Posts by DL5CN

Hi,
as Peter wrote above. Start a discussion. Collect ideas, do experiments. Test your equipment. Have fun. That's it. Of course there are more than one way to operate duplex. Switching to another sideband is one mouseclick.
73
Andreas

Hi George,

I understand your plan. But I think it will be hard to surpress your own speach. You get confused because of the delay. This is not the case, using two different sidebands. As long as there is enough space, the occupied bandwith doens't matter.
In a real duplex qso it happens that both stations talk at the same time to interrupt each other. On the same frequency there will be an interference with no copy.
At least, it was an limited experiment. It was very easy to do. It was fun and showed how linear our amplifiers are. And the Pluto with Console is good for full duplex.
73
Andreas

Hi,

a couple of minutes ago, I did a test with a friend. We used the two sidebands. Receiving and transmitting at the same time in different sidebands is very easy with the Console. Switch off the receiver muting also. The result is a crosstalk like a phone call. The delay caused by the satellites distance is no problem, because you do not hear your own voice while speaking. It was interesting to see there was no interference between the closed sidebands.
Again, use headphones without an acoustic feedback to the microphone. Probably switch the receiver AGC to a fix value.
Have fun.
73
Andreas

Hallo George,

one additional hint. To avoid acoustic feedback use a headset.

73
Andreas

Hi George,

I am ready for a test also. It is very eays to change Pluto frequencies. Switch off SyncRX and adjust the Rx and Tx Frequencies where ever you want. It is a kind of split mode which is very easy also. Just look which station is accepted from the DX and turn your transmitter to this
frequency. There is a very big advantage having a spectrum.

73
Andreas

Hi Miro,

most of the Pluto users operate with the SDR-Console written G4ELI, Simon. This program allows all you need for satellite operation. There are menues to adjust the 40 MHz Pluto-clock. The receive frequency can be locked with the help of the PSK-Beacon. The transmit frequency is controlled by the 40 MHz clock only. To adjust the transmit use XIT, nothing else. If the external clock is GPS-locked there is no need for adjusting anything. But sometimes unexpected offsets occur. The solution was set all the values in the SDR-Console menues to zero and do a cold start.
Set all the hooks also. We assume, there are correction values stored in the Pluto which cannot be changed easily setting the variables.
May be we continue discussion per email. <mycall>@t-online.de
73s
Andreas

Hallo Miro,

from time to time, there where reports about unexpected frequency offsets with the Pluto. I am not sure but my recommendation is, bring all calibration settings in the Console to zero. Use all the options that are shown. Probably in the Plutos firmware are factory offsets.
This happend to me using the pluto not for satellite operation but on 2m and 70cm. Returning to Sat-mode I found a strange offset altoughan external Leo Bodnar Clock is applied. After a cold start all was fine again.

Yout settings of the environmental variables above seem to be ok.
73
Andreas

...the Console must run in full duplex mode, otherwise you cannot monitor your transmission....

Hi Manu,

in the lower left Receive-Window is a switch for full- and halfduplex. Probably it helps to fix your problem.
73
Andreas

Hallo Vladimir,

1. WSJT unterstützt einen seriellen COM-Port für PTT. Ist dieser an aktuellen PCs nicht mehr vorhanden, kann man einen USB zu seriellen Wandler nehmen, z.B. einen FTDI-Chip wie FT232. Das erfordert einen FTDI-Treiber im PC. An einer der Statusleitungen (CTS, RTS) kann man ein Signal abnehmen. Dem Programm muss die COM-Port-Nummer mitgeteilt und die Statusleitung ausgewählt werden.

2. Um einen Pluto mit Ethernet zu betreiben ist ein USB zu Ethernet-Wandler erforderlich. Der Micro-USB-Stecker muss einen OTG-Kontakt haben. Damit wird der Pluto auf Ethernet geschaltet. Es gibt viele USB zu Ethernet-Wandler, nicht alle funktionieren, leider. Da sind Tests erforderlich. Zusätzlich müssen am Pluto und PC Einstellungen der IP-Adressen erfolgen oder DHCP benutzt werden.

dl5cn@t-online.de

73
Andreas

Hallo Valdimir,

ok, but a diagram isn't necessary. The POE-Adapters (can be seen above) with a RJ45-Socket are sticked to each end of a normal cable. And the RJ45-Plugs of the adapters are connected to Ethernet devices. This gives a normal Ethernet-Connection (red) with 2 twisted pairs, for example between Adalm Pluto and PC . The other two wire pairs can be used to bring the PTT-Information (green) from the USB-Relay at the PC to the Pluto. With other words, the POE-Adapter splits the Ethernet cable into two functions, normal Data exchange and PTT-Signal.

