HP
henry.powell.xx@gmail.com
Thu, Aug 4, 2022 6:05 AM
Hello,
I design a system on GNU Radio with USRP and coded it in Python. I am hopping frequency. Then I restart this process. I save all max. value at different frequencies. I am sharing datas with you. All data you can see in this document I take connection with cable. I mean I connect TX port to RX port with cable. I know possible dangers.
My problem is I expect all datas are same even they don’t be same frequencies. I would not expect the dB difference between 100MHz and 6Ghz almost 40dB.
Another problem is Even though I dont change the position of anything (Because I connect with cable) I take different values at replays. With the cable the difference is almost 3dB. But if I connect with antennas the difference at some frequencies is maybe 15dB even I don’t change the position of antennas. If I stabilize this, I change position of antennas dynamically.
I will be glad if you help.
Hello,
I design a system on GNU Radio with USRP and coded it in Python. I am hopping frequency. Then I restart this process. I save all max. value at different frequencies. I am sharing datas with you. All data you can see in this document I take connection with cable. I mean I connect TX port to RX port with cable. I know possible dangers.
My problem is I expect all datas are same even they don’t be same frequencies. I would not expect the dB difference between 100MHz and 6Ghz almost 40dB.
Another problem is Even though I dont change the position of anything (Because I connect with cable) I take different values at replays. With the cable the difference is almost 3dB. But if I connect with antennas the difference at some frequencies is maybe 15dB even I don’t change the position of antennas. If I stabilize this, I change position of antennas dynamically.
I will be glad if you help.
CH
Cédric Hannotier
Thu, Aug 4, 2022 8:22 AM
I design a system on GNU Radio with USRP and coded it in Python. I am
hopping frequency. Then I restart this process. I save all max. value
at different frequencies. I am sharing datas with you. All data you
can see in this document I take connection with cable. I mean I
connect TX port to RX port with cable. I know possible dangers.
My problem is I expect all datas are same even they don’t be same
frequencies. I would not expect the dB difference between 100MHz and
6Ghz almost 40dB.
IMO, this is expected.
If we consider the Friis transmission equation,
it tells us that the ratio between the power received and transmitted
decreases in 20⋅log_10(f) [dB].
From 100 MHz fc to 6 GHz fc, we loose ≈ 36 dB.
Regards
Cédric Hannotier
Hi Henry,
On 2022-08-04 06:05 +0000, henry.powell.xx@gmail.com wrote:
> I design a system on GNU Radio with USRP and coded it in Python. I am
> hopping frequency. Then I restart this process. I save all max. value
> at different frequencies. I am sharing datas with you. All data you
> can see in this document I take connection with cable. I mean I
> connect TX port to RX port with cable. I know possible dangers.
>
> My problem is I expect all datas are same even they don’t be same
> frequencies. I would not expect the dB difference between 100MHz and
> 6Ghz almost 40dB.
IMO, this is expected.
If we consider the Friis transmission equation,
it tells us that the ratio between the power received and transmitted
decreases in 20⋅log_10(f) [dB].
From 100 MHz fc to 6 GHz fc, we loose ≈ 36 dB.
Regards
--
Cédric Hannotier
HP
henry.powell.xx@gmail.com
Thu, Aug 4, 2022 10:28 AM
The data I share, I gave all of this when connected by cable. I calculated Friis calculation, too. But, Signal is transmitted by directly cable. I don’t think this equation is necessary.
The data I share, I gave all of this when connected by cable. I calculated Friis calculation, too. But, Signal is transmitted by directly cable. I don’t think this equation is necessary.
NB
Nikos Balkanas
Thu, Aug 4, 2022 11:09 AM
I am not sure you talk about the same thing...
Ofc your PC is connected to your USRP by cable.
But, to my knowledge, all USRPs are for wireless communications.
Are you saying that your USRP has wired daughterboards?
Friis equation applies to the signal received by your daughterboards...
BR
Nikos
On Thu, Aug 4, 2022 at 1:30 PM henry.powell.xx@gmail.com wrote:
The data I share, I gave all of this when connected by cable. I calculated Friis calculation, too. But, Signal is transmitted by directly cable. I don’t think this equation is necessary.
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I am not sure you talk about the same thing...
Ofc your PC is connected to your USRP by cable.
But, to my knowledge, all USRPs are for wireless communications.
