Need help in 88-108MHz preamp circuit!!

Status
Not open for further replies.
What is your interest Maxwelllll? Working on any projects? Other than trying to derrive equations for Electromagnetics of course
 
looks like we have made TEA5711 receivers "a la mode" (in fashion), everybody wants to make them

High voltage induction coils, I love'em... They were first made by Nicola Tesla, if am not mistaken, an obscure electrical genious
 
Can u remember the communication range of a Tesla Coil based radio transmitter. How is the receiver is designed for that?
 
rahulan999 said:
Can u remember the communication range of a Tesla Coil based radio transmitter. How is the receiver is designed for that?
Click to expand...

I am a little rusty on the subject, but I think you are confusing this with the Hertzian transmitter, he used an ignition coil which produced sparks and transmitted the sparks to an open metal ring with 2 small balls a few feet away, he proved the existence of electromagnetic waves. I don't know if Tesla transmitted anything, he played around with induction coils of all sorts and some of them produced very large sparks all over the place Of course I can research the net and my books to sound more knowledgeable here, but I will not do that
 
LM1036 also got in my pocket yesterday, very costly!
I have ordered it from Mumbai and the supplier told that only 5 number is available and no chance to find anymore. So all the remaining pieces shipped to Bangalore as per my order and I picked only one because the IC was very HOT!

Bought 10.7MHz filter(3pin) and discriminator(2pin). No one knows about the bandwidth whether its 150KHz or 450 like that. Its not written on the part also except the 10.7.
They told its from something Moratto, Japan company. Check on net for datasheet. But I didn't find anything.

455KHz Philips IFT is available for AM part. Is it necessary to use the same part no. mentioned on the datasheet?

Apart from IFTs every obsolete parts for this project is obtained! I'm very happy
 
Murata filters, not Morrato. You better know what the bandwidths are, u can't just use "whatever" in that circuit, and u shouldn't mix filters or your selectivity will be mashed potatoes
The IFTs don't have to be philips, but u have to respect the turns number as mentioned in the sheet. Like I said before, don't expect good selectivity on AM with just 2 IF tuned circuits!
 
Last edited:
150KHZ filters are good for this FM radio. Make sure the 2 filters are similar.

Selectivity on AM will not be great with only 2 IF tuned circuits, but the sound quality will be nice with a wide bandwidth, and you will get a lot of birdies from adjacent stations beating with each other from lack of selectivity... a real symphony
 
Last edited:
rahulan999 said:
LM1036 also got in my pocket yesterday, very costly!
I have ordered it from Mumbai and the supplier told that only 5 number is available and no chance to find anymore.
Click to expand...
National Semi has the LM1036 in full production.
Digikey has 367 in stock today for only $2.75US each (the cost of a cup of coffee in a restaurant).
Newark has 246 in stock today for only $2.62US each.
 
audioguru said:
Wait a minute. Bangalore is in India, not France.
Click to expand...

Un petit cafe a Paris coute a peu pres $5 a $6.. Ziss Minz ay small coffee in Paris costs about $5 to $6 and I waz talkin aybout Paris

By the way, Mouser Electronics doesn't carry the LM1036, and there is no NTE replacement for that chip.. Blouzers!
 
Here, coffee is a very cheap item, so we not at all bother abt the price. Even in my house also coffee production plant is there. So if restaurants want to increase the price also nobody will mind

My filters are marked as: SFA10.7MF
and discriminators: 10.7FGF
Can u differentiate it?

Is that MKA293,294...numbers on datasheet represents IFT part no.?
If I have to strictly follow the turns then, probably re-winding of IFT core is the only option. The highest gauge available for me is 49SWG. I think that specified .07mm may be something 52-54SWG ranges.
 
rahulan999 said:
My filters are marked as: SFA10.7MF
and discriminators: 10.7FGF
Can u differentiate it?
Click to expand...

It looks like the SFA10.7MF is a 50KHZ BW filter, which is too narrow for broadcast FM. Since you have internet, you can search the part for information. Search for muRata website also. I didn't get any results for "10.7FGF".
 

I don't know about the MKA... again, do a search on the net. For the oscillator coil (L4), I would use a can with the red core, and for the 1st and 2nd IFT coils (L5 and L6), I'd use cans with the white and black cores respectively. You can canibalize these coils from a cheap AM radio. I wouldn't advise you to re-wind the coils, you don't need to re-invent gun powder man! As far as the windings, you can test resistances at the pins to decide which pin goes where. Larger windings will have more resistance and vice versa.
 
Last edited:
Yea, I have old 2in1 boards with IFTs on them. Also I already have a set of general purpose transistor radio IFTs.
Once I will try to rewind for an experience, otherwise I will get a Philips part.
50KHz filter will degrade the audio fidelity though the selectivity is at extreme level. The specified part no. is 455KHz BW with moderate selectivity and excellent audio quality.
Here's a link:
How to select a tuner for 88-108 MHz broadcast FM DX
 
Last edited:
Status
Not open for further replies.

Similar threads

Q
  • Question
Input requested for DIY Mixer-Preamp
Replies
16
Views
2K
Quercus
Q
G
  • Question
My son need help with his circuit design!!!
Replies
14
Views
1K
ZipZapOuch
S
  • Question
Need help with spst toggle to momentary
Replies
5
Views
967
crutschow
T
  • Question
microphone mixer preamplifier howling
2 3
Replies
45
Views
6K
danadak
Z
Need some help for a FM LIFI communication
Replies
1
Views
1K
rjenkinsgb
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…