You just saved me from making a BIG mistake (from a spectrum standpoint). I'm in the market for a QRP FM Transmitter but don't want to sacrifice signal quality. I'm so glad I checked youtube and found this presentation. I really enjoyed this presentation. I got a lot of knowledge about whats on the market and the way you presented it was right up my alley. It was like I was in my uni engineering lab and you were giving me scoop on what you found in your research. Broke up the presentation with just the right amount of informality (i chuckled when you cursed). Going to watch it again I enjoyed it that much. Thanks! Subscribed.

Very interesting ,good presentation enjoyed watching ,take care 73 de ve3hip from Welland Ontario Canada 🇨🇦

Great video. The cussing made it even better. Usually these videos are so dry and boring, made it more exciting haha

Excellent video presentation, cleared up a lot of information, thank you

Thanks for sharing your thoughts on this topic. I've been looking at fm x matter. You really opened up a lot of research on this, great. Rid on maui

I have a vintage stereo with a nice FM tuner (Yamaha T-2). Broadcast radio is pretty horrible these days (as is broadcast television), so it never gets used. I want to simply transmit music from my pc to the FM tuner if only so that it is an active and organic part of my stereo system. Your video helped me to understand which budget transmitter choices there are and why I might choose one over another. I still don't know about audio quality, but at least I know of a couple transmitters on this list that I can try. Thanks.

I forgot to say that if you need MPX input, then you got to get the BH1414K transmitters. If you don't know what MPX is, then you don't need that - just get ELE or QN8066 transmitter.

Awesome presentation. This was a great dump of much needed information, thank you.

Very Informative...Thanks.

The one @18:05 are great FM transmitters. Clean and on point with great quailty. We have been running them for years.

Really great video! I would be pretty interested in your FM transmitter, 1w is good for me!

I've tried the shit QN8027 in the Little 1mw ebay tx module, and found there was a few spurs at +-12Mhz on each side of the carrier, but is nearly -35 and -40 dbc not 25 -15dbc like yours. I added a 1Watt rf booster amp on it, but used a tuned ring and stub ant it has a narrow bandwidth and the spurs end up -60dbc down, I tested the band splatter with a fm radio just meters from the transmitter and yes its like faint second station appearing across the band, but its so weak there is no way it will interfere with another broadcaster. The sound is good, you can actually plug the thing in and it powered via the usb socket and it comes up as a sound card CD002 you send digital audio directly to it. It sounds is surprisingly good.

I saw in the documentation that the Quintic QN8006 has RDS support. I can't wait for an antenna and test this out with Stereo Tools! Bloody excited!

One flaw I have discovered with many of these transmitters is the audio is very muddy due to the Pre-Emphasis being set incorrectly.

Legitimately incredible video. Thank you so much!

id like to thanks this vlogger. this makes my reference when buying my 7w fm transmitter with QN8066 . i just want to ask a question. if this fm transmitter with QN8066 is good to pair with booster transmitter pallet with 250watts output? thanks a lot.