Are you saying that your USRP has wired daughterboards?
Friis equation applies to the signal received by your daughterboards...
BR
Nikos
On Thu, Aug 4, 2022 at 1:30 PM <henry.powell.xx@gmail.com> wrote:
>
> The data I share, I gave all of this when connected by cable. I calculated Friis calculation, too. But, Signal is transmitted by directly cable. I don’t think this equation is necessary.
>
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HP
henry.powell.xx@gmail.com
Thu, Aug 4, 2022 11:59 AM
Sorry for misunderstanding. I think this is my fault. But as i mentioned my first question, when i say cable connection, i mean i connected tx port to rx port with cable. To see the device settings clearly, i did this. Also, I have b200.
Sorry for misunderstanding. I think this is my fault. But as i mentioned my first question, when i say cable connection, i mean i connected tx port to rx port with cable. To see the device settings clearly, i did this. Also, I have b200.
MD
Marcus D. Leech
Thu, Aug 4, 2022 12:50 PM
Sorry for misunderstanding. I think this is my fault. But as i
mentioned my first question, when i say cable connection, i mean i
connected tx port to rx port with cable. To see the device settings
clearly, i did this. Also, I have b200.
USRP-users mailing list -- usrp-users@lists.ettus.com
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Make certain that you have at least 30dB attenuation in that cable.
Otherwise you risk one of two things:
o Severe distortion and non-linearity at the receiver
o Severe damage of the receiver
The power output of an RF amplifier will necessarily vary across its
frequency range. I would expect that over 100MHz to 6GHz
that would be perhaps 5-10dB.
On 2022-08-04 07:59, henry.powell.xx@gmail.com wrote:
>
> Sorry for misunderstanding. I think this is my fault. But as i
> mentioned my first question, when i say cable connection, i mean i
> connected tx port to rx port with cable. To see the device settings
> clearly, i did this. Also, I have b200.
>
>
> _______________________________________________
> USRP-users mailing list -- usrp-users@lists.ettus.com
> To unsubscribe send an email to usrp-users-leave@lists.ettus.com
Make certain that you have at least 30dB attenuation in that cable.
Otherwise you risk one of two things:
o Severe distortion and non-linearity at the receiver
o Severe damage of the receiver
The power output of an RF amplifier will necessarily vary across its
frequency range. I would expect that over 100MHz to 6GHz
that would be perhaps 5-10dB.
NB
Nikos Balkanas
Thu, Aug 4, 2022 4:51 PM
Wow! That's rather drastic:(
I would expect that Friis equation is independent of transmission
medium (copper, air).
Besides your observations match the theory very well;-)
BR
Nikos
On Thu, Aug 4, 2022 at 3:01 PM henry.powell.xx@gmail.com wrote:
Sorry for misunderstanding. I think this is my fault. But as i mentioned my first question, when i say cable connection, i mean i connected tx port to rx port with cable. To see the device settings clearly, i did this. Also, I have b200.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
Wow! That's rather drastic:(
I would expect that Friis equation is independent of transmission
medium (copper, air).
Besides your observations match the theory very well;-)
BR
Nikos
On Thu, Aug 4, 2022 at 3:01 PM <henry.powell.xx@gmail.com> wrote:
>
> Sorry for misunderstanding. I think this is my fault. But as i mentioned my first question, when i say cable connection, i mean i connected tx port to rx port with cable. To see the device settings clearly, i did this. Also, I have b200.
>
> _______________________________________________
> USRP-users mailing list -- usrp-users@lists.ettus.com
> To unsubscribe send an email to usrp-users-leave@lists.ettus.com
MD
Marcus D. Leech
Thu, Aug 4, 2022 9:13 PM
On 2022-08-04 12:51, Nikos Balkanas wrote:
Wow! That's rather drastic:(
I would expect that Friis equation is independent of transmission
medium (copper, air).
Besides your observations match the theory very well;-)
BR
Nikos
The Friis equations describe only free-space propagation. Propagation in
a cable or waveguide is a completely
different regime.
On 2022-08-04 12:51, Nikos Balkanas wrote:
> Wow! That's rather drastic:(
> I would expect that Friis equation is independent of transmission
> medium (copper, air).
> Besides your observations match the theory very well;-)
>
> BR
> Nikos
>
The Friis equations describe only free-space propagation. Propagation in
a cable or waveguide is a completely
different regime.
