Sprint 4G rooftop antenna?

[tappan.david]

I am considering getting a Sprint Overdrive 4g Mobile Hotspot, and using it in my house for my Internet connection. I am about 1.5 miles from a road with good 4G coverage. Can I use a rooftop antenna to get signal at my house? If so, what kind would work best with the Overdrive?

[thuor]

The problem is that since the overdrive doesnt have an external antenna port we haven't found a passive coupler that works reliably to couple the external (roofmount antenna) with the internal integrated antennas.

[JWM]

Sprint WIMAX coverage from 6 miles out of range?

We are moving to a new home in a rural area soon, which is about 5-6 miles away from the nearest edge of Sprint's current 4G WIMAX coverage. There is existing 3G coverage, but that's about it for internet connection options besides the expensive & data capped Hughes Net Satellite internet service.

So I am researching if I can possible tap into the Sprint WIMAX coverage by using an external antenna setup. Here is what I came up so far (I don't know if this will work or not).

Equipment needed:
1) Sierra (Sprint) Wireless AirCard 250U Mobile Broadband Modem with Dual External SMK TS-9 Antenna Connectors for Sprint WIMAX

2) Sierra Wireless Sprint 250U 3G / 4G USB Modem External Antenna Adapter Cable - FME-M (Fits Sierra Wireless Models: Sierra Wireless Sprint 250U 3G / 4G USB Modem, CLEAR 4G+ USB (Series S) Modem)

3) 20-feet RG-58 Low-Loss Coaxial Cable (N-Male/ FME-Female) Note: 4 dBi attenuation

4) Coax lightning Arrestor, Gas discharge DC-6GHz. Includes N Jack (Female) to N Jack (Female) Bulkhead Connector. (optional equipment, and this might not be the right one)

5) External Directional Grid Antenna: 24dBi gain. 2.3 GHz - 2.7 GHz frequency range applicable for WiFi (802.11b/g/n) and WiMax applications.
Input impedance: (Ω) 50
Cable/ Connector: 10" RG-58U w/ N-Female

PLUS: - any Cradlepoint 4G (WIMAX) compatible router with USB input
- Antenna Mount

Could this configuration work?

I am also still searching for a line amplifier to make up for the 4 dBi loss from the 20-feet RG-58 cable.

[thuor]

Yes exactly you have everything you would need.

Unfortunately i hate to be the bearer of bad news but these antennas (and indeed any antennas) will simply not work if you are 5 miles away from reliable coverage. These antennas primary function is to overcome indoor coverage issues for people who have a pretty good outdoor signal but a very poor indoor signal. They are not really intended for signal amplification although you do get some boost-effect for marginal signals.

The reason is pretty simple actually. If you consider our most popular 16dBi panel antenna or even the 24dBi parabolic grid antenna you referenced above, then add a 20ft low loss LMR400 cable which has an attenuation of 6.9dB/100ft at 2600MHz or about 1.4dB for a 20ft run, you see your effective gain is about 22dB. (RG-58 not really recommended at this frequency but it may be used with the 4dBi attenuation you correctly noted).

On the other hand assume that at the edge of coverage you have a pretty strong -70dBm signal. RF propagation in free space attenuates as inverse of the square of the distance. so if you even assumed a rural environment with a decent path loss exponent (and even ignore multipath propagation effects, multiuser interference, reflections, obstructions etc) your path loss in a 5 mile range would be well above 100dB so even a 20dB boost doesn't do much good.

Now for 3G you can easily add cellular band bi-directional amplifiers/repeaters with high gain directional outdoor antennas similar to: http://www.rfwel.com/support/tech-dr...wwan_rev2a.pdf or http://www.rfwel.com/support/tech-dr...wan_800mhz.pdf but these don't exist for 4G wimax.

[tappan.david]

What about if I am within 300 feet of good coverage?

The Clear coverage map for my house shows that I am within a few hundred feet of 4G coverage. Would an external antenna setup work for me? Could I use the Sierra Aircard 250u or the Motorola USBw 100 or the Ubee PXU 1900? I would put the external antenna in my attic or in an enclosure on the roof.

[thuor]

Very likely but it is very difficult to say precisely. Coverage maps are never very accurate and RF propagation is quite unpredictable. There are often coverage holes not shown in the maps. Best way to know for sure is to get a WiMax device and during the trial period measure what the received signal strength is at the location where you would mount an outdoor antenna. You would be looking for the RSSI (Received Signal strength indication) and CINR (carrier to interference plus noise ratio) on the diagnostic page of the communication software that comes with the USB modem. If these are good outdoors and poor indoors then you are definitely a good candidate for these antennas.

