FrSky RX4R receiver test/review
Results 1 to 1 of 1
  1. #1
    R/C Newbie
    Join Date
    Apr 2012
    Rep Power

    FrSky RX4R receiver test/review


    Sent for review by -
    Discount Coupon ( GBold4570 )

    Dimension: 18×17×7mm (L×W×H)
    Weight: 2g/ 2.4g (with two antennas)
    Number of Channels:16CH (1-4CH PWM from conventional channel outputs, 1-16CH from SBUS OUT port)
    Operating Voltage Range: 3.5V-10V
    Operating Current: [email protected]
    Operating Range: >2km
    Servo Frame Rate: 9ms (HS—High Speed Mode)/18ms (FS—Normal Speed Mode)

    For testing I was sent the Frsky RX4R from .
    I was very interested in this receiver for DLG purposes and it's possible 1s capability making for a very light Rx solution .


    Please dont forget that the servos always plug into the Rx negative to the middle or signal wire on the outside .
    The bind button is very small ( diminutive ) , at first I missed it completely . I needed something to magnify the board with to actually spot it , some one must be getting old or this thing is small .

    Voltage Testing

    I really wanted to see how low the voltage could go before the RX4R browned out . Factory say's 3.5v and I wont argue with them . But in my tests I got the Rx down to 3.2v with a 500mAh maximum current setting on my power supply . This is the lowest any Rx has gone I have tested so far , especially at the 500mAh setting . Now I thought I might throw some other servos at it from my normal analogue servos . I just received some digital servos from HK so I thought , lets give them a try .

    The RX4R browned out straight away .
    With the Rx getting 3.2v , the RX4R was browning out with the servos simply connected to it . ( I kid you not )
    Increasing voltage to 3.6v the Rx stopped browning out with the servos connected , but any attempt to use a servo caused the Rx to brown out . So it would seem the RX4R does not like the HobbyKing SCM12-5 or SCM9-5 digital servos very much . On the other hand analogue servos seem to behave very nicely at low voltage . ( I would suggest this would need further exploration )

    Range testing the RX4R

    I was easily able to get the maximum distance of 50 meters with my Taranis Q x7 in range test mode . Even using my body to try and block the signal there were no problems .

    Interesting for DLG

    My main interest in this Rx was it's low voltage capability as well the ability to give me live Rx Voltage data . Now keep in mind that if you use a UBEC or such you will get the voltage of the UBEC . But if you directly connect a 1s battery , then you can monitor the battery live as you are flying . So as you are having fun , you get live telemetry data on the state of your battery ( voltage ) . You can monitor voltage sag under load and voltage when not doing anything . ( Get some idea of the load the battery is put under ) .


    The RX4R was put into my HK Raven 990 . And from past experience it does not take much weight in the nose to get the CG where the factory recommends . In fact with the RX4R and a small single cell lipo , maybe around 200mAh capacity . The CG is exactly spot on for the factory spec . So for my Raven at least , there is very little in the way of spare weight in the nose for CG . And the flying weight of the Raven comes in at almost spot on for 150 grams . So for models that require the minimum possible weight for CG , the RX4R looks to be the goods . And so far it's 1s capability looks very promising , but I would suggest caution and testing for hardware compatibility .

    Now it would be fair to say that the RX4R has far greater capability than what I am looking for at this time .

    Here is a very nice youtube video by Drone Mesh .

    Now at this time I have no real interest in long range drones , or drone racing etc .
    But I do like DLG , and I like the RX4R for it's size , weight ( lack off ) and live voltage telemetry if you chose to go 1s . ( Which I have done )
    As mentioned the RX4R will live in my HK Raven for now , and I will be doing updates on things as I play with the Raven .
    For a score , it has to be 10 out of 10 for now . Yes ok , what about the Digital servos from HK . Well this is something we always need to check for ( hardware compatibility ) especially when pushing extremes like low voltage . ( 1s )
    A lot of issues could be avoided by running a Rx at 5v to 6v but then the live voltage telemetry would be of little use to us .
    The Raven does have digital servos ( not very good ones in my opinion ) and I will be doing some tests shortly to see how low I can go with the Voltage in the Raven . ( EMAX ES - 9051 )

    Don't forget , there is a Discount Coupon GBold4570 that brings the price down to $29.99 @
    Last edited by old4570; 10-12-2018 at 01:04 PM.

Similar Threads

  1. Gearbest Coupon for Frsky RX4R ( 07 Dec 2018 )
    By old4570 in forum Vendor Deals
    Replies: 0
    Last Post: 07-12-2018, 07:47 PM
  2. Smartech Titan test/review
    By mike in forum Large Scale - General
    Replies: 71
    Last Post: 19-01-2008, 02:20 AM
  3. Throttle/Break Mod Review
    By Star Guitar in forum HPI Savage
    Replies: 15
    Last Post: 07-01-2006, 09:50 PM
  4. Review: Tamiya TL-01
    By PeeDee in forum Product reviews
    Replies: 23
    Last Post: 05-01-2005, 03:44 PM
  5. review!?? or my opinion!?!
    By foolSp33d in forum Batteries and Chargers
    Replies: 0
    Last Post: 12-05-2004, 06:37 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts