Wednesday, February 20, 2019

Moto 5G MOD comes at a cost measured in mW

Late last week, Motorola's Mobile 5G MOD (model number MD1005G, FCC ID IHDT56XL1) made its requisite appearance in the FCC OET database.  Part of the Moto Z series of modular attachments, the 5G MOD -- yes, repeatedly presented in all CAPS in the FCC OET filing, though we shall see if that sticks in the commercial branding -- is intended specifically as a 5G NR and LTE attachment for the VZW variant Moto Z3 (model variant XT1929-17, FCC ID IHDT56XJ1).  And the FCC OET authorization release likely is in advance of Mobile World Congress at the end of this month in Barcelona, when and where the 5G MOD may make its official debut before going on sale to the public.

While the retail price of the 5G MOD does not appear to have leaked yet, and maybe VZW will subsidize some of the cost, the device does not project to be inexpensive.  The parts list alone is significant, as the 5G MOD packs inside its own Snapdragon 855 chipset with X24 LTE modem, standalone X50 5G modem, multiple antenna arrays, and 2000 mAh battery.  Call the 5G MOD what it truly is -- a separate, cutting edge handset without a screen.

Of greater interest to this blog, however, is the potential effect on LTE RF performance that may come with the 5G MOD.  When the 5G MOD is attached, the Moto Z3 continues to rely upon its Snapdragon 835 with X16 LTE modem for any VoLTE or CDMA2000 voice duties.  But for cellular data, the X16 LTE modem goes idle, and LTE data handling gets passed over to the X24 LTE modem and RF signal path in the 5G MOD.  That means where 5G NR is not available, the Moto Z3 no longer dictates its own LTE RF performance.  Instead, the 5G MOD fallback LTE takes over.

Around Labor Day last year, I wrote a blog piece analyzing the Moto Z3 Play RF performance.  The focus was on the Moto Z3 Play, but the article also included the obvious comparison to the VZW exclusive Moto Z3.  In that spirit, let us extend another logical comparison -- Moto Z3 LTE both without and with the 5G MOD attached.

For level comparison purposes, I have reconfigured and reproduced first my last September graph of the Moto Z3 maximum uplink EIRP across its included LTE bands.  To this graph and others, standard boilerplate language applies.  All data has been gathered from publicly available authorization filings submitted to the FCC OET.  RF lab tests report maximum uplink transmission, not downlink reception.  Good baselines for maximum EIRP and antenna gain are 200 mW and 0 dBi, respectively.  And in the case of low band ERP figures, I have converted those manually to EIRP.


To add a few more facts and figures about Moto Z3 lab tested LTE performance, it hits conducted power targets of ~23.5 dBm and has antenna gain that ranges from 0 dBi for mid band to -1.8 dBi for low band.  That adds up to max uplink EIRP at ~200 mW for mid band, ~130 mW for low band.  On paper, that is average to good LTE RF performance.

To begin the comparison with the 5G MOD, start with LTE antenna gain.  Perhaps to accommodate the four 5G NR mmWave antenna arrays, the LTE antenna gain has suffered in the transition to the 5G MOD.  Note that on the Moto Z3, the maximum LTE antenna gain never falls below -2 dBi; on the 5G MOD, it never rises above -2 dBi.


That roughly 3-6 dB reduction in antenna gain is responsible for a substantial decline in EIRP across the board, maxing out at ~120 mW for mid band and ~40 mW for low band.  Conducted power figures are ~24 dBm, so on par with those of the Moto Z3 alone.  What that means is the 5G MOD is not making up for diminished antenna gain with inflated conducted power.  And that shows in the somewhat poor EIRP.


The takeaway is that the Moto Z3 with 5G MOD attached probably will experience some degradation in raw LTE performance and may struggle to maintain LTE connectivity in some challenging situations in which the Moto Z3 alone is fine.  Whether Motorola has engineered in a secondary fallback under those circumstances that idles the 5G MOD and shunts all LTE connectivity back to the Moto Z3 remains to be seen.

The Motorola Mobile 5G MOD has separate FCC OET authorization filings for its band 48 LTE and band n261 5G NR lab testing -- because those bands fall under different parts of the Title 47 CFR.  Maybe we will take a look at those high band and mmWave RF specs in a future article.

