Shopping for an Spectrum Analyzer - RF Explorer

[digiblur]

OK so I feel totally dumb as this is way outside my knowledge - how do you tell LTE from CDMA from GSM/WCDMA when doing the sweeps?

 

Sent from my SPH-L710 using Tapatalk 4

 

AJ will probably chime in with a better answer, but I noticed that the LTE ones when zoomed in look like a bunch of jagged lines in the realtime sweep.

[S4GRU]

I was just about to pull the trigger and buy one, then my router went down.  So I bought a really powerful AC 5GHz wifi router that should cover my entire house and front yard/gazebo.  So I will have to wait on the spectrum analyzer until next month.

 

Robert

[Thomas L.]

I was just about to pull the trigger and buy one, then my router went down. So I bought a really powerful AC 5GHz wifi router that should cover my entire house and front yard/gazebo. So I will have to wait on the spectrum analyzer until next month.

 

Robert

Not to derail the thread, but what kind of router did you get? I have had trouble finding a really good power and fast 802.11n router, but haven't tried AC

 

Sent from my SPH-L710 using Tapatalk 4

 

 

[S4GRU]

Not to derail the thread, but what kind of router did you get? I have had trouble finding a really good power and fast 802.11n router, but haven't tried AC

 

Sent from my SPH-L710 using Tapatalk 4

 

I linked it in the post.

 

Robert

[iansltx]

Hmm, I wonder if that router supports IPv6. My current Amped does not.

 

Getting back on-topic, I may pick up the SA next month. Not completely sure what I'm expecting I'll find, as I'll have a tri-band Sprint LTE device at some point. But maybe I'll be able to see when AT&T or VZW turn on LTE in AWS around here.

 

EDIT: Looks like it does. But I may opt for an AC1950 router instead, since I'm covering such a small area.

[digiblur]

I was just about to pull the trigger and buy one, then my router went down. So I bought a really powerful AC 5GHz wifi router that should cover my entire house and front yard/gazebo. So I will have to wait on the spectrum analyzer until next month.

 

Robert

I have used the 2.4ghz version of their product and it does work well but it doesn't solve everything. In one case we still had some clients like phones that were too low power and could "hear" the router but couldn't talk back. We ended up running a piece of CAT5 to the other side of the house and put a cheap everyday router on that side of the house configured as just a wireless access point to solve the issue.

[digiblur]

Hmm, I wonder if that router supports IPv6. My current Amped does not.

 

Getting back on-topic, I may pick up the SA next month. Not completely sure what I'm expecting I'll find, as I'll have a tri-band Sprint LTE device at some point. But maybe I'll be able to see when AT&T or VZW turn on LTE in AWS around here.

 

EDIT: Looks like it does. But I may opt for an AC1950 router instead, since I'm covering such a small area.

So what frequencies should I be looking for on the AWS side. I was also wanting to look for Tmobile LTE as well.

[MacinJosh]

Hmm, I wonder if that router supports IPv6. My current Amped does not.

 

Getting back on-topic, I may pick up the SA next month. Not completely sure what I'm expecting I'll find, as I'll have a tri-band Sprint LTE device at some point. But maybe I'll be able to see when AT&T or VZW turn on LTE in AWS around here.

 

EDIT: Looks like it does. But I may opt for an AC1950 router instead, since I'm covering such a small area.

My Linksys router is a basic model and covers most of my yard, except the back 10 ft and the front 5, and I live on a piece of property approx. 150 ft wide by 300 ft long.

 

 

Sent from Josh's iPhone 5 using Tapatalk 2

[iansltx]

So what frequencies should I be looking for on the AWS side. I was also wanting to look for Tmobile LTE as well.

 

Check out reboot.fcc.gov. 1710-1755 is the AWS band on the upstream side, but I forget what the DS side is.

[WiWavelength]

Check out reboot.fcc.gov. 1710-1755 is the AWS band on the upstream side, but I forget what the DS side is.

 

400 MHz duplex.  2110-2155 MHz.

 

AJ

[S4GRU]

My Linksys router is a basic model and covers most of my yard, except the back 10 ft and the front 5, and I live on a piece of property approx. 150 ft wide by 300 ft long.

 

 

Sent from Josh's iPhone 5 using Tapatalk 2

I live on a piece of property measured in acreage. Not feet.

 

Robert via Samsung Galaxy Note 8.0 using Tapatalk

 

 

[MacinJosh]

I live on a piece of property measured in acreage. Not feet.

 

Robert via Samsung Galaxy Note 8.0 using Tapatalk

That's much bigger than my 1.1 acres I live on.

 

 

Sent from Josh's iPhone 5 using Tapatalk 2

[WiWavelength]

I live on a piece of property measured in acreage. Not feet.

 

But put a nice big dam on the Rio Grande, and we could measure your property in acre-feet.

 

 

AJ

[S4GRU]

But put a nice big dam on the Rio Grande, and we could measure your property in acre-feet.

 

 

AJ

 

I think there are many who wouldn't mind seeing Espanola under a couple hundred feet of water.  And if the depth was set just right, I could have lakefront property.  

 

Robert

[WiWavelength]

I think there are many who wouldn't mind seeing Espanola under a couple hundred feet of water.  And if the depth was set just right, I could have lakefront property.  

