Well it's officially been a month or two since I first received the QYT KT-8900. As promised, I would like to do a one-month check-in on this rig!
Installation
When I first went shopping for a mobile radio, I wanted something that would be easy to install and remove should I ever find the need to. The 8900 fit the bill tenfold - it's small, measuring about the size of two stacked slices of bread. This gives it the profile to stick it anywhere in a vehicle, even the arm rest compartment!
In playing around with areas to put it, I decided to give up my front center seat instead of mounting it on the lower console. The radio now rests under the arm rest/center seat back, where it is out of the sun and out of view from any suspicious on-lookers or looters. The antenna and power cables run perfectly below the front seat without any issue.
My main concern after reading several reviews and posts on this radio was that the sensitivity would be terrible, especially in a noisy environment with RFI and EMI. To my surprise, it actually has a useable receiver front end! I do get occasional pops and crackles when the car is in motion on receive, but it's not enough to warrant a modification to the circuitry. Of course, I could install a filter capacitor on the 12V line, but I won't do it unless I deem it necessary. Receive volume is set to a comfortable listening level and is easily heard throughout the cabin. The fan also has room to breathe for cool air intake to cool the final down during prolonged activity.
RF Power Amplifier Mitigation
In my previous post regarding the KT-8900, I mentioned replacing the final's heatsink. I used an inexpensive aluminum type that is often used on a Raspberry Pi processor and I have had no issues with heat dissipation. I feel that it works excellent in comparison to the crappy "thermal foam" from the factory and I could've kept everything else the same.
In the end, I decided I didn't want to risk the final burning out, so I turned the middlemost pot down to what I can only assume is in the ballpark of 10W. I won't know until I get my test equipment from Amazon, which includes an SWR/wattmeter and a dummy load.
Right away I noticed that the fan didn't turn on as much as it did from the factory, meaning that the final was putting out significantly less heat, and with that, less power. I also couldn't smell any burning and I didn't see any smoke demons escaping, so for now, I'll leave it be. My car has a leather interior and we've had a few above 80-degree days here, but it hasn't seemed to phase the radio. It powers on and off perfectly fine without issue.
For now I've decided I will keep the stock A5M06 final and bypass on the A9M15 upgrade. I can't desolder and solder SMD to save my life and I don't want to risk damaging this radio. As long as I can run high power at around 10 watts, I'll be more than happy.
I also measured amperage draw from the radio, and I'm happy to report that it now draws 1 amp or less! There's definitely been a change in power output which is a very good sign. It means I won't end up killing the car's electrical system.
Mag Mount Antenna
The antenna I purchased alongside this radio was a simple, inexpensive mag mount for VHF/UHF. I put it on the center of my roof where I knew I would get the best SWR. I can get 1.2 or 1.3:1 on the entire 2m band and about 1.6 to 1.7:1 on 440. Not bad!
As much as I've been told not to pinch coax, I am feeding it through my driver door via the weather stripping. Yesterday, we had a HUGE rainstorm which I swear dumped around 3 inches of rain at my location. I checked on my car's interior periodically and found that it remained dry! The antenna also withstood the brute force of this rainstorm and is still holding on. To prevent scratching my car, I put a single sheet of wax paper down, waxed side towards the paint. After getting wet (or drenched for that matter!), the paper remained intact. I have also found that plastic Walmart bags work well too.
I have driven at least 45 to 50 mph with the antenna on the roof and I have not had to worry about it being blown off. The magnet seems fair and I think I'll keep this setup as it seems to suit the car well.
The End?
Recently, Amazon, eBay, AliExpress, and other marketing websites have been marking these models as "Out of Stock" or "Currently Unavailable." I have a feeling that these radios will no longer be produced as a result of the newer KT-8900D model, which claims to be an upgrade from the standard KT-8900. There is so much more that QYT can do to these radios to make them a truly robust 25W mobile radio option at such a low cost, so I hope that they are pulling them from the market just to re-innovate their design.
Final Thoughts
In the end, I think this radio was well worth the money. It may seem disappointing that I'm only getting 10ish watts out, but I think that's perfectly fine. I never trusted the claimed 25W output anyway, and 10 watts will plentily suffice for simplex and repeater work.
Many of the complaints and poor reviews were from when the radio was originally released, back in 2016 or 2017. QYT has come a long way from where they began with these radios, and I think they have improved quality control. They have added on a cooling fan as well as a separate programming port as a result of what I believe was customer feedback.
I'm still a little disappointed that I can't fully customize this radio with CHIRP, but I am thankful that it is compatible for programming frequencies. I might have to build a CP2102-based programmer instead of using the outdated PL2303-based one from the factory. It would be very nice to have a customized radio that is specific to me, but for now, I can live without that feature.
So what do you think about the QYT KT-8900? Let me know in the comments below! Hopefully I can get a video up on the KE0SBX YouTube page that discusses how I made these changes to the radio.
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