[Elecraft] Field Day rig experience

[Ian White]

>I think the LO phase noise should be pretty close.

Perhaps it *should* be... but some of the worst examples of wideband
transmitted noise are caused by additional amplitude noise in the TX
chain, or by poorly filtered DAC noise in SDR-based transceivers
[1]. These noise sources are additional to the LO noise, and are
present whenever the rig is in TX mode (even without modulation).

That unfounded *belief* that "the LO phase noise should be pretty
close" was precisely the reason why none of the designers paid any
attention to the excess transmitter noise. But the equipment reviews
were equally at fault for failing to draw attention to the problem.


[1] Band Pollution from Amateur Transmitters - SM5BSZ
http://sm5bsz.com/dynrange/dubus313.pdf

73 from Ian GM3SEK

>-----Original Message-----
>From: elecraft-bounces at mailman.qth.net [mailto:elecraft-
>bounces at mailman.qth.net] On Behalf Of K9MA
>Sent: 10 June 2018 20:14
>To: jim at audiosystemsgroup.com
>Cc: elecraft at mailman.qth.net
>Subject: Re: [Elecraft] Field Day rig experience
>
>I think the LO phase noise should be pretty close.
>
>----------
>
>Scott Ellington. K9MA
>
> --- via iPhone
>
>> On Jun 10, 2018, at 1:17 PM, Jim Brown
><jim at audiosystemsgroup.com> wrote:
>>
>>> On 6/9/2018 12:54 PM, K9MA wrote:
>>>> On 6/9/2018 14:52, David Gilbert wrote:
>>>> I think another major concern for closely positioned rigs would
be
>transmitted phase noise, and of course that doesn't show up in the
>Sherwood charts.
>>>
>>> Yes, it does!
>>
>> All I've ever seen from Rob is RX phase noise. Can you provide a
link
>to TX phase noise?  The TX phase noise data I've published came
from
>ARRL Labs.
>>
>> 73, Jim K9YC
>>
>>
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