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What range will we get with rx and tx but no antenna? (433MHz)

Discussion in 'Radio and Communications' started by Flyback, Jul 17, 2015.

  1. dr pepper

    dr pepper Well-Known Member

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    Hi gramps,
    The mrs found out.
    She wants a greenhouse watering system, with wifi and net control.
    Good job I have some esp8266 serial to wifi converters, once I've sussed them looks like I'll be doing that.
     
  2. Tony Stewart

    Tony Stewart Well-Known Member Most Helpful Member

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    From my experience building patch antenna radios in ISM band at 928MHz and trimming the antenna over a pcb ground plane 4x the area, was that a crappy piece of wire worked just as well broadside to an SA with antenna. Most antenna have a deadspot from diversity/directionality, even patch antenna, but with obscure ground planes ( like a hydro power meter) you gain a bit on dead bands while losing a bit on the peaks. A pure isotropic antenna is impossible ( Unity gain in every direction)

    WiFi antenna are notorious for deadspots and Rician Fading but only the better designs use a dual antenna with a diversity switch ( take stronger of two signal if errors)
     
  3. granddad

    granddad Active Member

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    Hi doc. wifi ? afraid I'm not that clever o_O my 433Mhz design still in trial mode, but the pic24 standalone version has done the job well , the wet end of the system is a 12v bilge pump dropped into a big poly water drum (~10gals) feed can be added when required, pump is attached to a copper pipe wiv holes in ! ( you may need an anti syphon device ) I did not go down the soil moisture sensor road, just a regular soaking , and really good drainage works . humidity and ventilation is worth monitoring . nice project for the winter....that seems to have started here already...
     
  4. dave

    Dave New Member

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  5. dr pepper

    dr pepper Well-Known Member

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    The esp8266 isnt all that compilocated, allthough I've been faffing about to get it working.
    I think its sensible not having moisture sensors, you'd need a load to make readings meaningfull, the caravan pump sounds a good idea, I have 2 55gal water butts a few meters away, I alsohave a load of brake pipe left over from fixing my old shed, so that might be handy too.
    DHT11's are good for temp & humidity, the good thing with the esp wifi device is that the thing speak website allows you to upload data and they will graph it out for you over time, for minimal effort and no cost.
     

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