I think your amp is behaving as it should. 3 tuned circuits, it is sharp. Stagger tuning is the way to go, as you did. The input circuit in the middle of the band, and the othet two near the ends of the band. But the most important thing is, that the amp should be right after the antenna, outside. There should be absolutely minimum feed line loss before the first amp stage, otherwise the extra amlification is useless. And as you found out, switching mode power supplies is no no for preamps, even not all linear power supplys don't work well. Btw. usually ferrite beads have a hole in the middle, and the coil is wound through that hole, but your bead seems to work as well
I've installed several dedicated FM broadcast antenna systems to me the most important part is the antenna, I've always used a dedicated commercially made outdoor FM dipole or a Yagi. In line 300 to 75 ohm transformer 75 Ohm "F" connectors to RG-9 or RG-6 coax run to the receiver then impedance matching to the receiver input I/E a second In line 300 to 75 ohm transformer. Sometimes this alone is sufficient for acceptable reception. If not I've added a mast mount broadband TV/FM preamplifier, and yes DC voltage supplied over the coax. Having the preamp next to the receiver is okay as long as the noise floor is not too bad and your well shielded. I think home brewing the amplifier is a great idea too good luck don't give up.
You can connect a high value resistor (ex 39k) in parallele to a coil to reduce its Q. At this frequencies I don't know if are introduced additional capacitances that can detune the resonance of the coil itself
Might it be better to design a high-gain antenna tuned to the FM band? It seems like the higher voltage that can be received. to begin with, the better
You can adjust the coils by opening them up, that lowers the induction and raises the lower frequencies. Then you adjust the trimmer caps to the high frequency, and Bob's your uncle ☺
@@electronicsoldandnew i was susoecting the coils and messing with them, this confirms it mine may be a valid idea. Great video too really enjoyed it it.
I think the problem is twofold. First the ferrite bead. The characteristics of ferrite beads can vary significantly, especially at 100MHz. This can affect the Q of the inductor on the bead. Did the original article specify a bead made from a particular type of ferrite? Secondly I believe you said that the copper wire you used for the inductors was not the specified diameter, but larger. The skin depth in copper at 100MHz is about 6 micron. So the impedance of the wire will decrease with greater diameter wire, increasing the Q factor. Another commentator suggests adding resistors to decrease the Q of the inductors. This would either mean a new PCB layout or modifications to the existing PCB. I think it is better to use the specified copper wire diameters for winding the inductors. Also try using a bead of a different type of ferrite for that inductor.
Its a pretty common looking amplifier going by the schmatic. Apart from the J-fets And your right not to touch the antenna that's working good for you.. if it's not broken... 😅 Plus been on an island all the more reason not to touch it..
In my experience, it all starts with a directional or tuneable antenna. Signal boosters will amplify noise along with the desired signal. If your domestic situation allows an antenna with a rotor, or several antennas pointed in different directions, DO IT ! Getting a clean signal that is free from multipath interference and adjacent station frequencies is step one before you even consider using a signal booster. Worst case scenario is using an omnidirectional antenna and trying to electrically pretune or bandwith-limit the signal right before the tuner's input. Hey, have you ever seen a BIC "Beam Box" antenna? It's a tunable Yagi antenna in a box about the size of a turntable, with element-selector switches to change directionality and a tuning condenser to narrow the output at any point from 88 to 108 Mhz. (The BIC FM-8 was 300 ohm in and out, the FM-10 added 75 ohm in/out and had nicer cosmetics). Great for pretuning stations and eliminating reflections and adjacent-station interference, although output is low and therefore may require a separate FM booster. Production of these was discontinued some 4 decades ago. I used to be able to buy them used for $20 or so here in the States but prices have skyrocketed. Somebody should clone these things! By the way, somewhere on a shelf in storage I have a Magnum tunable FM booster with front-panel gain and 88-108 adjustable bandwidth control.
