Boosting Cellular Reception: A Challenging Process Of Product Selection And Installation
by Brian Dipert, March 22, 2011
Speaking of AT&T cellular service…as regular readers may recall, I’ve long relied on amplifiers-and-rebroadcasters,
femtocells and other schemes to maximize the cellular signal strength at the various residences I’ve inhabited over the years. Back when I was a T-Mobile subscriber, Spotwave’s Z1900 wasn’t
consistently or substantially effective in Sacramento but
seemingly did the trick in Truckee, at least
for a while (why it quit working is still not clear to me).
After
switching to AT&T last summer, I revisited Spotwave’s website and realized that the Z1900 would no longer work for me. For one thing, its 1900 Mhz-only frequency focus meant that it wouldn’t amplify the 850 MHz band signals coming from Verizon’s cell towers (Verizon being my work mobile account provider), although the native reception at my location was sufficiently strong that boosting wasn’t strictly necessary:
More ominous, note the yellow exclamation point next to the green check box in the AT&T entry. Clicking on the ‘View full spectrum details’ link brought up a page which informed me that AT&T was also harnessing 850 Mhz band cellular service in my region (the carrier leverages the
1900 MHz PCS band in some other areas), therefore making the Z1900 incompatible with both of my mobile providers:
Fortunately, I still had the Wi-Ex zBoost YX510-PCS-CEL in my possession, which had
worked passably in the San Diego area. A dual-band device, it comprehended both AT&T and Verizon (not to mention Sprint and T-Mobile), and it’s handled amplification with aplomb in the roughly nine months I’ve used it here.
The zBoost YX510-PCS-CEL took care of the primary residence, but what about the garage next door?
As I’ve mentioned before, above it is a studio living space. Since it’s higher than the main (lower) floor of the house, I’d initially hoped that incrementally improved reception would preclude me needing to put a cellular booster there. But one too many dropped AT&T calls eventually prompted me to discard that delusion.
I could have outfitted it with an array of cellular provider-specific femtocells, but that workaround felt like overkill, especially since (as already mentioned) my
Verizon one is reception-unnecessary (and
doesn’t support data traffic anyway), and since
AT&T hasn’t seen fit to ship me a freebie. Instead, I dove into the garage and pulled out a
Wilson Electronics Desktop DT which I’d been remiss in evaluating:
Here are a few other (longer and more detailed) videos for particularly interested readers’ perusal:
The below image is of the booster module:
which the outside antenna (receiving signals originating at cellular
providers’ base stations) and inside antenna (rebroadcasting an
amplified version of that signal throughout the residence) connect to:
As the two-above booster image shows, the original version of the DT
Desktop came with an inside antenna that direct-connected to the
booster. However, the packaging and documentation for my particular unit
both indicated that a ‘free antenna upgrade’, shown both in the
conceptual layout above and on the left in the product shot below (with
the outside antenna on the right, and the booster in-between), was ‘now
included’:
Ironically, that antenna upgrade may have been the root cause of at least some the installation issues I experienced, which to be clear aren’t DT Desktop- or even Wilson Electronics-specific; my past Spotwave and Wi-Ex experiences had similar qualifiers and challenges. Realize that whereas the outside antenna is supposed to pick up AT&T, Sprint, T-Mobile and Verizon’s signals, it can instead incorrectly tune in the signal coming from the same-system inside antenna if insufficient spacing exists between the two of them.
To wit, Wilson Electronics recommends that the outside and inside antennas be at least twelve vertical feet from each other if they’re pointing in opposite directions. Else, depending on their relative elements’ orientations, they need to be between 20 and 50 horizontal feet from each other. In my particular case, at least for the moment, I have the ‘outside’ antenna (housed within its mounting bracket) suction cup-mounted to the inside of a south-facing window, approximately 10 feet above the floor. The inside antenna is sitting on a desk at the opposing wall, 24 feet away and 3 feet above the floor.
This separation is the maximum allowable by the studio’s dimensions save my actually installing the outside antenna outside (which would necessitate running coax cable through the wall), yet I still receive yellow-LED indications that the booster is automatically decreasing its amplification by between 4-8 dB in order to eliminate signal oscillation caused by outside-to-inside antenna interference. More accurately, I should say that I usually receive such indications…sometimes it seems to work fine at full strength for many hours at a time.
I can also get a ‘green light’ at the booster (indicating full amplification), for example, if I reorient the internal antenna’s front face away from the backside of its outside antenna counterpart. The latter ’solution’ is impractical in practice due to the internal antenna’s highly directional transmit pattern coupled with my desire for its rebroadcast to fill the room. Similar boosting-improvement results (temporarily) occur if I put my hand on the internal antenna or simply place myself between it and the outside antenna. As
Apple also learned with the iPhone 4 antenna design, a water-rich human body acts as an effective signal attenuator.
So far, initial indications suggest that the DT Desktop is working as designed, although the comparative (booster on-vs-off) signal strength measurements delivered by my Motorola Droid (Verizon) and Google Nexus One (AT&T) are inconsistent…in part because they also depend on how I grip the handset and hold it to my head (there’s that water-rich human body attenuation effect, again). But the comparative dearth of dropped calls versus prior to the install is a telling sign, in a positive direction. I’ll keep experimenting with the DT Desktop, including potentially relocating the outside antenna to an interior wall (versus the window) or…err…outside. Stay tuned for more reports here at Brian’s Brain.