Re: [USRP-users] 50 Ohm terminator on LFTX board

2017-09-05 Thread Ken M Erney via USRP-users 
Got a quick question regarding the LFTX board for the N210.  I have an N210 
configured with one LFTX and one LFRX board.  Each of those boards have two 
connectors (i.e. TX-A, TX-B and RX-A, RX-B).  I only have TX-A and RX-A 
connected out to the N210 bulkhead connectors.  Do I need a terminator on the 
TX-B connector just in case I accidentally configure it wrong and try and 
transmit through it?


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Re: [USRP-users] 50 Ohm terminator on LFTX board

2017-09-05 Thread Ken M Erney via USRP-users 
Here is another question for the RF folks out there.  I have a device that is 
sending a signal over a coax cable at about 8 MHz while receiving a signal over 
the same cable at around 3 MHz (both HF).  I have an N210 with both LFRX and 
LFTX boards installed.  Attached to the coax is a filter and DC block.  The 
filter blocks 0 to 1.7 MHz and passes 1.8 to 54 MHz.

What I wanted to do is take the output from the filter, split it, and send one 
feed to the LFRX and one feed to the LFTX.  I am then going to use gnu-radio to 
send (at 3 MHz) and receive (at 8 MHz).  My initial thought was to use a 
splitter but this setup would basically create a loop-back between the TX and 
RX boards on the N210.  I next thought of a duplexer, but I could not find 
anything that would split out 3 and 8 Mhz.

My question is… is this even possible?  If it is, what do I need to put between 
the TX and RX side of the N210 to prevent the TX signal going directly into the 
RX port?

The setup looks something like this:


  |—— (LFRX) ———(8 Mhz)———|
N210 |   |——(y-cable)——| 
(filter/block) |——— (signal coax 50 ohm)
  |—— (LFTX) ———(3 Mhz)———|


In this diagram, what would I used on the RX and TX ports on the N210 to 
prevent the loop-back condition?  The frequencies (i.e. 8 and 3) are not exact, 
so I can’t really use a hardware filter (I assume).  I could use a software 
filter in gnu-radio, but I was not sure about what might happen in this 
scenario (i.e. loopback).  One possible idea is to put an attenuator just 
before the LFRX board like the one supplied in the N210 loopback kit (i.e. 
30db, 0-6Ghz) but I assume this would reduce the power of the receive signal as 
well.  Noob here, so my apologies if these are simple questions.  I could not 
find much via google on this.

Thanks
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Re: [USRP-users] 50 Ohm terminator on LFTX board

2017-09-05 Thread Ken M Erney via USRP-users 
Marcus,

Thanks for the advice on the filter pairs.  This would seem to be a quick and 
cheap way to solve this issue.  Unfortunately, this is a bit above my 
understanding.  I forgot to mention I am a software guy…which will probably 
explain a lot to you regarding my question…lol.  I will pass this on to my EE 
work colleague.  She will understand this much better than I.

Cheers,
Ken

> On Sep 5, 2017, at 6:33 PM, Marcus D. Leech via USRP-users 
>  wrote:
> 
> On 09/05/2017 05:07 PM, Humphries, James R. via USRP-users wrote:
>> And I guess the other question would be if there is a circulator that you 
>> can buy at that low of frequency. I'm not sure that I have seen one, but 
>> never actually looked.
>> 
>> -Trip
>> 
>> 
>> -Original Message-
>> From: USRP-users [mailto:usrp-users-boun...@lists.ettus.com] On Behalf Of 
>> Humphries, James R. via USRP-users
>> Sent: Tuesday, September 5, 2017 5:00 PM
>> To: Ken M Erney 
>> Cc: usrp-users@lists.ettus.com
>> Subject: Re: [USRP-users] 50 Ohm terminator on LFTX board
>> 
>> Hey Ken,
>> 
>> Are you thinking of something like a circulator?
>> 
>> https://www.microwaves101.com/encyclopedias/circulators
>> 
>> -Trip
>> 
>> 
>> -Original Message-
>> From: USRP-users [mailto:usrp-users-boun...@lists.ettus.com] On Behalf Of 
>> Ken M Erney via USRP-users
>> Sent: Tuesday, September 5, 2017 4:47 PM
>> To: usrp-users@lists.ettus.com
>> Subject: Re: [USRP-users] 50 Ohm terminator on LFTX board
>> 
>> Here is another question for the RF folks out there.  I have a device that 
>> is sending a signal over a coax cable at about 8 MHz while receiving a 
>> signal over the same cable at around 3 MHz (both HF).  I have an N210 with 
>> both LFRX and LFTX boards installed.  Attached to the coax is a filter and 
>> DC block.  The filter blocks 0 to 1.7 MHz and passes 1.8 to 54 MHz.
>> 
>> What I wanted to do is take the output from the filter, split it, and send 
>> one feed to the LFRX and one feed to the LFTX.  I am then going to use 
>> gnu-radio to send (at 3 MHz) and receive (at 8 MHz).  My initial thought was 
>> to use a splitter but this setup would basically create a loop-back between 
>> the TX and RX boards on the N210.  I next thought of a duplexer, but I could 
>> not find anything that would split out 3 and 8 Mhz.
>> 
>> My question is… is this even possible?  If it is, what do I need to put 
>> between the TX and RX side of the N210 to prevent the TX signal going 
>> directly into the RX port?
>> 
>> The setup looks something like this:
>> 
>> 
>>   |—— (LFRX) ———(8 Mhz)———|
>> N210 |   |——(y-cable)——| 
>> (filter/block) |——— (signal coax 50 ohm)
>>   |—— (LFTX) ———(3 Mhz)———|
>> 
>> 
>> In this diagram, what would I used on the RX and TX ports on the N210 to 
>> prevent the loop-back condition?  The frequencies (i.e. 8 and 3) are not 
>> exact, so I can’t really use a hardware filter (I assume).  I could use a 
>> software filter in gnu-radio, but I was not sure about what might happen in 
>> this scenario (i.e. loopback).  One possible idea is to put an attenuator 
>> just before the LFRX board like the one supplied in the N210 loopback kit 
>> (i.e. 30db, 0-6Ghz) but I assume this would reduce the power of the receive 
>> signal as well.  Noob here, so my apologies if these are simple questions.  
>> I could not find much via google on this.
>> 
>> Thanks
> Ideally, you want a duplexor.
> 
> But you may be able to get away with a pair of filters--one for your TX 
> frequency and the other for RX.
> 
> Stick a deep NOTCH for your TX frequency into the RX path, and then a 
> bandpass for your RX frequency into the RX path.
> 
> Stick a stiff bandpass for your TX frequency into the TX path, and then a 
> stiff *NOTCH* for your TX frequency into the TX path.
> 
> At these frequencies, ordinary L-C filters work quite well, and "off the 
> shelf" SMD inductors/Cs can be used at low power levels (below +20dBm or so).
> 
> Check out:
> 
> http://www.wa4dsy.net/filter/filterdesign.html
> 
> 
> 
> 
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Re: [USRP-users] 50 Ohm terminator on LFTX board

