simple radio amplifier/radio help

[large_ghostman]

hi
i want to build a simple radio preferably not a crystal set as we dont get reception much here, i dont want to just buy a chip eigther, so any recomendations for links for a simple radio project?
i also have a question on signal generators but that can wait, also my meters are here but i havnt got the RTCC working yet so i havnt looked at them, i wanted to use (want dad to buy) a microchip serial tool to trouble shoot the RTCC but he said use the logic analyzer and pattern generator on it??? is this a good way? or is dad being a tight arse?

thank you

 

[gary350]

How about a vacuum tube radio?

 

[JimB]

While you have stated that you dont want to "just buy a chip", can I suggest a simple radio using a ZN414 IC.
The ZN414 has just 3 legs, looks like a transisitor.

Have a look here
https://www.circuitstoday.com/am-receiver-using-zn414
for a typical ZN414 circuit.

Does that spark your interest?

JimB

 

[MikeMl]

Get to know some local Hams (guys, usually but not exclusively, that have big antennas on their house). I have helped several beginners ("Elmered") get into radio and electronics.

 

[large_ghostman]

i would prefer to stay away from a single chip solution, as for guy's with big arials i would like that but we dont actualy live near anyone!! there is only a couple of farms for miles so i dont have that option, but ham radio would be realy realy cool! it's something i would like to build upto, i have a couple of old kits one is a oscillator that apparently is for making a transmitter or rather can be used for a transmitter circuit. but first i want to start off with something a bit more simple

 

[cowboybob]

hi
i want to build a simple radio preferably not a crystal set as we dont get reception much here, i dont want to just buy a chip eigther, so any recomendations for links for a simple radio project?
i also have a question on signal generators but that can wait, also my meters are here but i havnt got the RTCC working yet so i havnt looked at them, i wanted to use (want dad to buy) a microchip serial tool to trouble shoot the RTCC but he said use the logic analyzer and pattern generator on it??? is this a good way? or is dad being a tight arse?

thank you

Understand that ANY receiver is, to a large extent, only as good as its antenna.

That said, I would encourage you to re-consider a crystal set.

Admittedly low-tech and without much in the way of audio volume, it will work for you if you put up a decent antenna.

HINT: Night time reception is often (but not always) best.

Since most little xtal kits are for AM, a "long-wire" (the longer, the better) antenna will work quite well.

Here's a list of stations in Plymouth:



NOTE! Be very careful with ANY antenna as they ALL represent deadly potential lightning strike dangers.

Now, I don't presume to know anything about your level of experience or understanding of things electronic. I will say that a xtal radio, if you care to investigate the "why" of how they work, will teach you a boat load about radio signal detection that will be entirely applicable to most all radio work you may do in the future.

Throw in a variable capacitor and that addition alone will pretty much cover everything you come to play with that involves resonant circuits. And the list goes on.

I started out in electronics (a little younger than you, age 10) with a xtal set (and a long wire antenna) in the hills of Kentucky, well over 50 miles (at that time, late 1950s) from the nearest AM station transmitter (WLAP, 630KHz) , with mountains in between. And that little xtal set worked just fine...

And Ham Radio is, indeed, very, very cool...

73's
CBB
K4NFF

 

[large_ghostman]

ok sounds good, better than dad said it was so i will start with a crystal set, i assume i can add stuff to it like a amp for the volume? i have no experiance with radio and a bit of experiance with pics and bits of stuff i try, but i do have access to loads of components and some pretty good test gear! also in my box i have a unknown variable cap , i do work for dad at weekends sweeping up the store where he and Ron keep the components they buy in to sell on 9they buy end of production line stuff and buy cheap stuff from bankrupt companies) my payment is normaly in the things that they are going to dump for one reason or other so i have a great parts bin
i will google some circuits and get back here for guidence if thats ok. i can fit a antenna on the barn roof as its probaly the only place to get a signal lol i will also disconect it and hang it outside in storms ect to be on the safe side.

thanks for the help

 

[KeepItSimpleStupid]

I don't know what''s out there in terms of Software Defined Radio, but look around. It still might be way too expensive.

 

[large_ghostman]

I don't know what''s out there in terms of Software Defined Radio, but look around. It still might be way too expensive.

sofgtware define3d radio?? i dont understand that??

the project isnt actualy to build a super duper DAB or anything like that but i am interested in radio and stuff like inductive coupling, i want to have a go at building something with transistor and opamp's and old stuff also we have some very old radio's here that someday i would like to get going so realy it's a learning project rather than a radio to use every day. if that makes sense

 

[cowboybob]

...the project isnt actualy to build a super duper DAB or anything like that but i am interested in radio and stuff like inductive coupling, i want to have a go at building something with transistor and opamp's and old stuff also we have some very old radio's here that someday i would like to get going so realy it's a learning project rather than a radio to use every day. if that makes sense

Makes great sense.

There is nothing you could build that would be any simpler than a xtal radio.

Here is an example (it's on YouTube. You may have to ask your Dad for permission to go to this site) that is excellent. It shows you how to build the xtal set from scratch with stuff you probably have around your house (except maybe the crystal).

https://www.youtube.com/watch?v=VqdcU9ULAlA

The reason the germanium crystal diode (the 1N34) is used is because it has a very low "forward voltage" value, which makes more signal available for the earphone. A regular diode could be used, but will give a much lower audio output.

Also note that this design makes use of a variable capacitor.

