Question on antenna and amp configurations

alanvw · EVDO Newbie Joined: 18 Aug 2007 Posts: 5

I’m looking for feedback on antennas placement, amps and cabling to improve my EVDO signal and voice signal.

- I am on Verizon which uses 800Mhz for voice and 1900Mhz EVDO in my area
- I do NOT have line of sight to my tower due to slight hills and trees; tower is about 4.5 miles away
- Inside signal strength is around -90
- Best outside strength is around -75 (at about 10’ up facing the direction of the tower)
- I’m currently using PC5750 with the Linksys router and getting consistent 500kb/s download speeds and 185Kb/s upload (just using the crappy Verizon external antenna and jack connected to the port on the 5750 card)

Questions:
What are some good options to increase my signal strength for both EVDO and voice? EVDO is highest priority but I would like to get better voice coverage while I’m at it.
A local electronics store has suggested that I go with the following:
- Wilson 801306 60 dB 1900MHz amplifier
- Wilson 301123 Dome Antenna
- Wilson 301124 Yagi 1800-1900 Mhz antenna
I’m not crazy about this recommendation because it seems like it will only improve the EVDO signal and do nothing to boot the voice. Also, if it is only for the EVDO than the dome antenna is a complete waste as I would be better served via a direct plug-in to the 5750 jack. Is my understanding correct on this?

If I go with an omni antenna, does it matter where it is mounted outside? The yagi has warnings about it not being pointed over the building. Also, would I use a similar amp as listed above with an omni or something different?
To reach the best signal outside, I would need a cable run of about 70’ feet where I keep the Linksys/5750.
Any recommendations or questions are welcome…I’m just learning about all of this but it seems like I already know more than the local shop who put together the items listed about.

CraigCraig · EVDO Heavy User Joined: 15 May 2007 Posts: 141

Have a look at http://3gstore.com/index.php?main_page=product_info&cPath=41&products_id=156 it's a dual band, bi-directional Wilson amp. I use it and am quite happy with it.

I can use the amp indoors with a plain old magnetic mount cell antenna (looks like an OnStar antenna on a magnetic mount) on a metal plate and boost a -90 db signal quite a lot. 98% of the time I use the amp and antenna in my car for use on the road but in those instances where a hotel/motel doesn't have a great signal it sure makes things much better.

For your setup check out 3GStore.com and give them a call they have great customer service, know what they're doing and will get you running.

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

because you are asking for signal improvement to two devices at same time, what you are likely to want is a "repeater".

problem with repeaters is that while they can do what you want (if you get a good one, AND set it up right), the compromise is that they are not going to provide as good a signal improvement as a 'direct connect' amp. (even wilson explains it this way)

essentially, a repeater is grabbing better signal using an external high gain antenna, and using an internal amp to recreate a clone of the tower wherever you are putting the inside antenna.

if not done properly, or if the signal of the true tower is strong enough, then something called 'oscillation' can occur, freaking out your device as it tries to figure out which signal to use.

for this reason, 3gstore has struggled with the decision to sell (and more importantly support) digital repeaters, even though a lot of our customers ask for simultaneous signal gain to evdo device and cell phone.

we prefer the superior signal gain of the 3watt direct connect amp that we do sell and support, and just suggest that if there is an adapter cable available for the customer's phone, that they switch the devices as needed.

alanvw · EVDO Newbie Joined: 18 Aug 2007 Posts: 5

Would it be possible to create a setup where I would use a dual-band amp with TWO outputs: a repeater to broadcast the 800MHz voice signal and a direct connect cable from the amp to the 5750 data card?

It seems like most of the high-powered amps are single band (800 or 1900 MHz) but the repeaters (internal antenna) come in both single or dual band. The amp you recommended is dual band but I dont know if the output signal can be split this way or not. Also, how does the amp you recommend compare to the 50 or 60db single channel amps? My hunch is that it can't support multiple devices (Wilson shows a somewhat similar model configured with an internal repeater - This is the "In-Building Wireless Dual-Band SOHO Cellular/PCS Amplifier 801245")

It looks like the only way to do what I want is to go with two internal amps and repeaters (one for each band with the 1900 MHz in a direct connect config).

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

alanvw · EVDO Newbie Joined: 18 Aug 2007 Posts: 5

That makes sense Alex. Thank you. Question: If I go with the direct connect 1900MHz amp, can I use that with either a Yagi or the Omni? Can a 75' run be used or would a pre-amp be needed with that much cable length?

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

i've heard of many who use the dual-band amp we sell with both omnis and yagis.

75ft isn't too great a run, so long as you have excellent signal at antenna (like -75 or better), use ultra low loss cable and as few connections as possible.

if you can get the amp closer to antenna and 'push' signal down the length of cable, it should be better than trying to 'pull' signal with the amp placed at end of cable run.