longer cable for Omni External Antenna: options or methods?

ianbtv

Hi -

Apologies if this is an old topic - my searches of previous forum threads did not reveal any concise information ...

I have a Kyocera KR1 on order from 3GStore to establish ICS in my home. Logic would dictate that I also employ a (Verizon USB720) Omni External Antenna. Some data:

- right now, just using 3GStore's magnetic mount antenna INSIDE (i.e., no ground plane), sitting on a 1st floor windowsill in the NW corner of our house, direct into my Verizon USB720 and laptop, I get 5 bars, consistent 1.2Mbps down, low latency, very few dropped packets, etc.

- I would prefer to set up the Kyocera router in the same room ... this presents the problems of:
(1.) ~30-40 feet of cable needed b/w USB720 and prospective external antenna (if running from 1st floor up to roof ridge)
(2.) even a 2nd floor location for the Kyocera router will require more cable length than provided with the Omni External antenna as shipped
(3.) would it be best to make my own extension coax cable? RG6 quad-shield for low-loss? What type of connectors (M-F set) do I need for the 'splice' b/w the antenna and the supplied antenna lead (i.e., the one included -w- the Omni antenna)? Do these connectors attach to the coax directly, or do I add regular coax connectors and use converters?

Or ... should I just keep using the magnetic mount antenna when I get my Kyocera ('it ain't broke ... don't fix it')?

Thanks in advance for your suggestions. Happy Holidays!

- Ian Campbell
Cambridge, VT USA

Alex · Site Admin Joined: 19 Sep 2006 Posts: 1945

Glint · EVDO Fledgling Joined: 27 Apr 2005 Posts: 25

I have a similar issue, but my Omni is already mounted outside via a 15’ extension cable. I live in a very hilly area, and every foot I raise my antenna seems to help. I’d like to mount my antenna on a different spot on my roof, about 10 feet higher than it is now. To do this I would need an additional 25 to 30 feet of cable. I’m guessing that the additional 10 feet will give me about a 5 dbm improvement. If I buy the correct cable from 3Gstore, will I see a net gain? I’m hovering right around -82 dbm now, and < -80 dbm seems to make a big difference.

Also, I have my Omni antenna mounted on a 10’ long piece of steel conduit, which is then bolted to the side of my lower roof line. I plan on doing the same, but on my upper roof line. In reading this thread, it sounds like I need to attach some kind of “ground plane” to my Omni. If I do need to use a ground plane, please point me to a faq or something so that I can make/install one for myself.

Thanks for your help!

xrayman · Posted: Wed Jan 09, 2008 3:29 pm Post subject:

Glint,
What Omni antenna do you have? Some have the ground plane built in. Does it look like the photo below with spikes protruding at right angles? If it does you don't need to add another one.

When you add cable to your antenna you will need to use low loss cable. I like the LMR600 cable because of the very low signal loss. It will cost a little more than LMR400 but I like to keep all the signal I can. If you use cheap cable like RG58 you will lose much of the signal gain of the antenna. You can use this link to check your cable loss. http://www.ocarc.ca/coax.htm

Glint · EVDO Fledgling Joined: 27 Apr 2005 Posts: 25

Thanks for your quick reply.

Yes, my Omni antenna does look like the one shown.

The 15’ cable I’m using now is LMR-195. If I replace that with ~50’ of the LMR600 cable do you think I’ll loose more than 1 or 2 dbm? If I do go with the LRM600, I’m hoping that the connectors are the same as the 15’ of LRM-195 cable I already have.

xrayman · Posted: Wed Jan 09, 2008 5:19 pm Post subject:

Glint · EVDO Fledgling Joined: 27 Apr 2005 Posts: 25

I’m thinking of getting 50-feet of 9913-Equivalent Ultra-Low-Loss Coaxial Cable from 3Gstore.com (http://3gstore.com/index.php?main_page=product_info&cPath=99&products_id=642). From what I can tell, this is equivalent to the LMR600 cable. Am I correct?

Thanks.

Glint · EVDO Fledgling Joined: 27 Apr 2005 Posts: 25

I called 3Gstore to order the 50’ of 9913 Equivalent Ultra-Low-Loss Coaxial Cable to replace my 15’ of LMR-195 extender cable for my Omni antenna. The person I spoke with told me that if I use a cable extension of >15’ that I would need to also use an amplifier. Is this true? I was under the impression that the –dBm loss of the 50’ of 9913 equivalent cable would be about the same as the 15’ of LRM-195 cable. I’m willing to spend an additional $100 to get the cable, but the cable + amplifier is closer to $400 and that is a bit too steep for a potential 5 to 10 gain of –dBm.

Thanks again.