CH
Cédric Hannotier
Fri, Aug 5, 2022 10:21 AM
On 2022-08-04 08:50 -0400, Marcus D. Leech wrote:
Sorry for misunderstanding. I think this is my fault. But as i mentioned
my first question, when i say cable connection, i mean i connected tx
port to rx port with cable. To see the device settings clearly, i did
this. Also, I have b200.
Sorry, I forgot that part.
Make certain that you have at least 30dB attenuation in that cable.
Otherwise you risk one of two things:
o Severe distortion and non-linearity at the receiver
o Severe damage of the receiver
The power output of an RF amplifier will necessarily vary across its
frequency range. I would expect that over 100MHz to 6GHz
that would be perhaps 5-10dB.
On 2022-08-04 08:50 -0400, Marcus D. Leech wrote:
> On 2022-08-04 07:59, henry.powell.xx@gmail.com wrote:
> >
> > Sorry for misunderstanding. I think this is my fault. But as i mentioned
> > my first question, when i say cable connection, i mean i connected tx
> > port to rx port with cable. To see the device settings clearly, i did
> > this. Also, I have b200.
Sorry, I forgot that part.
> Make certain that you have at least 30dB attenuation in that cable.
> Otherwise you risk one of two things:
>
> o Severe distortion and non-linearity at the receiver
> o Severe damage of the receiver
>
> The power output of an RF amplifier will necessarily vary across its
> frequency range. I would expect that over 100MHz to 6GHz
> that would be perhaps 5-10dB.
For the B200, there is some data on RF performance:
https://kb.ettus.com/images/c/cb/B200_RF_Performance.pdf
Hope that's help.
Regards
--
Cédric Hannotier
Z
zhou
Fri, Aug 5, 2022 2:09 PM
I am using 2944 USRP which model is X310. We connect the Tx and Rx antenna ports to the DUT via RF cables. The received power at 5GHz is about 23dB lower than the one at 1GHz.We adjust gain in USRP to maintain the Rx power level at different frequencies.N310 USRP has built-in power control functionality.
Hongwei
On Friday, 5 August 2022 at 11:22:19 BST, Cédric Hannotier via USRP-users <usrp-users@lists.ettus.com> wrote:
On 2022-08-04 08:50 -0400, Marcus D. Leech wrote:
Sorry for misunderstanding. I think this is my fault. But as i mentioned
my first question, when i say cable connection, i mean i connected tx
port to rx port with cable. To see the device settings clearly, i did
this. Also, I have b200.
Sorry, I forgot that part.
Make certain that you have at least 30dB attenuation in that cable.
Otherwise you risk one of two things:
o Severe distortion and non-linearity at the receiver
o Severe damage of the receiver
The power output of an RF amplifier will necessarily vary across its
frequency range. I would expect that over 100MHz to 6GHz
that would be perhaps 5-10dB.
I am using 2944 USRP which model is X310. We connect the Tx and Rx antenna ports to the DUT via RF cables. The received power at 5GHz is about 23dB lower than the one at 1GHz.We adjust gain in USRP to maintain the Rx power level at different frequencies.N310 USRP has built-in power control functionality.
Hongwei
On Friday, 5 August 2022 at 11:22:19 BST, Cédric Hannotier via USRP-users <usrp-users@lists.ettus.com> wrote:
On 2022-08-04 08:50 -0400, Marcus D. Leech wrote:
> On 2022-08-04 07:59, henry.powell.xx@gmail.com wrote:
> >
> > Sorry for misunderstanding. I think this is my fault. But as i mentioned
> > my first question, when i say cable connection, i mean i connected tx
> > port to rx port with cable. To see the device settings clearly, i did
> > this. Also, I have b200.
Sorry, I forgot that part.
> Make certain that you have at least 30dB attenuation in that cable.
> Otherwise you risk one of two things:
>
> o Severe distortion and non-linearity at the receiver
> o Severe damage of the receiver
>
> The power output of an RF amplifier will necessarily vary across its
> frequency range. I would expect that over 100MHz to 6GHz
> that would be perhaps 5-10dB.
For the B200, there is some data on RF performance:
https://kb.ettus.com/images/c/cb/B200_RF_Performance.pdf
Hope that's help.
Regards
--
Cédric Hannotier
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