Description

Over 11 hours of video proof it passed This tested!!! here is the link:

https://youtube.com/live/h7AkLQsqAI0

Thanks to everyone who watched this video!! I may have to do a part 2!!!!

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Page update on 5/6/2026

NOTICE: keep in mind outside temp, how many fans are used, if air conditioning is used at the repeater site, what type of enclosure case is used to hold the radios,etc will effect the results, so the results can vary from setup to setup!

Planned YouTube live video date & time is Wednesday May 6 at 6:00pm Central time!! unless bad weather happens!

Reason for date change = Sorry for the date change but to be more accurate I am building a “duty cycle tester” circuit to do this testing with.  Duty cycle tester is done, here is a video link to that tester click here

This duty cycle tester will keep playing the same message in till the TX time is up, once that time is up it will cutoff message mid sentence this is normal operation of the tester!!!

go here to turn on notification for this live stream

https://youtube.com/live/h7AkLQsqAI0?feature=share

NOTE: The plan is to do a 90% duty cycle test, however if i see radio temps go to high or wattage goes to low I will stop the test and do another live feed using a lower duty cycle in the future!

info on radio gear setup:

Video of this setup and video info click here

LOOK AT PICTURE to see the setup!!

To download a picture of the setup( NOTE: white Wireless Thermometer was moved next to wattage meter)   click here

To see picture on how temp probe is hooked up to TX radio click here

repeater rack and retevis Ra-87 mobile fan mod if you are interested in buying this click here

(2) retevis Ra-87 mobile radios as a repeater (repeater setting in radio menu) with 80mm FAN mod on transmit (TX) radio which is the top radio.

(1) 80mm Fan mod that is blowing on the output I.C with radio cover off and fan will run all the time!! maybe two fans are need? We will find out!!!

temperature probe measuring temperature of the output I.C (its a small circuit) on the TX radio ( top radio)  to see how the temperature probe is mounted click here

workman wattage meter measuring wattage output of TX radio (top radio)

Wireless Thermometer which has indoor temperature =  top number is outdoor, middle current time, bottom number is indoor temp( white in color, This was moved to next to the wattage meter)

bottom radio is the receive (RX) radio

50 watt duplexer (above the power supply)

30amp power supply with built in fan ( bottom of repeater rack) power supply i am using is this one click here

SWR = about 1.265 ( tested with NanoVNA) are you using a dummy load? NO why? people don’t use dummy load when repeater is being used at a site! its hooked up to my adjusted SWR j-pole antenna, which uses my adjustable SWR j-pole antenna kit that i sell click here for that kit!!

wattage output AFTER the duplexer is about 30 watts

TX radio mic is plug in just in case i need to key up TX radio

Retevis RA-87 radio power supply is plug into a smart WiFi outlet so i am able to turn power off remotely!!

I have a private video feed to monitor radio temp,radio output wattage, indoor temp!

prerecorded message saying we are testing radio duty cycle with call sign. This message will key up radio for “about” 9 mins with a off/wait time of “about” 1 min which means about 90% duty cycle test!! This is being done with a handheld radio on low power using a battery eliminator which is plug into a 5 amp power supply! The is about 120 feet from the RA-87 repeater which is tuned to the repeater freq and duty cycle tester off camera. 

Hopefully I don’t have any hardware failures like power supply,key up radio,fan,etc then of course test will stop. if i see the probe temp go to high or the wattage starting to drop i will stop the test!

info on YouTube LIVE stream and video:

Length of this test is planned for “about” 12 hours! however YouTube live feed could be less do to internet,power,etc that could go out but i will try my best to keep the YouTube live going for as long as i can!! NOTE: YouTube only records/saves 12 hours of video!! 

NOTE: during the live video there MAY not be any audio/sound if there is sound it will be the message coming over the RA-87 repeater, I will have a handheld about 1 inch away from ipad microphone so this means you will also hear the fan running, my temp probe meter beeping once in awhile and outside noise too! also there is about 1 min delay meaning when something changes on my end (i.e wattage meter reading,etc) it will be about 1 min before you see it on your end!!!

NOTE: if all goes well YouTube will save this as a video so it can be viewed in the future!! NOTE: YouTube only records/saves 12 hours of video!!

any question send an email to:

[email protected]

if you would like to donate to help with future test like this send whatever you want using zelle, info on how to send using zelle here:

https://www.gmrstwowayradio.com/forum/viewtopic.php?t=175

Thank you!