I have come to the conclusion that your view is absolutely correct: Good antena first. I’ve actually gone more in that direction and am testing one of those omnidirectional folded dipoles. Still waiting for some hardware to get it mounted on the roof without it being too obvious to the neighbours in the building 😊
@@electronicsoldandnew , my wife won't let me put an antenna on the roof (the prevailing winds in New England would be tough on it anyway) so I settled for an 8 foot directional antenna in the attic, but there isn't sufficient space to rotate it, so I had to settle for pointing it in the direction of the most distant and desirable stations. I used to use a Beam Box, located in the attic and pretuned for the low end of the dial (where college and public radio stations reside), to feed a Proton FM 300 table radio on top of the refridgerator, but when we remodeled the kitchen I lost that space for the radio (we now have a cabinet mounted above the fridge) and so I need to relocate the coax cable from the attic antenna to a distant corner of the kitchen so I can hook up my radio again, sigh....
You could construct a small high gain antenna outside your booster box that revolves in the direction of the radio wave. The flux around this antenna should have a radius of 6 inches. That is to say when you put your hand near six inches away in any direction without touching the aerial the its reception increases.
Nice and educational project. All that remains is to make a little more broadband gain and place it at the antenna. Maybe instead of trimmers you can install varicaps with control according to AGC principle.
Interesting Manuel, although the initial outcome is not exactly what you were looking for I expect that someone out there will have some useful comments. Unfortunately it will not be me as I have no idea how to improve the amplifier but thanks for showing us, we will all probably learn something when you get some relevant replies....
Learnt a lot of ideas from the comments about improving bandwidth. I'm an electronics engineer, my knowledge lies more with the radio operation and not the art of RF preamps at the vhf range. So my suggestion is probably more naive, I don't know. But what I'm thinking is adding an extra tuned stage, spreading the bandwidth and just watching your overall gain. I would be interested to learn the pros and cons of my idea.
Greetings: I would suggest using an rf sweep from 87-102 MHz. Then make all adjustments while you watch the scope. I would lower the scope trigger level so that you have a stable display for the full sweep interval.
Since your Antenna Booster has a restricted band you could use it at your advantage making it tunable. Simply substitute the trimmers on the tuning coils with varicaps and regulating their voltages with a potentiometer you make your booster tunable.
BINGO, I have been quietly screaming at the screen, By selecting 3 matched Varicap diodes, and switching out your 2 wire NON coax 12V power feed to spare inexpensive 4 conductor Telephone wire, you can send up 12V, and a separate 5-20V typical range Tuning Voltage on the added 2 conductors!. Take these tuning diodes OR the whole RF Amp stage from any old electronically tuned FM radio or just 3 varicaps and branch out via 3 100k resistors and some decoupling caps. NOW you have a remote tuned, image rejecting PRESELECTOR, like the 3 stage one in my beattiful 1974 Kenwood R-599 "HAM" Communications Receiver utilizes for HF. Also maybe fashion some copper shield between the input and drain coils and trimmers to cut oscillation risk. Nice layout, here in the states I have layed out 200+ PCB's, many for USA Police Car Videotape Evidence camera systems using my trusty OrCad SDT and PCBII DOS tools, on a 486 computer which NEVER has been connected to the internet...Thanks for your wonderful videos and mild voice intelligent presentation! I am restoring and redesigning a 1944 Hallicrafters SX-28A HF Receiver into SX-28+, copying my HQ129-X BFO circuit, better regulation, and a DIY AUDIO modified dual 6V6GT ckt with 2 new Gold Lion tubes, matched pair from Russia, AND a HiFi audio TF from Hammond. It already has TWO tracking RF AMP tube stages, providing preselection automatically for 0.5-42MHz. Thanks from W4HDL in USA.
Try removing the second filter and use a variable cap on the first. You maybe able to create a scale to aid quick tuning of the antenna. might help ...
Hi Manuel. Great video. Sorry it didn't turn out the way you wanted. Could substituting one or two components (upgrading the existing design) give you the extra performance you are looking for? I really hope that you can rectify the problem, as it will be a very worthwhile addition to have. Best of luck. Cheers Chris.
