6W RF Amplifier Using 2SC1971 (85-110mhz)

I found this circuit online. It uses a 2sc1971 RF transistor. It works VERY well!
www.freeradio.o...
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[@Dazzwidd]

If you think the 2SC1971 is a good RF amp. for FM you should try the RD15HVF1. With a 6dB resistive pi attenuator on the input you can still achieve 15W out with 500mW drive. They're quite rugged and you can adjust the output power between 1w and 15w by adjusting the gate bias voltage. It makes the perfect accompaniment to a larger amp as a driver. I managed to use one to drive a pair of MRF455 transistors in tuned class B push pull. I know the MRF455 is specified as a HF device, but it will work as a low band VHF power amp to 110MHz. I got 150w out of this configuration, lol! Interesting experiment :D

[@daretodream25]

Got a schematic ?

[@Dazzwidd]

It is pretty easy to round one up by searching on google. I have one built into a die cast aluminium box, using it as a heatsink. It only ever gets warm. Draws a maximum of 1.5A at 15V and easily puts out 15W

[@AndyPayne42]

joy m www.mitsubishielectric.com/semiconductors/content/product/hf/sirfpowermosfet/siliconrfdiscrete/siliconrfdiscrete_lv4/rd15hvf1.pdf

[@dazzwiddwiddow6190]

Andy Payne That is the datasheet, yes. There are circuits for amps for the FM broadcast band using the RD15HVF1 on the internet. If you google RD15HVf1 and go to the results for images you will get schematics

[@AndyPayne42]

I like testing schematics in datasheets first since they are verified.

[@electronicsNmore]

All depends on how well your antenna is tuned, how high your antenna is, and the terrain. Over water, plains, or a desert is very high range, many miles.

[@andrewandrosow4797]

Good device!. I have been building such an RF amplifier for 1 monath. I found out , that the mathing LC networks are quite narrowdaband - the SWR in a coax cable is good in range of 200kHz. It`s the main problem. It will be a wideband amplifier.

[@electronicsNmore]

Thanks for watching Andrew! Be sure to look over my extensive video playlists below for other videos of interest to you, and most importantly share my channel with many others. kzbin.infoplaylists

[@electronicsNmore]

@NielBernPlatch Of course it works. I don't put out fake videos. Just make sure your coil orientation is as shown on MY VIDEO, not the link in the description box. Also make sure the RF transistor is REAL. There are videos on KZbin showing what a Fake one looks like. You may need to do some fine tuning / adjusting to get it perfect.

[@SkylerF]

ok. cool, well I love your videos and I love making DIY electronic projects. Its such a fun hobby

[@johnallenrichter]

Cool case. i'm interested in a circuit I can add to the tuner of an A.M. tube radio to boost it's reception. Would this RF amp be good for that or is it only used for transmitting signals?

[@Patc1187]

Few questions if you get the time to answer. Is a RF transmitter and amplifier the same thing or do you need a transmitter to plug into this amplifier? What kind of range would one get from this device? And one more, is there somewhere I could get a printout of this schematic?

[@electronicsNmore]

Lumped? LOL. Maybe according to you. The fact of the matter is the amplifier is MUY BUENO.

[@electronicsNmore]

This circuit is designed for transmitting, not receiving. It was designed for FM.

[@neodiy]

Is it possible to achieve 2600Mhz or 2.6Ghz using this circuit? if not do you have one schematic doing that?

[@electronicsNmore]

No. 2sc1971 is for VHF only. You're better off buying an amplifier at the link below. bit.ly/2soXMA6 (coupon codes: BGAFF7, affiliate6, or elec)

[@km4lkx497]

Nice project. I am interested in using this to power one of my projects but sadly the link no longer works. Do you have a schematic and parts list?

[@OOOO-wj2xt]

The link is working.... open the link in the browser... the link is a file pdf

[@electronicsNmore]

200-500mW.for the full 6W output.

[@ReedSwitchTube]

electronicsNmore I like it, would this amp require a ham license to operate, like RSGB before I built it.

[@electronicsNmore]

These are illegal to use in the USA without a FCC license. I was outside the USA when this video was made. Thanks for watching!

