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Thread: USB Dongle vs. SBS-1/1er

  1. #11
    Captain fungus's Avatar
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    The only thing you need to consider there is the different sizes of the cables. RG58 (which I've used in the past but wont any longer) is much, much smaller than LMR400 which is about the size of your thumb and cant be bent easily into tight places. But it is excellent for our purpose I understand. Another alternative is LMR195 which is very similar in size to RG58, has less loss but has more loss than LMR400. Depends entirely on length of cable run etc as to which will do the job.

    Gregg
    Last edited by fungus; 2013-07-01 at 08:11.

  2. #12
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    Quote Originally Posted by Responder View Post
    Hi Peter and Oblivian,

    Peter - I've been looking at the Collinear setup you described and it looks great but like you say, using the 2mtr plastic overflow pipe from Wickes and the wind we get, it wouldn't be long before it gets broken due to the flexing.

    I think my best bet, is to clamp together 4 or 5 sections of 27mm alu piping creating 16-20ft mast with a decent antenna on top and low loss cable and bracketing it to the back wall of my house with an earthing strap and try and get it above the roof.

    Oblivian - Do you think the Radar-Rama is a suitable antenna for the USB dongle providing (as you suggest) you use a good quality coax?

    Regards,
    Maybe it will flex and break - but then I've not spent much money on the receiver or the antenna (I had the mast and brackets in the shed) - this is all experimental and I take it lightly.

    I'd try the collinear for the time (and money) it takes to put together - just to see the performance - to stabilise it, try a more rigid tube and/or put some outriggers at the top if the mast to attach stays to (stays to support the collinear, not the mast). The outriggers could be something as simple as three shelf bracket type things (but nicer looking) with thick nylon cord (non-metallic so no effect on signal - like strimmer line) to the antenna.

    Maybe I should do a drawing.

    To reduce cable lengths - it would be quite possible for me to run the PI over POE (Ethernet only uses two pairs out of the 4 in a CAT5 cable), put the PI + Dongle is a sealed box and fix the whole thing to the mast. some may suggest that there would be a volt drop on the cable - but that can be avoided by getting a 12/24v to 5V 3A step down power converter from Ebay (£2.99) and putting that in the box too.
    Last edited by peterhr; 2013-07-01 at 12:53.

  3. #13
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    Oblivian: Didn't realise LMR400 was so thick and there's me going to put one end into a BNC lol. I might look at LMR195 as I think that's what they used on my SkyHD Satellite cable. What I have in mind in constructing and locating, I think I'll only need 15mtrs.

    Peter: Came up with an idea at work today. Instead of using alu piping. I'll use 2"x1" Treated Timber and buy 2 lengths of 4.9mtrs and bolt them together. That would give me virtical strength, wind loading, drilling to anchor to external wall and able to use cable clips to run the cable up. I'll get the timber tomorrow and I'll do a dummy construction over the weekend using one of my dongles and 15mtrs of Active USB cable, just to see if I can get above roof and test out radius. If all good, then I'll buy some decent cable as suggested by Oblivian and a decent antenna. If not as good as I thought, I haven't wasted money on expensive cable and antenna :-)

  4. #14
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    Pigtails. N-type connectors and step-down tails on the ends you need smaller. There they use sheilded RG58 to give you flexability. You keep the thick stuff straight, and use a 50cm length of RG58 on the tail to work with. There are also direct connectors for them.

  5. #15
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    Thanks Oblivian,
    I've just sent an email to a company here asking for a quote for 15mtrs of 195 with N-Type and BNC attached. I think the loss would be about 6dB at that length. Far less than RG58 anyway but obviously not as good as 400.

    I wouldn't be able to use 400, as I need to curve it at 90degrees to come thru an open window, which would remain open 24/7 365 lol

  6. #16
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    Quote Originally Posted by Responder View Post
    Thanks Oblivian,
    I've just sent an email to a company here asking for a quote for 15mtrs of 195 with N-Type and BNC attached. I think the loss would be about 6dB at that length. Far less than RG58 anyway but obviously not as good as 400.

