Manager


Manager - NA4M
Manager Notes

Reviews For: QYT KT-7900D Mobile

Category: Transceivers: VHF/UHF+ Amateur Base/Mobile (non hand-held)

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : QYT KT-7900D Mobile
Reviews: 9MSRP: 90
Description:
Quad band mobile Transceiver
Product is in production
More Info: http://www.qyt-cn.com/en/products2.html
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
21.592.4
W1LOG Rating: 2019-11-06
It's cheap... Time Owned: 3 to 6 months.
OK I got one on Amazon.
It was on sale, I had a credit and all said and done it cost me like $30.
For a $30 Radio it works well. The knobs will fall off but hey it was a $30 radio... If you buy one of these expecting the performance of a Kenwood you'll be upset. Keep in mind what it is and make sure you stay in the ham bands.
VA3UJC Rating: 2019-09-26
bad Time Owned: 0 to 3 months.
I purchased this Radio directly from china. I had seen this or a similar radio in a vehicle, and thought it would be a great size for my small car.
Delivery was just over a week.
I connected this up on my desk, to program etc.
a programing disk was supplied. this proved to be blank. I programed qty 10 local repeaters by using the hand mike ,no problem.
during the night, I was awakened by a loud continual click clack. I investigated through and outside the house. Eventually I realized it was the radio. This had power, but was switched off. I remove power, noise ceased.
the next morning I switched my computer on. the radio fired up transmitting. Again power on but radio off. later I tried the scan feature. The click clack noise was now apparent.
after reading KA7OEIs blog re this radio.
I understand it is not legal, and has many faults.
I am no radio expert, Wish I had researched prior to purchase.
my unit is back in the box and on the shelf.

KA7OEI Rating: 2019-02-01
Strong harmonics - Beware! Time Owned: 0 to 3 months.
One of these radios (also branded the "SocoTran KT-7900D" - and it is likely known by other names as well) landed on my desk and like any other radio - particularly "too-cheap-to-be-true" Chinese radios - I put it through its paces.

Sensitivity: Very good, but the front end overloads very easy.

Menu system: Infuriatingly poorly designed and laid out. Similar functions are not necessarily grouped near each other and something like the subaudible tone selection always forces you to start at the first tone (e.g. 77.0Hz) rather than the tone that you used - and a few other hair-pulling things. You will probably want to use a computer to program this thing.

"Bands": The 300 MHz range band is utterly useless to any law-abiding U.S. citizen.

The scariest part about this radio is that it seems to share a single output power amplifier (PA) for all of the bands - and a *SINGLE* low-pass filter that seems to have a roll-off in the 550-ish MHz range.

While the harmonic content on UHF was better than -40dBc - and the 2nd harmonic of the transmitter on 222 MHz was just barely legal (believed to be a quirk of this particular radio) 2 meter was just plain scary.

Our exemplar's 2nd and 3rd harmonics were just -23dBc - that is, at full power (22-25 watts) their effected RF power was around 100 milliwatts, each, approximately 4000 times (36dB) above the legal limit (see FCC §97.307). In fact, we were able to key distant (20+ mile away) mountaintop UHF repeaters with the 3rd harmonic on 70cm - something that we probably shouldn't have really done in retrospect!

On 222 MHz the picture is only slightly better: Its 2nd harmonic measured about 40dB down at 2.5 milliwatts - but this is still 20dB higher than regs allow.

Interestingly, this radio does have an "FCC" logo on it which indicates that it may (or may not) have been tested for part 15 compliance - but this has nothing to do with transmitter cleanliness! As any amateur should know, *they* are always responsible for the transmitter they use and making sure that it is complying with the regs - not the manufacturer.

Would I use this radio? Yes - only if I had the appropriate low-pass filters inline.

Would I recommend this radio to someone else? Yes, if I truly despised them.

Correction to the previous review: I mis-typed when I mentioned that this radio was "barely legal" on 222 MHz. As stated in later in the review, it falls about 20dB short
W8LGX Rating: 2018-07-10
Good Rig For The Money Time Owned: 0 to 3 months.
Bought this at Dayon/Xenia for $90 - I needed a 220 MHz rig in the shack for control of the local repeater.