2017-09-05 Thread Ken M Erney via USRP-users 
Trip,

The circulator idea is interesting.  Thanks for the link.  I did not understand 
the difference between a diplexer and a duplexer.  The link you sent has a 
great explanation of this.  It would seem that a duplexor is what I want, but I 
could not tell if a duplexer can be used in full duplex mode (i.e. send and 
receive at the same time).  My power needs are very low.  I am thinking that 
maybe a combiner/splitter has enough isolation to do what I need.  Again, thank 
you for the quick response.  I believe I learned something today :)

- ken

  
> On Sep 5, 2017, at 5:07 PM, Humphries, James R.  wrote:
> 
> And I guess the other question would be if there is a circulator that you can 
> buy at that low of frequency. I'm not sure that I have seen one, but never 
> actually looked.
> 
> -Trip
> 
> 
> -Original Message-
> From: USRP-users [mailto:usrp-users-boun...@lists.ettus.com] On Behalf Of 
> Humphries, James R. via USRP-users
> Sent: Tuesday, September 5, 2017 5:00 PM
> To: Ken M Erney 
> Cc: usrp-users@lists.ettus.com
> Subject: Re: [USRP-users] 50 Ohm terminator on LFTX board
> 
> Hey Ken,
> 
> Are you thinking of something like a circulator?
> 
> https://www.microwaves101.com/encyclopedias/circulators
> 
> -Trip
> 
> 
> -Original Message-----
> From: USRP-users [mailto:usrp-users-boun...@lists.ettus.com] On Behalf Of Ken 
> M Erney via USRP-users
> Sent: Tuesday, September 5, 2017 4:47 PM
> To: usrp-users@lists.ettus.com
> Subject: Re: [USRP-users] 50 Ohm terminator on LFTX board
> 
> Here is another question for the RF folks out there.  I have a device that is 
> sending a signal over a coax cable at about 8 MHz while receiving a signal 
> over the same cable at around 3 MHz (both HF).  I have an N210 with both LFRX 
> and LFTX boards installed.  Attached to the coax is a filter and DC block.  
> The filter blocks 0 to 1.7 MHz and passes 1.8 to 54 MHz.
> 
> What I wanted to do is take the output from the filter, split it, and send 
> one feed to the LFRX and one feed to the LFTX.  I am then going to use 
> gnu-radio to send (at 3 MHz) and receive (at 8 MHz).  My initial thought was 
> to use a splitter but this setup would basically create a loop-back between 
> the TX and RX boards on the N210.  I next thought of a duplexer, but I could 
> not find anything that would split out 3 and 8 Mhz.
> 
> My question is… is this even possible?  If it is, what do I need to put 
> between the TX and RX side of the N210 to prevent the TX signal going 
> directly into the RX port?
> 
> The setup looks something like this:
> 
> 
>  |—— (LFRX) ———(8 Mhz)———|
> N210 |   |——(y-cable)——| 
> (filter/block) |——— (signal coax 50 ohm)
>  |—— (LFTX) ———(3 Mhz)———|
> 
> 
> In this diagram, what would I used on the RX and TX ports on the N210 to 
> prevent the loop-back condition?  The frequencies (i.e. 8 and 3) are not 
> exact, so I can’t really use a hardware filter (I assume).  I could use a 
> software filter in gnu-radio, but I was not sure about what might happen in 
> this scenario (i.e. loopback).  One possible idea is to put an attenuator 
> just before the LFRX board like the one supplied in the N210 loopback kit 
> (i.e. 30db, 0-6Ghz) but I assume this would reduce the power of the receive 
> signal as well.  Noob here, so my apologies if these are simple questions.  I 
> could not find much via google on this.
> 
> Thanks
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Re: [USRP-users] Trouble Connecting to N210 in VMWare