I learned more in the last 20m about Chinese FM than I ever did on rqdionecks

I got the one at the lower left @15:46. I got it from "SZHQ Eelectronic [sic] Store" through AliExpress for about $30 including shipping to the US. It came without any documentation. Here's what I figured out: The DC input is specified at 12 volts at 1.0 Amp. It does not come with a power supply, so I used one I had on hand: 12 V up to 3 amps. The audio input on the heatsink side is apparently the stereo "line level" input. I presume the other is "mic level"; its tip has 5 volts on it (for a condenser mic?). On startup, a momentary message appears in Chinese. Google translate said "This kit is only for sale abroad. It is strictly forbidden for sale or use in China. Violators shall be liable for all legal responsibility!!!" There is a sticker on the heatsink that says the same thing. I guess the Great Firewall can't stop FM radio. After the Chinese warning, a settings screen appears. There are a total of three parameters that can be adjusted: "FRE", "VOL," and "PO" (frequency, volume [modulation level], and power). There are three buttons along the right side of the display; let's call them UP, MENU, and DOWN. To adjust the parameters: press and hold MENU for 4 seconds. The FRE item is highlighted, and the UP and DOWN buttons will adjust the frequency in 0.1 MHz steps. Once FRE is highlighted, pressing MENU highlights each other parameter in turn. Changes take effect immediately. VOL has a range of "0" to "30," and came set at 30. At 30, only tiny hint of audio was heard. It wasn't like it was very quiet, but more like only the loudest parts were punching through. Only by LOWERING the VOL setting to about 19 could audio be heard. It was like there was a DC bias on the audio and the VOL setting was amplifying and pushing the whole signal into clipping. This was with the line level input; I did not try the mic input. I suppose the mic and line level signals are summed at some fixed ratio? And the VOL adjust affects the sum? The "PO" power setting goes from "0" to "300". I used a Surecom SW-102 meter (kzfaq.info/get/bejne/aa2Sqaul07GRlX0.html) into a dummy load to measure the power. The SW-102 is designed for 125 - 525 MHz and I had set the transmitter to 106.5 MHz, which may explain why it only read "1.53" watts at setting "300". Or maybe it really only puts out less than 2 watts? Lowering the PO setting lowered the power as low as "0.071" watt at setting "100". Below setting "67" the power jumped up to full power again! Strange. After running about an hour at max power, the heatsink was 21 deg C above ambient. It sound like there is pre-emphasis, but there is no pre-emphasis adjustment; I don't know what it is set to (50 or 75 uS?). There is an SD card slot, but no menu item refers to it. Perhaps plugging an SD card with mp3 files will cause them to be played? And summed to the mic and line signals? With no audio input there was an audible whine maybe 30 dB down. Perhaps this was my power supply? Or maybe digital crosstalk on the board? More tests are required. The FM chip may be "the best" in terms of spurious RF harmonics, but as a whole (including the audio performance and menu settings) this transmitter is pretty rough.

Hi, great vid...I have the cze-7c. Can you recommend an affordable fm transmitter.

I bought a Retekess TR508. Any idea what FM IC those are? I looked inside and see a microcontroller of STC8G1K08. Not sure what that means. I think mine has grounding issues, and I'm not sure if that is inherent in all of the TR508 or not. If the transmitter is on and is within several feet of my mixer, whether it's plugged into the mixer or not, there is a terrible humming noise when I turn up the volume for channel 1 on my mixer. The only difference between channel 1 and the rest of the channels on the mixer (ARTPro USBMix4) is that channel 1 has phantom power. Though the humming is still there whether I have phantom power on or not, whether I have a mic plugged in or not, and the hum is in the actual audio (not just the radio listening in from the transmitter). If I touch the transmitter case, then the hum significantly lessens (though not gone), and if I turn off the transmitter, the hum is gone. So I have to have a big, long aux cable and have the transmitter far enough away that it doesn't interfere with the sound in the mixer. What in the transmitter could cause this?

Thanks. Great video with many good information.

Thank you for this video! But I found it to late, I still ordered a BH1415F transmitter....Retekess TR509 :-( The ELE EL-07 @ 26:48 with the "?" seems also to use the BH1415FIC (product information @ eBay). I´m searching for an QN8007 FM transmitter 5-25w in a case, ready to use for outdoor lasershows. recommendations? Thank you!

Very grateful that you've done all of the R&D with these various chips. I have one with the BH1415F chip that I picked up a couple years ago to go with a Christmas light display. Out of pure curiosity, I put it on a spectrum analyzer and saw a whole mess of spurious emissions and noticed a bunch of other "undocumented features" that I'm not happy about. I'm looking to kick this to the curb for another with better audio quality. I can't see the model number on the ELE that you have. If anyone could reply with the model number I would appreciate it. Also, don't use garbage telescopic antennas on these. I built a folded dipole which gives me about 3dB of gain and makes a low power transmitter far more effective for neighborhood use. Worse case scenario, make a standard dipole with a ground radial hanging below. Both should be at 33.5" for 88MHz and 27.25 for 108MHz. Using a trash antenna will result in high VSWR and can eventually fry your final amplifier.

Many of the Qintec small 8027 transmitters, use a low grade resonator instead of a decent quarz X-tal. As it used in PLL comparator, I am wondering what will be the affect on noises/wider carrier ? Maybe just replace it with a decent X-tal and put some decoupling Capactors around the chip and checkthe results first. (just to ensure it is the chip and not the design) But for me the 8027 sound great,really perfect. But you must ensure you cap your audio at 15khz, as it is not filtered. (and indeed use limiter and audio chain if you want to sound loud)

Also, I recently took apart the CZE-T251 and i found a bh1415f inside of it, not a bh1414k

Dear Spectraman, does TZT ELE15 W based on Quintec, have "radnom-play" function? And sre there some protection over high SWR? Best Reagards

Great video. Though it's hard to get the model numbers of some of them from the pictures. Also, I think some of these transmitters will not come back on after a power failure (someone has to push the power button to turn it back on) which is a no-go for some applications, yet few of them mention whether they do or not.