Oh, I remeber a symbolic graphic, I did for a friend some time ago. Here it is.

To switch to transmit, the PTT-Button gives a "low" to a USB to TTL-Converter and the Console goes in transmit mode.

If there are more questions, don't hesitate to ask.

73
Andreas

Hallo Ahmed,

i wrote such an article but it is in German.
73
Andreas

Hi,

my recommendation are chinese boards with SZA2044 or SZM 2166 Chips from Sirenza. These boards work well between the Pluto and the SG-LAB Amplifier. All this is available on ebay. The french offers seem to expensive to me.
In addition a PC, a USB to Ethernet Converter and Power over Ethernet Adapters are useful. Please use the search function in the forum.
All this was discussed and written down so many times.
It would be nice to know your name.
73
Andreas

Hi,
yet another wish. If you talk about amplifers and power don't forget the intermodulation distortion. Single tone values are useless.

The Console in combination with Pluto gives an excellent two tone signal.

The screen shot is an AMSAT-PA (with preamp) with good linearity. Please note, two carriers with 30 dBm give 36 dBm, that are 4 Watts.

With the preamp, the amplifier does not need any driver and can be used direct after the Pluto.
The intermodlation distortion products can be related to the carrier level or to the PEP-level, which is 6 db more. This looks much better in the datasheets.

Not only a "dB world" but a linear world too :-).

73
Andreas

Hi Guys,
which unit do you use for return loss? What shoes your network analyzer for S21?

With modern concepts like network and spectrum analyzers and SDR-Technology we have to get used to logarithmic systems. There is a little software from Rohde & Schwarz for Android and PCs also. It is called "dBm Calculator". You can transform linear and logarithmic units to each other. It helps, to get familiar with all this.

73
Andreas

Oh Boys,

did you ever heard, with logarithmic values, gains and attenuations can be added easily instead of multiplying and dividing. We should follow the professionals.

Look forward, please.

73
Andreas

Hallo Josh,

ok, all is fine. And if you take care, the radio function ist satisfied.
It is a pity that ICOM didn't go one step further to bring the 705 to duplex operation.
A simple approach to a portable Radio is a Pluto followed by the AMSAT-6W-Amp.

The rest is power supply and - if wanted - a GPS-RX. The rig is mounted with two clamps closed to the LNB holder.

The only Connection is a Ethernet cable. And Power. 12V from a battery or from mains. With a short wiring to the Helix, 4 linear watts out of the amp are enough. As you see in the first picture with my dirty setup it can be done smaller still. A WEBSDR requires a PC. This is good to operate a Pluto too. In the field it is nessecary to have a sunshield. This is a disadvantage of modern displays not working in a bright environment.

73
Andreas

...."there is no radio that can work duplex"....

Hey Guys, don't know if I should laugh or cry.
Is it nessecary to talk about the Pluto again and again really? From my point of view full duplex means listening exact on the same frequency. One can see and hear stations transmitting very closed to or direct on used channels. Or finding their own transmit frequencies, scratching across the full transponder with full power. This is modern technique, horrible. I am sure, they have no spectrum displays and no duplex radios. I don't like to repeat all the other advantages of SDRs.
But I like to repeat offering help and support if needed and or wanted. Radio Hams were always seen as open to future technologies. SDR is not future is present. I don't see any reason not to use it.

Give you a kick and start....it is easy.

73
Andreas

Hi George,

I'll try to post a picture.

The Controller on the board is an ATMEL TINY 45. There are Boards with a - well known - C340 Chip. There were not recognized by the Console. I don't know, why Simon uses so hard restrictions.
I use a PTT-Chain, starting with a button (USB to TTL Converter) which pulls a status input to GND. This triggers the Console and the above shown relay. The PTT-Signal is send to the amplifier with two Power-Over-Ethernet-Adapters in combination with the ethernet cable. With this configuration, the Console itself can control PTT when transmit call sign or voice keyer.
73
Andreas

Hi Guys,

use a modern SDR-Concept and all the trouble is gone. Full duplex, easy tuning, synchronize with the PSK_Beacon, only one oscillator for tx-stability, tx-equalizer, envelope compression, spectrum display, two tone signal for linearity tests, what else do we need? Don't be afraid in front of digital technologies. You are not alone. Don't hesitate to use it. If nessecary, you get help. The terminal program from G4ELI is free of charge. From my point of view this is very remarkable.
Have fun.
73
Andreas