Love this channel. Does anyone know where I can find a full complete readable schematic for my Braun WW2 RC 56 UK chassis ? All I can find online are very bad splotchy unreadable schematics.
Hi manuel, probably you were searching some article like this"EE July/August 1986 36 by R Shankar 1 111 tuneable FM booster 01 BB106 C1 II Op 75 n BF961 BF981 This FM band (88-108 MHz) preampli- fier, this was an article at elektor magazi ne, & doesn't lacks , modest gain /Q, but tunable on the whole FM band
Hi Miguel ! There are much more simpler and better solutions for making a WIDE BAND min. 20 dB low noise (NF~0.6dB) over the FM broadcast band: I use single chip MiniCircuits PGA103 (there's also the SPF5189Z). They can be found easily and cheaply on chinese sites, even already built. The only drawback is that they run at high quiescent current (typ. 70-90 mA). Located just after a simple vertical dipole (+ balun) that makes a huge difference on receiving (I also added a 88-108 MHz bandpass filter in front of the LNA to get rid of intermittent airplane communication intermodulation).
Wow! You have made a very selective active notch filter with a significant gain on the pass frequency. :-) Maybe if you make 5 of them, tune them precisely that one follows the other then mix their outputs, you can cover the whole FM broadcast band.
I was itching for you to test this with either a spectrum analyser with tracking generator, or signal generator in sweep mode, triggering your scope to show what the band pass looked like. You do it for radio alignment so why not here? Thanks for another interesting video.
Olá, circuitos RF gostam de alimentações bem filtradas, sem ruídos e uma boa terra. Olhando para o circuito e pela experiencia no osciloscópio, chegar aos 100mV para a frequência em teste, o que diga-se, é excelente. Para abrir esse ganho para a uma range de 12Mhz, penso que o ganho vá descer um pouco, mas julgo ser possível. O que faria era selecionar o posicionamento desses 12 Mhz na faixa 88 108, posicionar na frequência mais baixa e fazer o tuning para o maior ganho e depois ir à outra ponta (+12Mhz) e fazer o mesmo, e depois voltar atrás, e ir jogando com as 4 afinações até obter um ganho médio entre estes dois pontos e já agora, apurando como fica também a meio (6Mhz desde o inicio). Essas seletividades ao fim ao cabo são os filtros de ressonância, entre as bobines e os condensadores variáveis e o trim, que acredito com paciência, se consegue abrir uma janela de 12Mhz com um bom ganho.
Obrigado pelas dicas. Vou brincar um pouco mais com este bichinho, e lembrei-me de uma coisa: Vou ter de confirmar que o gerador está a produzir a mesma amplitude está gama de frequências, pois tentar linearizar um amp alimentado por um gerador rasca não é boa ideia 😊
some Radio have signal strength indicator led , its brightness increased when tuned . how this circuit works ? i wanna built such indicator for IF output
Also, in addition to amplification of the FM band RF the device seems to amplify the audio of family’s doggie @ 35:49 min. A very cool side benefit. 😃 lol
Thanks for sharing the design and build! I would be interested in making something to cover a spread of 30 to 1000Mhz without using the filtering. I am guessing coils and trimmers could be eliminated from the build in a breadboard version, then design and make some PCB's. I have also used PCBWAY to create some linear power supply replacement prototypes for a Feeltech FY6600 Function/AWG that has a bad issue of leaking some ( 50 to 70VAC) power line voltage through the SPS to the common / shield connection ( video to be created soon).
Excellent Video, thanks for making and sharing it. I think this will be excellent for a FM DX project I am planning. Is it possible to get the files to order a board from PCBWay?
I was not at all happy with this version of the project, so Decided not to share the boards, which would be wrong. I may do an improved version in the future and then I should publish that.