Source: FCC OET

Wednesday, November 7, 2018

OnePlus 6T shows its pluses, minuses in FCC RF tests

The OnePlus 6T (variant A6013, FCC ID 2ABZ2-A6013) had its authorization documents uploaded to the FCC OET database early last week in conjunction with the OnePlus launch event in New York.  Typically, I would not run analyses of lab tested RF and write blog posts about mobile handsets that are intended for sale primarily outside of the US.  In fact, such devices and variants, while almost always FCC authorized for use in the US, often are not RF optimized for domestic LTE bands -- but I digress, as that is the intended subject of a future article.

Back to the OnePlus 6T, though, it presents something of a paradigm shift.  Not only is T-Mobile selling the One Plus 6T directly but also VZW has certified it as an LTE only device for use on its network.  That really puts the OnePlus 6T on similar footing to that of the Pixel 3/XL.  So, in light of those developments, let us take a look at its certified RF testing lab report submitted to the FCC OET.

First, a quick rundown of a few gigabit LTE capabilities drawn from the FCC filings and the OnePlus 6T tech specs page:
  • Downlink 5x CA, uplink 2x CA
  • Downlink 256-QAM, uplink 64-QAM
  • Downlink 4x4 MIMO (operational bands undisclosed, likely limited to mid and high band)
Also, because many who read my iPhone XS/Max articles (1, 2, 3) had difficulty understanding my graphs and accepting my factual analyses, let me reiterate some of my standard boilerplate:
RF power figures below represent best averaged and rounded estimates of maximum uplink EIRP test results provided to the FCC OET in individual device authorization filings.  Or in the case of ERP low band test measurements submitted in the filings, that ERP has been converted manually to EIRP for level comparison purposes.  Caveats about lab testing versus real world capability and uplink transmission versus downlink reception always apply.
Uplink transmission, folks, not downlink reception.  Uplink transmission.

Now, on to the graphs...



Radiated power figures for the OnePlus 6T look okay, nothing great, nothing terrible.  The pluses are the mid band figures, which do reach or exceed 200 mW.  The low band figures are not exactly minuses, as most do closely approach 200 mW.  And due to low band antenna efficiency, we just do not see low band output above 200 mW that often.

The biggest minus here would be the high band EIRP.  Because of high band path loss and antenna efficiency characteristics, we would prefer to see high band radiated power above 200 mW.  Furthermore, the OnePlus 6T does not indicate support for HPUE on band 41 or otherwise.  Honestly, though, that minus may be rendered irrelevant for use in the US.  Bands 7 and 38 are not deployed here.  Band 41 effectively is a Sprint exclusive, and the OnePlus 6T shows no signs of being added to Sprint's device whitelist.  Lastly, band 30 always will be power constrained, since it must limit adjacent channel interference with nearby satellite radio operations.

As a sidenote, I also have included uplink 2x CA figures in this graph.  The gist is that EIRP does not increase with uplink CA but remains basically the same.  Each uplink carrier is reduced in power by 3 dB (50 percent) to maintain the same total EIRP across both combined uplink carriers (half power × double bandwidth = equivalent total power).  As I like to point out, uplink CA does not come without a cost.  And uplink CA may not be operational near cell edge, where uplink radiated power will be most stressed.

I have not included a conducted power graph.  Just be aware that conducted power targets for all tested bands fall within 23-24 dBm -- the only exception is band 71 at a slightly greater 24.5 dBm.  The takeaway is that the OnePlus 6T appears to be using primarily 24 dBm as its conducted power target.  That is well within the +/-2 dB margin of the 23 dBm standard for Power Class 3.  And while conducted power is slightly elevated, it is not excessively so.  As we will see next, the OnePlus 6T offers decent antenna gain, mitigating power loss, such that conducted power can remain in the 23-24 dBm range.


Technically, this main antenna gain graph is a composite of two antennas.  The OnePlus 6T does not support simultaneous transmission, but it does contain multiple antennas.  Antennas 1 and 2 both cover low and mid band, while antenna 3 does so for high band.  Thus, the graph above is a combination of antenna 1 below 2 GHz and antenna 3 above 2 GHz, since each of those two antennas is the primary or highest gain antenna for its respective bands.  To conclude, antenna gain across the board is negative, albeit minimally so, and that contributes to fairly consistent radiated power output -- with a few pluses and minuses along the way.

