[time-nuts] WWVB Response

J. Forster jfor at quikus.com
Thu Sep 27 14:07:57 UTC 2012


The AM just makes the situation in low S/N areas worse. The BPSK wipes out
the possibility of any very narrow band prefiltering, because of filter
time response.

I suspect, although have not tested, that active antennas with either
mechanical or crystal filters in their preamps will be rendered useless.

-John

===============


> The AM characteristics have not changed. That means that there is at least
> 10% carrier present at all times.
> The transmission format seems pretty well documented. The remaining
> mysteries are in data formatting.
> Regards,
> Dale NV8U
>
>
> -----Original Message-----
> From: Peter Monta
> Sent: Thursday, September 27, 2012 1:52 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] WWVB Response
>
> Hi John,
>
> Thank you for clarifying the openness of the transmission format.
> Could I ask whether there is any scenario under which aspects of the
> signal transmission design might be patented?  If companies or
> individuals wish to patent aspects of receiver design, that's fine,
> but I'd be uncomfortable with a patent-encumbered transmission format.
>
>> ... It is an unfortunate consequence of improving the reception
>> capability of our broadcast that this segment of our loyal user base are
>> so
>> adversely affected.  The decision to proceed was not taken lightly, but
>> in
>> the end it was decided that the improvement in reception capability
>> (especially along the JJY interference prone East Coast) outweighed the
>> loss
>> of use of existing PLL devices.
>
> I suppose it's a matter of balancing the value of the PLL receivers
> and the loss of BPSK signal power to the residual carrier.  If the
> power loss is small, though, say 0.5 dB or below, then given the large
> process gains of the advanced receivers, it might be worth
> considering.  I don't imagine that the mere presence of residual
> carrier has any effect on the advanced receivers (since it is similar
> to interference from MSF and JJY, as you say), but please correct me
> if I'm wrong.
>
> Cheers,
> Peter
>
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