Do you have someone who can print 3-D ?
You can 3-D print a electrical lense.
Or turn a piece of Teflon with a lathe.
Unfortunately, I have no access to 3D printer or lathe, I'll need to buy the lens.
Thanks much for answering my other questions. Still raining here today but I'll try to make some progress.
The best lens for a offset dish is the original Lens from a rocket LNB.
You can buy this cheap LNB and remove the lense.
Any other options for a good lens? The rocket LNB is hard to find. The one in the link from amazon.de has a brutal shipping charge to Slovakia.
I use the adaptor LNB cap which can be found here:
https://github.com/dl9sec/POTY_Parts
73, Thorsten
Thanks, Thorsten! Is that cap available for sale individually? Would it fit my LNB? It looks much nicer than my home made hole in the cap.
Remember, you will get 2-3 dB more RX Signal if you add a electrical lense.
So be not worried if without lense the RX signal is 2-3 dB less than before.
Yes, exactly as you said. I'm seeing signals but weaker than before. It is also still raining which does not help the signal.
Noted a couple of mechanical issues:
1) I'll have to file out a groove on the outside of the plastic mount, the N connector jack and plug will not pass.
2) The bottom of the reflector touches the metal arm, is that a problem?
Yes, you need only glue for waterresistance and maybe mechanical fixing through the pastic cap.
There is no electrical or HF influence.
I'll try it tonight as soon as it stops raining.
Hm,
I have no experience with adapting square to round.
But, I don´t believe thats necessary to for such a smooth flatten.
Comercial round to square adapter have a step from square to round.
Just connect them together and it will work well enough.
OK, I'm ready to cut the tube, I've not been able to remove the old LNB. How is the POTY secured to the LNB. Just glue to the plastic cap?
Yes,
close the case agn and drill a hole in the cap.
That is so interesting! I would have guessed that a much better fit would be needed.
Do you recommend inserting the POTY as is, or flattened at the end, as suggested by someone else as in the attached photo?
The two sides are clipped together.
You have to find the clips by pressing and with a knife or scewdriver you can delock the clips.
OK, thanks, I got it open. But this LNB is square, not round like the broken one. It won't fit in, is there some way to use it?
The POTY construction looks ok. Nearly 4mm. Is ist home built?
I did not build it but it looks home built.
Do I need to break apart the plastic outside of the LNB or is there a trick to opening it? I've been trying to pry it open with no success.
I can't remove the old LNB with soldering gun, will need to borrow a torch or cut it off as you suggested.
How do I remove the broken LNB? Can I do it with a soldering gun or do I need a blow torch? I can't tell if it is glued or soldered.
I tried to remove it with a soldering gun, no success.
What is the inner distance between the two plates?
About 4mm.
Is this the lens I need: https://www.passion-radio.com/…qo-100/poty-lens-927.html?
How do I remove the broken LNB? Can I do it with a soldering gun or do I need a blow torch? I can't tell if it is glued or soldered.
And how do I open the LNB? It seems difficult to pry apart.
73, Bill
there is a 3rd option (which I would prefere) :
Buy a POTY feed, then you have all the advantages you need.
You can still use your LNB
Is that a POTY in the attached photo? It came in the box with the rest of the QO-100 gear that has been loaned to me. Is it a POTY with the inside of an LNB attached to the bottom? That LNB does not work, I've tried it. Maybe I could remove it.
Well, according to the motto: something always works ...
as long as the feed is mounted outside of the reflected beam path (i.e. next to or above the LNB), a loss of several dB will occur because the main lobe of the emitted signal is simply not directed towards QO-100.
Anyway, not a good solution.
Yes, Robert, I tried several different positions for mounting the feed next to the LNB and as you say all were lossy. And the owner of the BamaTech has asked me not to cut off the bottom or otherwise modify the feed.
So this seems to leave me with 2 options:
1) separate dishes for TX and RX, or
2) buy the dual band feed with LNB for 130 euros (photo B above).
Does anyone have a used dual band feed with LNB for sale?
Yes, take a look here in this thread ...:
Thanks again, Robert. I'm not sure the owner will allow me the cut the feed, but good to know it is possible.
In the meantime, for a poor man's solution, a local ham told me I could just tape the feed on top of the LNB. I was skeptical but gave it a try, see attached photo. I was able to make a QSO with DL4RS. He said my signal was weak (-80) but readable. Maybe with some adjustment I can improve the signal. Has anyone tried anything like this, perhaps a more sophisticated version?
DCD was used in the old software versions. CTS is used in actual versions.
I have Raspberry Pi 3B, so I'm using the older software (02.img). Should I use DCD?
If it is possible then you can connect CTS to TX GND. But it is not absolutely necessary. The PTT signal from FT817 is also available via CAT command (you can enable this in the software). But via CAT the PTT detection is a little bit slower.
Thank you, Frank. I can solder a wire to the CTS hole on the converter board.