Source: FCC OET

Thursday, September 27, 2018

iPhone XR trades 4x4 MIMO for greater antenna gain and higher EIRP

iPhone XR (model A1984, FCC ID BCG-E3220A) made a somewhat surprising early appearance in the FCC OET database this morning, since the phone will not be available yet for another month.  Typically, iOS devices have their authorization filings posted right before the devices go up for sale to the public.

Upon examining the certified lab tested RF data and crunching some numbers, what is immediately apparent is that the iPhone XR has -- as expected -- dropped the 4x4 MIMO antenna design from the iPhone XS and XS Max in favor of a standard 2x2 MIMO antenna.  This tradeoff of fewer antennas and MIMO channels, though, ostensibly has allowed for greater antenna gain and, concomitantly, higher radiated output power compared to those same metrics on the iPhone XS and XS Max.

Further analysis may be forthcoming, but for now, the graphs of the iPhone XR EIRP and antenna gain largely can speak for themselves.



For graphs and analysis of iPhone XS and XS Max lab tested figures, see my previous articles (1, 2, 3).

Source: FCC OET

Tuesday, September 25, 2018

Antennagate 2018: "You're getting my findings wrong"

Two weeks ago, I dug into the FCC OET authorization filing documents for the iPhone XS and XS Max the afternoon that they were made public, and I started to review and extract data on the certified lab tested RF performance of both forthcoming handsets.  This is something that I have done for dozens of devices over the last decade.  Some of the 2018 iPhone RF measurements struck me as comparably and unexpectedly low, worthy of some graphical and contextual analysis that might be of interest to a few hundred readers.  I did not expect another so called antennagate to emerge, nor for tens of thousands of average viewers to take note of what is a fairly technical topic.  And because my work (1, 2) has drawn an audience well outside its intended scope, I feel a need to editorialize a bit.

Correlation does not equal causation.  My goal long has been to present findings, raise questions, and posit possible explanations/solutions.  My goal has not been to assert that iPhone XS and XS Max low gain antenna designs are the exclusive or even partial causes of all the wireless signal ills that some new users are experiencing.  The correlation exists, but the cause(s) remain(s) undetermined.

Unfortunately -- though I do not think nefariously -- some forum posters and media outlets have run with my findings, questions, and explanations/solutions to form distorted or at least simplified conclusions that say something to the effect of the new 4x4 MIMO antenna array is to blame, the Intel baseband modem is not to blame, the Intel baseband is indirectly responsible due to design compromises that would not have been made for a Qualcomm baseband, etc.

In the interest of clarity, let us find some solid bedrock on which to stand.

What can be said definitively is the iPhone XS and XS Max exhibit lab tested RF performance for antenna gain and radiated power output (EIRP) that almost invariably measures lower than the same metrics on 2017 iPhone variants and other recent, comparable handsets.  A visual recap...



Additionally -- as I already have stated -- the Intel baseband categorically is not the source for conducted power output, radiated power output, or antenna gain.
...Apple's decision to forgo Qualcomm this year and source all cellular modems from Intel is not responsible for the RF power output limitations in the new iPhone models.  The cellular baseband modem is separate from and well upstream of the amplifiers that generate the conducted power and antennas that generate the radiated power being measured in lab testing.
Those two findings are demonstrable facts.

To follow up the latter of the two facts, I posted this on Twitter last night, though if you have been following just my blog pieces, you may have missed it.

The two 2017 iPhone X variants -- with Qualcomm baseband and with Intel baseband -- perform almost identically in RF testing submitted in their FCC authorization filings.  And I do mean almost identically, right down to the decimal place -- this speaks well to Apple's precision tolerances in design and manufacturing.  The lone deviations between the two variants are on bands 41 and 66, and only band 41 presents a difference worth discussing.  The maximum antenna gains across all bands are exactly the same for both Qualcomm and Intel variants, but for unknown reasons, the Qualcomm variant puts out 50 mW greater conducted power on band 41, hence also 50 mW greater EIRP on band 41.  That is absolutely it for the raw RF output differences.  Any other cellular performance differences likely can be attributed to the Qualcomm baseband versus the Intel baseband.  That controversy is well known.

