Posts by PC5E

Jerry,

PE1CMO is no longer selling transverters, since he ran out of parts. And duplex is the rule... While I would like a computer free setup, that can only be done with something like the Icom IC-9700... Or Pluto SDR.

I think I might order an already TCXO modded Pluto from Ebay. Will cost more than a non-modded one, but then it is at least modded the right way.

DO1OHB , I chose to step up from 12v because I want to be able to use the setup off-grid if needed. With 12v I can easily use my car battery as power supply.

Now if only I could buy a already TCXO-modded Pluto... To do the TCXO mod myself I need better eye-sight, better hand-stability and better soldering equipment. The equipment can be bought, but the rest not...

DO1OHB , thanks for your message! Like to hear what you need to use as an attenuator to get the v3 PA not overloading and what power out you get. The v3 should be able to handle 50mW in (for 22W out), so it should about 3dB attenuation.

Your setup sound a lot like what I am planning!

HB9SKA : mMy IC7300 and IC7000 are not full duplex, unfortunately. So a transverter solution @10m will not help... But their 2400MHz PA also looks interresting!

G0MJW , hmmm... That is an idea I had not thought about, using the cable losses as attenuation.

HB9SKA , unfortunately the AMSAT-DL shop does not carry equipment other than for transverter use... I would gladly shop there, but I cannot build a full-duplex set with transvertes within budget...

And thanks for the link to the v3 PA, now I just need to get the Pluto output to 40mW (or add an attenuator between the first PA and the SG Labs).

David G0MRF , I used the specs from the Pluto and PA's for the link budget calculation. Not tested in use yet. I also did not calculate the loss of the connectors and pigtail.

And a new SG Labs PA? Do you have a link to it? That sounds interesting! Attenuation is indeed simpler than ampification.

Thanks!

I guess it will be either small dish with no attenuator or big dish with possibly an attenuator. I will try a big dish first, so we will see.

Okay, the promised graphic for the PlutoSDR setup:

Not drawn is the Pluto network converter and the USB OTG Y cable with 5V power input and the 90cm off-set dish. And I might need some sort of attenuation in the down link signal if it overpowers the Pluto RX.

I want to use 12/13.8v as the only power supply, so I use DC/DC converters to get to the needed 5.5v (Pluto, CN0417 PA), 14/18v (LNB) and 24v (PA).

I am still looking for a 739MHz band pass filter, to clean up the down link signal going to the Pluto.

If I get this all righ, I now designed a networked QO-100 full-duplex SDR setup that produces about 10W output for the up link (enough for SSB). Cost will be below 1000 euro's (all parts shown are just over 700 euro's and I need some coax, a dish, a case and some assorted stuff).

Questions:

- is the setup okay? Suggestions welcome.

- is the placement of the 2400MHz band pass filter in the up link in the correct place? I want the up link signal to be as clear of unwanted RF as possible.

- I think reading the LNB would need 14v for the correct polarization, am I correct?

- the LNB is unmodified, so not as stable as I want. Putting in another TXCO is possible, but beyond my soldering skills. However I like the stainless steel POTY. Can you recommend another LNB/wifi combination that is more stable and equally weatherproof? Or will the sync of SDR Console with the beacon remove the need for a stable LNB?

@DD5ER , the LNB connections were mixed up, I know. And the GPS module was not meant to be in correct orientation. So your remarks were correct. But since I posted that picture I changed from a simplex transverter solution (beacuse of cost and no full-duplex) to an SDR solution. No picture yet, but I intend to create one if I get the components identified.

HB9SKA , I read somewhere that people put 20dB attenuators between the LNB and the Pluto SDR (not to overload the RX), so biger is not always better, I guess. On the other hand, adding attenuation is better than adding an amplifier and the only drawback to a bigger dish is less portability.

Thanks for your reply. I will also look for the LimeSDR, if that is more stable. And if the SDR Console can lock onto the beacon, I will try that first (in addition to a better TXCO in the Pluto if I use one). Can the Lime SDR be used over an IP network, like the Pluto? I can probably use it over a long USB cable, but rather use a network connection.

I don't mind SDR, as I am an IT guy for work. But I do like physical knobs. And I intend to use the QO-100 setup for JOTA too, and a physical device with knobs looks better to scouts.

From a price point SDR is way better indeed. Physical full-duplex setup will cost about 3000 euro's, since I do not have an IC-9700 already (2/3rd of the cost...). SDR full-duplex setup is way under 1000 euro's.

As for the dish, I will go for 60cm for portability and aim for 10W output to the POTY.

dd9fj , your setup looks nice and simple! Do you have a list of the individual parts? The Pluto and SG Labs PA I can identify from the picture, but not the rest. I would also like to use a relatively small dish (40 to 60 cm) and thus need a bit more power than a larger (90 to 120 cm) dish. How much power is needed with your small dish?

I am now thinking of going the Pluto route. Pluto and all other parts in a waterproof box near the dish (to avoid loss of power) and IP remote access from SDR Console to the Pluto. Then I also only need 2 cables: power and network. I used ADALM PLUTO Full Duplex Transceiver For QO-100 - YouTube for inspiration. It is cheaper than using transverters, full-duplex, but also needs more attention to configuration and a computer for the SDR Console.

