NOTE: I believe that this transmitter can be easily modified to boost the RF output to 15 watts by substituting the RF output MOSFET with a Mitsubishi RD15HVF1 MOSFET. It should be noted that ALL FM broadcast transmitters using this same motherboard can ALL be upgraded to 15 watts by simply replacing the RF output MOSFET with a Mitsubishi RD15HVF1 power MOSFET !
NOTE: I suspect that this transmitter utilizes the same motherboard as MANY of the other Chinese transmitters marketed under various brand names, e.g., NioRFNio, the Generic ST-15B, FMUser, CZE, CZH, Signstek, HLLY. Since I have not been able to get a glimpse of the motherboard for this transmitter I cannot say with 100% certainty but I would bet, from experience, that this transmitter also utilizes the exact same motherboard as many other transmitters in this class.
"Knowledge Is Always Made More Valuable By Sharing It With Others !" Always Remember To Be Kind ! True Greatness Often Has Very Humble Beginnings ! Help A Kid Out Today ! *** High Mountain Radio *** "Broadcasting From Somewhere High In The Remote Appalachian Mountains"
Post by HighMountainRadio on Mar 11, 2018 5:13:11 GMT -6
Good Morning Dave !
I apologize for not replying sooner, I just now noticed your comment and question here. I'm not sure what you are seeing on your end of my thread created for the FMUser FM-05C transmitter specifications though. It looks fine on my end, but if there is some sort of issue reading threads I have created it is good to know so if I may be doing something incorrectly in my threads I want to know so that I may correct any issues so that all forum users may read the information very easily so I am glad to brought this issue to my attention ! Can you please describe to me what you see regarding this thread that appears as hieroglyphics so that I have a good understanding of the issue you are encountering ? If you don't mind, I would really like to view a 'screen captured image' of what your screen looks like. You may send any screen captured images to my station's e-mail address: highmountainradio@gmail.com ....
Yes, I too noticed that low end specification and thought it odd as well. I simply took the specification data from the manufacturer, FMUser, and included that data in the transmitter specifications on the forum here. It may very easily be an error on their part, I'm sure you are familiar with some of the crude Chinese to English translations in the past. lol !
On that note, I purchased a 3 Element Folded Dipole Yagi Antenna from a guy on EBay, originally meant for FM radio reception. It was quite cheaply priced so I took a gamble for $14.95 and $15.65 shipping. I am impressed with the quality, I expected far less for that cheap price so it was money well spent ! I want to be able to 'loosely' direct my signal in one particular direction which is why I purchased this antenna. I plan to try using it as-is, right out of the box and see if it fits my needs for the desired effect. If it is too narrow in the forward direction I figure I will simply remove the single director element to make it more 'broad' in the forward direction, even though it will favor one particular direction, enough signal coming off the back and sides should still be ample to keep my current coverage area intact.
On this forum, under the Radio/Electronics and Tech subforum, I placed a thread that shows a picture of this antenna as well as a link to a good website that has a great antenna calculator available that permits you to very easily calculate the coaxial cable length, configuration and type from which to fabricate the necessary 'balun' which must be used to match 50 ohm coaxial cable feedline to the 300 ohm antenna feedpoint impedance. The matching transformer that comes with the antenna is good for RECEIVE ONLY and will handle no appreciable amount of RF power so it must be removed from the antenna boom and retrofitted with the fabricated matching line section. The necessary TRANSMIT balun is very easily and cheaply fabricated using a short piece of proper coaxial cable cut to a pre-determined length and connected properly. See here: darkliferadio.proboards.com/thread/962/match-folded-dipole-antenna-bcast
I plan to mount the antenna vertically so that it favors car radios for now until I soon will utilize a pair of Shively Model 6812B Right Hand Circularly Polarized antennas configured in a 2 Bay array. Of course these are ideal antennas for FM broadcast since you can split your RF output power in half and send half of your transmit power into the vertical plane and the other half into the horizontal plane for the ideal, optimum, FM broadcast signal used by just about every commercial FM radio station. I was very lucky enough to score a pair of these antennas complete with 'radomes' to make the antennas weatherproof ! The price = FREE !! And, the best part of it is the fact that they came from another nearby college radio station that broadcasts on 99.5 MHz ! As a matter of fact, they are resonant much closer to the frequency that I use, 99.9 MHz so I don't believe that any further tuning will be required ! Basically they will be pretty much 'plug and play', very cool !! According to their specifications they will easily handle a full 1500 watts of RF power input ! Since no forward gain is realized with a 2 Bay Array I plan to double my RF output power to 150 watts, thus putting 75 watts into the vertical plane and 75 watts into the horizontal plane. I will see what performs better for my intended area of coverage, either the 3 element folded dipole or the 2 Bay CP array. It will be a very good educational experience at the very least !
I would love to hear back from you regarding the 'hieroglyphics' you are seeing on your display ! Also, if you may have any questions, I would be more than happy to try and answer them as accurately as humanly possible ! By the way, I have attached a few pictures of the Shively antenna to this reply as well.
Take care Dave, hope to hear back from you soon ! 73... Spooky...
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"Knowledge Is Always Made More Valuable By Sharing It With Others !" Always Remember To Be Kind ! True Greatness Often Has Very Humble Beginnings ! Help A Kid Out Today ! *** High Mountain Radio *** "Broadcasting From Somewhere High In The Remote Appalachian Mountains"