Thanks for this video. Can you recommend a portable FM transmitter that would be good for 1km vehicle to vehicle transmission in a busy city? Sonic quality highest possible. 12 volts or lower is a bonus.

I have a t251.. I don't know if they changed it at some point, but mine has the bh1415f, not the bh1414k.

Thank you, for the explanation. A lot of information from you! TNX I have some chinese fm tx...... the CZE-01B Czerf Pll Stereo Fm-tx Mono Radio Broadcast Station 0-1W is crap.....produce mirrors on much frequencys. The other 1 is like you described St 7c 1W/7W Fm Stereo Radio-tx. Last one CZE T251 . 73 de PA3GEO Robert

I’d prefer to purchase one of your 15 watt units… can you please advise on how to get more info to order?

Hi thanks for the video. The Retekess TR-505 I've tested is far superior to the CZE-7C. 25 watt maximum but it has a problem between say .4 watts and 5 watts where a pulsing noise is generated but if you do anything in the menu the noise goes away, would you happen to know why?

Great video, lots of useful information for someone like me looking to enter the HAM community but on a strict tight budget. You mention you have built your own transmitter and don’t plan to sell it, can I ask if you are willing to share the schematics / build instructions?

Looking for a quality FM stereo encoder. What's your opinion of the RBS-RF102 from Robonson Engineering Co sold on Etsy?

I have a NIORFNIO T15A, which with an internal antenna gives interference to other stations within a radius of 15 meters, further than that it does not cause interference, I want to know if the 'ELE transmitters' give less interference than it does.

Very interesting Fm transmitters presentation . What could be happen if i use one of this Qn8007 transmitter in texas...with about 30 w..can i have issue with Fcc?

Great videos thank you

Very good review about fm transmitters from China, Thank you Spectraman

A question for all of you: Is it forcing your quality to 480p? Remember to change to 720p.

Can you tell us more about the Silicon Labs ICs? I own a Si4713 breakout board (controlled by an arduino) and there is much RF noise on the band.

Excellent video !!!

Wow I learned so much.

Hey Spectraman, I have an nrg pro 4 but to right side of the transmission it's 75khz but to the left it's like 85 khz. What should I do?

Looks like there's already two transmitters I missed. If you go to my site: dosaidsoft.com/wp/ Scroll down until the end of the right side column and click the donate button and then I will buy more of these transmitters to review. Thanks!

Wonder if it's possible to get RDS running on the QN8066 chip? I see on the data sheet that it supports it. However, the chip also seems to be a transceiver, so it's possible its for receive only. I can't see an MPX input pin on the chip which there is with the BH chips and a way to inject the RDS? I wonder if It's possible to do it through the audio chain, if the transmitter supports mono then it could be possible to use a stereo encoder, then in to RDS as then in to the audio? Not sure if it will work very well with the transmitter in stereo?

Great video. Do you know what chip is used in the fmuser fu 25A transmitter.

22:56 The "Elechouse FM Transmitter V2.0" also has this chip.

Found this video after purchase and looks like I got lucky, from the images it looks like the board I have coming is the one in the bottom right at 15:08 It will be here in a day or two so will be able to see for sure what chip it has. I already have a 45w amp so plan to run the main transmitter at 1w rather than 15w and run it through the amp but also have the option of changing the output transistor on the amp to one that will do 60w for less than £5 which is no big deal for me as I soldered the amp from a kit.

Your videos are very good. I have a question 🤔 What is external modulation on these transmitters and what does it do? I have one with this feature but I don't really understand its purpose.

Is it safe to feed the Pll/vco kit transmitters like you showed an mpx signal? Or are they already set to 50uS?

