Question about the Motorola CPEi 725 - Clear Model M

[bluepoint951]

First and foremost, thanks to everyone that has posted detailed information about the Ubee PXU1900 and other Clear devices; I have found many posts here useful at enhancing my experience with Clear thus far.

I have been using the Ubee PXU-1900 while mobile and with the dock while at home to catch a signal. While in my house I usual get between one and two bars in the connection manager and using the PXU1900 connected to a Cradlepoint CTR-500 I own I can get a steady two bars. I have been very pleased with Clear service, but I occasionally lose signal and have to reconnect; therefore, I started to explore my options to improve my service.

At the recommendation of the local Clear store in the Northpark Center Mall in Dallas, I added the Clear Series M modem to my account to just leave the modem/antenna in one spot instead of moving around and having to "sit just right" to keep signal/connection as i have with the PXU1900.

I am majoring in Telecommunications Engineering so I decided to open up my new little toy to see what was on the inside; I took a few pictures for you all to examine:


Clear Motorola CPEi 725 External Center by bluepoint951, on Flickr


Clear Motorola CPEi 725 External Ports Closeup by bluepoint951, on Flickr

Clear_Motorola_CPEi_725_Antenna_Closeup_3 by bluepoint951, on Flickr


Clear_Motorola_CPEi_725_Antenna_Closeup_4 by bluepoint951, on Flickr

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I have a set of 14 pictures I took of this modem you can view here:
Clear Series "M" - Motorola CPEi 725 Pictures

Since using the new Motorola modem at home I have found I get a steady two bars throughout the house; however, I'd like to get this to a more stable 3 or 4 if possible. if I connect the modem outside I get a solid 4 and even occasion 5 bars on the modem. I own this equipment; therefore, I was curious if it possible to use a pigtail [and a small case modification] to hook up an external antenna to this modem. I have a perfect spot where I can run an 5-8ft line from an external antenna on the outside of the home to the modem; unfortunately, I am not sure which type of connector to use based on what I see on the modem PCB. Just comparing from pictures of the Gemtek modem, the connector does not appear to be an U.FL/IPEX type; thus I am here to seek help & information from you all.

I have seen the suggestion of many here to use the Ubee PXU1900 as it already has an external adapter; however, Clear would not allow me to port my number from Verizon and have only an "On-The-Go" service type. The reason for this setup comes down to $. For what I pay for "On-The-Go" service and POTS, I get the "Choose 3" from Clear; consequently, I get to use Wi-MAX while around town, a good service at home, and cheaper phone service with more value.

[Petro5]

Motorola CPEi 725 & CPEi 25150 antenna port

Thanks bluepoint951 for your post and informative pics.

That is a Murata SWD antenna connector/switch combo. Muratas P/N for switch is MM8430-2610 and pigtail P/N is MXHS83QE3000. See http://www.murata.com/catalog/o30e8.pdf . Incidentally this is the same as the antenna connector used in the CPEi 25150 Motorola CPE.

Note though that these connectors are not designed for constant removal and re-insertion. Typical mating durability is in the order of 100 cycles.



We currently don't stock the pigtail that mates to this but it's available from Mouser or digikey (search for Manufacturer P/N MXHS83QE3000). It has an SMA-Female connector so you can convert it to anything else you need using an appropriate adapter.

So for your example you would need
1) 10ft LMR-400 cable: less than 0.7dB attenuation even at the upper 2700MHz band.
2) SMA-Male/N-Female adapter: Allows the pigtail above to mate to N-Male LMR-400 cable.
3) Appropriate wimax antenna. Most popular is the 16dBi directional panel.
4) If you are mounting this in the roof below any other structures that could reliably arrest lightning we strongly recommend a lightning surge device. Since this has N-Female/N-female ports you would need a jumper with N-Male/N-Male to allow for convenient installation.

Since your indoor coverage seems not so terrible you would likely benefit with just a single outdoor antenna but see this article on when adding a 2nd antenna would really make sense for MIMO performance gain.

[bluepoint951]

The honor of thanks goes to you Petrol5; you have been most helpful in many of the post here that I have reviewed. With your information, and a little elbow grease on my end, this little project may come together quicker than I expected.