Recommend the Sierra 250U or the PXU1900 since these have external antenna ports. The Gemtek WIXB-175 (Series G) modem also has external antenna posts on the PCB but this requires opening up the case and, goes without saying, voiding the warranty.

Preferably the external antenna should be outdoors and you would run a low loss coaxial cable to the modem. For example: http://www.rfwel.com/support/tech-dr...ENERIC_USB.pdf

[erenner]

Spint 4G Roof top antenna

I checked out the connection from my roof and was able to get connected. I am in a fringe area. Didn't have the specific settings values for RSSI or CINR but chanced it anyway. I put up my directional antenna and ran and LMR400 cable 50ft and hooked up to sierra wireless 250u. I see the network and from the sprint smartview software at least am able to attempt the connection, but it goes into a long authentication process and ultimately fails.

The signal strength is 49% -66 dBm
CINR is 9 dB

I have no idea what good values should be. If someone could comment I would appreciate it. I am hoping I can improve this so that I can get connected.

I was wondering about the sierra wireless statement below

>>>
"If you use an existing “single antenna” accessory, it will only improve CDMA and GPS performance. WiMax performance will be degraded on the primary path, and the secondary path will remain internal to the device. Be aware that Sierra Wireless has not certified these antenna accessories to work with the AirCard 250U and cannot recommend their use.

How are the two external antenna ports used?

The AirCard 250U now has two external antenna ports, each with an SMK TS-9 connector. The lower primary port is for CDMA, GPS, and WiMax. The upper port is WiMax only. The antenna connector housing is designed to ensure that the new blade antenna will be correctly orientated when connected.
<<<

I am plugged into the SMK TS-9 on the lower port (WiMax Only). I assume sierra is talking about a single CDMA antenna plugged into the port that would degrade performance on 4G and that I should not have any degradation in performance as I am using a WiMax antenna and am plugged into the lower port.

Also is there anything I could do to increase the transmission power of the 250u? I don't think any repeaters or amplifiers exist yet, but am not sure. also saw some power settings in the smartview software and was curious if that might be an avenue to improve my transmission power.

Any suggestions or comments welcome...thank you

[thuor]

The signal strength is 49% -66 dBm
CINR is 9 dB

The RSSI is pretty good and in fact would not necessarily recommend adding antennas to improve it beyond this. The CINR could be better but I have personally seen very exceptional results with worse RSSI/CINR. I would get in touch with Clear to see what's going on on the network side since it might not be an RF issue at all at this point.

"If you use an existing “single antenna” accessory, it will only improve CDMA and GPS performance. WiMax performance will be degraded on the primary path, and the secondary path will remain internal to the device.

This is specifically talking about adding a cellular/GPS antenna on the primary ANT#1 port. Sprint 3G EVDO uses 1900MHz PCS frequency and GPS L1 band is at 1575.42 MHz. Of course if you added an antenna which doesn't cover the WiMax 2500-2700 MHz band then WiMax performance would be degraded. Since you do have a WiMax antenna then this is not the case. However if you are using the popular 16dBi 2.5-2.7GHz directional panel antenna or any other antenna that doesn't cover frequencies below 2.5GHz then you will degrade the GPS and 3G CDMA performance. We do have a cellular/wimax wideband log-periodic dipole array antenna (LPDA) that covers both 1.9GHz and 2.5-2.7GHz should you need both 3G/4G. The gain is only 8dBi though so consider that in your link budget analysis.

I can attest from first hand experience though that these directional panels definitely improve the 4G WiMax performance.

Also is there anything I could do to increase the transmission power of the 250u? I don't think any repeaters or amplifiers exist yet, but am not sure. also saw some power settings in the smartview software and was curious if that might be an avenue to improve my transmission power.

No there are no amplifiers/repeaters yet and you cannot improve transmit power.