 

Yeah, but lakefront property in New Mexico just does not have quite the same ring to it as does oceanfront property in Arizona...

 

 

AJ

[S4GRU]

Yeah, but lakefront property in New Mexico just does not have quite the same ring to it as does oceanfront property in Arizona...

 

 

AJ

 

"From my front porch you can vista del mar."

 

Robert

[MacinJosh]

Yeah, but lakefront property in New Mexico just does not have quite the same ring to it as does oceanfront property in Arizona...

 

 

AJ

HAHAHAHAHA! You are hilarious! You made my day!

 

 

Sent from Josh's iPhone 5 using Tapatalk 2

[S4GRU]

Yeah, but lakefront property in New Mexico just does not have quite the same ring to it as does oceanfront property in Arizona...

 

 

AJ

 

"If you'll buy that I'll throw the Golden Pride BBQ in free!"

 

[WiWavelength]

"From my front porch you can vista del mar."

 

Now, that sounds like a more convincing sales pitch.  Plus, con puerta de oro gratis.

 

AJ

[WiWavelength]

If we continue down this path, Robert is not going to need a spectrum analyzer.  He is going to need SONAR.

 

My time is up.  Thank you, folks.  You have been a great audience.  Goodnight...

 

 

AJ

[WiWavelength]

To get off the stand up comedy stage and return to digiblur's observations from the field, a primary limitation of the RF Explorer seems to be its inability to adjust sweep time.  Whether an FFT or swept filter based analyzer, two things affect the detail in an RF sweep:  resolution bandwidth (RBW) and sweep time.  The smaller the RBW, the greater the detail.  The longer the sweep time, the greater the detail.

 

To illustrate, as I did on Twitter for Milan and Neal, look at two sweeps from my analyzer that I took a few seconds apart.  These are from inside my house, but fortunately, I have a VZW site located on top of a university residence hall just a few hundred feet from my backyard.

 

Both sweeps are set to an RBW of 30 kHz, but the first has a sweep time of 200 ms (to emulate the RF Explorer), while the second has a sweep time of 3000 ms (which is my established default).  Note how much better defined the VZW LTE 750 carrier is in the second sweep than in the first sweep.

 

 

 

AJ

[MacinJosh]

So RBW sweep time set to higher settings really make a big difference. That's very interesting. But for someone like me, do I need that much detail if I'm just doing a simple hunt like digiblur?

 

 

Sent from Josh's iPhone 5 using Tapatalk 2

[WiWavelength]

So RBW sweep time set to higher settings really make a big difference. That's very interesting. But for someone like me, do I need that much detail if I'm just doing a simple hunt like digiblur?

 

Normally, when we think resolution, we think high resolution (e.g. 1920 > 1280).  But RBW is the inverse.  The smaller the RBW, the greater the resolution.  The reason for this is that RBW represents the FFT bin size or swept filter passband.  Without going into the discrete math -- trust me, you do not want me to -- the smaller RBW takes a closer look at the RF involved.  It makes actual peaks and valleys more defined.

 

Now, that said, you may not need that resolution/definition for site spotting and carrier hunting.  If you know, for example, that 1990-1995 MHz will be Sprint LTE or nothing, then it is either there or not.  If it is there, then you know it is Sprint LTE.  But if you are running a sweep of the Cellular, PCS, or AWS bands and want to know what airlinks are being used, then you need greater resolution.  With my spectrum analyzer and my settings, I cannot necessarily distinguish CDMA1X from EV-DO, but I can certainly differentiate CDMA1X and EV-DO from W-CDMA and LTE, as well as W-CDMA from LTE and vice versa.

 

AJ

[MacinJosh]

Normally, when we think resolution, we think high resolution (e.g. 1920 > 1280).  But RBW is the inverse.  The smaller the RBW, the greater the resolution.  The reason for this is that RBW represents the FFT bin size or swept filter passband.  Without going into the discrete math -- trust me, you do not want me to -- the smaller RBW takes a closer look at the RF involved.  It makes actual peaks and valleys more defined.

 

Now, that said, you may not need that resolution/definition for site spotting and carrier hunting.  If you know, for example, that 1990-1995 MHz will be Sprint LTE or nothing, then it is either there or not.  If it is there, then you know it is Sprint LTE.  But if you are running a sweep of the Cellular, PCS, or AWS bands and want to know what airlinks are being used, then you need greater resolution.  With my spectrum analyzer and my settings, I cannot necessarily distinguish CDMA1X from EV-DO, but I can certainly differentiate CDMA1X and EV-DO from W-CDMA and LTE, as well as W-CDMA from LTE and vice versa.

 

AJ

 

I understand this all now. Thanks.

[irev210]

I was just about to pull the trigger and buy one, then my router went down.  So I bought a really powerful AC 5GHz wifi router that should cover my entire house and front yard/gazebo.  So I will have to wait on the spectrum analyzer until next month.

 

Robert

 

you should check out the smallnetworkbuilder reviews.  He has the best test process/methodology.

 

I would go with the Asus RT-AC66 - there is a reason why netgear is suing Asus over it (and why it out-performs every other AC router out there).