[hpsdr] New kind of Hermes

[Shirley Márquez Dúlcey]

The 2.8KHz bandwidth limit on HF digital modes is about allowing more
modern, higher data rate modes to be developed, while maintaining
coexistence with existing users of the bands. I think we can all agree
that we don't want to see an HF mode that blankets the entire band
with high power signals/noise. If HF were a tabula rasa we might be
able to use it differently (nobody has yet proposed legalizing spread
spectrum modes on HF), but so long as SSB exists we have to deal with
a channel-based framework.

My main problem with the 2.8KHz proposal is that it could lead to a
lot of wide signals appearing in parts of the HF bands that have been
historically used for narrowband modes such as CW and low-bandwidth
digital modes. We should preserve a narrowband portion of each HF
band.

On Sun, May 11, 2014 at 10:23 PM, AA8K73 GMail <aa8k73 at gmail.com> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
> *rant on*
> IMO
>
> I agree Brian.
>
> Witness ARRL CEO K1ZZ lobbying for a 2.8 kHz bandwidth limit for HF digital
> transmissions.  Great for half-century old radios.
>
> Or, let's go back a full century.  Look at the inordinate amount of effort
> spent re-writing and re-writing code, altering design, and creating special
> cases for HPSDR CW transmitting; all because someone wants to hear another
> station between the dots of his own transmission.  Sure, it is a technical
> challenge, but so are new digital modes that we haven't started using yet.
>
> I was fortunate to enter ham radio when SSB was new and only used in small
> parts of the "phone" band.  I sold my CW/AM transmitter and bought a
> Central-Electronics 10-A phasing SSB transmitter with 10 Watts PEP.  Now I'm
> pleased when someone across the ocean hears my barefoot Penelope on WSPR.
> What could we do with a Chirp transmitter that spanned the 7 kHz VLF band?
> Old things are fun and comfortable, but new things are exciting!
>
> *rant off*
>
>
> AA8K
> On 14-05-07 06:07 PM, Brian Lloyd wrote:
>>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>>
>>
>> Well, as long as I started on this outline of What Should Be, I
>> should probably throw in a couple other systems concepts that
>> occur to me.
>>
>> One of the very first things is that hams have to relinquish
>> their love-affair with the Collins KWM-2. For something like 60
>> years we have been building variations of the KWM-2 and nothing
>> has changed appreciably. Most transceivers you see today are
>> STILL a variation of the KWM-2. Even PowerSDR is a glorified
>> copy of the KWM-2. Basically the KWM-2 downconverts a "channel",
>> usually on the order of 3kHz wide, to baseband. It also
>> upconverts from baseband to someplace in the HF spectrum. So we
>> have this one-3kHz-wide-channel mindset/view of the world.
>
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