RX Audite - SDR splitter/switch with protections

This is very powerful device combines TRX switch, RX splitter, RF limiter protection for both RX outputs, INBAND RX antenna input and optional RX preamplifier. You can share your main TX/RX ANT to two RX with RF power limiter protection.

This is ideal solution for Spectrum Panadapter, WebSDR or Skimmer Server - RBN.

When the controller is OFF then main TX/RX antenna goes to the SDR RX output - with 10 mW RF limiter protection. You can switch ON preamplifier even you left controller OFF by the POWER switch. When the controller is ON, Main TX/RX antenna is shared between TRX and SDR outputs. During TXing, the SDR RX output can be connected to the internal dummy load or to the INBAND RX antenna input. You can switch the SDR RX output to the INBAND RX ANT port not only while the TRX is TXing, but by the front panel switch, it can be switched all time. Optional HIGH IP3 internal preamplifier can be used for insertion loss compensation. Additional gain is variable, up to 14 dB.

Main functions:

• Frequency range: 0,1 to 60 MHz
• Main TX/RX ANT splitter to two RX
• RX RF limiter protections for both RX outputs
• HPF (> 100kHz), high voltage and current protection at both RX outputs
• RX ANT (INBAND) input - works only for SDR output
• TX-RX switch controlled by the PTT
• Designed for 2nd RX, WEB-SDR, SKIMMER or Panadapter
• Controller OFF = TX/RX ANT port to SDR RX out via RF limiter protections - Skimmer/web-SDR
• Controller ON = TX/RX ANT port splitted to TRX and SDR RX out via RF limiter protections
• TRX TX to main TX/RX ANT = SDR RX out to dummy load or INBAND RX ANT input via RF limiter protections jumper switch
• Front panel Switch - SDR RX output to RX ANT (INBAND) during transmitting or all time
• Preamplifier (optional): insertion loss compensation, up to 14 dB of additional gain
• Preamplifier could be ON for SDR even the controller is OFF
• Very high isolation when TRX transmitting and SDR goes to RX ANT (INBAND) 100 dB @ 14 MHz and 80 dB @ 50 MHz
• Please, see also Frequently Asked Questions There FAQ

One black box but many different parts inside:

• TX / RX switch controlled by PTT signal
• PTT splitter (IN/OUT) in sniffer mode (IN directly to OUT) or output PTT FET switch picture
• 2-way RX splitter with low insertion loss
• 2 x RF limiter RX protections - the best on the market :-)
• RX switch for RX ANT (INBAND) (only for SDR output) settings
• Both antennas with HPF > 100 kHz (blocking AC noise)
• RX preamplifier (high IP3, 18 dB gain) with variable ATT - OPTIONAL link
• RX lines with High Voltage protections > 60 V AC
• RX lines with SuperFuse current protections > 100 mA
• Very high isolation TX to SDR, between RX output ports, INBAND RX and TX/RX ANT port

Parameters:

• Supply voltage DC + 12 to 14 V (13,8 V recommended), DC plug cable
• Supply current DC max. 0,7 A with preamp
• Maximal TX power 250 W, recommended 200 W
• Very high isolation when TRX transmitting and SDR goes to RX ANT (INBAND) 100 dB @ 14 MHz and 80 dB @ 50 MHz
• PTT IN open PTT = RX, GND = transmitting
• PTT OUT sniffer (IN=OUT) or output FET (max. 35V DC and 0,5 A) picture
• PTT is not designed for QSK but you can use with right PTT lead/tail/TX delay time: min. 20/20 ms
• Default configuration SDR to the internal dummy load (older 2211xx to RX ANT (INBAND) input) while TRX transmitting settings
• Optional Preamp preset to insertion loss + 6 dB (total gain abt 10 dB)
• Low insertion loss see measurements picture
• TX insertion loss less than 1 W from 100 W @ 28 MHz

RF limiters:

• Limiter for RF signal to + 13 dBm = 20 mW (could be + 17 dBm) @ 50 Ohm
• Current SuperFuse - the only at market
• Can survive high input power (current) for long time
• The soft clipping reduces the IMD products of a classic hard diode clip limiter

Internal Preamplifier module: (OPTION / version with preamp) link

• Preamplifier could be retrofitted also by you - customer
• High IP3 preamplifier module with 18 dB gain
• With 2SC5551 transistor
• Real OIP3 is +34 dBm
• Preset to 40 mA @ 13,8 V
• Low Noise Figure (NF) < 2 dB (60 mA 50 MHz)
• Variable gain by output ATT
• Preset to 10 dB for TX/RX ANT to both RX outputs = insertion loss + abt. 6 dB (1S) of gain
• Bypass relays
• Could be switched ON even the controller has got power switch OFF - preamp for SDR output.

Included in package:

• Controller assembled and tested
• DC plug cable connection

Controller without Optional Preamplifier

Controller with Optional Preamplifier

Example of connection

Example of connection with external 2-way splitter for 2 RX

Block diagram of the examples for all functions:

1. Controller is switched OFF

Even the Power Switch is OFF, you are able to switch ON the internal Preamp. (Controller must be powered by the DC voltage)

Signal from the main TX/RX ANT goes to the SDR RX output port. There are protections and RF limiter

2. Controller is switched ON

Signal from the main TX/RX ANT goes to the TRX and SDR RX output port via the 2-way splitter.

There are protections and RF limiters for both outputs

You can use Preamplifier when it is assembled inside.

3. Controller is switched ON: TRX is transmitting

TRX is transmitting to the main TX/RX ANT and the SDR RX output port is connected to the internal dummy load or to the INBAND RX ANT port. There are protections and RF limiter

4. Controller is switched ON: SDR RX out switched to INBAND RX ANT by the front panel switch

In this case main TX/RX ANT goes to the TRX port via the protections and limiter and you can use also preamplifier.

SDR RX output port isconnected to INBAND RX ANT input. There are protections and RF limiter

Measurements:

TX way parameters	BOX OFF: TX/RX ant to SDR out	BOX ON: TX/RX ant to TRX and SDR out
Isolation between RX ports	BOX OFF: TX/RX ant + PREAMP to SDR	TX/RX ant + PREAMP to TRX and SDR

RX AUDITE VHF - version designed for 6 and 4m with filters and LNA

more here

Related products:

Beverage RX antennas

3-way RX splitter

Optional preamp module

User review

QST 04/2023 review by Pete N4ZR : There is PDF from QST, many thanks! QST 04/2023 PDF

Thanks for email from Julio, PP2BT (RX Audite - CQWW CW 2022 PT4A): Hi Jan, good morning. We used RX Audite throughout WW CW and it worked wonderfully. Congratulations! Nice equipment!! We use a single SDR RSP1A + CW Skimmer Server + Aggregator. Despite the SDR only working on 3 bands at the same time and the old notebook (I7 second generation + 8GB of RAM) we didn't notice a loss of performance and the information arrived in great quantity/quality. We had a quality leap in the multiplier hunt. Now let's calmly study what we will do to improve what we already have based on what was observed during the contest.

Thanks for email from Mike, DF3VM: Hi Jan, first of all, my RX-Audite worked perfect during the last contest feeding my RSP1A SDR with CW-Skimmer. No overload, perfect switching. Love this little thing :-)