Posts by PA1EW

    Hi again Nicolas,


    Looking closely at your picture it seems that your LNB skew-angle is not correct!. It should be about -30 degr for Madrid and I estimate that your LNB skew is close to 0 degrees?. When you compare with my LNB set to abt.-15 degrees than yours would have to be turned a bit more into the same direction. This would explain the small signals....!


    73 Ed

    EA4GQY Hi Nicolas,

    Thanks for posting the pictures. Your situation for adjusting the dish and/or LNB clearly is not very easy!.


    I am just thinking about another HAM having receive problems some time ago, but was using his dish with the (adjustable) LNB-arm not in the correct position = fully downward. Did you check this on your dish, otherwise the LNB will be not in the focal point....


    73 and stay safe!

    Ed

    Hi Werner,


    Die rechts polarisation RHCP stimmt fuer deine Helix. Luft-isolation ist besser statt das PVC Traegerrohr. Siehe dass 1e Bild unten.

    Du wirst sicher 10W oder mehr benoetigen mit diese art Helix ohne Spiegel...


    Mit Spiegel ist der Gewinn viel hoeher und dan kann der (5,25 wind) Helix so gemacht werden wie meine im Bild 2.

    Viel Erfolg!


    73 Ed PA1EW

    PA3GUO Dag Henk, to my surprise the difference between the "bare" LNB in the upper picture and the patch/LNB/rocket-lens combination in the lower picture, was close to zero!. I checked the QO-100 beacon SNR via SDRuno (SDRPlay RSP2pro) on both systems with short interval and found very much the same SNR (there is always a kind of QSB...).

    I probably was lucky to find at first try the optimum focal point position for the patch/lens, so you might have to play with this as mentioned by others as well.


    Note: I used two identical LNB units in this test. Both are unmodified (just one having the 22mm hole in the front cap) and from a batch of six pieces they all had very close SNR performance.

    As a general remark on the 22mm hole drilling: try to keep it centered very well to get the patch-waveguide tube inserted centered with the LNB waveguide. With the drilled hole offset, the LNB will be mounted at an angle, looking at least ugly...


    73 Ed

    PA3GUO Hello Henk, my test setup shown here is certainly not new and shown by others as well. It is VERY easy to construct by drilling a 22mm hole in to the plastic LNB cap and sliding in the waveguide tube. My quick NB test last year showed in comparison a more or less equal SNR performance between the LNB placed in the 70cm wide Triax78 dish feedpoint and the combination LNB - Patch antenna with Venton rocketlens. The lens is just taped quickly to the patch for the test.

    The LNB's used are Megasat Diavolo Twin PLL 25MHz that work very well for me. Highly stable without modification and perfect NB reception using SDR-Console with Beacon-Lock.


    73 Ed


    I suggest to use the "number-system" instead of split-mode. This should reduce the number of simultaneous calls a bit...


    "Only stations with 1 in the callsign, please...."


    73 Ed

    Hello PA1EW,

    i am also build a portable station with 60cm Dish.

    IF all will work, i hope i am qrv at the end of Novemebr from EA7 near Cadiz IM66VO,

    See also ur Camper Car. If i am ready there i will post a picture on qrz.com

    vy 73 Klaus

    DL2FP Hi Klaus, looking forward to work you from your camper holiday location near Cadiz.

    Wishing you good operations with your portable setup, it is real fun!.


    73 Ed PA1EW

    Hi, what size did you make the reflector in mm? and relative distances

    73 of iw5bsf Roberto

    iw5bsf Hi Roberto, the helix + Octagon LNB reflector dimensions are 120mm wide - 150mm height. The aluminum sheet I used is 1,5mm but 2mm would be fine as well. The LNB opening in the lower part is 58mm in diameter, this diameter is for Octagon OTLSO model. The LNB hole is at 10mm from the bottom of the reflector.

    The 5,25 turns helix, with 43mm diameter, is positioned just above the LNB (should have been in the middle, but mine came a bit offset to the side). You can see the construction in the pictures below. Also visible here is that the focal point can be adjusted at the same time for both helix and LNB.. The LNB skew rotation can be adjusted easily as well.


    P.s. I found that using a non-metallic (Teflon/Nylon) centre-support inside the helix provides less attenuation to the LNB signal.


    Good luck en see you on QO-100!.


    73 Ed PA1EW

    As a precaution with Bias-T option: do not exceed the maximum allowed RF power that the device can handle safely!. A few Watts from the driver transceiver will damage the common receive types of bias-T. Otherwise, this is very good solution for remote control over longer distances.


    73 Ed

    hb9iiu Hello Daniel, I am using a Kuhne Up-converter for QO-100 as well and use a simple two-wire cable from the "TUN/LIN" connector on the transceiver, in my case a FT991A (this is ACC-conn on FT817, etc) . This cable provides a ground connection during TX, just as required for the Up-converter.

    This type of cable can be ordered here TechnoFix and just needs to be attached to the Kuhne-cable (White/Brown wires). Good luck!


    73 Ed PA1EW


    i2NDT Hi Claudio, I should have mentioned that the drawing is not mine, but info by PA1AIS. So, just passing info that seems relevant, I have found on the web.
    I would suggest using two (small value) capacitors for each signal & ground connection, blocking DC and low freq interference. The ground connection in the Pluto outputs will be isolated in this way. When others have a better suggestion, please let us know!

    My Pluto has arrived and needs to be set up in a portable system that I have planned.


    73 Ed

    Hi Frank, a very welcome to this forum and congrats on succesfully setting up your QO-100 station.


    Just a thought on your question: Maybe there is interference from the USB-cable between Pluto and PC/laptop?. A ferrite will improve this.

    Simon Brown has a note on this subject...


    73 Ed PA1EW

    DL5CN Hi Andreas, perhaps you already know, but there is also an empty component-space below the circulator-hole. I expect this is where you want to solder a good 50 ohm load needed at the circulator 3rd pin.


    73 Ed PA1EW

    Zhaofeng, it is a PDF-document that I can provide to you via e-mail. I have to find a way to put it online somehow...

    I will first add some more information about the the helix-type you are building.


    73 s Ed


    BG0AUB My updated document is sent by e-mail to you

    From your pictures it seems that the carbon-fibre support is not in the centre of the helix. When not connected to the reflector, this may be the reason for the heating.

    You do not have to be afraid that an aluminum support in the centre of the helix will heat-up!


    Good luck with your experiments!


    73 2 Ed PA1EW

    BG0AUB Hello Zhaofeng, the use of a conductive support, diameter < 0.1 wavelenght, INSIDE a helix is perfectly OK!. SWR may change a little bit, but will be good. The helix construction shown by G4SDG on the 1st picture in the other thread "DIY Helix for 2.4 GHz uplink . Can I use 5mm copper tubing?" is a very good example how to do it, in my opinion. See also the examples and explanation from G8AWB in the same thread.

    You can use 10mm x 10mm square aluminum support tube which is light and strong.

    Use only a few (nylon/teflon) vertical supports, exactly as seen in that picture and do not use any other support fixing the helix wires. This is to avoid degradation of the beam pattern.

    I have written a "How-To-Construct a helix" document with a lot of practical information, that I can provide to you (and any other interested)!.


    You probably know that this type of helix has less gain than a small offset dish with a small helix- or patch feed. My 1.0m wide offset dish with dualband helix/LNB-feed is putting out a very nice signal to QO-100 , but smaller dishes working equally good.


    73 s Ed PA1EW