I shall post a few pictures once I get my setup in a week or two. Maybe I can return the favor for a few others who are out there in a similar circumstance.

[thuor]

Good thanks guys for starting this thread. I too have seen a lot of interest in this very solution. Looking forward to hearing about your experience.

One of my customers was kind enough to provide link on step by step instruction of his mod: http://www.instructables.com/id/Addi...-Motorola-CPE/

[rcr7]

Can anyone say whether j1o or j11 is the correct port to use for the external antenna?

[sigung]

Correct Port

Can anyone say whether j1o or j11 is the correct port to use for the external antenna?

There's a video on YouTube:

http://www.youtube.com/watch?v=ypa_e...layer_embedded

that shows the pigtail being attached to j10

[RickyP03]

J10 and J11

Can anyone say whether j1o or j11 is the correct port to use for the external antenna?

One source I've read said one is receive only and the other is receive/send

Do you know where to get that SWD connector??

[RickyP03]

Thanks bluepoint951 for your post and informative pics.

That is a Murata SWD antenna connector/switch combo. Muratas P/N is MM8430-2610. See http://www.murata.com/catalog/o30e8.pdf . Incidentally this is the same as the antenna connector used in the CPEi 25150 Motorola CPE.

Note though that these connectors are not designed for constant removal and re-insertion. Typical mating durability is in the order of 100 cycles.



We currently don't stock the pigtail that mates to this but it's available from Mouser or digikey (search for Manufacturer P/N MXHS83QE3000). It has an SMA-Female connector so you can convert it to anything else you need using an appropriate adapter.

So for your example you would need
1) 10ft LMR-400 cable: less than 0.7dB attenuation even at the upper 2700MHz band.
2) SMA-Male/N-Female adapter: Allows the pigtail above to mate to N-Male LMR-400 cable.
3) Appropriate wimax antenna. Most popular is the 16dBi directional panel.
4) If you are mounting this in the roof below any other structures that could reliably arrest lightning we strongly recommend a lightning surge device. Since this has N-Female/N-female ports you would need a jumper with N-Male/N-Male to allow for convenient installation.

Since your indoor coverage seems not so terrible you would likely benefit with just a single outdoor antenna but see this article on when adding a 2nd antenna would really make sense for MIMO performance gain.

I finally got the case open...where can I get the connector for the antennae and what do I need to connect to the USB Modem (Siera 250U)

[thuor]

One source I've read said one is receive only and the other is receive/send

Do you know where to get that SWD connector??

SWD Pigtail:
http://search.digikey.com/scripts/Dk...3000&x=16&y=23


Sierra 250U Pigtail: http://www.rfwel.com/shop/Cellular-d...-Pigtails.html

[Thecat1080]

New-B question

I am a new subscriber to Clear, I am being a bit picky. The best receptio my modem has is in teh middle of the upstairs in the way of everything. I get a full 5 bars with with a CINR between 24and 27 (pending on weather) and an RSSI of -63. with the Clear modem with Wifi.

OK here is my question I want to move my modem to a more convinient (hidden) location so it is more asthetically pleasing, so I was thinking of using the external antenna on a CPEi 725 M series modem and mounting the antenna ouside aimed towards the Clear Tower. I have a very high roof line of 30 ft, so I would actually be higher than the Clear antenna array, so i might have to aim it down toards the tower. I am thinking this will work fine but I am not that familiar with the system yet. Does this seem a reasonable method? Can I expect similar or better recpetion than I currently have? I was planning on useing the 18.3 dbi flat panel antenna and no more than 50ft of wire.

[thuor]

If you have good reception at some location in your house then it is very reasonable to assume you will have excellent reception outdoors which means that this solution will definitely work even with 50ft cable (LMR-400 cable has an attenuation of about 6.9dB/100ft so a 50ft run will lead to about a 3.5dB loss but with an 18dBi antenna you still have plenty of residual gain).

You can get the antenna, cable and optional but strongly-recommended lightning protection as part of this kit: http://www.rfwel.com/shop/4G-USB-Mod...tenna-Kit.html

[Thecat1080]

Awsome, thank you!

[RickyP03]

What are the connectors?

