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CQ all Prop headed radio amateurs — Parallax Forums

CQ all Prop headed radio amateurs

w4fejw4fej Posts: 264
edited 2010-09-13 08:58 in Propeller 1
Has anyone used the Propeller in a close proximity to 430 Mhz RF field? My original Submarine project using the BS2P40 had the transciever mounted right to the back of the control enclosure.

This version using the Prop will have both the antenna and the transciever itself mounted on a 6-8' pole, away from the control unit with just an RS232 connection to the control unit. The Prop and all the control components are mounted in a plastic enclosure. The radio itself is not one of the little jobs Parallax sells or an Xbee, this is a full blown, comericial, data radio capable of 50 milliwatts to 5 full watts in 256 steps.

Any thoughts on RFI?? I'd also be interested in hearing about your experiencies in your ham radio applications.

73 and thanks for reading

Mike B. - W4FEJ ex: W6FFC, K7FQ, WA6URR, WV6URR

Comments

  • LeonLeon Posts: 7,620
    edited 2010-09-12 11:17
    If you get problems they will most likely come from the supply cable or RS-232 lead, if they just happen to be the wrong length and act as antennas. You might need to use filters. Checking with an HT might be useful, if you don't have the radio yet.

    At a radio club I once belonged to we used to set off the PIR unit at a house 50 yards away when we transmitted on 2m, and all the security lights came on. The owner kept complaining about it, but wouldn't let us investigate the problem.
  • w4fejw4fej Posts: 264
    edited 2010-09-12 11:25
    Wow, Dx on my first try! lol.. Yea, I'll probably try ferrite beads or something like that to keep the RF out of the box. I won't be using the full 5 watts unless the link gets flakey.

    The radio on both ends has a signal available that is relative signal strength. the PLAN is to establish some level and if the signal approaches this level then both sides will (automatically) bump up the power until the link is firm again and if it can't be re-established then the Prop in the sub will initiate an emergency "blow" to get it back on the blue side of the sky. (I hope!)

    Also, the radio is 16 channel also capable of being changed in software. If a non submarine signal (or carrier) is detected then a pre-arranged frequency change scheme will take place. Again, if unable to re-establish comms then "Thar she blows!".

    Mike B.
  • LukeHLukeH Posts: 22
    edited 2010-09-12 11:27
    What kind of radio are you using? I've been considering buying an Argent FC-301 for my radio+prop experiments, let us know how it goes.
  • w4fejw4fej Posts: 264
    edited 2010-09-12 11:48
    The radio is a "GLB GL400X11bb1" The web site used to be "glb.com" but that is now a swimming pool company!

    I bought two of them on Ebay years ago for $100 for the both of them. They are pretty small measuring about 3"X5"x1.5". there are no user controls on the box at all, 100% software controlled. If I recall correctly they talk up to 9600 baud over the air. Have to look that up tp be sure. Nice, sturdy metal enclosure. Light weight..

    Mike B.
  • sylvie369sylvie369 Posts: 1,622
    edited 2010-09-12 11:51
    w4fej wrote: »
    Has anyone used the Propeller in a close proximity to 430 Mhz RF field?

    Just with XBees, at 60 mW, about 1.25" separation. No problem.

    Paul
    KC9KST
  • w4fejw4fej Posts: 264
    edited 2010-09-12 13:14
    Ok Paul and thanks. I don't forsee a problem even at 5 watts. We will see. Been on the other computer fine tuning the front panel graphics. Going to try a Tee shirt transfer paper by Avery and see how that works on aluminum.

    If the attachment worked here is the preliminary layout of the front panel.

    MIke B.
    Submarine.jpg
    800 x 395 - 35K
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2010-09-13 01:25
    @ Leon

    PIRs at 50 yards? Thats nothing. Whilst I was in BBC Transmitter group we paralleled up two 250 KW HF sets, and banged it into an exprimental tri-band array. About 50 yards the other side of the perimeter was an old cottage, which we wanted to buy for demolition but VOA wouldn't stump up. The poor bloke that was in it came rushing out, yelling about sparks a yard long coming out of the light fittings, sockets .... Good old days.

    I recently tried the I & Q radio object on the Prop but got nowhere. Unsurprisingly it seemed to pick up its own internals. The interferance would be in the form of clusters centred about harmonics of the clocking frequencies. In the case of the Demoboard that would probably be 80MHz but I suspect that the 5MHz xtal frequency would kick up some dust too. A different Xtal bight shift those clusters up or down a bit so that the wanted frequency was left in a quieter zone. A screened box with filtered io/outs would help.
  • w4fejw4fej Posts: 264
    edited 2010-09-13 04:06
    LukeH wrote: »
    What kind of radio are you using? I've been considering buying an Argent FC-301 for my radio+prop experiments, let us know how it goes.

    Hi Luke. Well I just looked up that Argent radio you mentioned. It looks exactly like the radio I have under the Name "GLB". Amazing. The programming software looks identical as well! I think these guys started designing their stuff with a clean sheet of paper.....carbon paper!!

    I also looked at some of their other goodies and the OpenTracker looked like a TinyTrak4 knock off.. (Bet Byron isn't too happay about THAT!)

    If the FC-301 works as well as the radios I have they should make you very happy.

    Mike B.
  • sylvie369sylvie369 Posts: 1,622
    edited 2010-09-13 06:02
    w4fej wrote: »
    I also looked at some of their other goodies and the OpenTracker looked like a TinyTrak4 knock off.. (Bet Byron isn't too happay about THAT!)

    I'm not dead certain, but I'm pretty sure that the OpenTracker+ predates the TT4. I have both, and I do remember buying the OT+ in part because it had some features the TT3 didn't have.

    Both Byron and the Argent guy seem to be doing a nice job of supplying hobbyists - my older brother W9WI bought some Argent GPS and Arduino/AX.25 stuff at Dayton that he was really pleased with.

    That reminds me that the original Big Red Bee GPS transmitter uses a reasonably powerful transmitter right next to a PIC. I know that's not really the same as the question about a Prop, but you can look in the BRB GPS documentation at the board layout and maybe get some useful information (or maybe it would just be useful for us newbies - I have no idea).
  • LukeHLukeH Posts: 22
    edited 2010-09-13 06:54
    Thanks Mike. I'll probably pick up a couple of those then when I get a chance. They make the VHF version with an integrated tracker/tnc; wish they did the same for the UHF version.

    Somewhat related, anyone had good results using a prop to bit-bang AX.25 through a KISS TNC?

    -Luke AC0AV
  • NR1XNR1X Posts: 111
    edited 2010-09-13 08:20
    My breadborded prop was vy unhappy when I started sending CW on 20 meters (14MHz) at about 500w.. Then again it was only about a foot away from the amplifier. Im not sure it was so much the Propeller itself. Seemed more like the powersupply as it would power off and on but the program and eeprom data were untouched.
    NR1X Al CT
  • kf4ixmkf4ixm Posts: 529
    edited 2010-09-13 08:58
    w4fej wrote: »
    I also looked at some of their other goodies and the OpenTracker looked like a TinyTrak4 knock off.. (Bet Byron isn't too happay about THAT!)
    Mike B.

    I've also used the OpenTracker with great results. as stated above, i chose it over the tt because of features.

    Looks like a great project, keep us updated on your progress!

    73's
    de kf4ixm
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