Subject: [NEXTEL-1] RE: Receiver regulation--opinion

From: [email-masked]
Date: Wed, 23 Jul 2003 17:16:10 -0400

------- Original Message --------
   From: Anderson John-P29444 <[email-masked]>
Subject: RE:  Receiver regulation--opinion

 MTS2000 and XTS3000 are different generations of hardware.  MTS2000 is
essentially discrete hardware while the XTS3000 and later radios use a DSP. The
DSP radios simply work better than the discrete component radios.

     -----Original Message-----
     From: jbarbour [mailto:[email-masked]]
     Sent: Wednesday, July 23, 2003 12:21 PM
     Subject: Re:  Receiver regulation--opinion

     eric995us wrote:

     >I was attempting to get heat exhaustion yesterday by climbing
     >Piestewa Peak at noon.  To get my mind off of my misery I got to
     >thinking about different things besides how I felt.  Thinking about
     >cold drinks didn't help as it only highlighted the difference in how
     >I was feeling and how I could feel.  So I got to thinking about
     >something that was even more miserable than my impending heatstroke.
     >
     >800MHz interference.
     >
     >As everyone knows, a transmitter's unwanted emissions impacts the
     >utilization of the spectrum.  There are two choices here.  One is to
     >improve the performance of the transmitters (lower unwanted
     >emissions, etc.) or modify the spectrum utilization.  As everyone
     >knows, the transmitters performance requirements have been regulated.
     >
     >
     >A receiver also has an impact on the utilization of radio spectrum.
     >I could go technical here, but I won't.  I'll just say this...I have
     >seen lots of areas where a Motorola XTS-3000 radio works perfectly,
     >but a Motorola MTS-2000 radio fails.  To me this is strong evidence
     >that the transmitter(s) being blamed are not putting out any unwanted
     >emission on the receiver's channel.  Anyway, just as with the
     >transmitter example above, we have two choices.  One is to improve
     >the equipment's performance (in this case the receiver) or modify the
     >spectrum utilization.
     >

     Likewise, we have seen MPA's and MRK's work, and LPE-200/Prism's fail to

     receive in the same area. Both spec the same sensitivity, but on the
     bench, the MPA's and MRK's will beat spec by 3-6dB, where the LPE's just

     make spec. I bet same thing applies to XTS vs. MTS. (BTW, I think the
     LPE's/Prism's have been dropped in favor of the Jaguar line and the
     300P, both of which are MUCH better radios!)

     >Currently, it is being proposed that we modify the spectrum
     >utilization to allow the receiver to work.  That may be what is
     >needed.  After all, transmitters are not required to have no unwanted
     >emissions, they just have to reduce the unwanted stuff by a certain
     >amount.
     >
     >If "we" do modify the spectrum utilization to allow a receiver to
     >work, how much modification should be made?  Enough so a Motorola XTS-
     >3000 portable works, enough to allow the Motorola MTS-2000 to work,
     >enough to allow my 25 year old Bearcat Scanner to work, enough to
     >allow my *really old* Radio Shack Astronaut 8 receiver to work or
     >enough to allow anything to work?  Each of these would require
     >different amounts of modification to the spectrum utilization to work.
     >
     >Which brings me to what I was thinking about to avoid concentrating
     >on my misery.  Should the receivers' performance be subject to
     >regulation?  And, should a minimum level of receiver performance be
     >expected in the regulations?
     >
     >
     >If spectrum utilization decisions are going to take receiver
     >performance into account, then I think "Yes" to both of my questions.
     >
     >If yes, then where do we set the bar and who should pay.  I think if
     >these questions were answered, the "800MHz interference issue" would
     >be much easier to handle.
     >
     >
     >Hopefully my flameproof pants are in good working order......
     >
     >Eric
     >
     >
     >

     I definitely agree, Eric. There are too many junk radios out there
     passing themselves off as commercial grade, when I can find ham-grade
     rigs with tighter receivers. And having decent receivers is important!

     Jim