1. Is the Muranta probe the ONLY connector for rhe M Modem? It can't be used with the U.Fl connector to RP-SMA Pigtail?
2. The instructables video is so short...is that J10 or J11, and is one receive only?
3. Someone said the connector is Blocked (M series) is this true?
4. Somewhere it is said that the Sierra USB coneectors are 3G and 4G. Some one else said they are BOTH 3G only.
5. Why do the D/L rate change during certain times aday and/or go roaming and not locking onto another tower in the area? They are omnidirectional????
6. why does the foil work sometimes with some people and not with others

QUOTE=thuor;1875]SWD Pigtail:
http://search.digikey.com/scripts/Dk...3000&x=16&y=23


Sierra 250U Pigtail: http://www.rfwel.com/shop/Cellular-d...-Pigtails.html[/QUOTE]

[thuor]

1. Is the Muranta probe the ONLY connector for rhe M Modem? It can't be used with the U.Fl connector to RP-SMA Pigtail?

Motorola CPEi 725 uses a Murata SWD antenna probe so this is the pigtail that works for it. You cannot arbitrarily use any pigtail with any device since any other would not mate to the probe. We might start to carry that probe check here: http://www.rfwel.com/shop/4G-USB-Mod...tenna-Kit.html

2. The instructables video is so short...is that J10 or J11, and is one receive only?

Not sure what video you are referring to. However, both antenna are used for receive while typically only the primary antenna is used for transmit (i.e there's no MIMO for the uplink channel).

3. Someone said the connector is Blocked (M series) is this true?

Not sure what you mean by "Blocked".

4. Somewhere it is said that the Sierra USB coneectors are 3G and 4G. Some one else said they are BOTH 3G only.

The primary antenna port for the sierra 250U is for both 3G & 4G (1900MHz PCS and 2.5-2.7GHz WiMax plus GPS L1 at 1575MHz). The secondary antenna port is just for 4G only (i.e there's no MIMO for 3G).

5. Why do the D/L rate change during certain times aday and/or go roaming and not locking onto another tower in the area? They are omnidirectional????

Many reasons. The primary reason is number of users currently online. In general this is true for any wireless broadband system including cellular 3G (EVDO/HSPA). The more users that are using the same wireless network the more demands on the wireless channel capacity so to arbitrate among all the users the speed of each user goes down. This is especially so for CDMA or more specifically OFDMA multi-user access systems like WiMax. More users add to the interference noise power so the CINR (Carrier to Interference plus noise ratio) degrades which causes the modem to pick a lower modulation mode so as to minimize bit-error-rates which in turn affects speeds and ability to connect to a tower.

Other RF channel effects such as rain, snow etc would also affect the Signal to noise ratio.

6. why does the foil work sometimes with some people and not with others

This is a very crude approach which i frankly don't think should work for anyone in general. True there are people who claim it works but my opinion is that they are just plain lucky. While for low frequency HF, VHF, UHF (such as amateur Ham frequencies) such foil-based reflectors might work, at microwave frequencies (Clear WiMax operates at 2.5-2.7 GHz) you cannot easily create a reflector with well controlled or deterministic radiation properties using foil. In fact i would argue further that if you can design a corner reflector that works well then you are a very good candidate for getting better reception by simple re-locating your CPE to a better location not very far from current location.

This is further complicated by MIMO techniques used in WiMax to improve channel capacity (using spatial multiplexing and spatial coding improves diversity and coding gain). MIMO works best when the different RF paths from the multiple Transmit to Receiver antennas are uncorrelated. By using corner reflectors you improve correlation of these different signals which reduces your MIMO performance advantage. In fact the internal integrated antennas are specifically oriented 180 degrees apart for this very reason so it doesn't make much sense to concentrate the signal to it. This is the same reason why we say if you will get 2 antennas for your modem to separate them as much as possible and orient them differently.

[ninoriff]

Series M MOD Update

Hi everyone!

After sitting around and messing with the series M Modem, I have come up with another way to improve the signal and add a perm fix to this problem. Take a look at my video.

My Youtube Video is at
http://www.youtube.com/watch?v=m4VMylif0Gs

Email at [email protected]

Also will be providing the service for a small fee on ebay.

Check out my other awesome mods at ninoriff2 youtube channel!