Search results

  1. flippineck

    rf transparency of plastic

    I am trying to cook up a simple collinear antenna for 1800 MHz and one for 800 MHz. I'm following plans which involve bending coils into copper wire and then enclosing the copper wire inside a length of white pvc electrician's conduit. the plans are for 2.4GHz though. they regard the pvc...
  2. flippineck

    Oxygen machine back up power

    sorry, did a few edits which you probably missed You might get away with an 85Ah battery but for the small extra price I'd get a 100Ah or even 110Ah. Regards the fuse, I'm with Arouse1973
  3. flippineck

    Oxygen machine back up power

    From the manual for "XPO2 Portable Concentrator" http://www.invacare.com/doc_files/1148112.pdf: AC Power Supply: 100-240 VAC 50/60 Hertz DC Power Supply: 11-16 VDC Rated current input: 1.0 amps at 120 VAC 3.3 amps at 18 VDC this is for XPO100B it seems to say the step-up converter takes...
  4. flippineck

    Horticultural led's

    at all, in a All I can remember from reading up about this subject (in relation to fishtank illumination where I was trying to encourage plant growth) is that in general plants are green because they absorb all wavelengths apart from green, which they reflect. So, stay away from green LEDs and...
  5. flippineck

    audio transformer

    When I was a kid I used to make audio oscillators with small transformers like this. I had a Radio Shack (Tandy) 10-in-1 project kit, and with a small speaker, a resistor and a ceramic capacitor, and a 2SB56 transistor, it made a little beeper :) I wish I could remember the circuit diagram. I...
  6. flippineck

    Antenna design again

    I thought I had a great idea involving arduinos and multiple yagis then I read about something called WiBE (Wireless Broadband Enabler).. seems it's already been done http://www.deltenna.com/products/wibe.aspx 4 antennas arranged at 90 degrees to each other covering all 4 points of the compass...
  7. flippineck

    Antenna design again

    I was wondering about that. Maybe if it 'locked on' to a good mast with a decent signal it wouldn't swap around from tower to tower? I did try standing in an upstairs room with the yagi on a broom pole, slowly rotating it through all points of the compass for a good long while.. never 'found'...
  8. flippineck

    Antenna design again

    I've given up with my yagi for my 2100MHz mobile phone / internet unit. Firstly, it seems that the tower I have it pointed at, probably isn't in use anymore :o The UK Ofcom database of cellphone masts appears to be horrendously out of date. I tried installing an app on my smartphone...
  9. flippineck

    Homebrew passive antenna coupler

    hmm pin 4, yes I will look into that :) ok looking at the plug on the end of the wall transformer that came with the phone, - it's 5 pin - it has the USB symbol stamped into the plastic housing of the plug - label says "sony model ec450" - googling it, it does look very much like micro...
  10. flippineck

    Homebrew passive antenna coupler

    Hiya Thanks for the link. I'm still looking for any sign of a connector on the phone (maybe one of the pins in the power lead is for an antenna?) but no joy so far. The generic patch antenna connector is generally a flattish, squarish sticky thing which does not match up well to the antenna...
  11. flippineck

    Homebrew passive antenna coupler

    Hi Olivier thanks for responding. I'm in the UK and I use 'Three': http://blog.three.co.uk/2011/11/25/spectrum-2/ This is why I'm under belief my 3G phone will be using the 2100MHz frequency. It's a Sony Xperia E model C1505. I couldn't find an exact document for my phone but I...
  12. flippineck

    Homebrew passive antenna coupler

    I have a Sony Xperia phone. As far as I know it works on the 2100MHz band, and the antenna is housed in the bottom part of the phone, widthwise along the base. There's no jack on the phone for an external antenna, but I'd like to try connecting one. I've come across 'passive coupler'...
  13. flippineck

    Limiting car audio volume

    if the amp is expecting to see 8 ohm speakers and claims an RMS max output of 500 watts get 16 ohm speakers capable of handling 250 watts RMS, and wire 16 ohm resistors (or near equivalent) capable of dissipating 250 watts across their terminals making, the amp split it's output equally...
  14. flippineck

    Yagi-Uda antenna 2100MHz

    the 2.5M LMR195 cable from the yagi is terminated with two identical male SMA connectors. pin to pin shows very low DC resistance as does connector body to connector body. Haven't done a megger test across the dielectric but a basic continuity test shows open circuit between pin and connector...
  15. flippineck

    Yagi-Uda antenna 2100MHz

    So, should I try to get some of the LMR-400 you speak of? Would that fit into the same SMA connectors as I bought for the RG58? What makes LMR-400 a good choice? Was wondering.. the yagi has a short length of the RG58 coax which is soldered to the driven element inside the connector box, with...
  16. flippineck

    Yagi-Uda antenna 2100MHz

    Right by the yagi, smartphone on same network, 3 bars out of 4 :confused:
  17. flippineck

    Yagi-Uda antenna 2100MHz

    Approx 2 Metres, maybe 2.5 Flicking between 1 & 2 bars this morning.
  18. flippineck

    Yagi-Uda antenna 2100MHz

    Well I'm only *assuming* that it's RG58. It seems to fit the descriptions I've read online for RG58, it fits the RG58 SMA connectors I've bought nicely, and it came as a 10 Metre length attached to the 2100MHz yagi. There's nothing printed on the cable itself though, it's just plain black. I...
  19. flippineck

    Yagi-Uda antenna 2100MHz

    Have now bolted up the yagi properly. Very little improvement, still only 1 bar :( well, it's useable but I was hoping for better. Perhaps I need a signal amplifier or something? Will have a look at bi-quads. I figure this antenna must transmit as well as receive, so thinking back to my 27MHz...
  20. flippineck

    Question About Relays

    I didn't know contactors had replaceable contacts.. that's pretty neat :-)
Top