2017 iPhone X with Qualcomm MDM9655 Snapdragon X16 LTE baseband:


2017 iPhone X with Intel XMM 7480 baseband:


So, a takeaway here is that Apple designed and manufactured the two 2017 iPhone X variants effectively the same -- just plopped a Qualcomm modem in one, an Intel modem in the other.  Now, definitely not a fact but informed conjecture, Apple ostensibly would have done likewise this year if there had been a Qualcomm variant.  In other words, a hypothetical iPhone XS or XS Max with Qualcomm baseband probably would have followed precedent with the same antenna array, thus the same radiated power levels as that of the current Intel model.  Take that for what you will.

To return to my soapbox for a time, many end users posting their experiences with signal bars and speed tests are not helping, actually are muddying the waters further.  Regarding signal bars and speed tests this is what I previously wrote:
...signal bars are just a coarse approximation of signal availability/quality and can be calibrated to almost any arbitrary standard. 
Comparing speed tests also is not very useful for gauging weak signal performance.  Unless a speed test fails or produces very slow speeds due to exceedingly marginal signal conditions, devices with 4x4 MIMO reception -- such as iPhone XS and XS Max -- likely will exhibit higher download speed test results under most good to normal signal conditions.
To expand on the above advisement, iPhone XS and XS Max possess capabilities -- aforementioned 4x4 MIMO reception, additional low band (bands 14 and 71), LAA (band 46), and downlink carrier aggregation combinations -- that are not available on previous iPhone models.  Some may argue that those are RF improvements, but again, they are capabilities or features that are not at parity with those of iPhone predecessors.

Greater signal bars, for example, could reflect signal strength on a new low band, thus presenting the illusion that the new phone has better reception than the old phone.  In actuality, the new phone might have worse reception than the old phone if both were on the same band.  The new low band could be thought of as a band aid -- pun intended -- that masks some of the RF deficiencies of the new phone.

Much the same, a faster speed test on a new phone, for example, could be the result of additional MIMO spatial channels or carrier aggregation SCCs that are not possible on the old phone.  Meanwhile, the old phone with measurably superior RF performance might provide faster speeds on a per spatial channel or per carrier basis.

That said, I get it.  To those who want to try to assure themselves that their new iPhones can meet their everyday needs and do not care whether that is accomplished through raw RF strength or new network capabilities, fine, okay.  Check signal bars and run speed tests.  Just understand that signal bars and speed tests -- absent thorough additional documentation from Field Test -- are not replacements for objective measurements. 

Source: FCC OET

Monday, September 24, 2018

Antennagate reduXS? If so, what can Apple and iPhone users do about it?

About 10 days ago, shortly after the Apple announcement event, I published an article that analyzed iPhone XS and XS Max RF performance as revealed in lab test measurements in the devices' FCC OET authorization filings.  Some of the lab test data raised potential red flags regarding the new iPhones' RF reception and transmission abilities in low signal strength conditions.  My analysis in that article concluded with...
...iPhone EIRP in the lab has not always been so compromised as it appears to be this year.  Real world RF performance comparisons when some users switch from the iPhone X and 8 generation to the iPhone XS generation, no doubt, will be interesting.
Well, over the weekend, more and more early adopters started getting their hands on their brand new iPhones, posting their real world impressions online.  While opinions on RF performance have varied from high praise to utter disillusionment, some anecdotal user reports and empirical signal comparisons at MacRumors forums and in more than one Reddit thread have been notable because they appear to corroborate how the aforementioned lab test results submitted to the FCC might extrapolate to less than stellar real world performance.

In many ways, this harkens back to iPhone 4 antennagate in 2010.  Without rehashing all of the details, iPhone 4 users just by holding the handset could bridge together unintentionally two antennas on the edge of the phone, thereby accidentally detuning both antennas and significantly degrading RF performance.  In response to the issue, Steve Jobs famously was misquoted as saying to users about the phone, "You're holding it wrong," which since has become a blame redirection meme unto itself.  Apple's official response was to provide all iPhone 4 purchasers with a free case to insulate the antennas from users' casual embrace.