Thank you for this interesting project. It appears that good antenna amplifier design can be a challenging process. I've often wondered if an old-fashioned TV-FM antenna amp would be useful in a case like this. They're dirt cheap, very wide-band (50 to 2200MHz) and, back in the days of analog TV, were often used to boost fringe signals into clear signals. Or is there some technical reason why this won't work?
I think you got it wrong regarding ferrite beads- they should be "beads" with a hole through which you pass the wire and not a normal ferrite rod as any other coil
@@electronicsoldandnew Does it have a hole through its sides? ferrite beads with the wire just passing through are used in RF circuit to suppress ringing. no windings, just pass-through
Its a nice little device but having static and stuff on FM while listening to music is kinda... pointless. At least for me! :D My "solutions" so far are bigger and bigger antenna streched and build all over my place.
I’m curious: How did this ban work? I’ve seen quite a few comments appear and then disappear with no input from me. What is happening? Is this a YT feature or bug?
@@electronicsoldandnew Good to know. How it works I haven't got a clue, I only know it happens. At one point I placed a short comment here, added one line a few minutes later and got a red 'return error'. That mostly happens when you do something that is not allowed, or by youtube (breaching community rules like 'false' medical info), or by you as creator (e.g. you don't allow links in comments). But in this case, and I have seen that before, nothing of that was in my comment. But this form is still signalled by youtube with a red warning telling: "return error". So you are informed. But the bad one is the shadow banning: you will NOT be informed that your comment is ONLY SEEN by yourself, and no one else. That is plain misleading, because the text fiield says: "Add a public reaction", and keeps you under the impression everyone can read it. No, only you as commenter. The way you can check is to look at the same message but with another browser, NOT logged in to YT, the link is under the time stamp of the comment. I wonder if YT will place this text..... I have seen this explanation disappear many times.
I think your amp is behaving as it should. 3 tuned circuits, it is sharp. Stagger tuning is the way to go, as you did. The input circuit in the middle of the band, and the othet two near the ends of the band. But the most important thing is, that the amp should be right after the antenna, outside. There should be absolutely minimum feed line loss before the first amp stage, otherwise the extra amlification is useless. And as you found out, switching mode power supplies is no no for preamps, even not all linear power supplys don't work well. Btw. usually ferrite beads have a hole in the middle, and the coil is wound through that hole, but your bead seems to work as well
Thanks for that.
Thank you. 👍
How Kool is to build a antenna. Booster your slif you save money
I like your utube videos
I've installed several dedicated FM broadcast antenna systems to me the most important part is the antenna, I've always used a dedicated commercially made outdoor FM dipole or a Yagi. In line 300 to 75 ohm transformer 75 Ohm "F" connectors to RG-9 or RG-6 coax run to the receiver then impedance matching to the receiver input I/E a second In line 300 to 75 ohm transformer. Sometimes this alone is sufficient for acceptable reception. If not I've added a mast mount broadband TV/FM preamplifier, and yes DC voltage supplied over the coax.
Having the preamp next to the receiver is okay as long as the noise floor is not too bad and your well shielded. I think home brewing the amplifier is a great idea too good luck don't give up.
Definitely food for thought. I’ll just keep tinkering and see how it goes. Thanks.
Awesome video ! I really love your restoration projects/radio's ! A nice heritage !
👍
Interesting project Manuel, pity it didn't do what you hoped but good luck if you can improve it in the future.
Thanks Dave. I’ll need to play with it some more and see how it goes.
You can connect a high value resistor (ex 39k) in parallele to a coil to reduce its Q. At this frequencies I don't know if are introduced additional capacitances that can detune the resonance of the coil itself
👍
Might it be better to design a high-gain antenna tuned to the FM band? It seems like the higher voltage that can be received. to begin with, the better
You can adjust the coils by opening them up, that lowers the induction and raises the lower frequencies.
Then you adjust the trimmer caps to the high frequency, and Bob's your uncle ☺
Thanks. Will be playing with it some more.
@@electronicsoldandnew i was susoecting the coils and messing with them, this confirms it mine may be a valid idea. Great video too really enjoyed it it.
