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mr. pips

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About mr. pips

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  1. With the Linx mounted on a new pcb I did a range test. Again an 8,2 cm wire antenna was attached with no ground plane to mention. Now range is at least 1500 meter!!!!!(close to the ground) At that distance my video connection was too bad. Strong stuff... I like to make a patch antenna and see what distance can be reached. Thomas, you use a brass front side for your improved patch. Do I need to repeat also that material? My plan is to solder the patch directly to the pcb, no sma connectors. For 868mhz the distance between the plates will be about 10mm. Would it be wise to use a piece of 50 ohm coax to connect the upper plate? (and still those harmonics! I am afraid to ask!) Thanks, Rienk
  2. Some time ago I got the Linx..... In the mean time I changed my plan and decided to add the linx to a ready made product. Plantraco makes a nice 4 ch RX witch happens to handle 10 gram servo's very well. Also they have a so called monolith TX witch plugs in the trainer port of a Futaba Tx. The monolith has an IA4221 chip with a kind of open loop antenna. The datasheed however gives an output network (page 28 as I remember) for a singel ended dipole antenna So first I did changed the antenna to see if it works. And it does. It is rather strange but range appeared to be twice as far! (now it is about 500 mtr) after the modification. Now I have some questions... Again an output network: also "tons of harmonics and noise"? ...This output network seems to be less complicated and promised to have some self tuning abilety at least for those loop antenna's. Only special RF components were used in the modification. Anyone (Thomas?) can give me a prediction? Can I just connect the Linx to this antenna system without adding components in between? What can I change to the PCB design, where should the microstrip start? Rienk
  3. Thanks Thomas, also from me! Finally my Linx BBA is on it's way !(for a normal price ) So first I like to see results from that Linx... And be back here for more advice form you guys.... Rienk
  4. Thanks, That's a nice rooster! I'm intending to use it for an uplink. That's why it's the other way around. So I'm waiting now for a price from Linx themselves... Rienk
  5. Sorry pushed wrong button. What is depressing me At Digi-Key: one Linx bba-519-A $15 S&H to Europe $37 Tax(aboutimpossibletoavoid) $10 TOTAL $62 Can you beleve that?!?! I did email some other shops (they not have it in their catalog) to get it for a 'normal' price. Waiting for their reply now... Rienk
  6. Thanks Mr Rc-cam' That looks very good to me. What would be range.... 868 MHz/18 dbm/50 mW/(improved) goof proof TX antenna/small dipole rxantenna.... And now the things what put me down :
  7. Thanks, Kilrah. Now that makes me really stop this project But still I'm desperatly looking for an amplifier. I did some more searching on the web, but didn't find something usefull... Can anyone help me with a name? Thomas, are you still there? Rienk
  8. Thanks guys! With your comments I'm about giving up on this project! Yeh, really thank you. Too bad because this Maxim is intresting. Kilrah: I forgot about polluting other bands, stupid! Do you expect the non correct placement of a single capacitor in the output line to give a lot of pollution? Thomas: can you give more info on those smarter devices for gaining up? Old man: Kilrah did explain exactly what I was aiming at.. Rienk
  9. Thomas, Thanks for your interest. The formula you mentioned did blow my brain and calculator because the many zero's. Now your questions... no no no no no no 1 dbm I was hoping, even with a bad design, from the potential 30 dbm of this chip, a 6dbm would be a realistic result. Please don't tell me I will end up with 0.1 dbm! I like to have a 10km range with a recalculated goof proof tx antenna. But for another application a 2km range would also be nice. I like smart stuff, Can you give me a clue? Thanks, Rienk
  10. Thanks! I will follow your advice. Meanwhile I did find a dummies calculator for at least calculating the impedance of a given L//C. It proofed you are more than right. With that L//C combination the imp -AT-868 is even 3 times bigger than @ 915! So when the components are coming I'm ready to make a lot of mistakes.. When it will be not a complete failure, I will post some results here. Rienk
  11. Help! For a Maxim 2235 amplifier output end, I like to make a L//C parallel resonance 'harmonic trap'... For high impedance @ 915 MHz Maxim give a 10 nH/3.3pF combination as a good design. Now I like to make such thing for 868 MHz. Can someone help me to find a nice combination or knows the formula to calculate it? I did try to find it on the net but I really don't understand noting about that hocus pocus. Thanks, Rienk
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