I agree with Jim.
The Eagle is just as good.
The Flex 6xxx is just as good but people haven't accepted it yet.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Friday, July 25, 2014 9:04 PM
To: tentec@contesting.com
Subject: Re: [TenTec] SOFTWARE at WRTC
On 7/25/2014 11:26 AM, Ron Notarius W3WN wrote:
> Of course, what is the “best” radio is a very subjective thing these days.
> Size, shape, other ergonomics, manufacturer/brand loyalty, filter
> selection... all are factors.
#1 -- the ability of the RX to reject very strong signals
#2 -- ergonomics, reliability, familiarity
#3 -- I have it, or the place where I want to operate has it, or I can borrow it
As to filters -- In modern radios, IF filters are done in DSP, and can be set
to any bandwidths and shapes that are provided by the firmware.
The K3 and KX3 can be set for any IF bandwidth between 100 Hz and 4 kHz in 100
Hz steps, and can be shifted in 100 Hz steps. The K3 allows for additional
hardware plug-in crystal filters, but these are ROOFING filters whose primary
function is to protect the DSP IF from overload by strong signals outside the
selected IF bandwidth. You don't have to buy a 400 Hz filter to get 400 Hz
bandwidth, you just turn the front panel knob to 400 Hz, and if you want 250
Hz, you turn the knob to 250 Hz.
Of course, like any signal path, a roofing filter will cascade with other
filters in the path (the IF filter) when their bandwidths are nearly equal to
provide steep slopes and deeper rejection of off-frequency signals.
My K3s have 8-pole 2.8 kHz filters for TX which serves as the "wide"
roofing filter, and I've added a 1.8 kHz for SSB, and 400 Hz and 250 Hz roofers
for CW and RTTY. All are 8-pole filters. FWIW, I find the 1.8 kHz filter too
narrow for SSB, and like the 2kHz filter better.
If you're not a contester, you need only the stock 2.7 kHz 5-pole or extra cost
2.8 kHz 8-pole filter.
Note that I'm describing what the K3 and KX3 do because those are the DSP
radios I know, but the concept applies to other DSP radios.
There are at least three major reasons Flex radios have not "caught on"
among contesters. #1 is the strong signal problem, -- what Rob called the Field
Day problem. #2 is user interface when you're contesting, you want knobs so you
can do several things quickly. A mouse doesn't cut it, both because it isn't
fast enough, and also because you're doing computer logging. #3 is the other
half of the Field Day problem -- many are pretty dirty on TX.
Think about this -- the Eagle, K3, KX3, and the Flex radios are all SDRs. The
K3 and KX3 have knobs, the Flex radios do not. The K3 and KX3 have superior
strong signal performance, the Flex radios do not. Don't know about the Eagle.
Only a few (count on one hand and have fingers left over) radios in the $10K
range are as good, or nearly as good, as the K3 and KX3 for strong signals. The
K3 is super clean on TX, the KX3 and Flex radios are not. Some of those $10K
radios are cleaner than others on TX.
73, Jim K9YC
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