Changing the band (frequency) which the E1820 modem uses

[chrisc]

There is expensive one, external antenna. But router is easy to move, you can reposition it around the house to get stronger signal or more stable connection or both.
There is a reason of using latest generation of modems, even they don't give expected maximum speed. This is because HSPA+ (21mbps and above) introduced many improvements to the signaling between device and BTS. Result is much quicker allocation of resources on demand, such applications like WEB browsing are more responsive. However these modems consume more power than previous generation, causing problems like frequent handovers or disconnects.

I have already got an external antenna. Using the command AT+CSQ, the aerial improves the signal from 19,99 to 11,99. However, the speed only improves slightly, under 10%. I still think it is congestion, as the PING speeds are so slow. On a 6mb ADSL connection the ping time is 45ms whereas with CellC it is between 115 and 135ms.

Some guy (Porsche) showed posts that he was getting 18mb/sec. That's what I want. Even 2/3 or half would also be ok, not being a greedy bloke.

 

[sajunky]

I read from 11 (-91dBm) to 19 (-75dBm).

 

[chrisc]

I read from 11 (-91dBm) to 19 (-75dBm).

I do beg your pardon. In my excitement, I swopped the results around. I'll do some more checks this week-end and let you know if its progress or regress.

 

[sajunky]

Other messages can be queried from the modem. The most important are CellID, and SNR. There is a small application by ginggs MDMA, you can watch all these, no need to study AT commands.
I give you some tip: With the latest modems you also can query SNR (signal to noise ratio). RSSI, SNR with conjunction with BER (bit error rate) can trigger handover requests. For now we can't see BER, but we can observe whether Cell ID is stable. When it is changing, something goes wrong. So point is that you need to position antenna on the CellID which is stable and gives the best throuput. Usually the one with the stronger RSSI or SNR, but now always. You must be patient, it takes a time, as there is another mechanism in place. The tower is constantly changing radiation patern in the attempt to comfort your device, it is called beamforming. You see that during connection RSSI drops little bit, but SNR increases, you can guess that tuning is in progress.

 

[chrisc]

Other messages can be queried from the modem. The most important are CellID, and SNR. There is a small application by ginggs MDMA, you can watch all these, no need to study AT commands.
I give you some tip: With the latest modems you also can query SNR (signal to noise ratio). RSSI, SNR with conjunction with BER (bit error rate) can trigger handover requests. For now we can't see BER, but we can observe whether Cell ID is stable. When it is changing, something goes wrong. So point is that you need to position antenna on the CellID which is stable and gives the best throuput. Usually the one with the stronger RSSI or SNR, but now always. You must be patient, it takes a time, as there is another mechanism in place. The tower is constantly changing radiation patern in the attempt to comfort your device, it is called beamforming. You see that during connection RSSI drops little bit, but SNR increases, you can guess that tuning is in progress.

This is really useful, may I share with you what's on the MDMA screen..

CellID 40411
SNR -75.6
RSSI -75dbm

I notice from time to time, the bar-graph moves a little. Yesterday the SNR was -101.6, this afternoon at 2.00 it was -91.4, now (at 5.30) it is -75.6. The actual aerial is on a 2 metre mast outside and I have aimed it where it was suggested by CellC. However, your poster 1geoff99 uses the mast at the Total service station in Diep River which isn't much farther away, so I'll try it when it stops raining for a bit.

 

[1geoff99]

This is really useful, may I share with you what's on the MDMA screen..

CellID 40411
SNR -75.6
RSSI -75dbm

I notice from time to time, the bar-graph moves a little. Yesterday the SNR was -101.6, this afternoon at 2.00 it was -91.4, now (at 5.30) it is -75.6. The actual aerial is on a 2 metre mast outside and I have aimed it where it was suggested by CellC. However, your poster 1geoff99 uses the mast at the Total service station in Diep River which isn't much farther away, so I'll try it when it stops raining for a bit.

CellID starting 4041x is actually the tower in Diep River. You should get a better signal if you point your antenna more towards Diep River. CellID starting 4029x is for the tower on the Main Road somewhere near the Plumstead/Wynberg border.

 

[chrisc]

CellID starting 4041x is actually the tower in Diep River. You should get a better signal if you point your antenna more towards Diep River. CellID starting 4029x is for the tower on the Main Road somewhere near the Plumstead/Wynberg border.

Right, I aimed it at Diep River. It now states
CellID 40411
SNR -103.6
RSSI -103dbm

There is a big tree in the way between the aerial and Diep River

Why would the CellID not change when I aimed the aerial towards the Wynberg/Plumstead border? I thought these LP aerials were quite directional, maybe 6 deg or so.

Where can I find what the Cell ID means?

Thanks

 

[sajunky]

It means nothing. Just a number, The last digit gives some rough indication to the direction of the antenna and frequency it is operating. Just remember that different CellID means different antenna. If it differs only in the last digit, it belongs to the same base station.