👍
I think the problem is twofold. First the ferrite bead. The characteristics of ferrite beads can vary significantly, especially at 100MHz. This can affect the Q of the inductor on the bead. Did the original article specify a bead made from a particular type of ferrite? Secondly I believe you said that the copper wire you used for the inductors was not the specified diameter, but larger. The skin depth in copper at 100MHz is about 6 micron. So the impedance of the wire will decrease with greater diameter wire, increasing the Q factor. Another commentator suggests adding resistors to decrease the Q of the inductors. This would either mean a new PCB layout or modifications to the existing PCB. I think it is better to use the specified copper wire diameters for winding the inductors. Also try using a bead of a different type of ferrite for that inductor.
All good tips. Will tinker with it some more.
Its a pretty common looking amplifier going by the schmatic. Apart from the J-fets And your right not to touch the antenna that's working good for you.. if it's not broken... 😅 Plus been on an island all the more reason not to touch it..
👍
Great booster for FM band !
Im looking a scheme.
Tanks a lot.
Very interesting work like ever, Manuel!!!
thanks
In my experience, it all starts with a directional or tuneable antenna. Signal boosters will amplify noise along with the desired signal. If your domestic situation allows an antenna with a rotor, or several antennas pointed in different directions, DO IT ! Getting a clean signal that is free from multipath interference and adjacent station frequencies is step one before you even consider using a signal booster. Worst case scenario is using an omnidirectional antenna and trying to electrically pretune or bandwith-limit the signal right before the tuner's input.
Hey, have you ever seen a BIC "Beam Box" antenna? It's a tunable Yagi antenna in a box about the size of a turntable, with element-selector switches to change directionality and a tuning condenser to narrow the output at any point from 88 to 108 Mhz. (The BIC FM-8 was 300 ohm in and out, the FM-10 added 75 ohm in/out and had nicer cosmetics). Great for pretuning stations and eliminating reflections and adjacent-station interference, although output is low and therefore may require a separate FM booster. Production of these was discontinued some 4 decades ago. I used to be able to buy them used for $20 or so here in the States but prices have skyrocketed. Somebody should clone these things! By the way, somewhere on a shelf in storage I have a Magnum tunable FM booster with front-panel gain and 88-108 adjustable bandwidth control.
I have come to the conclusion that your view is absolutely correct: Good antena first. I’ve actually gone more in that direction and am testing one of those omnidirectional folded dipoles. Still waiting for some hardware to get it mounted on the roof without it being too obvious to the neighbours in the building 😊
@@electronicsoldandnew , my wife won't let me put an antenna on the roof (the prevailing winds in New England would be tough on it anyway) so I settled for an 8 foot directional antenna in the attic, but there isn't sufficient space to rotate it, so I had to settle for pointing it in the direction of the most distant and desirable stations. I used to use a Beam Box, located in the attic and pretuned for the low end of the dial (where college and public radio stations reside), to feed a Proton FM 300 table radio on top of the refridgerator, but when we remodeled the kitchen I lost that space for the radio (we now have a cabinet mounted above the fridge) and so I need to relocate the coax cable from the attic antenna to a distant corner of the kitchen so I can hook up my radio again, sigh....
@@goodun2974Wow - Proton 300 table radio! Total I've known to exist now is *two*, including my own. Excellent fidelity!
You could construct a small high gain antenna outside your booster box that revolves in the direction of the radio wave. The flux around this antenna should have a radius of 6 inches. That is to say when you put your hand near six inches away in any direction without touching the aerial the its reception increases.
👍
Nice and educational project. All that remains is to make a little more broadband gain and place it at the antenna. Maybe instead of trimmers you can install varicaps with control according to AGC principle.
Good idea.
Interesting Manuel, although the initial outcome is not exactly what you were looking for I expect that someone out there will have some useful comments. Unfortunately it will not be me as I have no idea how to improve the amplifier but thanks for showing us, we will all probably learn something when you get some relevant replies....
