Posts by S57RW

    Hi Phil,


    Pluto will work and you can use it also for receiving at the same time. One thing you should know about Pluto as it comes out of the box its local oscilator isn't that stable for narrow band modes. It is not that it is completly useless and for start will do but with time gets a bit annoying your correspondents have to adjust the frequency for your drift. Inside the house when it warms up is stable enough for SSB but you will most probably like to put all the stuff outside close to the dish to avoid long coax cable runs. Of course there is a solution you can change the TXCO with a more stable one but involves soldering a very tiny SMD component. If you are not comfortable with that find a friend who has experience with soldering SMDs to do it for you. Than you will need 2 stages of amplification to get few watts out, an dish illuminator and you are ready to go. Most of this stuff are commercially available and quite plug and play :)


    Personally don't have the Lime so cannot tell about. Maybe some others here who are using it can. But as have red it has some drift problems as well with original TXCO.


    You can check this channel on Youtube from M0DQW, he has a series of videos about making the setup and he tried both with a Pluto and Lime. https://www.youtube.com/c/TechMindsOfficial/videos


    In the case you have a 2m and/or 70cm SSB rig you can consider using an upconverter instead of the SDR.


    73 de Andrej - s57rw!

    Hi Phil,


    Glad to hear it works. Welcome the club :) Now as you mentioned you have to think about TX side. Don't be affraid you will make it. For any thing ask on the forum here are planty of hams whit experience how to do it. Also if you are a member of your local club check if there is somebody with experience in microwaves and can give you a lot of support making cables, connectors, good advices etc.


    Looking forward to hear you calling CQ one day over the QO-100 :)


    73 Andrej - s57rw!

    Hi Phil,


    Looking for your results. Think will do. If not we will check next steps how to make it work. At the end this is one of the functions of this forum. If you give up at certain point won't never work :)

    73 Andrej - s57rw!

    Hi Phil,


    Yes if you set the scale at 26-27 deg elevation and 149 deg for azimuth you should be in about right position. Of course you will have to make some fine adjustments by azimuth and elevation to find the right spot. Do it azimut and elevation separately by not releasing all screws wobbling the dish all around. You have to assume probably your mast isn't perfectly at 90 deg, the printed scale for elevation is more for indication and also you didn't point the sun exactly. But you are in the area so make small adjustments by few deg. Take also in consideration when receiving with a sdr dongle that it has some small delay. But when you move the dish if you are doing it slowly you will get it at the right place.


    Once you will fix it at right position you are done. Just make sure the mast is stable and not wobbling in the wind with a 80cm dish on it :)


    73 Andrej - s57rw!

    Hi Phil,


    You have a offset dish which is mostly used nowdays for SAT TV. Check on google difference betwen offset and prime focus dish and you will get the idea. Anyway your dish being offset type means when the dish faces exactly vertical means the dish is looking abt. 26 deg up (depends on the dish model but is here around). So trust the printed scale. If you used a level and pointed the dish at 26 deg means your dish is looking probably 50 deg up.


    Set it using the dish scale and than search for azimuth. After you find the sat make fine adjustments.


    After some time you will get practice. I can find the sat with a dish holding it in my hands so it isn't that hard :)


    Make sure also as mentioned above that you mount the LNB to vertical polarization -19 deg of skew angle. On the LNB flange usually is printed a angle scale. 0 deg on the scale is vertical than rotate it to -20 deg for your location. You will se this scale is quite rough but the setting isn't critical at all. Just don't be off by 45 deg or more :) Before messing with that you can set it to 0 deg and after you point the dish adjust. Better not to have too much parameters at one time...


    For 1st test you can check ask mentioned above receive with the LNB alone. You should hear the beacons, quite weak but you will if the rest of the setup is working properly.


    73 de Andrej - s57rw!

    Hi,


    For pointing the dish if your mast is leveled vertically than for elevation you can use the angle scale which most dishes should have printed on the mount. It will bring you close enough. Than search for azimuth and after you find the sat do fine adjustments to azimuth and elevation to get the strogest signal.


    Just to try if your hardwere is working and assuiming you are on right frequency span you can just point the LNB in the direction of the sat. The LNB alone isn't very directional. So +/- 15-20 deg off the direction would still receive. You should hear the beacons and maybe also some strong SSB stations. The signals will be weak but you should hear them. I can elasily copy the lower CW beacon just with a LNB.


    Make sure you oriented the LNB in right polarization. For NB transponer should be vertical. If you mounted it in horizontal probably you won't hear anything. Than adjust it also for the skew angle which should be -19 deg for your location. This angle isn't that critical to be set very precise. Even 10 deg off you won't notice much difference.


    73 Andrej - s57rw!

    Hi!


    I've ordered from DX Patrol the version with down converter since for portable operation prefer to have the rx on the rig not needing to carry the laptop around. Generally it works fine. If the unit is inside in the shack the frequency stability is fine. If operated outside there is some drift due temperature changes, but still not a big problem for SSB or CW operation. In any case a big improvement over the previous LNB with an 8ppm reference.


    When used with a FT-817 as RX even with its gain set to minimum have to use a 20dB attenuator to get better S/N ratio.


    Have still to test digital modes like KG-STV where stability is a must. I suspect for this a GPSDO as external reference will be necessary.


    Dirk tnx for the information that the bias is not short circuit protected. Usually is difficult to make a short when screwing the F connectors but you never know. Better have the unit switched off when screwing cables on it or LNB.


    Best 73's Andrej - S57RW

    Don't forget thermal methods. How much a load heats up with RF compared against a second identical load fed with DC.

