sdrangel/sdrgui/limerfeusbgui.md

LimeRFE USB control

The LimeRFE or Lime RF Front End is a power amplifier and LNA board designed to augment the capabilities of the LimeSDR in order to build an operational radio solution. The usage is not limited to LimeSDR any Rx or Tx device can be connected to it. The LimeRFE can be controlled directly via its USB port independently of a LimeSDR device. This interface allows exactly that from the SDRangel GUI.

To open the LimeRFE USB dialog open the Preferences sub-menu from the top bar and click on the LimeRFE item. This item is available only when the code is compiled with the LimeRFE branch of LimeSuite.

The dialog is non-modal so that it can be left open and keep the control on LimeRFE while other functions can be used.

⚠ Disclaimer: please use this interface and the LimeRFE sensibly by making sure you are licenced to operate it on the selected frequencies. If you are a licenced amateur radio you should make sure you operate on the bands allocated in your region as some bands are exclusive to a specific region or country.

1. USB serial devices list

This combo lists all USB serial devices list available in the system regardless if they are LimeRFE or other devices. You must specify the device corresponding to a LimeRFE device to be able to open it successfully with (2)

2. Open device

Click on this button to open the serial device selected by (1). You need to open the device successfully prior to any operation. The open status is displayed in the status window (5).

3. Close device

If you have more than one LimeRFE connected to your system you have to close one before opening another by using this button.

4. Pull device configuration to GUI

Use this button to retrieve the LimeRFE device current configuration and populate the GUI with its data.

A. Rx channel control

A.1. Rx channel group

Select the channel group using this combo. Groups are:

• Wideband: covers all frequency ranges in two sub-bands
• HAM: covers amateur radio bands
• Cellular: covers cellular phone bands

A.2 Rx band selection

Depending on the channel group selected in (A.1) use this combo to select the band.

Wideband channels

• 1-1000MHz: 1 MHz to 1 GHz
• 1-4GHz: 1 GHz to 4 GHz

HAM channels

• <30MHz: HF bands i.e. lowpass up to 30 MHz
• 50-70MHz: covers the 6m and 4m bands
• 144-146MHz: covers the 2m band
• 220-225MHz: covers the 1.25m band (region 2)
• 430-440MHz: covers the 70cm band
• 902-928MHz: covers the 33cm band (region 2)
• 1240-1325MHz: covers the 23cm band
• 2300-2450MHz: covers the 13cm band
• 3300-3500MHz: covers the 9cm band (not available in all countries)

Cellular channels

• Band 1: 2110-2170 MHz
• Band 2: 1930-2000 MHz
• Band 7: 2620-2700 MHz
• Band 38: 1800-1880 MHz

A.3 Rx port

Select which port to connect the Rx to:

• Tx/Rx (J3): this is the J3 port combining Rx and Tx. When cellular bands are selected this is connected to a diplexer internally
• Tx/Rx 30M (J5): HF port only available when wideband channels are selected

A.4 Attenuator

Select attenuator value from 0 to 14 dB in 2 dB steps.

A.5 AM/FM notch

Toggle AM/FM broadcast bands notch filter.

B. Tx channel control

B.1 Copy Rx band settings

When selected the Rx channel group (A.1) and Rx band (A.2) is copied to the Tx channel group (B.2) and Tx band (B.3) respectively.

B.2 Tx channel group

Select the channel group using this combo. This is identical to the Rx side (A.1).

B.3 Tx band selection

Use this combo to select the band. This is identical to the Rx side (A.2).

A.3 Tx port

Select which port to connect the Rx to:

• Tx/Rx (J3): this is the J3 port combining Rx and Tx. When cellular bands are selected this is connected to a diplexer internally
• Tx (J4): Tx connected port only. Can be used to split Rx and Tx to drive a higher power P.A. for example

C. Power and SWR

C.1 Activate power measurement

Check this box to enable power measurements.

C.2 Refresh measurements

Use this button to refresh the power measurements.

C.3 Forward power (relative)

This is the relative forward direction power in dB.

C.4 Reflected power (relative)

This is the relative reverse direction power in dB.

C.5 Return loss

This is the return loss in dB and is exactly (C.3) minus (C.4).

C.6 Voltage Standing Wave Ratio

This is the VSWR computed from the return loss in (C.5)

C.7 Power measurement source

Use this combo to select the power measurement source:

• EXT: External: select this when a dual directional coupler is connected to Ref (J17) and Fwd (J18) ports
• CEL: Cellular: select this to use the internal coupler when cellular bands are engaged

C.8 Monitor power continuously

Use this switch to activate the continuous monitoring. A measurement will be taken every 500ms.

C.9 Power correction

Use a power meter and apply this correction to obtain the real delivered power in dBm. There is one correction factor by band. The values are saved in the persistent settings.

C.10 Corrected power

This is the corrected power in dBm and is exactly (C.3) plus (C.9).

C.11 Corrected power in Watts

This is the corrected power in Watts.

C.12 Corrected power averaging

Use this switch to activate the averaging of corrected power. This is a moving average over 10 measurements thus over a 5s period.

D. Rx/Tx mode selection

D.1 Rx mode

Use this button to switch on Rx. This has no effect when Cellular channels are engaged.

D.2 Tx mode

Use this button to switch on Tx. This has no effect when Cellular channels are engaged.

D.3 Rx/Tx toggle

Use this switch to activate Rx/Tx toggle. When Rx is switched on Tx is switched off automatically and vice versa.

D.4 Rx/Tx device synchronization

When switched on this connects the Rx (D.1) and Tx (D.2) switches to a Rx and Tx device set selected by (D.5) and (D.6) respectively in order to start or stop devices accordingly.

D.5 Rx device set sequence

Select the Rx device set sequence with which you want to synchronize the Rx switch (D.1). Note that this is the sequence of Rx in increasing order of Rx tabs and not the tab number itself.

For example if you have a configuration with R0, T1 and R2 tabs the device set corresponding to R2 will be identified with sequence number 1.

D.6 Tx device set sequence

Select the Tx device set sequence with which you want to synchronize the Tx switch (D.2). Note that this is the sequence of Tx in increasing order of Tx tabs and not the tab number itself.

Using the same example as above T1 is identified with sequence number 0.

D.7 Refresh device sets sequences

When the configuration of device sets changes you can use this button to refresh the device set sequences in (D.5) and (D.6).

5. Status window

This is where status messages are displayed.

6. Apply changes

Use this button to apply configuration changes. You must press this button to make any of your changes active.

7. Close dialog

This dismisses the dialog.