I hope so. Always great to learn from others.
👍😊
Elektor magazine 1/12/1991 .40mhz to 850mhz 20db mast head pre amp useing the ne5205 rf wide band amp
👍
Learnt a lot of ideas from the comments about improving bandwidth. I'm an electronics engineer, my knowledge lies more with the radio operation and not the art of RF preamps at the vhf range. So my suggestion is probably more naive, I don't know. But what I'm thinking is adding an extra tuned stage, spreading the bandwidth and just watching your overall gain. I would be interested to learn the pros and cons of my idea.
That could work, even if we had three smallish peaks along the band.
Greetings:
I would suggest using an rf sweep from 87-102 MHz. Then make all adjustments while you watch the scope.
I would lower the scope trigger level so that you have a stable display for the full sweep interval.
My sig gen that has a sweep function doesn’t go that high.
Since your Antenna Booster has a restricted band you could use it at your advantage making it tunable. Simply substitute the trimmers on the tuning coils with varicaps and regulating their voltages with a potentiometer you make your booster tunable.
👍
BINGO, I have been quietly screaming at the screen, By selecting 3 matched Varicap diodes, and switching out your 2 wire NON coax 12V power feed to spare inexpensive 4 conductor Telephone wire, you can send up 12V, and a separate 5-20V typical range Tuning Voltage on the added 2 conductors!. Take these tuning diodes OR the whole RF Amp stage from any old electronically tuned FM radio or just 3 varicaps and branch out via 3 100k resistors and some decoupling caps. NOW you have a remote tuned, image rejecting PRESELECTOR, like the 3 stage one in my beattiful 1974 Kenwood R-599 "HAM" Communications Receiver utilizes for HF. Also maybe fashion some copper shield between the input and drain coils and trimmers to cut oscillation risk. Nice layout, here in the states I have layed out 200+ PCB's, many for USA Police Car Videotape Evidence camera systems using my trusty OrCad SDT and PCBII DOS tools, on a 486 computer which NEVER has been connected to the internet...Thanks for your wonderful videos and mild voice intelligent presentation! I am restoring and redesigning a 1944 Hallicrafters SX-28A HF Receiver into SX-28+, copying my HQ129-X BFO circuit, better regulation, and a DIY AUDIO modified dual 6V6GT ckt with 2 new Gold Lion tubes, matched pair from Russia, AND a HiFi audio TF from Hammond. It already has TWO tracking RF AMP tube stages, providing preselection automatically for 0.5-42MHz. Thanks from W4HDL in USA.
Thanks for that. Lots of ideas to work with.
Regards
Hi Manuel. I have a question regarding the printing on the board. I see the name ‘E Q&N…’
Shouldn’t that read ‘E O&N…’ the letter ‘O’ not Q?😉
You’re absolutely right. Only noticed it now that you mentioned it. Spelling mistakes were always one of my biggest faults 😊
Try removing the second filter and use a variable cap on the first. You maybe able to create a scale to aid quick tuning of the antenna. might help ...
👍
Hi Manuel. Great video. Sorry it didn't turn out the way you wanted. Could substituting one or two components (upgrading the existing design) give you the extra performance you are looking for? I really hope that you can rectify the problem, as it will be a very worthwhile addition to have. Best of luck. Cheers Chris.
Thanks Chris. I’ll be tinkering with it for some time, I’m sure.
Love this channel. Does anyone know where I can find a full complete readable schematic for my Braun WW2 RC 56 UK chassis ?
All I can find online are very bad splotchy unreadable schematics.