But returning to the present, if the disappointing RF performance that at least some appear to be experiencing eight years later with iPhone XS and XS Max does boil down to another antenna issue -- weak antenna gain this time -- holding the handset differently or adding a case/bumper is not going to solve the issue.

Some have proposed that, if necessary, an Apple firmware update or two will sort this out.  Yes, iOS revisions and/or carrier updates can tweak the way the baseband modem interacts with wireless networks at large.  And, from an end user perspective, this can improve (or degrade) perceived performance.  However, what software cannot do is update physical qualities locked in during design and manufacturing.

An analogy for this could be the LCD or OLED display screen on your handset.  New firmware might improve image quality by way of adjusting gamma curve, color calibration profile, scaling algorithm, etc.  But that software update cannot change the screen size or pixel resolution -- both are physical characteristics.

In that spirit, if Apple acknowledges an issue and a fix, what software or hardware remedies could it propose?

Apple could submit to the FCC OET a Class II permissive change filing, which is an amendment to an original equipment authorization filing with additional lab testing to reflect a material change in the device.

Let us take a look at two possible Class II changes that Apple could implement, though for reasons to be explained, Apple probably would not pursue either one.
  • Increase conducted power via a firmware update
Conducted power is the input to the antenna, while radiated power (EIRP) is the output from the antenna.  But with increased conducted power, increased EIRP also would result.  This could help RF performance in situations in which the uplink hits its power limits before downlink reception drops below usability.

However, this is not a likely solution.  For an LTE device that operates in Power Class 3 (non HPUE) in a specific band, its target conducted power is 200 mW (23 dBm) +/-2 dB.  Similarly, for Power Class 2 (HPUE), target conducted power is 400 mW (26 dBm) +/-2 dB.  As noted in my previous article -- see quote below -- Apple already has applied conducted power somewhat liberally, pushing the +2 dB margin for conducted power across most bands.
...conducted power is not the issue.  The standard conducted power target of 200 mW (23 dBm) is +/- 2 dB.  And Apple is using the +2 dB margin to enhance its figures, pushing 250-320 mW (24-25 dBm) conducted power across many included bands.  This extends to band 41 HPUE, which has a standard conducted power target of 400 mW (26 dBm).  Again using the +2 dB margin, Apple has upped that ante to 500 mW (27 dBm).
Then, for visual reference, see a graph of iPhone XS Max conducted power.  Note that this graph is expressed in dBm instead of mW to reflect more directly the up to +2.5 dB boost Apple already has applied to conducted power above the standard 23 dBm and 26 dBm target levels, respectively.


Without HPUE across all bands, Apple has little, if any additional wiggle room to increase conducted power.  And, remember, bumping up conducted power helps only with uplink transmission.  It does not improve downlink reception.
  • Increase antenna gain via a hardware manufacturing revision
Increased antenna gain would cause increased EIRP -- with or without increased conducted power.  Additionally, as long as the same antenna arrays are used for both uplink transmission and downlink reception, improved antenna gain can assist in received signal strength, too.

This sounds like the ideal solution.  And, quite frankly, it is.  But for even more obvious reasons, Apple would be highly unlikely to go this modified hardware route.  This would be the nuclear option, so to speak, that would require some redesign and retooling of yet to be manufactured iPhone XS and XS Max units as well as possible replacement of extant phones for any dissatisfied users.  Instead, any antenna design changes probably will be saved for next year's iPhone generation.

So, what can iPhone XS and XS Max users do right now?

The new iPhones undoubtedly show some measured RF shortcomings compared to their predecessors and other comparable handsets.  However, the jury very much is still out on how much and how often this will affect typical use cases.

In the interest of investigation, many users already have jumped to comparing signal bars, though doing so is not very useful, since signal bars are just a coarse approximation of signal availability/quality and can be calibrated to almost any arbitrary standard.

Comparing speed tests also is not very useful for gauging weak signal performance.  Unless a speed test fails or produces very slow speeds due to exceedingly marginal signal conditions, devices with 4x4 MIMO reception -- such as iPhone XS and XS Max -- likely will exhibit higher download speed test results under most good to normal signal conditions.