[@rudzion]

OK. Thanks a lot! :-) I've got all parts and pcb is almost done. I will try to run it today. I'm worried about my 2sc1971, it may be fake. Sorry my English is not good. :/ Thanks for the reply! Greets!

[@radarsonic6227]

If i use fix 22pf on the output instead or a trimmer cap connected parallel in 470 pf can i still have the 6 to 7 watt output?

[@radarsonic6227]

Can i use coaxial cable with 75 ohms for antenna? Will this have problem for the c1971 performance?

[@electronicsNmore]

I made my case. You can buy nice aluminum project boxes on Ebay. Your 500W rf amp will draw 55 - 70 Amps. Really cannot help you with your project. I'm not an RF "expert", and I would have to see it in person.

[@radarsonic6227]

Can i put signal directly from a cellphone to the rf in without pll system or something like that with 50 percent volume? How can i tell if I have 200mw signal input or correct me if im wrong.

[@electronicsNmore]

I'm glad you like them. Be sure to tell your friends about my Channel. Thank You

[@electronicsNmore]

Not too much. I had the scrap stainless steel for the housing from a non-repairable microwave oven. The rest of the parts I had pulled from scrap electronics. The 2sc1971 I bought online. Beware of fakes. There are videos to help you identify the fake RF transistors. I bought used ones pulled from older electronics.

[@freshfm99.5dublin4]

Hi man great to see you did this is have seen and baught other people's models Same concept. Can you send me the full sheet of details with diagram and parts list u have on the sheet of paper Please

[@electronicsNmore]

If the input power is too low, the amplifier will not work. It won't oscillate. You can try a NTE342. Thanks for watching my video.

[@hrf1007]

What if feed 1971 with more power than 500milwt example 900milliwat what can happen,? even witn conected antenna İ have one amplifire like this but when i ste last stage trimmer to the more power my frist made signal goes out from right frqunecy wich is set from pll!! Whats my problem ,please a little guide !!

[@UpinkProduction]

I love it good 👍

[@haitianstthomas]

Where can I get a case just like yours? I need help finish building my rf amp,I brought a 500watt rf amp pallet and need help finish building it.I need a BLF78 also want to know how can I connect the coax to a power supply and what max power supply should I get for the 500 watt rf amp pallet.also what max should the fan be and how to conncect it.

[@electronicsNmore]

I know, there are plenty of fakes out there. There are a couple videos on KZbin to help you identify if yours is a fake. BTW, Your English is fine, We have Americans that don't speak as well. LOL

[@km4lkx497]

Also, are there any problems with harmonics in this design? Do you use any filter inline with your antenna?

[@electronicsNmore]

I'm posting a new link right now. I did not notice any harmonic issues. I walked all around with my frequency counter and did not notice 100mhz/200mhz. Only 100mhz. I'm sure you can add a low pass filter to prevent any harmonics above the frequency you choose.

[@Dazzwidd]

Your frequency counter will only respond to the fundamental frequency as it is always going to be significantly greater than the output though. You need a tunable rf sense meter. I believe they are referred to as a wavemeter. It's really just a tuned field strength meter or tuned rf sampler. It could be a great next project for you :)

[@klausbrandt5064]

Use RF spectrum analyser for any spurious emissions

[@TheComp462]

Is it possible to use this to amplify an AM signal around 1MHz? Do you know of a circuit for an AM 1MHz transmitter?

[@rudzion]

Hi! What if the input power is less than 200mw? About 100 mW or less? Any replacement for this 2sc1971? The case is perfect. :D Greets from Krakow/Poland!

[@3015gaurav]

from where yuu got these... and please sugges me some me some electronic referncer websites

[@Mustdeny]

Its ready brother?i am in order 😀...from Indonesian

[@annyan904]

how many turns for ferrite bead??

[@maxmayMaxmay]

where can I buy something like this

[@lucianopep]

Lavora in 27 MHz?

[@ijetv1020]

mine doesnt work,, can you help me please? no output at all, fine temperature on my Transistor.

[@electronicsNmore]

+Jomel Brent Arances Possible causes: Fake 2sc1971 Faulty 2sc1971 Incorrectly installed 2sc1971 Transmitter is too low in power for the RF amp's input. Improperly tuned amplifier Thanks

[@ijetv1020]

i dont know how to properly tuned the amp

[@electronicsNmore]

It is almost impossible to tune a RF amplifier without a field strength meter and DMM to measure the current draw by the RF amplifier.

