форум Радиолюбительского ДВ портала > Технический раздел
Juma и другие передатчики/трансиверы промышленного производства
rw3adb:
Весьма любопытное продолжение дискуссии за передачу с промышленных трансиверов на ДВ и СВ:
I ran a test of the FDM-DUO at 137.500 kHz using my OCXO reference for both the DUO and my FA-2 counter, to see if there is any systematic error or jitter within the DUO. On a 20 minute key-down carrier, the frequency averaged 137499.9905 with a peak to peak error at 10s gate times (reciprocal counted to 11 digits/sec) of 0.014 Hz. RMS error was down at about 3 mHz. That's pretty much a result of quantisation noise in the counter.
I can't use my Agilent E4406A to look closer at the phase noise as it only goes down to 7 MHz.
I should try the same test with a tone from a USB sound source to see if there is any other systematic error, but life is too short and I am beset with visitors
--
Neil G4DBN
=================================
Chris
How much dosh do you have! If you want a black box, the TS-990S would fit the bill
0dBm drive output, to drive a FET PA, receiver is excellent on LF/MF.
I have an IC-7100, output is dirty, needs LPF'S to clean it up realises around 2 Watts.
73
Ian G4GIR
====================================
Hi all!
I have been using an Elad FDM-DUO on 137 kHz for a few weeks (it also works on 474 kHz) without any problems (FST4W-120 to FST4W1800, WSPR2 a.s.o.). The control (frequency switching, PTT) takes place via CAT and the signal transmission for RX and TX via the built-in USB interfaces. A 10 MHz GPSDO is used for frequency stabilization (via the input provided on the FDM-DUO).
I have also extensively tested the FlexRadio 6600. Unfortunately, the audio interface occasionally crashes and generates a faulty broadened signal (several hundred hertz). In addition, during the transmission there is occasionally (after seconds to hours) a brief blanking of the carrier signal, which leads to broadband interference. In principle, however, the 6600 can also be used very well via CAT and digital audio drivers.
73
Albrecht
DL7NN
==================================
http://g4jnt.com/FDM-DUO_Notes.htm
Andy
www.g4jnt.com
==================================
Про использование DL4DCL Icom IC-7300 на ДВ:
Hi Chris, LF/MF group,
my setup for LF and MF is a 7300 with a transverterinterface board (DB6NT-Kit, 28€).
I am using this board without a transverter ;)
The board bypass the pa/filter unit of the 7300 (for tx only) switching 12V with the send control jack.
An additinal band pass filter at the output of the board is must have.
At LF a 10dB pre-stage driving my PA with 1dBm.
At MF the 7300 has enough power driving most PAs.
For rx I'm using the TRX out of the box (MF ATT disabled in setup, default is on).
Maybe it is not the best rig for LF and MF, but it is one I already have and it is quite stable for long term modes.
Adding the interface to the 7300 is not a 'real' modification and has no affect to other functions.
HNY
Hubertus
==================================
Сергей UB1APE:
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 :)
rw3adb:
--- Цитата: Сергей UB1APE от 06 Январь 2022, 12:08:15 ---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 :)
--- Конец цитаты ---
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
===================================
rw3adb:
С нашего чатега:
EW8HP [14 Апр 05 17:34]: Всем добрый день. В продаже появились СДР трансиверы на диапазоны 136 и 477 кГц, цена 135 долларов. Сайт - fivedash.com
ua0aet [15 Апр 03 03:11]: Если очень хочется, можно попытаться через посредников-shopotam.ru.Пользовался неоднократно.Изучите сервис. В конце марта рабртал. На сегодня сайт доступен. Сведений о прекращении работы не увидел
ua0aet [15 Апр 03 03:34]: Правда пишут об ограниченном количестве данных изделий
UF4A:
Полезная штука в хозяйстве. Вот интересно: из здешних старожилов кто-нибудь 2-х сторонними QSO занимается? Или это больше на 477 кгц?
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