2017-10-06 Thread Ken M Erney via USRP-users 
What are you using as the VM software client (e.g. VMware, virtual box,
etc.). I was able to get mine to work but I had to configure my VM eth as
"bridged". I also set it with a manually configured ip in the same subnet
as the N210.

- ken

On Oct 6, 2017 10:23 PM, "Tellrell White via USRP-users" <
usrp-users@lists.ettus.com> wrote:

Hello Guys.
I'm currently trying to connect to the N210 using an ubuntu 14.04 virtual
machine. I've tried the commands uhd_find_devices and also uhd_usrp_probe
and they both indicate "no devices found". Pinging 192.168.2 comes up empty
as well. I used the command sudo ip address add 192.168.10.1/255.255.255.0
dev eth0 to set the ip of the virtual machine. I'm connected to the
internet via wi-fi. The version of UHD i'm using is 3.10.2. Any help is
greatly appreciated.

Regards
Tellrell

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Re: [USRP-users] Trouble Connecting to N210 in VMWare

2017-10-07 Thread Ken M Erney via USRP-users 
Hi Tellrell,

I am using virtual box but I have used VMWare Fusion as well and both have the 
option to specify that the network adapter should be bridged.  I am not a 
network guy, so I cant offer any advice regarding the alias approach you 
mention.  What I do know regarding my setup is that when its configured in 
bridged mode, the adapter on the VM will show up on your network as another 
machine and not be NAT’d behind the VMWare client.  So for VMWare Fusion (OSX) 
and virtual box, there is a setting in the guest configuration that allows you 
to specify if the adapter is NAT’d, bridged, host only, etc.  In that config, 
specify bridged.  Once the OS boots, you can then go into the Ubuntu network 
config and configure the adapter with a manually assigned IP (i.e. not DHCP). 
In my case, I modified the interfaces file in ubuntu to use a static IP 
(192.168.10.5) and subnet (255.255.255.1).  No gateway.  It then worked without 
issue.

Another option is to change the IP of the N210 to a fixed address on your real 
network.  The N210 won’t do DHCP but you can usually reserve and IP on your 
network and then just burn it into the N210.  Then on the guest OS config side, 
also specify bridged mode and let your network DHCP assign an IP to the guest.  
It should work that way as well.

Give that you are using an alias, it would seem that this would do the same 
thing as what I am describing.  What we need is somebody with network 
experience to chime in here.  Oh one thing… when you say “alias” are you 
referring to setting this in the hosts file on ubuntu?  That may not work the 
same way, but I don’t know.  One other thing is to make sure that IP tables or 
the ubuntu firewall is turned off.  You CAN run a firewall on Ubuntu and still 
support the N210, but turning it off for right now would make sure that it is 
not interfering with the comms.

Also, when running the uhd_find_devices… try calling it and passing it the ip 
address of your N210… just in case.

- ken


> On Oct 6, 2017, at 11:31 PM, Tellrell White via USRP-users 
>  wrote:
> 
> Ken
> I'm using vmware. Not sure if you used the same client but how exactly did 
> you configure your vm to bridged. Also, I used the command to set an alias ip 
> to 192.168.10.1 which is in the same subnet as the N210, not sure if thats 
> different from the manual approach you're suggesting.
> 
> Tellrell
> 
> 
> On Friday, October 6, 2017 10:32 PM, Ken M Erney  
> wrote:
> 
> 
> What are you using as the VM software client (e.g. VMware, virtual box, 
> etc.). I was able to get mine to work but I had to configure my VM eth as 
> "bridged". I also set it with a manually configured ip in the same subnet as 
> the N210.
> 
> - ken
> 
> On Oct 6, 2017 10:23 PM, "Tellrell White via USRP-users" 
> mailto:usrp-users@lists.ettus.com>> wrote:
> Hello Guys. 
> I'm currently trying to connect to the N210 using an ubuntu 14.04 virtual 
> machine. I've tried the commands uhd_find_devices and also uhd_usrp_probe and 
> they both indicate "no devices found". Pinging 192.168.2 comes up empty as 
> well. I used the command sudo ip address add 192.168.10.1/255.255.255.0 
>  dev eth0 to set the ip of the virtual 
> machine. I'm connected to the internet via wi-fi. The version of UHD i'm 
> using is 3.10.2. Any help is greatly appreciated. 
> 
> Regards
> Tellrell
> 
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> 
> 
> 
> 
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