Accessing Field Test to compare signal metrics (RSRP, RSRQ, CINR) across multiple devices actually is useful.  But this must be done with a watchful eye and solid understanding.  PCI, GCI, and EARFCN all must be the same in the same location to ensure that both devices are on the same PCC of the same site and sector.  Any difference among those matching signal characteristics eliminates a legitimate apples to apples comparison.  So far, Field Test reports are scant, though many more should be forthcoming as savvy users put their new phones through the paces.

Source: FCC OET

Wednesday, September 12, 2018

[UPDATED] iPhone XS and XS Max mostly fail to impress in lab tested RF power output

Following Apple's keynote presentation yesterday, authorization filings for many of its newly announced mobile devices started being made publicly available in the FCC OET database.  Among others, this included the US variant iPhone XS (model A1920, FCC ID BCG-E3218A) and iPhone XS Max (model A1921, FCC ID BCG-E3219A).  The US variant iPhone XR (model A1984, FCC ID BCG-E3220A) was not included.  Its authorization documents likely will be disclosed closer to its October release, thus may be the subject of a later update or a different blog post.

Before proceeding any further, RF power figures to come represent best averaged and rounded estimates of maximum uplink EIRP test results provided to the FCC OET in individual device authorization filings.  Or in the case of ERP low band test measurements submitted in the filings, that ERP has been converted manually to EIRP for level comparison purposes.  All EIRP figures are normed against a baseline of 200 mW (23 dBm), which corresponds to a standard conducted power target with unity antenna gain and generally represents good RF transmission performance.  Caveats about lab testing versus real world capability and uplink versus downlink always apply.

Now, let the EIRP graphs speak for themselves...



As the blog post title indicates, the lab tested radiated output from the two new iPhone XS models does not set the world on fire.  Nearly all bands on both handsets fall short of the 200 mW benchmark.  Only band 41 HPUE on iPhone XS looks pretty good on paper, and even that comes with a conducted power asterisk to be analyzed later.

But first to nip in the bud one potential conspiracy theory, Apple's decision to forgo Qualcomm this year and source all cellular modems from Intel is not responsible for the RF power output limitations in the new iPhone models.  The cellular baseband modem is separate from and well upstream of the amplifiers that generate the conducted power and antennas that generate the radiated power being measured in lab testing.

Furthermore, conducted power is not the issue.  The standard conducted power target of 200 mW (23 dBm) is +/- 2 dB.  And Apple is using the +2 dB margin to enhance its figures, pushing 250-320 mW (24-25 dBm) conducted power across many included bands.  This extends to band 41 HPUE, which has a standard conducted power target of 400 mW (26 dBm).  Again using the +2 dB margin, Apple has upped that ante to 500 mW (27 dBm).  That inflated conducted power is fine.  But bear in mind that it assists only in transmission, never in reception.  Plus, it also can be used to mask some antenna shortcomings.

Yes, with often greater than standard conducted power being generated -- rhetorical questions ahead -- where is all that power going?  Where is it being diminished?  The answer lies in antenna gain.

Indeed, deeper analysis of the FCC OET authorization filings shows the underwhelming EIRP figures to be almost entirely products of negative antenna gain.  For every 3 dB drop in antenna gain, 50 percent of conducted power is attenuated.

To illustrate visually, look at a graph of the iPhone XS Max antenna gain (Ant. 1) across its entire uplink low band, mid band, and high band frequency range.  Antenna gain inevitably reduces conducted power by about 5-7 dB.


Now, both iPhone XS and XS Max this year incorporate four antennas operational across many but not all bands.  That antenna diversity in and of itself is a good thing.  However, even with the four antennas -- and possibly because of the four antennas crammed inside -- antenna gain is universally negative.  And simultaneous transmission from multiple antennas is not possible due to a "break before make" switching mechanism among the antennas.

For a partial look at all four antennas, see a snapshot from the iPhone XS Max authorization filing:


Lastly, for an interesting comparison and stronger RF output, see lab tested EIRP figures from last year's iPhone X (model A1865, FCC ID BCG-E3161A) and iPhone 8 Plus (model A1864, FCC ID BCG-E3160A).



The takeaway is that iPhone EIRP in the lab has not always been so compromised as it appears to be this year.  Real world RF performance comparisons when some users switch from the iPhone X and 8 generation to the iPhone XS generation, no doubt, will be interesting.

Also, see follow up articles (1, 2).

