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FPV advice needed on power supply + Antenna

Discussion in 'Racer Technical Discussions' started by moneyhunster, Nov 27, 2011.

  1. moneyhunster

    moneyhunster Member

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    Nov 8, 2011
    redruth, cornwall
    Posted by moneyhunster, Nov 27, 2011 #1
    Hi guys, im venturing out into the world of FPV with my WKM x650, i have a 600mw tx with kx sony camera, (cant remember which one) im powering the tx with an extra battery but im wondering if i should keep it on the same battery as the WKM FC as there is a failsafe on it. is this not advisable, should i keep 2 batteries on my quad?

    Also, i have a ImmersionRC DUO5800 5.8GHz Receiver with Diversity with clover leaf and skew antennas and one whip antenna, i have it installed in a back pack so i can explore with it but im getting quite a bit of interference, im flying outside my house and up and down the street at the moment just so i can get the hang of it, im guessing interference might be from the houses but it is still line of sight??

    I have a 5.8ghz 8db patch antenna which i want to use as the 2nd antenna on my receiver, replacing the whip antenna, should i raise the height of it more to keep it away from me? obviously i wont be blocking its path.

    Cheers
    Alan
     
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  2. Macsgrafs

    Macsgrafs Active Member

    Posted by Macsgrafs, Nov 27, 2011 #2
    5.8GHz is so high & with a small wavelength, the higher the better I would say as its a RLOS device (Radio Line Of Sight)..in other words if one antenna loses sight of the other..there goes your link. You could always sit behind the antenna & make sure you keep in front when flying!

    Ross
     
  3. ovdt

    ovdt Member

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    May 23, 2011
    Posted by ovdt, Nov 27, 2011 #3
    I have 5.8 GHz 200mw FPV system. With high gain antenna, I can reach maximum 1 km range. No more. It's one of the HobbyKing cheapest solutions. And it should be at line of sight. For better range, 1.2GHz or even 900 MHz solutions are recommended.

    I always use a second battery, 2-cell 1300 mAh small battery. It doesn't add to the weight. Higher gain antenna is usually more directional, output power of tx is more important than the antenna.
     
  4. Macsgrafs

    Macsgrafs Active Member

    Posted by Macsgrafs, Nov 28, 2011 #4
    wrong! Let's explain why. a 1Kw transmitter (1000watts) pumping its power into 6" of damp string will get you no where. But 1w of RF power into a high gain antenna will get you further than the 6" of damp string. When I was taking my radio ham exam back in 1993 an old ham mate proved a point to me. He made all his own transmitters but had a wonderful antenna system, he coinnected my Yaesu FT890 (100W) to a vertical antenna, tuned it in with my auto tuner & fired up on 21MHz CW. Then during the chat he was having with someone in Argentina, he switched the antenna over to his high gain 5 element HF beam & the received signal was 2 S points higher...both ways!!!

    Ross
     
    Last edited by a moderator: Nov 28, 2011
  5. Jake Bullit

    Jake Bullit Fly,crash,glue,repeat!

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    Posted by Jake Bullit, Nov 28, 2011 #5
    Thought it would be more than 2 s points gain with a 5 ele over a vert.Depends whether the argie was vertical I suppose.

    73 (G0KHG) retired.
     
  6. Macsgrafs

    Macsgrafs Active Member

    Posted by Macsgrafs, Nov 28, 2011 #6
    Retired G0...that's 2 of us G0TXK ;)

    Ross
     
  7. gadgetkeith

    gadgetkeith likes gadgets

    Posted by gadgetkeith, Nov 28, 2011 #7
    wow 1kw though 6" wet string

    bet you could fry an egg on them output transistors

    wait you prob wont even get the egg out the box before they popped

    sorry just couldnt resist that

    keith
     
  8. moneyhunster

    moneyhunster Member

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    Nov 8, 2011
    redruth, cornwall
    Posted by moneyhunster, Nov 28, 2011 #8
    would i be better situated if i could sit higher than i was planning to fly?
     
  9. moneyhunster

    moneyhunster Member

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    Nov 8, 2011
    redruth, cornwall
    Posted by moneyhunster, Nov 28, 2011 #9
    before it sounds to daft, carn brea castle is almost 800 ft above sea level and i can see line of sight for 10 or more miles in all directions.
     
  10. Macsgrafs

    Macsgrafs Active Member

    Posted by Macsgrafs, Nov 28, 2011 #10
    No...because most antennas radiate with an upwards angle & if your above the aircraft you wont have the same distance as if your below it..hence why at distance most FPV'ers fly higher. If your near water as stated, then your signal might be pulled down a bit due to the large groundplane effect of the water.
    Alan can I ask where did you get your 5.8GHZ patch antenna? There was some wild claims by one firm & when someone opened it up...well lets just say a 1/4 whip would have given better results!

    Ross
     
    Last edited by a moderator: Nov 28, 2011
  11. Macsgrafs

    Macsgrafs Active Member

    Posted by Macsgrafs, Nov 28, 2011 #11
    It's a good one though ;)
    But it conjures up a picture in the minds eye to make it easier on all concerned...namely simple little me ;)

    Ross
     
  12. Tahoe Ed

    Tahoe Ed Active Member

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    Sep 14, 2011
    Posted by Tahoe Ed, Nov 28, 2011 #12
  13. Macsgrafs

    Macsgrafs Active Member

    Posted by Macsgrafs, Nov 28, 2011 #13
    Ed, Alex does seem to know what he's talking about from reading the different topics over at RCG, you could easily make one of these yourself, Alex shows you how to in a step by step guide. But if you want to buy ready made then go for it. Have you seen the FPV videos on youtube? Search for these antennas on youtube, see the results people are getting!

    Ross
     
  14. rwilabee

    rwilabee Member

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    Oct 15, 2011
    Palm Springs, CA USA
    Posted by rwilabee, Nov 28, 2011 #14
    Can you provide some pics of how you layed out your gear. I have an x650 and was thinking of doing the same thing.

    Rich

     
  15. moneyhunster

    moneyhunster Member

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    Nov 8, 2011
    redruth, cornwall
    Posted by moneyhunster, Nov 29, 2011 #15
    View attachment 1662
    My Portable video rx gear, holding recorder, battery, receiver and headplay goggles

    View attachment 1660
    Side view of my layout, put antenna facing down after goeff at Quadcopters.co.uk pointed out in a crash it would likely snap off!

    View attachment 1661
    Small camera mounted above the battery holding plate on sponge tape, works pretty well really, had 3 sucessfull FPV flights now, 2 of which were at night using the street lights. ive got a WKM FC and i gotta say its perfect fror FPV!
     

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