Heathkit Question

[Steve Harrison]

At 04:31 PM 11/11/98 -0500, Bill Coleman AA4LR wrote:

>Most of the current radio designs lack phase noise problems because they
>no longer depend on phase locked loops. Instead, they perform Direct
>Digital Synthesis (DDS). DDS doesn't have random deviations of phase.
>Other designs from the early 90's had PLL designs that were greatly
>cleaned up.

DDS was what I was thinking of rather than DSP, sorry. DDS generates spurs
whose amplitude is related to the number of bits. On HF with the limited
dynamic range due to atmospheric noise, DDS VFOs generally work fairly
well. In V/UHF radios where you're listening to thermal noise one moment
and a local pops up, presenting you with a signal level of 10 or 100
microwatts the next, DDS doesn't cut it very well. But it does generally do
better than PLLs did with their phase noise, true.

Still, even today, neither technique is adequate for serious weak-signal
V/UHF work.

>Unfortunately, the reality is that putting together such a kit could
>easily be a > $1000 proposition.

I'm quite aware of that and think that even if anyone were to attempt to
resurrect Heath, I rather doubt the company could profitably either
duplicate kits of the bygone eras nor anything really worth buying using
today's technology. It'd be nice to see someone try, but it'd be
heartbreaking to see them fail, too.

73, Steve Ko0U/1

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