How much is good enough?
Floyd, you said 80dB is probably good enough; for my own thinking, I would
go with 90.
I think what the ham community needs to get a grip on is the fact that there
are only a few days per year where the difference between 80dB and 90dB make
a difference. CQWW DX Contest being the best example.
Outside of these big contests, it really is not so important unless you have
a really crappy radio. (and there are plenty of those out there too). Under
normal circumstances, 70 dB might even be sufficient.
I've said this at least 10 times on this reflector and I believe it to be
the holy grail:
"It's horses for courses".
Until we know exactly what the user wants to do (to have out of his radio),
it is wrong to try and define which radio is the right one for him.
73
Rick (my personal "right radio" is the Eagle - your mileage may vary.)
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Floyd Sense
Sent: Friday, November 11, 2011 11:56 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Omni VI+, VII, or Orion for next rig. Can't decide
A couple more comments regarding receiver evaluation. There's
interesting info at W8JI's site here:
http://www.w8ji.com/receiver%20IM3%20sorted.htm . Note his comment
about an IM3 DR of greater than 80 dB being overkill for most of us.
Also, note in the Sherwood rankings that there are a ton of rigs with an
IM3 DR of 80 or better and some of those go back to the late 1960s to
early 1970s. Also, most of Rob's testing was done with a sample of ONE
of each rig, and that testing of different examples of the same rig
produce results that might vary by 2-3 dB. That might put a lot more
receivers on Rob's list into the category of "good enough for most of
us". And a last point - if your problem is one of poor adjacent
frequency interference, you might be further ahead looking at the
"Filter Ultimate" column of Sherwood's rankings instead of the IM3 DR
column.
73, K8AC
On 11/11/2011 1:35 PM, Richards wrote:
> Thanks for the clarification and confirmation. Quite an education
> this hobby, for sure.
>
> My wife does not always seem to understand why I spend more time
> reading the books and on the internet, than on the air... but it is
> amazing how much there is to learn.
>
> The materials you mention are top notch. I cannot tell you guys how
> much I appreciated the personal notes I have received from guys like Rob
> Sherwood, explaining what is out there on his web pages. Others like
> Rick DJ0IP at Spiderbeam, Jay Hallas of ARRL, Rudy Severns N6LF, Phil
> Salas, AD5X, Jim Brown of this list, Bob K4TAX on the Omni VII list,
> and so many others who have taken time to help me get started.
>
>
> Thanks.
>
> =========================== Richards- K8JHR =====================
>
>
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