@Spectraman Spectraman , At 7:36 you mention the transmitter that I have, the SD card one 7watt pll. So I've built it a few years ago and it didn't want to work properly at all, the greatest distance transmission I could get was like 300 meters. As I was just a kid I got bored with it, tossed it away at my grandma's. 6 years later now I found it by accident, and went all Jerry Reed Amos Moses on it, disassembled the whole thing, and cleared the connection points because solder wouldn't stick to them AT ALL, and after re soldering, the thing decided to give life, and work properly without overheating for the first time, and I made a big proper dipole antenna in hope it would work better this time, I calculated the antenna in that android app, made the thing out of two metal broom pipes that were hollow 22mm diameter thin metal pipes. And I put it at the top of my rooftop, and my house is like really tall and on the top of a MOUNTAIN. Fired the thing up, went for a test drive, and what I got was 800 meters (half a mile) of clear signal, and all else was just cutting out and nothing after 1 mile *approx 1,6 km*. I am still very dissapointed, because people claim that you can get 6 miles with that thing if your antenna is at a height, and my antenna is not only high, but, really high up, at full power this is my result. TERRIBLE. Also i use expensive coax tv cable about 3 meters long for the transmitter output. (i think that the cable is 75 ohm, or it says on it I think). SO, there could be more things involved, I use 13 volt 1 amp power supply, is it too weak? Is my transmitter too close to the antenna? Too much feedback power? Bad antenna? Bad cable? PLEASE HELP IF YOU CAN, or everyone, thanks in advance, means much to me, i cannot describe how much.

do you heave qn8007 exciter ? do you run RDS on it?

Ehh spectraman!! Thank you so much again for your videos!! I have a couple of these chinese xmitters but I dint recall what chips are in them but lol.....I'm still rockin a bw warehouse xmitter/exciter that I built as a kit about 25 years ago!! I can get approx 6-8kms with a home made copper pipe slim Jim! I recently picked up a warnerrf fm150a but it has issues. I replaced the roasted final but now it hunts the rf power output after 30 seconds of running. Im gonna try and borrow a thermal camera to hopefully see what is failing. It seems as there is rf getting in the b+ because voltage spikes up n down on the + rail when it starts hunting......odd huh?

Thanks for posting this good and informative Video, with all it´s Informations. I also have a transmitter here, prolly using the 1415F chip, stating it puts out .5Watts. Occasionly (really rare) use it for some private broadcasting, but thinking about it, the last 2-ish years it just stood in my shelf. I´ve checked the harmonics (double, tripple Frequency etc) and it is supressed well enough to make me feel ok using it. The audio quality is not the best. The stereo seperation is by ear quite good, but the bass-sounds don´t sound to good. There seem to be no real "low" frequencies, and the bass that is transmitted just sounds... cheap... hard to describe. I´ve got another transmitter that has no volume / mic controls on front. Just a frequency up / down key and the display (the on off key is at the back). Also a .5Watt version bc I think for some "hobby neighbour" broadcast this is far more than enough. However, this transmitter (in a silver metal case) puts out far more power than the CZE one (I think the other .5Watt Tx is a CZE, its the same housing as your CZE7 Watt-er but with .5Watts only)... anyhow, the sound quality is excellent to the ear, and also the harmonics are well supressed. Unfortunately it broke by itself... I used it with original antenna (which I know, may not have had the best SWR, I didn´t measure it...), and what happens now, is that it cycles the power. So it would transmitt with full .5W for like 2 seconds, then go to like ...1/2mW (that´s how the range is) then go back to .5Watt aggain... maybe it´s lose solder connection which bends back and forward as the final transistor heats up? Whatever. ... What do you think of the BH1417 Chip? The one with some fixed Frequencies either at the low FM band or the top FM band... Have you ever heared of the "Veronica" Transmitters? They claim to be professional transmitters. They have seperated VCO / PLL (and PLL is lots of ICs not a single IC) but they run the oscillator at half frequency for better frequency stability. In a forum people tested these, and said that they produce lots of harmonics or... not so good signal bc the doubler circuit may not be perfect. I do have one of these myself (1Watt) but in all the years I own it, I just plugged it in a few times mostly for testing... It´s more like a "novelty" item to have... because it has lots of memories of my childhood for me. You could get / test one of these? What do you think of the combination(s) used in wirless speakers or headphones ... the ones that use the old BA1404 and use it´s internal oscillator, but "steer" it with an external PLL? There´s a company here selling a transmitter based on the SI74 something?? Chip... it is said, that the signal quality is ok for super weak output power, but it´s very "broad" so better not amplify it. Also have one of these transmitters - to me the audio sounds excellent, nearly as good as a professional station (others think that too) but my Tx has issues with its signals because it can for example not log in at Frequencies over 100MHz... Just a "few cents" from me. Good Vids you make there :)

Looking for advice....was using Si4713 adafruit for my Holiday Light Show but am unhappy with audio quality of FM transmission.....looking for an alternative with better quality audio but would like to retain RDS capability.....most people in holiday light show community use Signstek ST-05B but there is no RDS capability with that unit.....Also it lacks an MPX input ......maybe a modification to allow MPX input?......Then use a separate encoder for stereo and rds?......Any suggestions? Thank you 😊

Nice explanation!

Great video

Awesome video idea, I really haven't seen another channel that does stuff like this. What do you think of building an fm transmitter from an FPGA + DAC?

I had the same display issue on my broadcast warehouse kit many years ago. The guys sent me a new pic for it and it's still working great some 20 or so years later!!

I would be interested in a 15 w cost ? Thanks

it is possible to set the FM frequency with a digital circuit such as MCU, I mean digitally change the variables of LC parameters

The 8027 is good for up to a few watts, before the side spurs are a problem I find. The Freq is off on those cheap usb powered modules too, you can pad the crystall with a cap to get it within 2Khz of dead on freq. You can filter out harmonics and spurs if needed. However none of those transmitters in the video you discussed are good enough for professional use, not even pirates should use them they are terrible, just fun toys.

Have you seen an STC chip labeled "11F02E"? Other numbers on the chip are "35I-S0P20" and "1950H10S02.XA".

Any links to the Qn8066 150watt?? Thank you

Hi, do you know the factory website of the ELE transmitters?

Did you know that there is st-7c that is 3.0 version. Maybe it is better than st-7c 2.0 version. If know what is difference between them please advice.the chip is stc 12c2052

good info but what is the original transmitter from and where can get one ?

Hello Spectraman, many thanks for your video, very informative. Do you know if the QN8007 is still on production? If so, where can we buy it. Best regards.

Ευχαριστώ γλύτωσα από περιπέτειες Spectraman

good day to you suir idol, i would like to ask if what kind or a halfwave GP antenna is suitable for chinese fm transmitters sir idol... that my question sir idol

I'm going to buy one chinese 15W and I have a question. What about antenna radiation safety, if I will mount it on my house window. How far from human beings it must be mounted?

I cant find the good ones on amazon / ebay, where I live that are the only options to buy things, could you leave a link? Thanks!

I've bought FM transmitter with QN8066 from Ali. Sound quality is very good. With good audio processing I can professional sound.

what about the NIO-T50R? I have the NIO-T50R and its pretty expensive.

I have bought an ELE EL-15s in 7 W version and can verify that the near spectrum is very good! BUT can also tell you that second harmonic suppression is extremely bad! At full power at 88 MHz it is 22 dB down, at 1W -14 dB and at 0.3W (lowest power) it is only -9 dB. Second harmonic is thus fairly constant around 15-16 dBm (30-40 mW) regardless of output power, which is at least 50 db worse than permitted in the EU and cannot be used without an external LP filter. Another disappointment is the very strange AGC function on the AF input which cannot be switched off.

Just add a low-pass LC filter to the output to kill harmonics.

Thank you.

I realy appreciate your work. I have seen all your videos and they are useful. Here I must give some clarification. By the data sheet, regarding the spectral spurs there are no significant difference between BH 1414K and QN 8007. But QN is slightly improoved. This Made in China transmitters up to 30 Watts RF Power are not EXCITTERS. They are quite good as LP FM standalone transmitter. No further amplification !!! Soundwise, BH 1414K is very, very good. But, to achieve good (professional radio station) sound, it demands a lot of knowledge and additional equipment. 31 band equalizer, at least one compressor/limiter device, this is if you want to make program by studio connected to audio input of transmitter. If you want to air USB device recording, you must process all sound recordings by special sound filter curve and compressing/limiting . This demands some knowledge with experience. If you have done this process properly, your China FM Transmitter will sound as good or even better than Professional FM Radio station.

Bh1417f chip any good?

Doe any one know of the best studio to link 1 radio for fm broadcast transmitter

Hi, thanks for your informative video. I have niorfnio t15b, every time i go on air, it can be heard from other stations than the one selected. How can you help me with this issue.

Kt0803 is not a bad one.it has a well defined digital interface . When the i2c programming done very well it has awesome output like qn8007 and bh1415. so please try to program very well in c or cpp with respect to the datasheet

am interested in buying your transmitter 25w ,30 or 50 which of them will i get from u ?

