Possible preamp project??

[wrecker]

I was wondering if anybody has built a small preamp before?.

I'm curious about the circuit and components of a preamp but have no idea on how to build one so I'm wondering if anyone has any schematics of the circuit and list of parts and where it where it goes and how it all works

[cjay]

I was wondering if anybody has built a small preamp before?.

I'm curious about the circuit and components of a preamp but have no idea on how to build one so I'm wondering if anyone has any schematics of the circuit and list of parts and where it where it goes and how it all works

http://gridtoys.com/preamp/preamp.html

You'd need to add TX switching and could 'borrow' the circuit from any number of linears out there. Perhaps even build the pre-amp into one.

MMICs are excellent little devices, cheap and really simple to use to excellent effect. Might want to question why you need a pre-amp though, it's often a problem with your setup that can be rectified.

[wrecker]

Just found this:

http://www.youtube.com/watch?v=jiaQLXQMh0g

And this:

http://www.youtube.com/watch?v=cMT4bx4O4JY

they look similar but the smaller one looks more ideal and I could make it switchable but I cant really see where the tracks go to each component

[cjay]

Just found this:

http://www.youtube.com/watch?v=jiaQLXQMh0g

And this:

http://www.youtube.com/watch?v=cMT4bx4O4JY

they look similar but the smaller one looks more ideal and I could make it switchable but I cant really see where the tracks go to each component

Wow.. Just... Wow...

That gatekeeper guy is either a comic genius playing those videos for effect and winding up the 'good buddies' or a complete moron.

[Anthony123]

Go for a low noise design, Using a fet rather than a bipolar transistor, also have the pre-amp tuned rather than fully wideband..There are loads of designs out there.. have a look in the ARRL handbook ... its a really great book for ideas and info...

Also a Pre-amp can add noise.. a Lot of the cheaper types such as is found in the common CB linear amp dont seem to do a lot other than bump the signal and the noise up by the same ampount but then again there not normally a tuned design.., This is why you want a low noise amp.. dont have to much gain as this can overload the reciever .. also te best place for a pre-amp is at the antenna, Yup.. Its true, The coax can actually introduce noise, hence the preamp is placed at the antenna..... Ive a few home made 10 mtr band preamps..using just a single Mosfet... They work well... Ive used them for various things such as when i used a low dipole for RX-ing to get away from the PLT noise.. The preamp brought the signals back up but because the dipole was low.. Under a meter high.. the noise level was almost non existant...