At my location in JO22xx I can "see" the QO-100 from my garden, by pointing a dish parallel to my home, if the various apps are correct. That is good, if the sat was only visible from the front of my home, I need a permit to place an antenna...

A new sketch is not a problem.

But I am also thinking of using a Pluto and SDR Console, it seems that SDR Console can sync the two VFO's over CAT. That would make life much easier and free my 7300 for HF. I could then use my 7000 for TX only.

Now I just need to figure out if I will use the Pluto for both RX and TX or just for RX. I can stop using transverters for RX and/or TX and just need amplifiers for the TX path.

Back to the drawing board!

Any comments on the full-Pluto setup? Drawbacks?

I read it here on the forum. But I can use the 7300 for RX, it is just an extra coax cable and setting the selector on the downconverter to a different setting. And the SDR Console also sounds like an option, linking both bands. I will look into this.

With that change in mind, would the setup above work as expected?

Thank you for your answers!

The IC7000 can do a band-split (TX on 70 and RX on 2 or even down to 80m), but the VFO's will not be linked. So to QSY I need to change both VFO's by hand. I could do RX on the 7300 (with the nice waterfall to watch my signal), but then I still need to manually adjust both VFO's. Unless there is a CAT program that does this for me, then there is no problem.

I know I can link two Icom sets by CI-V, but they will then be on the same frequency. And since the 7300 cannot do 70cm and I cannot TX on 10m or so (bands that both the 700 and 7300 have) into the upconverter, that wil not work. And the IC-7000 is not full-duplex, So even if I would take the manual VFO adjustments for granted, I cannot monitor my own signal. Same goes for the 7300, not full duplex on different bands, only split operation.

And yes, I know full-duplex is a golden rule (but also read that it is mostly for LEO's and it might not apply for QO-100 that strictly...), but I can do that with the Goonhilly SDR as a pan-adapter. Not as good as with a 9700, but spending almost 2000 euro's for a slight improvement could be a bit overkill...

I am looking for a setup that can be my entry into the world of satellites, using as much of the equipment I already have, but without needing to adjust two VFO's at the same time. The setup above will cost me over 1000 euro's, so adding 2000 for a 9700 is not what I would like right now. If satellite operations becomes a favorite part of my hobby, I then might buy myself a 9700, but we are not there yet.

P.S. a reply in German is no problem for me. I understand it quite well, but writing it comes with some errors.

Hi!

I am thinking of getting into the wonderful world of satellites and the search for transverters got me here. I am a newbie on anything higher than 70cm, but willing to learn. So I read lots of websites on the subject and came up with the setup below. And yes, long post, so my apologies in advance.

As you can see it consists of a UpConv6W and Downconverter V3d. I intend to use an Icom IC-7000 as the TRX (would love to buy myself an IC-9700, but funds...). That also means I need to go single-band simplex, switching between the up- and downconverter. That is where the RF-sensing MFJ-1707B comes in (suggestions for other brands welcome).

The upconverter feeds the POTY, the downconverter is fed by the LNB and the 10MHz reference is also sent to the upconverter for stability.

What do I expect this setup to do?

1 - let me TX on 435.5 MHz with 1 to 2 Watts of power and get into the uplink of the QO-100, for either SSB or NB digimodes

2 - let me RX at 435.5 Mhz (as set by the setting on the downconverter) from the downlink of the QO-100

3 - the 435.5 Mhz frequencies need to be in sync, since the IC-7000 does not have the ability to do a linked split, where both VFO A and VFO B change at the same time. I need an IC-9700 in satellite mode for that.

4 - no full duplex, so no real time monitoring my signal in the IC-7000. But I can use the Goonhilly websdr and compare the PSK beacon strength (shown as -72dB) to my own signal and avoid overpowering the uplink that way.

5 - everything can be built into a case, attached to the off-set boom for the LNB, keeping all cables nice and short there and I only need to connect 12v power and the coax for the IC-7000 70cm signal. If the case is plastic, the GPS antenna for the GPSDO can be installed inside the case, a metal case means putting it on the outside.

6 - only minor soldering to be done, as I am not an experienced fine solderer. The odd connector is not a problem (and required in this setup), but SMD is not an option for me.

7 - be stabil enough, but I do not expect rock stable signals as the IC-7000 will drift on 70cm (not noticeable there, but probably on the uplink). I can fine-tune the VFO if needed.

8 - if I buy an IC-9700 in the future, I can remove the 1707B antenna switch, add another coax cable and reconfigure the downconverter for either 145 or 1290 MHz and go full duplex. If needed I can then also feed the 10MHz reference to the IC9700, but I probably need some way to split it between the upconverter and the 9700.

9 - I do not intend to do DATV and go on the WB transponder.

Questions:

- #3 is something I cannot find in the documents, the upconverter is listed as configurable at "435 MHz", but as both are from AMSAT-DL I expect them to be in sync. But am I right?

- for 435MHz on the upconv6w I need to put a bridge over the low-pass filer (17). The documentation does not list from where to where the bridge needs to be put. Is that listed somewhere?

- is this a setup that can work? Will it meet my expectations?

- suggestions on cases to mount this in?

- any suggestions on improving this setup?

Thanks for your time and advice!