    I wouldn't be able to use 400, as I need to curve it at 90degrees to come thru an open window, which would remain open 24/7 365 lol
    What I did with the LMR195 to keep it as short as possible (and intended initially) was to bring it down through an internal wall above my computer desk directly under the antenna mounted on the ridge capping of the roof on a 20ft mast (installed by professionals with a 1090SJ antenna sitting at the top). I got an old TV antenna wallplate (the name and type of which I cant remember now) removed the centre pin of the connector, reemed out the plastic to suit the cable and ran it straight to my basestation (no connections at all at the wallplate, just straight through it) sitting atop the desk. That saved me about 6-7 metres of antenna cable run (and extra connections) to an external wall/ wallplate. The amp is up at the mast but the injector I've split from it and mounted at the basestation as it doesnt need to be at the amplifier and it's pretty close to it in any case. I've hidden that wallplate, injector and cable behind a 10" X 8" picture of my mum and dad's wedding. All you can see on top of the desk is the basestation flashing away to itself. I deliberately chose the top of the desk to avoid the noggins (the horizontal timbers in an internal wall about half way down) as well as to keep the cable to it shorter. If I hadnt told the missus, she never would have known it was there (btw i did get her nod of approval afterwards). It sure works a treat compared to my old discone antenna with the RG58 cable. Like you are doing, I got the professionals to make up the cable from the antenna down to the amplifier ('N' type and BNC) on the mast and had them put a BNC on one end of the cable so I could run it from the amp down to the basestation so I only had one BNC connection to make up myself. Hope you dont have to leave your window open and no you cant have my mum and dad's pic.

    Forgot to mention I also tape all external connections with weatherproofing rubber tape to seal them against the weather and to help prevent deterioration of the connection.

    Regards,
    Gregg
    Last edited by fungus; 2013-07-02 at 09:00.

  7. #17
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    Fungus,

    Sound quite complicated. Can you post a few pictures of the setup ? A picture replaces a thousand word.
    F-WSSS1 - Cats refused to Pee & Pooh on RadarBox - Running a FR24 Receiver & DVB-T Dongle 24/7 to piss off The Chief Thief.

  8. #18
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    Quote Originally Posted by Birdie View Post
    Fungus,

    Sound quite complicated. Can you post a few pictures of the setup ? A picture replaces a thousand word.
    You want pictures of my family room or the missus? And you cant have my mum and dad's wedding photo either
    Seriously Birdie, it's really very, very simple if you break it down into sections. Some even choose to mount the basestation (or other receiver type) in the roof cavity or externally closer to the antenna. A great idea to limit losses but it's just my preference to see mine and it gets exceedingly hot in the roof spaces here in the aussie summer.

    Regards,
    Gregg
    Last edited by fungus; 2013-07-02 at 09:04.

  9. #19
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    Quote Originally Posted by fungus View Post
    You want pictures of my family room or the missus? And you cant have my mum and dad's wedding photo either Seriously Birdie, it's really very, very simple if you break it down into sections.

    Regards,
    Gregg
    Don't show your missus or parents pictures or family room details - Privacy Respected. Temporary remove the wedding photo.

    Take pictures of the relevant parts. Please don't forget the antenna part.
    Last edited by Birdie; 2013-07-02 at 02:35.
    F-WSSS1 - Cats refused to Pee & Pooh on RadarBox - Running a FR24 Receiver & DVB-T Dongle 24/7 to piss off The Chief Thief.

  10. #20
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    I was just pulling your leg Birdie (an aussie way of saying I was sharing a joke with you), I'll see what I can do for you
    BTW it wasnt a slur on you Birdie when I said it's really simple- it needs to be for me to be able to do it and I apologise if it's difficult to follow.
    Regards,
    Gregg
    Last edited by fungus; 2013-07-02 at 03:54.

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