[@ijetv1020]

thanks sir

[@electronicsNmore]

***** You can find them. Look up videos on KZbin showing how to identify fake 2sc1971's

[@electronicsNmore]

@Tekkid1981 Best places to buy: Ebay / Electronic Goldmine / Unicorn Electronics / West FL Components

[@Xeophane]

where can i buy a fm rf amplifier 10w assembled?

[@SkylerF]

how far can that transmit

[@kaygibby8997]

About how much did everything cost?

[@kamaloddinsayyad3305]

From where you got this RF power transistor 2SC1971? Please me address !

[@electronicsNmore]

Try Ebay.

[@RakshithPrakash]

10pcs for $3 on Aliexpress

[@NielBernPlatch]

was this stuff tested and working guys?

[@hosenansari9344]

sir can I transfer 433mhz through this amplifier.. please let me know..

[@electronicsNmore]

No, the 2sc1971 isn't designed for that frequency range. It's designed for up to 175mhz.

[@tawfiqulalam8928]

Plz mention it's range.

[@electronicsNmore]

All depends on the transmitting antenna, terrain, and if you're in a rural or urban area. At least a few to several km.

[@hotbikerguywithscar]

Hey, if you get time check my amp out. Some similar construction points as you.

[@momi5656]

i have 2sc1678 transistor can i use it ???

[@electronicsNmore]

momi You need to compare the data sheets. Look them up on Google.

[@radarsonic6227]

what is the maximum range of this?

[@electronicsNmore]

Hello. All depends on the terrain. Across open water or a desert? 10 miles or more. Thanks for watching! Be sure to rate thumbs up and share.

[@joesitter20101]

This looks like a very nice amp. How much input power is needed for this amp? With a 5/8 wave, tuned omnidirectional ant. I can get about 2.5 miles in a residential suburban area having some large trees using about 3 watts. I can decrease the output to drive your amp to maybe get about 5 or 6 miles omni. range.

[@joesitter20101]

Oh, the drawing says 1/2 watt drive.

[@hosenansari9344]

sir please give me the circuit diagram. i need it.

[@electronicsNmore]

Video description area. :-)

[@TheFlyre]

look soo hard geee trying to find or build 1 to 40mhz and 50watt soo hard to do i dont get this stufff

[@electronicsNmore]

Lation Fly 50W? LOL Good luck with that. Lots of $$....

[@TheFlyre]

why is it soo much money?? i found some amplilter on ebay for 150.00 with 50 watt but its 100mhz.. i dont need it that high.. But if 150 is alot to you i understand..

[@TheFlyre]

you are right why are they soo much? what can i do? can you help me?

[@NielBernPlatch]

@myvideoisonutube Thanks a lot. :)

[@radarsonic6227]

diagram and parts list please...

[@electronicsNmore]

Video description area

[@malonekalbi8239]

you can buy those fm amplifier at fmthai,com or some at alibaba.com

[@radarsonic6227]

what is FB?

[@electronicsNmore]

A small ferrite bead goes over the lead of the resistor on the side of the resistor that connects to the base of Q1. :-)

[@annyan904]

what are the turns in fb??

[@-TV-NEWS]

FB?

[@electronicsNmore]

Ferrite Bead. Thanks for watching! Be sure to check out my extensive video playlists for other great videos of interest to you, rate thumbs up, and share my channel.

[@annyan904]

i dont have a ferrite bead

[@electronicsNmore]

Varun Panikar Very cheap on eBay.

[@annyan904]

here they don't ship the item .however i have a torroid 1cm dia. can i use that??

[@coffeegoblin7727]

Varun ya wanna get some, theyre really handy!

[@catherine_elizabeth]

This circuit is fake. Because I try this but not working.

[@electronicsNmore]

Just because you put it together and it doesn't work.........doesn't mean what I show is fake. More than likely you screwed up. As a result of you mouthing off, you now get ZERO help getting it to work.

[@electronicsNmore]

**ATTENTION: Please make sure video ANNOTATIONS are turned ON for this video. I added additional important information. Thank You!

[@NielBernPlatch]

How much exciter wattage fits for this?