[Scan-DC] Jeff's recent observations

[Jeff]

Hey, Mike,
Understand all and pretty much agree. But please keep in mind here that my
intent was not to "review" these scanners for the purpose of saying one was
better than the other. I don't have the necessary experience to even attempt
that. I just wanted to see which of m current rigs would do what I needed
with my current setup. At the onset this was the part of the email I posted:

>Doing a little experiment for a week or 2 to determine which of my scanners
>would be the best for recording with using Spectrum Commander. I have set
>up
>the BC780, ICOM PCR-1000 & Pro-2035 W/OS535 Board all on different
>computers
>with the exact same Scan files. All hooked to the same attic mounted RS
>Discone via a Stridesberg MCA-208 Multicoupler. Once I pick the best
>scanner
>out of these three, then I am going to compare it with the BC-250. This
>should help me pick out the best scanner for recording purposes. I figured
>I
>would post my thoughts daily with my Audio Log Notes in case there where
>any
>other folks who might my curious as to what I come up with.

I am looking to figure out which of my scanners will work best for "me"
being used with "my" set up. Every shack set up has its strengths and
weaknesses as does every radio.

Your thoughts on sensitivity are on the mark. Running this little experiment
helped me out in recognizing which characteristics of these radios I wanted
to take advantage of. For my purposes I would not want the 780 being used as
my primary recording scanner simply because it pulls in a little too much.
Would be fine as simply a listening scanner but for the purpose of
collecting recorded audio I think I would end up listening to too much stuff
that was not worth listening too. It takes me well over 2 hours a day
reviewing audio, researching freqs, making notes and posts at this time. I
really don't want to spend too much time reviewing audio from the 780 that
might be the result of it being too sensitive and pulling in stuff I am not
concerned about at this time. Maybe later, once I have gotten to a point
with recording with the other 2 scanners that I am not getting much recorded
audio each day then I might swing the 780 back over and record with it. But
I think at this time it would be giving me a little more than I have the
time to sift through. At this point clean, local comms are my focus.
Anything other than that would get me off project.



Take it easy,
Jeff 

> -----Original Message-----
> From: scan-dc-bounces at mailman.qth.net [mailto:scan-dc-
> bounces at mailman.qth.net] On Behalf Of Mike Agner
> Sent: Wednesday, June 02, 2004 22:38
> To: scan-dc at mailman.qth.net
> Subject: [Scan-DC] Jeff's recent observations
> 
>    Hi Jeff and list; Jeff, I would be very careful about thinking that one
> scanner has an edge in overload and intermod resistance, based on your
> recent logs.  To be honest, I'm wondering if you're observing more a
> sensitivity issue - that is to say, that the 780 is VERY sensitive - vs.
> some actual receiver fault.
> 
>    Let's take the first 2 logs you reported as harmonics in last nite's
> batch as an example.  There's no such thing as a perfect repeater or
> transmitter - EVERY transmitter will put out harmonics, though they should
> be attenuated way down to the point that they're not detectable.  Is it
> possible that, with your setup (particularly with any amplification in
> place), that it's TOO sensitive, and is picking up even the faint
> harmonics
> from other systems?
> 
>    The 3d log you supplied with the ham repeater mixing in with other
> signals is a clear indication of an overload or intermod product.  In
> point
> of fact, this report, combined with the other 2, suggest that you are
> possibly pushing the 780 too hard - if you have some amplification ahead
> of
> it, which I think you had mentioned that you do.  Your recent observations
> about hearing more 'harmonics' and 'false hits' on the 780 adds
> circumstantial evidence to this observation.
> 
>    Remember, a harmonic does not have to be generated by some fault in the
> scanner/radio; if it's an even multiple of the base frequency, the chances
> are good it's the transmitter at fault, not just the receiver.
> 
>    I have mentioned this before in other forums, but it bears repeating -
> using any kind of amplification can cause all sorts of headaches if used
> in
> an area that has a high RF density.  Sometimes you're better off NOT using
> amplification of any type.
>    I should also stress that comparing a 780 (which is not a DSP based
> scanner) to a PCR1000 (which is, at least in part, DSP) is like comparing
> apples to oranges; both fruits with very different characteristics.
> 
>    73s for now...Mike
> 
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