Topband: The Quest to save AM radio

[Brad Rehm]

Mike, et al.,

I wasn't aware of the FCC inquiry, but I'll do some checking on line.  I'll
also talk with the compliance rules guru at the EMC lab where I was an
engineer for some years.

But we should clear up a potential for misunderstanding here.  When we talk
about allowing the noise floor noise to rise, this suggests broadband noise
emissions limits would be raised.  Typical sources of this kind of noise
are switching power supplies, digital devices, and UWB communications
devices.  Last time I checked, Ultra-WideBand systems are required to be
bandwidth-limited (using simple filters), and they typically raise the
noise floor in the UHF and higher parts of the spectrum.  So power supplies
and digital devices (computers, routers, etc.) would be the main culprits,
but I don't understand how you could exempt ham receivers from a rule
concerning them.  Nothing can be exempted from noise that covers up
everything.

We should also wonder how manufacturers might build a "more robust"
receiver.  When the noise floor rises, weak signals are covered up.  Yes,
you can narrow the channel bandwidth, but this typically reduces audio
quality.

If ham radio receivers were big broadband emitters, they would certainly
reduce their own weak signal sensitivity.  This is the reason that in our
compliance testing we rarely saw broadband emissions, conducted or
radiated, in receivers of any kind, much less ham radio receivers or
transceivers.  Their most common problem was radiated narrowband emissions,
and we wouldn't want to see the FCC granting any exemptions from NB
requirements.

So here's the question: What kind of exemption has been floated?  Just
curious.  And BTW, I wouldn't want to see AM radio go away.  Just drive
through the high country of west Texas and you'll see how important
low-cost, low-power AM radio is to the folks who live there.  Satellite
radio isn't going to be interested in broadcasting the daily price for pork
bellies or the traders' show for Dalton, Texas or for any of the other
small towns that rely on AM radio.

Brad
KV5V


On Tue, Sep 10, 2013 at 3:49 PM, Bill Cromwell <wrcromwell at gmail.com> wrote:

> On 09/10/2013 02:57 PM, Mike Armstrong wrote:
>
>> Brad,
>>
>> *I* say.... GOOD, let them kill AM broadcast and give the band to US.....
>> we will put it to good use.... he he he he.  Plus, since so many people
>> have AM broadcast receivers, it will be like automatic advertising for
>> Amateur Radio...... and that rumors of ham radio's demise, as a hobby, were
>> a bit premature.  LOL LOL.
>>
>> Mike A  AB7ZU (as opposed to the Mike you were referring to below... Mike
>> L)  :) :)
>>
>> Kuhi no ka lima, hele no ka maka
>>
>> On Sep 10, 2013, at 9:47, Brad Rehm <bradrehm at gmail.com> wrote:
>>
>>
>>  So...
>
> Topband would extend from about 500 kc to 2 mc.
>
> 73,
>
> Bill  KU8H
> _________________
> Topband Reflector
>