Source: FCC OET

Wednesday, September 5, 2018

Moto Z3 Play hits a home run on band 41, swings big and misses on low band

The Moto Z3 Play (model variant XT1929-4, FCC ID IHDT56XE1) is sold directly by Motorola and via other third parties as an unlocked handset compatible with all North American cellular operators.  As such, it must support a wide swath of LTE bands.  And, indeed, the Moto Z3 Play is one of the first and only handsets thus far to support two nascent 600/700 MHz bands -- band 14, which AT&T is deploying for public-private FirstNet, and band 71, which T-Mobile and other smaller operators are deploying in more recently vacated UHF TV spectrum.  Somewhat unfortunately, though, that low band inclusion on the Moto Z3 Play seems largely nominal, since low band RF output across the board is rather meager.

Where the Moto Z3 Play shines is in its band 41 HPUE output.  Not only bumping up conducted power to better than 400 mW (26 dBm) as expected from HPUE Power Class 2 but also adding +2.0 dBi antenna gain makes a potent combination that peaks at over 700 mW EIRP on band 41.  This level of band 41 power and positive antenna gain is basically unprecedented and ostensibly should make the Moto Z3 Play a stellar performer on Sprint.  Almost all other antenna gain, however, is negative, even exceedingly negative -- all low band antenna gains run below -5.0 dBi.  High band antenna design, in this case, may have come at the cost of low band antenna optimization.  Questions arise how well the Moto Z3 Play will respond in low signal rural areas where low band or "Extended Range" LTE is supposed to be the coverage saving grace.

Before moving on to the graphs, let us run down the standard boilerplate.  RF power figures below represent best averaged and rounded estimates of maximum uplink EIRP test results provided to the FCC OET in individual device authorization filings.  Or in the case of ERP low band test measurements submitted in the filings, that ERP has been converted manually to EIRP for level comparison purposes.   Caveats about lab testing versus real world capability and uplink versus downlink always apply.   And for better visual comparison purposes, the vertical scale heightened to 800 mW needed to display Moto Z3 Play EIRP remains consistent across follow up EIRP graphs, too.


We would be remiss not to include at least a cursory juxtaposition with the VZW exclusive Moto Z3 (model variant XT1929-17, FCC ID IHDT56XJ1), which shares the very same external design with the unlocked Moto Z3 Play.  Note even the same basic model number between the two.  But, internally, the Moto Z3 carries a higher end Qualcomm Snapdragon 835 with X16 LTE modem chipset, and as the FCC OET lab testing figures show, it also offers more mundane yet consistent RF output across its disclosed bands.  Clearly, some internal RF hardware has been changed and/or radio software tweaked in the transition from the Moto Z3 Play to the Moto Z3.  This is corroborated by the many additional LTE bands that the Moto Z3 supports but are not similarly present in the Moto Z3 Play nor disclosed in the FCC OET documents -- because those bands are downlink (i.e. reception) only or software disabled for US operation on VZW.  Absent from the Moto Z3, though, is band 71 capability, and perhaps its inclusion in the Moto Z3 Play antenna design is at least partly responsible for that model's low band challenges.


For additional comparisons, look at two of my favorite Motorola handsets of the past year, both with which I have had ample user experience and both of which are compatible with MVNO Project Fi, the Moto X4 (model variant XT1900-1, FCC ID IHDT56WK1) and Moto G6 (model variant XT1925-6, FCC ID IHDT56XD1).  Neither has HPUE, yet each still manages to pump out some solid band 41 EIRP by way of positive antenna gain.  The Moto X4 provides superb +2.80 dBi antenna gain on band 7/38/41.  And my experience has been similarly positive -- the Moto X4 has an above average affinity for band 41.  Beyond that, the Moto X4 is about average.


On the flip side, the Moto G6 offers above average EIRP across most other bands, too.  And that is achieved not through conducted power inflated above 200 mW (23 dBm) but mostly good old fashioned positive antenna gain.  In particular, the low band antenna gain of +1.36 dBi for band 12/17 is impressive.


That covers the lab tested RF figures for the Moto Z3 Play along with several related or recent handsets from Motorola.  If you have requests for analysis of other devices, feel free to submit them in the comments.

Source: FCC OET