Да-а, не всё так просто на ДВ. Гугл мне перевёл. У всех всё по разному. Да-а в общем то так и должно быть.
There is no equipment for a range of 2000 meters. Therefore, everyone has their own.
Thanks Roma 
Всячески, Сережа!
deepl.com еще в помощь. там иногда получше переводит.
Переводить особо некогда, но посчитал сию дискуссию там очень интересной для нас.
Продолжение оной:
Chris, et.al.
I ordered a FDM Duo (black) Monday evening (local) and received it
Thursday. There was one red case unit available, but I see it's gone now...
Over the last couple of nights I had a chance to do side-by-side
comparison of it's reception ability against my TS-590SG and K3. I am
running it in stand-alone mode and only have the "TX" USB port hooked up
to the PC for TX/RX audio (shows up as a C-media USB soundcard device in
Linux). As I run Linux here, no intention to use the IQ from the "RX"
USB port (though I have heard of at least one OP doing that w/
GNUradio... but I was never impressed w/ GNUradio performance in the
past anyways). For any IQ stuff I usually use SDR-core (Dttsp) and
SDR-shell (a version I heavily modified), which always did a better job
than GNUradio, etc.
The FDM Duo on MF (630m) compared to the TS-590SG or K3 (straight thru
w/ upgraded synths) was always 1-3 dB behind on SNR reports per WSJT-X,
averaging 2dB down. On LF (2200m), the FDM Duo was always 1-5dB worse
than the TS-590SG, averaging 3dB down. Incoming RF line was simply
split and run to the respective radios under comparison w/ a 1:1
isolation xfmr on each radios RF input. Also used a well choked (for
LF/MF) power cable.
Tried different AGC settings (Off, etc.), thresholds, audio levels, etc.
and never could get the FDM Duo receiver to perform as well as either
the 590SG or K3 on either band. It does "OK", may work well for someone
else compared to other options, but it would not be my go-to receiver
for weak signal work on LF/MF. As far as that goes, the TS-590SG is
still the best RX I've used on LF (2200m)... but not w/o some aides, a
1:1 isolation xfmr on the RX input (as previously mentioned) and a 17dB
LNA (DXE RPA-1 clone). The RF environment here is extremely quiet and
w/o a preamp I would not get sufficient input to the radio from my
double anti-phased loops (aimed west, hears VK4YB regularly as long as
the band prop is half-decent).
Anyways... you can see my tests and opinion are very RX-centric... the
rig has plenty of merits like portability, well thought out 10MHz ref
input (Elecraft's implementation on the K3 is a mess), study
construction, and more... but at the end of the day, RX ability trumps
everything else for me personally. I have no idea if I'll keep the rig,
return it, or sell it... it has some good points, but for the price, I
was expecting more from the receiver.
If there is some setting or combination thereof that I might be missing
to liven this thing up, I'm all ears...
73 Eric NO3M
==========================
Hi Eric,
I would be careful to judge DX performance of two competing receivers just by SNR.
Currently I compare my IC-7851 against Perseus on MW.
With optimized settings like preamp and AGC the 7851 mostly shows
a SNR better by 2-3dB than Perseus.
It even makes more spots totally, about 1%-3% more than Perseus
but this morning I was surprised to see that Perseus had one unique T/A spot more.
It also pays off to run several nights with different settings of the receiver
which is compared to the reference receiver.
73
Clemens
DL4RAJ
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