What do you think about building an FM amplifier by THS9001?

Thread Starter

leche

Joined Apr 1, 2011
23
Hello everybody.Nowadays i think to build an FM amplifier circuit to wire it to my car's radio to amplify the receiving fm signals.I looked for some circuits but generally they consist of some transistors.I thought that using a good ic would have been a better choice for the quality, efficiency and capacity.I searched some ics on the net and found "Texas instruments THS9001 50 Mhz to 750 Mhz Cascadable Amplifier."What do you think about it to use as a IC for that kind of circuit?Or i am open some suggestions about another way to build it, but i want a powerful good quality and efficient one to use it on my car without any problems.Do you advice this ic for me or another one to build that?Thank you.

Ic information link:
ths9001
 

Papabravo

Joined Feb 24, 2006
17,310
How do you plan to match the amplifiers output the the receiver threshold to prevent overloading the front end of your radio?
 

AlbertHall

Joined Jun 4, 2014
11,610
I don't think that chip would make a good aerial preamplifier. It is intended for higher level signals.
There are plenty of ready made units, designed for this purpose , available cheaply. I would advise using one of these.
 

Thread Starter

leche

Joined Apr 1, 2011
23
I don't think that chip would make a good aerial preamplifier. It is intended for higher level signals.
There are plenty of ready made units, designed for this purpose , available cheaply. I would advise using one of these.
Thanks for your response.Can you please give me an example ic to use for that needing?I thought ths9001 would be okay because on the datasheet it shows it gains on 100mhz freq.I was not sure thats i asked it here.Yes there are many items on the market to buy but the problem is generally their boards have some transistors coils capacitors.And i think their build quality is not good.I have one on my radio now, but randomly it boosts the volume to max and i have to volume down it.Thats why i try to build a good one myself, so i can fix it if i face some problems because i would know every component it has because of i build it myself.I thought instead of some transistors, the quality would be better if i use a good ic which is produced by a known producer.
 

AlbertHall

Joined Jun 4, 2014
11,610
If the volume changes on an FM station, that sounds like a a problem with the radio not the aerial amplifier. With an AM receiver the audio volume can change with signal level but that shouldn't happen with an FM receiver.
 

Thread Starter

leche

Joined Apr 1, 2011
23
If the volume changes on an FM station, that sounds like a a problem with the radio not the aerial amplifier. With an AM receiver the audio volume can change with signal level but that shouldn't happen with an FM receiver.

The problem is not about any fm station.It makes that on every freq every channel randomly :(Edit: Sorry.You meant that if the problem occurs only when it is on fm, the problem might be about the radio itself right?
 

Papabravo

Joined Feb 24, 2006
17,310
Thanks for your response.Can you please give me an example ic to use for that needing?I thought ths9001 would be okay because on the datasheet it shows it gains on 100mhz freq.I was not sure thats i asked it here.Yes there are many items on the market to buy but the problem is generally their boards have some transistors coils capacitors.And i think their build quality is not good.I have one on my radio now, but randomly it boosts the volume to max and i have to volume down it.Thats why i try to build a good one myself, so i can fix it if i face some problems because i would know every component it has because of i build it myself.I thought instead of some transistors, the quality would be better if i use a good ic which is produced by a known producer.
There is a basic disconnect here. Designing and testing an RF amplifier is not something you can do with minimal information and effort. It is hardly a matter of slapping a few random components on a circuit board. To get to where you want to go will take some time, effort, and expense. This is one of those situations where you need to learn how to crawl and walk before you try to run a marathon. It is possible to do this on your own, with self study, but you need to start with realizable goals. This site has has some good reference materials that can serve as a starting point.

One more thing. Modern electronic manufacturing techniques produce products that are far superior in performance and reliability to things that most people are capable of building. Homebrew projects became way more difficult after 2006 when there was a worldwide push to get rid of the lead (Pb) in solder. Building electronics with lead-free solder is way more difficult nowadays. You can learn the required skills, but it can be way more frustrating than it used to be. Because most components are in small surface mount packages, the old methods of point-to-point wiring and dead-bug style construction are way more difficult with the components available.

You have a formidable task ahead of you. Good luck.
 

AlbertHall

Joined Jun 4, 2014
11,610
You meant that if the problem occurs only when it is on fm, the problem might be about the radio itself right?
A problem in the radio may affect either AM or FM, or both.
A random volume change on an FM station cannot really be caused by an aerial amplfier.
 

Audioguru again

Joined Oct 21, 2019
3,866
A half decent FM radio has excellent sensitivity and has AGC so that it is not overloaded by strong stations in a city.
My cheap Sony Walkman FM radio has a "local" or "distant" switch instead of an automatic circuit.

Some very cheap FM radios do not have a proper FM detector. They use an AM detector that detects FM when tuned to the side of an FM station (slope detection) so the volume changes with signal strength.
 
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