First, an apparent software bug. When programming PL/CTCSS from the mic, the TX and RX tones occasionally get reversed. Haven't noticed this when programming from the PC (I used the latest CHIRP program). So if you put in a tone for transmitting and it doesn't seem to work, reprogram it or try putting it in the RX tone slot.

And yes, it WILL transmit outside of the ham bands out of the box, with NO warning, so be careful with your frequency settings!

Checked it out on an older CT Systems/ Wavetek 5100S service monitor. Frequency accuracy out of the box was excellent, 144 - 220 -440 frequencies all within +/-100 Hz. Receive sensitivity was very good, 12 dB SINAD was less than 0.15 uV on all bands (except above 450 MHz where it would degrade to about 0.25 uV near 470 MHz).

PL/CTCSS was accurate, within +/-0.2 Hz on TX, and receive acceptance was +/- 0.7 Hz. I did notice that tone recognition on signals of less than 20 dB quieting was not that good, but once the tone was detected the squelch would stay open until the signal dropped out.

The transmitter power output was below spec on all bands (measured with a Bird 43 wattmeter, 13.6 VDC supply). High power @ 146 MHz = 19 watts, high Power @ 223 MHz = 23.5 watts, high power @ 440 MHz = 16.5 watts (Spec is 25/25/20 watts).

Modulation was good, mic audio peaked out at +/-4 KHz deviation; Touch tones were at +/-3.5 KHz deviation; PL/CTCSS at +/-0.5 KHz deviation.

The 'S' meter is more like an RSSI meter. Wider log range than a standard S meter, so it might be good for fox hunts. The meter maxes out with a reading of 110 with a 200 millivolt signal(!); you ought to be able to see the transmitter antenna when the meter maxes out!

The one thing I do not like about this rig is that when you have it on scan, the channels with carrier squelch will often 'burp' when it lands on the channel, delaying the scan and becoming annoying after a while (noticed this only on 2 M/VHF channels). I have the squelch setting up to 6 and it doesn't fix it. Synthesized rigs made in the last 35 years mute the audio until the LO settles down - apparently a feature they left out of this radio. This is why I gave it a 3 rating.

I have not done an adjacent channel rejection test, and I live in a rural area, so I don't know how well it handles high RF environments. I have also not used this mobile yet, but as a base in a rural area, it performs very well.

A final note - good possibility this is a Baofeng HT with a TX amp, a color display, and 220 MHz filters/ tuning packed in a mobile case. Many Baofengs have a receive spur at 442.000 MHz. This rig has it as well. The menus are similar to the Baofengs. And you can hear a relay click when going to or from a 220 MHz frequency - switching in the outboard 220 MHz circuits?


KG7FIU Rating: 2018-07-08
Kind of sucks Time Owned: more than 12 months.
Bought the QYT 7900D about a year ago and installed in my mobile. At first I thought it was a great deal for a tri-band < $100. But over time I've become less-and-less enthusiastic about this radio. Now I kind of hate it...

The good: TX seems fine. Am able to hit most of the local 144/440/220 repeaters OK. And the mike audio is nice and hot. Like that part a lot.

The bad: The RX leaves much to be desired. Sensitivity sucks, and so does noise handling. When driving around, I keep the squelch as low as it will go ("1") in order to prevent stations from cutting out, and even that isn't close to being successful. The LED meter is quick-response, and shows that signal levels are fluctuating widely, almost out-of-control. Unless you happen to be connected to a super-strong repeater, the picket-fencing makes things almost unlistenable (Note: radio might work better if you use this rig only while stationery and not driving around).

I've read that someone else purchased this unit and found the scan feature didn't actually work -- but on my unit the scan seems to function OK.

Have come across some software "bugs" in the menus and in general usage. This radio does not seem particularly easy to program.

Another annoying thing on this radio is that when programming channels using the front panel/microphone, some important settings (such as the transmit CTDCS offset) do not seem to save properly(!) [Not sure if this is a defect in the firmware, or a problem in my radio] Makes it virtually impossible to program channels from the front panel alone. Fortunately the channel programming works as expected when programmed through software via computer/USB-serial jack on back.


W4NNF Rating: 2018-05-29
It's cheap and it works Time Owned: 0 to 3 months.
It's amazing what the Chinese can sell you for less than a hundred bucks these days. Like this little quad-band FM rig. It's small, cute, light and has a pretty color display that's legible even in bright light.

Did I say quad band? For us in North America, this is really a tri-band radio, 2-meters, 220, and 440. Oh, there's another band, 350Mhz; I guess that's a ham band in the far east, but in this region it's a military band, so, yeah, tri-band. Still, three bands at about 25 watts per band (power output varies a little band to band) for less than 100 dollars amazes me.

I've gotten good audio/signal reports with it. It's cheap. It's small so it's easy enough to find a place for it in a modern vehicle with not many places where you can put a radio. Anyhow, do you really want to spend a lot of money on a mobile rig to chat on the analog repeaters? I didn't think so.

What comes with it? Not much, a mic with the usual (illuminated) buttons. A DC power cord terminated in a cigarette style plug. A mobile bracket and a few screws. But that is enough.

The bring down? I've had fairly good success programming Chinese radios by hand when I've had to. Not this little sucka. I had zero success with it. Its manual is madness. It's in some sort of English...but no sort I've ever heard. Get the programming cable (the radio is supported by Chirp). I threw in the towel after an hour of fiddling with the tiny buttons and trying to figure out what the manual REALLY meant.
KC4RAF Rating: 2017-10-02
Not too bad a transceiver so far. Time Owned: 0 to 3 months.
Hate to admit that I own one of these, but it was a gift and no money out of my pocket.
Connected it to my J-Pole and made a few contacts, simplex and repeaters. All reports said it did very well, (never told any of the other operators what brand or model till later on in the qso.
The receive was really good also; I was surprised that it could pick signals up out of the mud!
For the price it cost the friend who bought it for me, well I told her it did the job just fine.
BTW, it was able to hit all the repeaters in the area, (~40 miles radius).
The 350 to 390 Mhz is only good for listening to military only. I actually haven't tried it on that band to see how well it receives yet. More than likely will this coming weekend.
For the price, I would say it's ok for playing around with, but not to save your life with it.
W6CAW Rating: 2017-08-26
Great for $99.00 Time Owned: 6 to 12 months.
What do you expect for a $99.99, 25 watt, quad bander? Even for the money I think it is a nice little radio. Talks and receives just fine.
SV1HEP Rating: 2017-08-26
Garbage RX Time Owned: 0 to 3 months.
This radio is one of the poorest receiver ever made by the humanity and suffer from incurable diseases.
I will start with receiver.
It's not exactly a receiver, but a broadband front end stage only, without any bpf on it, especially in first coverage band 136-250. The incoming noise from whole this band makes the front end overload all time, and signals bellow S-5 to 6 it's not possible to passing over this mess.
Even with a small antennas the incoming RF from every corner of universe makes a wall for and to desired frequency signals bellow S5-6.
For a local repeater works ok, but not better from a hand held with a hand held antenna on it for sure.

In to the other bands section 350-490 seems to work better. Not any special, but ok.

In the transmitter section. Just a normal trx. Around 18watts plus or minus depends of band.
I don't make any out of HamBand test without a dummy load.

The menu is easy and shows but not working functions like:
No backlight on-off
No scrambler on or off(not needed but)
When use RX CTCS with squelch open from menu (not from monitor button), the receiver opens to any incoming signal with or without CTCS tone and just silencing the receiver like a normal squelch. Garbage.

For a good signal reception, needs to monitoring from menu, over to one band. I don't know why, but with dual monitor the receiver slightly works better. Example. Main to 2meter band, and simultaneously monitoring 70cm band. If use the other two bands for monitoring, a annoying relay works continuously makes click click drives him self to death.
I have read some of them not scanning. My radio scanning but like a slumber sloth.
Any way. This radio is Chinese Made. Thats means a lot by self.

Conclusion. For my unit. For the money it's a good expensive Rubik's cube to kill someone his time, searching how to make this bad transceiver to play like a real radio.

A give only a 2 points for size, screen and transmitter.

Keep your money for something better than this.
Sorry for my bad English.
73
Chris