Not sure if you have ran into these but if not please take a look at these two articles I wrote that cover what you are dealing with:

1. How/When Can External WiMax Antennas Actually Degrade Performance instead of Improving It?
   Specifically look at item #6 which explains an experiment on how to determine if you need a 2nd antenna.
2. WiMax Antenna Primer - Using One External Antenna vs Two Antennas

[JoeB]

Question for external antenna for Sprint 4G with 250U data

I have just purchased but not received yet the Sprint 250U data USB card (will receive 12-13-10) and will more than likely need an external antenna of some sort. The 4G went up last week at the nearest tower which is about .5 mile to the north. I have the EVO phone and can receive a good 4G signal outdoors but goes marginal to no signal indoors. Obviously, I will be able to tell more once I receive the card but want to do a little homework ahead of time. Can you recommend a few antennas that I should be checking out and what I will need for the connections to the 250U? Thanks, Joe

[thuor]

Here is the most common setup: http://www.rfwel.com/support/tech-dr...ENERIC_USB.pdf.

For a single outdoor antenna the most popular antenna is the 16dBi panel antenna. Which can be configured from this kit: http://www.rfwel.com/shop/4G-USB-Mod...tenna-Kit.html

Also check out the article on when to decide between one vs two external antennas. Ideally if your budget allows you should install two outdoor antennas then you wouldn't need to worry about whether you are getting the best performance that you can since the sierra 250u is actually designed for use with two external antennas.

If for some reason you would also want to boost the 3G side of the Sierra 250U check out this article: http://www.rfwel.com/forums/content....r-WiMax-Modems (usually wouldn't need to do this if you can get 4G working reliably in a fixed location).

[sweetjoe777]

is there now an antenna or any other device available that can boost a low 4g signal indoors in an area that should have 4g coverage. I'm in an urban section of South Florida with -84 dbm and 11 cnir but only getting 20% signal strength and very long pings and slow dl times.

[sweetjoe777]

hi i recently bought an overdrive device from sprint hoping to replace slow dsl. So far the speeds im getting according to speedtest are not much faster then dsl have slower pings and are nowhere near as reliable. currently i have very low signal strength 20% -84dbm and a cinr ranging from 9-12. Is there currently an antenna or any other device that could boost my signal strength and improve performance because otherwise I'm going to have to stick to DSl. Also i live in a second floor apartment with nothigna bove me but i have no access to the roof just a balcony and I love in an urban South Florida area that is supposed to be under 4g coverage. Any help and advice would be greatly apreciated.

[NickDBLG]

No still no amplifiers/repeaters for WiMax. Rule-of-thumb is still that if you can't get a decent signal within 10's of feet from outdoor location where you would mount an external antenna then you are likely out of luck.

If you can pick up a decent signal outdoors then the external outdoor antenna kits here: http://www.rfwel.com/shop/4G-USB-Mod...tenna-Kit.html will almost always work for you (especially for modems with external antenna ports which excludes the overdrive).

[mraroid]

WiMax repeater updates

Hi...

I have been reading this thread because I am looking around for a WiMax repeater (for my Sprint HTC EVO phone).

I have read that Sprint/Clearwire installed WiMax repeaters in many radio shack stores because of the roll out of the Sprint HTC EVO 4G. You can google it. However I have been unable to find the make and model number of this repeater. How can we get this information?

I found another item that was just rolled out by Sprint. It is this:

http://www.gottabemobile.com/2011/01/04/sprints-novatel-mifi-3g4g-hotspot-goes-official/

It looks like a 4G repeater. Is this true? Maybe I could take it apart and somehow wire in a connector(s) for a roof mount antenna(s)?

When I am in my backyard or front yard, my 4G reception is "fair". It is "poor" in side my house. If I walk down the street, it turns to good, then to excellent So I do have a signal at my house to work with.

Any new developments for a 4G repeater? Why is this stuff not on the market? 3G repeaters fall out of the sky like raindrops. Why is it that it is *so hard* to find a WiMax repeater? Isn't this stuff "off the shelf" technology?

Any help or suggestions welcome.

Thanks

jack

Portland Oregon

[mraroid]

WiMax repeater for 4G cell phone?

No still no amplifiers/repeaters for WiMax. Rule-of-thumb is still that if you can't get a decent signal within 10's of feet from outdoor location where you would mount an external antenna then you are likely out of luck.

If you can pick up a decent signal outdoors then the external outdoor antenna kits here: http://www.rfwel.com/shop/4G-USB-Mod...tenna-Kit.html will almost always work for you (especially for modems with external antenna ports which excludes the overdrive).

This looks *almost* exactically what I am looking for, but not quite. I have a Sprint htc evo 4G phone. Outside, in my yard, I get "fair" reception accourding to my phone. Indoors, I get "poor". The Sprint map says I am in the best area for 4G.

So I do have a signal to work with. The above kit loooks close, but not quite. Any solutions for me?

jack
Portland Oregon