[PCR-1000] CWGet

[Matt Loretitsch]

I agree that it is not the solution for CW monitoring.  I mentioned once
before though that it IS more resistant to front end overload than my other
receivers (yaesu FRG-100 and the vr-120 small handheld unit among others)

Two main sources of noise for me are an FM transmitter on 107.9 close to my
house and also the national weather service on 162.55.  The first completely
wipes out my frg-100, not a problem with the Icom.  I just don't see the
glaring front end problems everyone else does.

Yeah it's not your 756pro (I've used them and find the LCD screen a little
less sharp than I'd like, but otherwise a pleasure to use), but it IS cost
effective =)  I like the filtering options on the 756 by the way.. Cool!  I
can't afford a 3k rig though so I have to stick up for the little icom.
*grin*

-Matt

-----Original Message-----
From: George, W5YR [mailto:w5yr@att.net] 
Sent: Thursday, May 30, 2002 10:48 AM
To: pcr-1000@mailman.qth.net
Subject: Re: [PCR-1000] CWGet


CWGet, like most such programs, requires almost perfect signals in order for
the decoding to be accurate. That means a minimum of noise and absolutely
correct tuning and timing of the signal. Most amateur radio CW is marginal
in timing such that most programs give fairly poor results. That is not true
of all stations since many use keyboards and computer-generated code with
perfect timing.

A further stringent requirement for machine decoding of CW is the need for
correct signal level management. If the signal to be copied is of too high
amplitude or of too low amplitude, the decoding logic is prevented from
operating correctly. Since it is common for amateur CW signals to vary in
amplitude with time due to band conditions, interference, etc. a receiver
with very effective AGC is required to maintain a fairly constant signal
level to the decoding program.

In view of these requirements and based upon a great deal of listening, I
have to conclude that the PCR1000 is uniquely *unsuited* for CW reception
for any purpose. It is literally, as the old saying goes, "as broad as a
barn door" on CW and the SSB modes and suffers from a lack of
"single-signal" reception on CW as well. That means that you can tune in a
CW station on "both sides of zero beat." While this does not prevent most
humans from reading such code, the effect of the wide bandwidth is to
contaminate the desired received signal with all manner of noise and
interference from other stations.

My 1000 does not have the DSP module, and it may be that the additional
audio filtering it provides might make the signal more decodeable. In the
absence of the internal DSP, one could add an external audio digital
processor and improve upon the selectivity shortcoming.

The second area of substantial shortcoming for the 1000 is the lack of
capability of the front-end circuitry to deal with strong signals. The
result of the lack of adequate selectivity both in the IF and the front end
is that strong signals tend to take over the AGC and dominate the receiver
function. Multiple strong signals cross-modulate and inter-modulate to such
an extent that they become just a jumble of "noise." The use of either
internal or external DSP filtering cannot overcome the deterioration of
signals produced by an inadequate front end.

The bottom line is that these two shortcomings of the 1000 play a major role
in restricting the uses of the radio. I hate to rain on anyone's parade, but
for CW monitoring the PCR-1000 is just not a suitable radio to use. 

I might add that the Icom R-10 scanner-sized "comunications receiver" has
about the same shortcomings with a serious lack of selectivity. I called the
Icom technical support people shortly after getting my R-10 and they
explained that the operational problems that I noticed were normal for the
radio since it was just too small to contain effective filters.

I have found that of all the digital programs with CW capability, MixW is
the only one that can provide consistently accurate copy of marginal
signals. It provides over 20 signal modes, including most of the digital
modes and CW, SSB, SSTV, etc. But even MixW requires clean signals and
narrow bandwidths to remove as much interference and noise as possible.

These are interesting little receivers for casual monitoring, but their
shortcomings in the areas of selectivity and front-end robustness rule out
any serious use for communications and limit their applications for
monitoring. I bought the first PCR-1000 sold at Texas Towers when they first
came out and one of the first R-10 receivers. Many hours of listening to
these little receivers have demonstrated the deficiencies described above.

73/72/oo, George W5YR - the Yellow Rose of Texas         
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe   
Amateur Radio W5YR, in the 56th year and it just keeps getting better! QRP-L
1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735 Icom
IC-756PRO #02121  Kachina 505 DSP  #91900556  Icom IC-765 #02437