    Hi!


    Agree with you to consider differente between DC and RF. In the article the author recommends max 0,5W but for very short time. Anyhow not clever pushing the limits. If you burn the resistors it is a real hassle to desolder the box for replacing not speking about burning an expensive rf final after… For this reason got some attenuators I use when applying more than abt. 1/4 W.


    73's Andrej - s57rw

    Hi!


    For power measurements I'm using a rf probe published years ago on the following article:

    http://lea.hamradio.si/~s53m/phare/Mikrovalovna%20sonda.pdf


    The article is in Slovene language but it is not complicated to make so can be understood from the schematic and building scheme. Mine is working up to 6cm band. The author states it should work on 10GHz as well but don't have any source on 3cm to try it. One thing to know is that seems the disk capacitor has a resonance on 13cm and for this reason the probe is showing abt. 20% less. On other bands is quite accurate. It was the case also with mine so after build is good to check it against a known source. After you know the % of error on 13cm than thats not a problem for measurements. The max power is limited by the dummy load resistors and is abt. 0.5W. For very short measurement mine survived up to 1W... For more it is good to have some attenuators at hand.


    One warning if somebody decide to build it. Don't buy the BAT62-03W diode on eBay from Chine. They are fake at last from the seller I got it. 1st got the diodes from China and could measure power up to abt. 440 MHz corrcetly. On 23cm was showing only abt. 30% of the true power and almost nothing on 13cm. After bought from https://www.rf-microwave.com/en/home/ and got it working as expected.


    73's Andrej - s57rw

    Hi!


    As was mentioned under this topic don't understand why there should be any tolerance limit. With beacon level signal strength you have a great readable signal so why need to go over. Such signals can be even understood just with a LNB without the dish. Don't think anybody has problems of a huge local QRM on 10 GHz being unable to copy signals at beacon level...


    Concerning pirates, idiots and psychos don't think additional chat rooms would help. Will even make it worse. They are not doing that to test their technical abilities but to make troubles. What they enjoy is people speaking about them and knowing they are really making troubles. If we don't speak about too much most of them will lose interest.


    What I enjoy the most working QO-100 is making CW QSOs using just the upconverter giving out abt. 80mW into a 85cm dish and still getting a quite solid readable signal back. I find that fascinating that so low power can travel 36.000 km and still usable. Hope will complete soon a more stable LNB so can try digital modes and make tests what is the lower limit the signal can be decoded back. Know other have tried but like to do myself and have fun.


    Best regards,

    Andrej - s57rw

    My last QSO trough FO-29 was abt. mid June when was still perfectly working. After had some construction work in the house so was out from any ham activity. So unfortunately don't have a telemetry record from the last days. Also by working LEO's usually just used the CW telemetry beacon to find the SAT and than tuned to find somebody calling or to call CQ.


    However tnx for the post it is an usefull request if maybe somebody has a record of last days.


    Best 73's

    Andrej Jerman

    Not a new news but apparently the FO-29 LEO SAT went SK somewhere between 9th and 10th July after 23 years of great operation. Nobody heard from since than. I'm sorry for that since it was a great bird. Made my 1st LEO SAT QSO with linear transponder over this bird and many more later.


    Wasn't active on LEOs since abt. 2 months and tried the FO-29 few days ago without checking the SAT's status prior. Of corse heard just silence.


    Best 73's!

    Andrej - S57RW

    Was reading in the morning the docs published on the CEPT website from Ancara conference and I think IARU-R1 and DARC (as heard they were the most involved, but probably also others not to discriminate somebody) done a great job. The IARU view on the topic was written very professionally and the German regulator in their view used most of the facts from the IARU document. Probably apart the document there were many activities made by IARU. Finger crossed enough members will oppose to the French proposal. If understood well if we get 7 opposing the 2m band is safe for now.


    Just wanted to point out how important is to be a member of your national amateur radio union. By being you also support IARU and we can do something against such interests. Unfortunately I'm afraid in the future there will be more and more interest by commercial users for RF spectrum and our bands especially VHF and above are the most interesting being easy to take away if needed by commercial users. So far didn't happen here but in US they lost part of the 220 MHz band due interests from the USPS.


    Having our sociaieties we have some chance avoiding above from happen. It is like throwing bricks when you don't agree with something. If you throw them alone maybe you broke a window or two before the police arrest you. If an organization throws bricks is like "all their members" are throwing. Having many people trowing bricks is a different story and we have some power.


    I'm also interested what will come out for the 23cm story. In the agenda is mentioned there is no intention to take us the band away but I'm afraid about power limits, etc… There is an IARU response on that topic too.


    For quite the same reason have decided to become also an AMSAT-DL member. Since I like satellites it is how can give some small support to this activity. Probably without AMSAT organizations around we wouldn't have a single bird in space.



    Best 73's!

    Andrej - S57RW

    For LEO SATs I'm using a LPF on the 2m side with 2x FT817 and the arrow antenna. Simple to make. Got the schematic from the PA1IVO website:

    https://ivok.home.xs4all.nl/pa…able_satellite_setup.html


    Works great both in mode J and B with no noticable desense on RX part. 1st time when tried to work LEOs without the LPF had interferences in both modes when using the arrow and couldn't hear my transmission back at all.


    Never measured the response of the filter but PA1IVO claims should have -50dB on 70cm. Seems that for FT817 and 5W it provides enough attenuation. Probably by using more power and a pre-amp on RX this one wouldn't cut enough and the one Peter posted would be more suitable.


    73 de S57RW