Hi manuel, probably you were searching some article like this"EE July/August 1986 36 by R Shankar 1 111 tuneable FM booster 01 BB106 C1 II Op 75 n BF961 BF981 This FM band (88-108 MHz) preampli- fier, this was an article at elektor magazi ne, & doesn't lacks , modest gain /Q, but tunable on the whole FM band
👍
Hi Miguel ! There are much more simpler and better solutions for making a WIDE BAND min. 20 dB low noise (NF~0.6dB) over the FM broadcast band: I use single chip MiniCircuits PGA103 (there's also the SPF5189Z). They can be found easily and cheaply on chinese sites, even already built. The only drawback is that they run at high quiescent current (typ. 70-90 mA). Located just after a simple vertical dipole (+ balun) that makes a huge difference on receiving (I also added a 88-108 MHz bandpass filter in front of the LNA to get rid of intermittent airplane communication intermodulation).
I actually ordered on of those some time ago, but deliveries are taking months at the moment.
Wow! You have made a very selective active notch filter with a significant gain on the pass frequency. :-) Maybe if you make 5 of them, tune them precisely that one follows the other then mix their outputs, you can cover the whole FM broadcast band.
True 😊
I was itching for you to test this with either a spectrum analyser with tracking generator, or signal generator in sweep mode, triggering your scope to show what the band pass looked like. You do it for radio alignment so why not here? Thanks for another interesting video.
The signal generator I use for the sweeps only goes to 20MHz. For 100MHz I only have that old manually adjusted generator.
Regards, MC
Hi Manuel. Did you get an improvement on the design of this booster? Many thanks for your videos and designs.
Parts haven’t arrived yet 😞
Olá, circuitos RF gostam de alimentações bem filtradas, sem ruídos e uma boa terra. Olhando para o circuito e pela experiencia no osciloscópio, chegar aos 100mV para a frequência em teste, o que diga-se, é excelente. Para abrir esse ganho para a uma range de 12Mhz, penso que o ganho vá descer um pouco, mas julgo ser possível. O que faria era selecionar o posicionamento desses 12 Mhz na faixa 88 108, posicionar na frequência mais baixa e fazer o tuning para o maior ganho e depois ir à outra ponta (+12Mhz) e fazer o mesmo, e depois voltar atrás, e ir jogando com as 4 afinações até obter um ganho médio entre estes dois pontos e já agora, apurando como fica também a meio (6Mhz desde o inicio). Essas seletividades ao fim ao cabo são os filtros de ressonância, entre as bobines e os condensadores variáveis e o trim, que acredito com paciência, se consegue abrir uma janela de 12Mhz com um bom ganho.
Obrigado pelas dicas. Vou brincar um pouco mais com este bichinho, e lembrei-me de uma coisa: Vou ter de confirmar que o gerador está a produzir a mesma amplitude está gama de frequências, pois tentar linearizar um amp alimentado por um gerador rasca não é boa ideia 😊
some Radio have signal strength indicator led , its brightness increased when tuned .
how this circuit works ? i wanna built such indicator for IF output
I’m afraid that requires a full explanation that I’m sure you can easily find on the web with a little searching.
what about using a 220R resistor in parallel with the inductors to widen the response curve.
👍
Also, in addition to amplification of the FM band RF the device seems to amplify the audio of family’s doggie @ 35:49 min. A very cool side benefit. 😃 lol
Yes, but unfortunately it’s the neighbour’s 😊
Thanks for sharing the design and build! I would be interested in making something to cover a spread of 30 to 1000Mhz without using the filtering. I am guessing coils and trimmers could be eliminated from the build in a breadboard version, then design and make some PCB's. I have also used PCBWAY to create some linear power supply replacement prototypes for a Feeltech FY6600 Function/AWG that has a bad issue of leaking some ( 50 to 70VAC) power line voltage through the SPS to the common / shield connection ( video to be created soon).
Definitely can’t use sharp filters, and building on a breadboard may not be too easy due to parasitics. probably best manhattan style on a blank pcb.
Excellent Video, thanks for making and sharing it. I think this will be excellent for a FM DX project I am planning. Is it possible to get the files to order a board from PCBWay?
I was not at all happy with this version of the project, so Decided not to share the boards, which would be wrong. I may do an improved version in the future and then I should publish that.
Thanks for the reply. Can you please advise the size of the Ferrite Bead?
about 8mm
Try balancing the High & Low end to the same peak.