The BH1414 single ic awful, its worse than the 8027 the spurs can be managed, and that 30 Watt tx u showed as being the better, has big issues, you need to set the power to 30watts max, else its splatters the band, I found you can drop the power down by reducing the dc supply, works fine, but its unstable at full power, i run the thing for a few hours only to find it suddenly splatters the band with large spurs everywhere. All those medium powered ebay transmitter are awful, I got 15w module that keeps drifting out of pll slightly and then suddenly corrects every few seconds and makes a pop sound in the audio, just crap, spectrum was not that clean either. You wonder what the guy was thinking who designed these and put them on the market.

As i didn't Test yet >1. QN8007 and 2. QN8066 < ..... The BH1414K is the Best IC, compared with the others IC's ((except 1. QN8007 and 2. QN8066 As i didn't Test yet )) that i Used and Tested......BH1414K has very good Audio Modulation but it has a problem in Carrier S/N. (has a noticable"hiss" noise in carrier than some others IC's). BH1414K DataSheet declaires that it has a S/N ratio of -55dB Min / -68dB Normal, 🤔 but i think the Normal S/N is -55dB for this IC....and this value is not good for me. 😠 This S/N carrier problem of course affects, and increase the "hiss" noise on carrier when use it in Stereo Mode. It's not such a serious problem, but it is quite noticeable if we are seriously interesting about the best Fm TX IC in market. Also, I take very seriously the Spurious/Harmonics dBc/dB values and the BH1414K is the best in that case...Unfortunately...😢 the carrier S/N ("hiss") problem is quite serious for me, so my rating for BH1414K IC is 8/10...and still the best than the others IC's that i tested. If BH1414K it doesn't had the S/N carrier problem my rating it will be absolutely.... 10/10 !!!!🙂

What about the Niorfnio t15b?

Ive got the unassembled 7w one 15:55 (Quintic) the 3.5mm jack doesnt work. It produces high-ptched beep noises when I hooked up my phone or PC to rebroadcast DAB-only stations which is weird but good thing: no harmonics. I would have to use the built-in SDcard slot. Also, the antenna port doesnt work (I tried copper wire connected to the pin since I dont have a 50 ohm antenna. The distance is just 6 feet away, dissappointed. 7W is a lie. UPDATE: The jack works but the sound is very low (like BBC Radio 3). Youll need a receiver with a really loud speakers! I tried turning on compressor and it doesnt work.

28:33 LoL

What about FMUser FU-25A?

I have the niorfnio 15watt.. been on air about 3 years...still sounds good, and no FCC warnings yet.. idk. I dont think they give a rats ass unless your on top a comercial station and they request that the fcc " fix " the issue with you transmitting on top of them..

How to get good one brother

How good or bad is QN8006 ?

У меня был CZE T251, там установлен bh1415f

Wow. Thank you. So really the 8015 from pcs electronics is best because why?

A lot of great information..But for those who don't want the FCC knocking on our door.. How about reviewing Part 15 FCC Certified FM transmitters in the future.. Great information for church, drive-in movie theatres,etc. Thanks.

Cek harga

Its the best

What if my Transmitter is only pll not vco?

Good video. I'm surprised you liked the ones with the little LCD at 15:04 They might have a better quality FM chip, but the test sample I got in to play with had HORRIBLE harmonics, especially the 3rd harmonic which is smack in the middle of the UHF DTV band, and if you put these things on air, they would cause TVI(TV Interference) to any of your neighbours. Perhaps I was unlucky and got a bad unit or something, but the one I tested, I remember rejecting it as one of the WORST I had ever tested in terms of harmonics and spurs. I'd be interested to hear if you had that problem. If it sounds fab, but radiates masses of interference, then that is not a good choice for a transmitter either. ;) The 7C's at 18:13 have inferior audio performance, but their RF output is extremely good, with well suppressed harmonics and spurs. Not the best, sure, but certainly good enough that you can use them(with a license!) without breaching the regulations. EDIT: I just dug up that unit from my transmitters box, and retested it. 107.7MHz test frequency, 3W output. 1st harmonic is +2dBm or so UP on the carrier. The 1st harmonic at 215.4MHz is actually radiating MORE power then the fundamental carrier in other words - NOT good. 2nd harmonic is about -20dBm, and 3rd harmonic is about -40dBm. First and second harmonics are disastrously bad. As I say, perhaps I just got a bad unit or something, but would I use this transmitter on-air? DEFINETLY not. They'd triangulate you and fine you for causing massive VHF-H and UHF/DTV interference - never a good thing, and never a cheap fine.

Play this video at 1.25x speed