Get this puppy workin' and you will be understandably proud of yourself!

You can, of course, later add a transistor or OpAmp amplifier to the output of the xtal set to drive a speaker, for instance.

 

[KeepItSimpleStupid]

Proabably way over your head, but here is a blurb that's simple: **broken link removed**

What's happened is that digital signal processing has gotten so fast, that you can almost create the radio and modulation and tuning in software, Hence, a software defined radio.

When I was about your age, I was fixing simple 5 transistor car radios from the 60's or so without any real test equipment. Just a DVM. It was really tough. I also fixed tube TV's from that era as well without a decent scope. I didn't even have a signal generator.

I'm trying to slowly put a bench together that I can fix and repair the older tube radios effectively. Time, though, is slipping away. I did purchase the FM section for an old Motorola console. It will need to be restored completely. No tubes were in the chassis. I have the FM/AM and Phono Mahogony furniture that the FM section belongs in. The AM needs help too.

 

[dr pepper]

This is a really good site:-
A superhet receiver is most certainly a lot better than an xtal set.
And allthough it uses transformers it shows you how to build them, they look just like the ones in some of my old time valve sets.

https://www.noniandjim.com/Jim/RadioProjects/RadioProjects.html

Not sure what you mean RTCC, are you referring to the timer on most pic chips, or a real time clock chip.
If you want to program and debug chips then pursuade your old man to buy you a pickit, its a really good tool.

 

[large_ghostman]

i have looked at the you tube one and i might have a go at that as it is then see about modifying it if i can, the super hetrodyne one looks good so i will have a go at that second then i found a simple FM one i might try . will any of theese give me a chance to use the signal generator for testing or tuneing?? i would like to get some practice in with as much test gear as i can, even if it seems a bit pointless or overkill it gives me practice

thanks for the links i will go study the hetrodyne one in better detail and get together a part lists for both (dad might have to crack the wallet open lol)

 

[cowboybob]

i have looked at the you tube one and i might have a go at that as it is then see about modifying it if i can, the super hetrodyne one looks good so i will have a go at that second then i found a simple FM one i might try . will any of theese give me a chance to use the signal generator for testing or tuneing?? i would like to get some practice in with as much test gear as i can, even if it seems a bit pointless or overkill it gives me practice

thanks for the links i will go study the hetrodyne one in better detail and get together a part lists for both (dad might have to crack the wallet open lol)

The sig gen, if it has an Amplitude Modulation (AM) feature, could be used on ALL the AM receivers (rcvrs) you're considering (depending on the frequency range of the sig gen). Just attach a short (like 1') wire to the output of the sig gen (to act as an antenna), select an output frequency that's within the range of reception frequencies of the rcvr, and tune the rcvr until you hear the modulation. SAME would be true for the FM rcvrs if the sig gen has FM modulation options.

BE SURE to turn the output of the sig gen to no more than the minimum output that allows you to hear the signal on your rcvr. That should keep you out of trouble with the government.

Quick way to test your rcvr's tuning acccuracy is by selecting a local station and adjusting your tuning dial (if you have one) to reflect that known frequency (same would be true for calibrating your sig gen [if not crystal or VFO tuned).

 

[large_ghostman]

i got hold of a supposedly non working AM/FM signal generator that goes from 100kHz to 200 mGHz, i have tried it on dads oscilloscope and it looks spot on every frequency i dialled on the generator matched the scope read out!! so was working afterall


actualy just checked and its a KIKUSUI KSG 4100 FM/AM SIGNAL GENERATOR 0.1 100MHz but seems to work good dad got it super cheap in a job lot and gave it to me as it was meant to not work so i was going to take it apart but i always try and fix stuff first

 

[cowboybob]

i got hold of a supposedly non working AM/FM signal generator that goes from 100kHz to 200 mGHz, i have tried it on dads oscilloscope and it looks spot on every frequency i dialled on the generator matched the scope read out!! so was working afterall

That's the ticket. Although for a thorough test a frequency counter will show how spot on it trully is.

actualy just checked and its a KIKUSUI KSG 4100 FM/AM SIGNAL GENERATOR 0.1 100MHz but seems to work good dad got it super cheap in a job lot and gave it to me as it was meant to not work so i was going to take it apart but i always try and fix stuff first

Sounds like you saved a nice piece of gear that you'll end up using for years to come. Congrats

 

[dr pepper]

Look after your test gear, I've still got stuff I had/made 20 years ago.

 

[large_ghostman]

i am realy lucky to have the gear i do so i look after it the best i can, will any germainium diode work? if not i will have to try and get some, we some here but not sure wich they are

 

[unclejed613]

i've got a radio engineering textbook from 1917, and they had a trick for effectively reducing the forward voltage of crystal detectors to zero. they would feed a DC bias across the detector crystal through very large resistances (several megohms), and bias the junction to within a hair of conduction. that way, any additional forward voltage from an incoming signal would cause conduction easily. this was especially useful with carborundum (silicon carbide) crystals, where the forward voltage is close to 2V. there are currently several companies making SiC diodes. one of these days i'll test one and see how well it works in a crystal set... i know SiC was popular back then because it worked better at higher frequencies.

 

[cowboybob]

i am realy lucky to have the gear i do so i look after it the best i can, will any germainium diode work? if not i will have to try and get some, we some here but not sure wich they are

Just give'em a try. Using the sig gen as an xmitter, you'll have plenty of signal available.