```
Dear Ranjan,

A meeting yesterday where we discussed ARTS got me to remember that you
calculats some special effects, such as defocusing. To just calculate
the transmission between two points can be done by
iyTransmissionStandard if it is combined with ppathFromRtePos2. Like this:

AgendaSet( iy_main_agenda ){
Ignore( iy_unit )
Ignore( iy_id )
ppathFromRtePos2
iyTransmissionStandard
}

So if you set rte_pos2 to the position in the atmosphere in
consideration, and set sensor_pos to hold the position of the
transmitter and the receiver, you will get out two transmissivities that
together give you the atmospheric transmissivity between sender and
receiver for scattering at the point given by rte_pos2.

You did not state a frequency of the radar. If we talk about existing
radars below 100 GHz, the transmissivity will be quite high and the
question is if this is of concern for you. If you want to do some rough
estimates.

The dominating term will be the strength of scattering. To estimate this
you need first of all to find data on the size distribution of the
(dust?) particles and scattering properties. If the particles are small
compared to the wavelength, you can likely start with Mie calculations
but you still need to specify sizes and refractive index.

You also need to consider the antenna pattern, both of the transmitter
and receiver, for the direction towards rte_pos2.

Regards,

Patrick

On 2021-09-02 15:58, Ranjan Mehta wrote:

Dear Patrick,

Thanks for the prompt response !

Can you provide some pointers on how we can create a bi-static configuration ?

We were thinking of two things:

1. Either see if iyRadioLink can be studied and then modified to bi-static
configuration

2.  Look at the iyRadar :  but it only looks are purely back scattered
radiation:  and it takes Z based on the back-scattering direction,
If we can put the transmitter at the same place, and change the sensor
position,  and use Z  based on the sensor-LOS direction (i.e. relative to the
transmitter LOS),  could we then use the iyRadar use case ?

Please let us know! And ARTS is a phenomenal tool !  Just awesome  (We are not
atmospheric scientists, but can still understand a lot from how ARTS is
developed, structured and documented!!)

More later!

Thanks
Ranjan

Ranjan S. Mehta, Ph.D.
Director / Senior Principal Engineer
CFD Research Corporation

p:  256-726-4964   m:  814-404-5926
w:  www.cfd-research.com    e:  ranjan.me...@cfd-research.com

Confidentiality Notice: The information contained in this communication and its
attachments is intended only for the use of the individual to whom it is
addressed and may contain information that is legally privileged, confidential,
or exempt from disclosure. If the reader of this message is not the intended
recipient, you are hereby notified that any dissemination, distribution,
copying, or reliance on this communication is strictly prohibited. If you have
received this communication in error, please notify
confidential...@cfd-research.com

-Original Message-
From: Patrick Eriksson
Sent: Thursday, September 2, 2021 1:19 AM
To: Farid Alam ; arts_users.mi@lists.uni-hamburg.de;
Ranjan Mehta

WARNING: This email originated from outside of the organization. Do not click
links or open attachments unless you recognize the sender and know the content
is safe.

Farid, Ranjan,

Looks like method "*iyRadioLink*" is missing in ARTS 2.4.0, and ARTS
2.5.0 (dev).

Sorry, there is no replacement in v2.4 or v2.5. It should be resurrected to v3,
but unclear when that version will appear.

I take the opportunity to also answering the question from Ranjan, sent to me
personally:

1. Source  and receiver are similar to a bi-static radar arrangement.
2. And the cloud is more of a  "dust-cloud" than hydrometeors !

Unfortunately, there is no ready setup in ARTS for bistatic radars.
Simply as we have never encountered such an user case.

Is it the case that you want to solve this by iyRadioLink? That would be a
possibility, but you have then to switch to v2.2.

Please note that you in any case have to provide the scattering data for dust
yourself.

Kind regards,

Patrick

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```

```Dear Patrick,

Thanks for the prompt response !

Can you provide some pointers on how we can create a bi-static configuration ?

We were thinking of two things:

1. Either see if iyRadioLink can be studied and then modified to bi-static
configuration

2.  Look at the iyRadar :  but it only looks are purely back scattered
radiation:  and it takes Z based on the back-scattering direction,
If we can put the transmitter at the same place, and change the sensor
position,  and use Z  based on the sensor-LOS direction (i.e. relative to the
transmitter LOS),  could we then use the iyRadar use case ?

Please let us know! And ARTS is a phenomenal tool !  Just awesome  (We are not
atmospheric scientists, but can still understand a lot from how ARTS is
developed, structured and documented!!)

More later!

Thanks
Ranjan

Ranjan S. Mehta, Ph.D.
Director / Senior Principal Engineer
CFD Research Corporation

p:  256-726-4964   m:  814-404-5926
w:  www.cfd-research.com    e:  ranjan.me...@cfd-research.com

Confidentiality Notice: The information contained in this communication and its
attachments is intended only for the use of the individual to whom it is
addressed and may contain information that is legally privileged, confidential,
or exempt from disclosure. If the reader of this message is not the intended
recipient, you are hereby notified that any dissemination, distribution,
copying, or reliance on this communication is strictly prohibited. If you have
received this communication in error, please notify
confidential...@cfd-research.com

-Original Message-
From: Patrick Eriksson
Sent: Thursday, September 2, 2021 1:19 AM
To: Farid Alam ;
arts_users.mi@lists.uni-hamburg.de; Ranjan Mehta

WARNING: This email originated from outside of the organization. Do not click
links or open attachments unless you recognize the sender and know the content
is safe.

Farid, Ranjan,

> Looks like method "*iyRadioLink*" is missing in ARTS 2.4.0, and ARTS
> 2.5.0 (dev).

Sorry, there is no replacement in v2.4 or v2.5. It should be resurrected to v3,
but unclear when that version will appear.

I take the opportunity to also answering the question from Ranjan, sent to me
personally:

1. Source  and receiver are similar to a bi-static radar arrangement.
2. And the cloud is more of a  "dust-cloud" than hydrometeors !

Unfortunately, there is no ready setup in ARTS for bistatic radars.
Simply as we have never encountered such an user case.

Is it the case that you want to solve this by iyRadioLink? That would be a
possibility, but you have then to switch to v2.2.

Please note that you in any case have to provide the scattering data for dust
yourself.

Kind regards,

Patrick

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arts_users.mi mailing list
arts_users.mi@lists.uni-hamburg.de
https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi

```

```
Farid, Ranjan,

Looks like method “*iyRadioLink*” is missing in ARTS 2.4.0, and ARTS
2.5.0 (dev).

Sorry, there is no replacement in v2.4 or v2.5. It should be resurrected
to v3, but unclear when that version will appear.

I take the opportunity to also answering the question from Ranjan, sent
to me personally:

1. Source  and receiver are similar to a bi-static radar arrangement.
2. And the cloud is more of a  “dust-cloud” than hydrometeors !

Unfortunately, there is no ready setup in ARTS for bistatic radars.
Simply as we have never encountered such an user case.

Is it the case that you want to solve this by iyRadioLink? That would be
a possibility, but you have then to switch to v2.2.

Please note that you in any case have to provide the scattering data for
dust yourself.

Kind regards,

Patrick

___
arts_users.mi mailing list
arts_users.mi@lists.uni-hamburg.de
https://mailman.rrz.uni-hamburg.de/mailman/listinfo/arts_users.mi

```