Hi everybody, So I am brand new to this. I saw a cheap 7W FM transmitter on Amazon and got it just to try it out. I want to give a go at hosting a pirate station. I'd like to learn about how to do this, particularly with this cheap transmitter. The model number is CZE-7C (I think, I don't actually have it with me right now). I've tested it out a bit with just the telescoping antenna it came with and Stereotool. I noticed that it bleeds over to other frequencies a bit. I know I would need a low pass filter and a different antenna. I'd like to just make the low pass filter myself. Can anyone recommend a guide, or even a schematic, for doing so? Similarly, I was thinking about just making a dipole antenna by following a YouTube video. That's fine, right? It goes off a 12V power supply, so I was considering powering it with a car battery sometimes. Is there anything I can do to keep it from bleeding to other frequencies, or is that just an unfortunate result of how cheap it was? Another question I had was about pre-emphasis. It is my understanding anything in the U.S. should have 75us. Is that something I have control of? Being Chinese, would the CZE-7C be alright? Thanks
My advice would be to FORGET this transmitter if you're planning to use it in the USA.....as you yourself stated --- it's CHEAP, not very well-made, and certainly NOT clean from an RF standpoint....a quick check with a spectrum analyzer will bear this out!!! You are correct.....FM in the USA uses 75uS pre-emphasis, NOT 50!! Trying to "mod" that Chinese "toy" is basically a pointless piece of surgery -- IF you're even able to DO it!! For not much more $$ you can get an AAREFF/Veronica 1 watt exciter.....with a decent OUTDOOR antenna (one made specifically for FM broadcast, 88-108 MHz) this little unit will perform VERY well!!! It will get you up and running.....THEN....save your pennies and look into an RF amp if you "need" to extend your range...I've found the 1 watt unit - with a 3db gain antenna - will put a GOOD CLEAN STEREO signal out 1-2 miles, and a usable MONO signal out 3-4 miles from my house. One nice feature of the AAREFF/Veronica exciter is being able to use COMPOSITE INPUT for the audio, rather than being stuck using the old RCA plug/jack setup! The INPUT jack on the exciter IS an RCA, BUT the audio circuit accepts COMPOSITE input from processors like the Orban 8000-A or 8100....I've used an 8000-A for several months now and the sound rivals ANY of the commercial FMs in my area!! RE; the low-pass filter....IF you're good at kit-building there are a myriad of designs available online....OR, just scope out a 7 or 8 pole PRE-BUILT filter on eBay for around $30 -- these will do the job nicely!! Keep in mind, if you stay with low power and a good design, like the AAREFF/Veronica, the low-pass filter isn't necessary - ONLY if/when you start talking POWER (that's anything OVER 15-20 watts, IMHO....) Hate to burst you bubble re: the CZE-7C.....but I KNOW you won't be happy with the results....I had the 15 watt version of this unit and just gave up after several days of pulling out what little hair I have left trying to get the thing to "sound right"!! I spent the extra $$ for the AAREFF/Veronica and have never regretted it!! Good Luck.....and Happy Broadcasting!
Thanks for the input. I'll keep an eye out for a transmitter like the one you mentioned. In case any good deals pop up, are there others worth buying or avoiding?
I spent the extra $$ for the AAREFF/Veronica and have never regretted it!!