Did you determine it is better to use CTS than DCD? In post #17 above, you wrote, "Via USB/TTL converter (like CP2102) you can control transmitter (FT-817). For this connect RXD/TXD signals crossover and PTT GND output from CAT/ACC socket to DCD input of USB/TTL converter." But then in post #83 you suggested connecting to CTS.
73, Bill
SAT Controller SDR Nano - CAT interface
For connecting FT-817 (CAT/ACC socket) you can use USB/TTL converter below (CP2102). Very nice: All handshake signals are available. It also works fine as PTT output from a seperate digimode computer. For this only one external diode in series is required to connect DTR signal to PTT input (DATA socket) of FT-817.
For fast PTT detection the signal TX GND from ACC socket can be connected to CTS input of the USB/serial adapter (because via serial CAT command there will be some delay):
Hello,
Could someone please advise me how to make the proper connections from my USB TTL converter (photo attached) to the ACC plug to the FT817? The pinouts on my converter are different from the ones in the devices posted by DL3DCW. If I understand correctly, the TXD pin on the converter goes to the RXD pin on the FT817 ACC plug, the RXD pin on converter goes to TXD on the FT817, and GND goes to GND. But what about CTS? My converter does not have a CTS pin, although there is a hole in the board labeled CTS. Am I supposed to solder a wire to the CTS hole and run it to TX GND on the FT817? Or something else?
Thank you for helping and 73,
Bill OM3BD
I just heard my downlink on the web SDR! The main problem was that the prior owner of the FT817 had set the menu for the front antenna jack, and I am using the SO-239 on the back, bad mistake by me to overlook this. Now all LEDs are green. Thanks to all for the help.
Now, does anyone know how I can mount the LNB and the BamaTech feed on one dish? I originally thought I could insert the feed into the LNB, as in photo A below. But Markus at BamaTech told me this would not work with his duo feed, I would need the feed shown below in photo B (130 euros). I was also told I could not use a dual holder like the one in photo C, because this holder points each feed at a different satellite. It was suggested that the easiest and cheapest way to proceed would be to buy a second dish.
Thanks to all for the replies. My setup for TX is an FT-817NB to the SG Lab transverter (using TX side only) to a 6db attenuator to the SG Lab amp to the BamaTech duo feed on a 79x71cm dish. My setup for RX is a Raspberry 3B with RTL-SDR to a GoSat LNB modified with TCXO. I got all of this equipment from another local ham who says it was working for him and he was making QSOs via QO-100. I put the LNB back on the dish this morning to verify it is still pointed correctly and it is, I'm getting good reception from QO-100. But TX is still an issue.
First, I may have been wrong yesterday when I guessed the transverter was not working. I thought so because I put another SDR on my laptop, loaded SDR Sharp, tuned to 2400.2 mhz, and did not see my own signal. But even though I was able to tune to 2400.2mhz on SDR Sharp, I later discovered that, according to rtl-sdr.com, the upper limit of this hardware is 1.75 ghz, which would explain why I heard nothing. Also, following your advices, I removed the covers off the transverter and the PA and measured all voltages. They seem a bit low but largely in accord with what is said in the manual. The jumpers appear to be set correctly for LO 1968 mhz (jumpers 1 and 2 on, photo attached if you would like to double check me). So at this moment I don't really have any good clues as to what is wrong, maybe the angle of the BamaTech feed is off, as suggested by Robert.
Transverter voltage readings:
B+ 12.1v
SWR voltage Forward 0.8v Reverse 0.04v
PA voltage readings:
B+ 24.2v
DRV 0.35v
SWR voltage Forward 3.1v Reverse 0.1v
There are some anomalies that I don't understand. Perhaps most importantly, Mike says moving the feed should not affect the SWR. In my case, moving the feed (both when it is on and off the mount) does cause the LED to change from red to green. I tried connecting the feed directly to the transverter output (bypassing the PA) and it became much more difficult to get a green LED. To check if perhaps there was a bad coax connection, I tried a different coax cable to connect the feed, same result. The PA has no LEDs, but the voltage readings indicate the SWR is OK.
I'm also having trouble getting a green LED for transverter input. The manual says orange for low, green for normal, red too high. I'm always seeing the LED with a yellow/green color, and it never changes regardless of the output setting on the FT-817 and regardless of the position of the TX POWER trimmer. I don't know what to make of this.
Any further thoughts? I can send a video, more photos, or any other details that might help.
73, Bill
Thanks for the replies. I tuned my SDR receiver to 2.4ghz and could not hear myself, so I'm guessing that the problem is that the upconverter is not working. I can hear myself on 432mhz, so it seems the FT817 is OK.
DD4YR - Robert, yes this is the SG Lab transverter V1.4 with the 20W PA V2. A photo of the dish and mount is attached, it's the same as it was in yesterday's photo, except that the feed is now further from the dish, with the reflector pushed flush against the mount, as shown in the diagram you posted.
G0MJW - Mike, it is not a 60cm dish, it is 79x71cm. It is possible the dish moved when I took off the LNB and inserted the BamaTech feed, but I don't think so. I'll put the LNB back in to confirm.
Assuming the problem is a bad upconverter, anyone have an extra for sale?
73, Bill