👍🏼
Thank you for this interesting project. It appears that good antenna amplifier design can be a challenging process. I've often wondered if an old-fashioned TV-FM antenna amp would be useful in a case like this. They're dirt cheap, very wide-band (50 to 2200MHz) and, back in the days of analog TV, were often used to boost fringe signals into clear signals. Or is there some technical reason why this won't work?
not sure, but could be as simple as that.
How interesting would an application be for a car radio with an android player?
The coils should probably be tuned bit more wideband.
👍
Seems like you need several Ariel amplifiers for different frequency's getting rather complicated.
I agree. This project is a definite fail.
I have small FM radio for my Church. Is there a attenna that will boost the power going out? 90.5 FM
Not sure if that’s going to give you a good result. Also be careful about the legal limits.
@@electronicsoldandnew is there a device that boost signal going out?
An RF amplifier
@@electronicsoldandnew thanks
I think you got it wrong regarding ferrite beads- they should be "beads" with a hole through which you pass the wire and not a normal ferrite rod as any other coil
This was the bead specified in the article, but I’ll obviously try alternatives.
@@electronicsoldandnew Does it have a hole through its sides? ferrite beads with the wire just passing through are used in RF circuit to suppress ringing. no windings, just pass-through
I know, but I decided to follow the instructions exactly, and this is what they describe.
Can i put a transistor jfet in 1st stage. ?
O have a 2n3819 and BB981.
The BF 981 is rare here.
I can’t say. Look at the data sheets and see if the characteristics match.
@@electronicsoldandnew Tks.
Was that a Project by T.Giesberts for ELEKTOR Magazine BV
not sure.
Onde eu encontro esse amplificador pra mim comprar?
Este é um projecto teste e não está a venda.
Its a nice little device but having static and stuff on FM while listening to music is kinda... pointless. At least for me! :D My "solutions" so far are bigger and bigger antenna streched and build all over my place.
I’m heading in the same direction 😊
Can you share the PCBWAY files you used to order your boards?
I will when I’ve done some tweaking to make sure it’s the best possible.
Can I use tubes instead of those mosfets?
I’m sure you could, but the entire circuit would need to be drastically changed.
A TV antenna pre-amp will solve your FM reception problem ..Tony HP1KL . We.visited your lovely island in 2017!!!
Got to try one.
Hope you enjoyed the island.
Can you put in some tinplate screens to kill off the oscillation.
what purpose are of two gate ?
Excuse me ..but building this is a nonsense ...use BFR91 transistor and made simple FM or VHF amplifier
and you will be surprised !
You’re probably right. 😊
sorry Manuel, I got shadowbanned here, on a simple one line comment.
I'll try here: your 'bead' should be a torus I think, not cylindrical, but you may have seen the picture of the finished product.
I’m curious: How did this ban work? I’ve seen quite a few comments appear and then disappear with no input from me. What is happening? Is this a YT feature or bug?
@@electronicsoldandnew Good to know. How it works I haven't got a clue, I only know it happens. At one point I placed a short comment here, added one line a few minutes later and got a red 'return error'. That mostly happens when you do something that is not allowed, or by youtube (breaching community rules like 'false' medical info), or by you as creator (e.g. you don't allow links in comments). But in this case, and I have seen that before, nothing of that was in my comment.
But this form is still signalled by youtube with a red warning telling: "return error". So you are informed. But the bad one is the shadow banning: you will NOT be informed that your comment is ONLY SEEN by yourself, and no one else. That is plain misleading, because the text fiield says: "Add a public reaction", and keeps you under the impression everyone can read it. No, only you as commenter. The way you can check is to look at the same message but with another browser, NOT logged in to YT, the link is under the time stamp of the comment.
I wonder if YT will place this text..... I have seen this explanation disappear many times.
This one got through 😊
@@electronicsoldandnew Yep... Then I am invited to try my original message, lets see what happens 😉 in the next comment below here: