000 and TenTec RX-340 use 16-bit A/D
converters. The JRC NRD-545 uses an 18-bit A/D and the latest DSP
receivers, such as the Icom IC-756Pro-III use a 24-bit A/D.


True in a sense, but it's a "paper" difference more than a practical
difference. I and friends have run SDR-IQs back to back with
excellent receivers like the 746Pro, HF-1000, R&S EKD-895, NRD-525 etc
with relatively high signal levels without problems and with
comparable results. A potential problem with a receiver which
demodulates a 190 kHz wide spectrum (and wider spectra is available)
is that manual or tracking preselectors can't be used. The IQ has
bandpass filters to partly help this. But of course, in certain
settings an IQ-type SDR will get in trouble. Also, the IQ is somewhat
less sensitive than I'd prefer (2 uV). That said: For me as a MW DX-
er the SDR-IQ has not evolutionised but revolutionised my listening
post. Although I will keep the standard receivers I have, I will never
go back to DX with standard receivers only.
BM


When receiving digital modes make sure the radio you pick can turn the
AGC off or at least have the option to change the attack and delay
values. You might want to do this depending on conditions and the radio.

--
Telamon
Ventura, California