•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

Job Board

About RF Cafe™

Sitemap

Building a 16Mhz radio for Senior design project. have Q's - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


donjonson
Post subject: Building a 16Mhz radio for Senior design project. have Q's Posted: Wed Sep 19, 2007 7:23 pm

Lieutenant


Joined: Wed Sep 19, 2007 6:58 pm
Posts: 3
Hello Very Happy This is my first post on this forum. I am building a 16Mhz radio for my senior design project and Have a few questions. I have been working in PSPICE and am ready to start building and testing.


1)What kind of capacitors should I use in my tuned amplifiers, oscillators, and filters? I have been looking online and there are so many to choose from. I think I should be using something with a small temp coefficient but what material should I use etc..

2)Does anyone know of a place online with low shipping costs and a good selection of components? I have been looking at mouser it seems to be pretty good any other suggestions?

3)In my transmit oscillator I am using an NFET to switch in and out a cap. I am having a difficult time trying to Find one in a TO-92 package with a good enough Ft. Does anyone know where I could go to get this? or perhaps suggest a better device for me to use than an NFET.

thank you for taking the time to read and answer my questions.

I posted this in the amateur radio forum first but I noticed it is pretty much a dead forum so I reposted it here. If a moderator wants to delete one of them please delete the other one.


Top

IR
Post subject: Posted: Sat Sep 22, 2007 2:51 am

Site Admin


Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
Hello donjonson,

First of all, welcome to our forum!

To answer some of your questions:

Quote:
1)What kind of capacitors should I use in my tuned amplifiers, oscillators, and filters? I have been looking online and there are so many to choose from. I think I should be using something with a small temp coefficient but what material should I use etc..


In principle, you should use high Q capacitors. As for the material you are right there are materials with large temperature coefficient like Y5V. You should use X7R or X5R capacitros which have a low temperature coefficient.

Quote:
2)Does anyone know of a place online with low shipping costs and a good selection of components? I have been looking at mouser it seems to be pretty good any other suggestions?


You can try: Digikey www.digikey.com

Quote:
3)In my transmit oscillator I am using an NFET to switch in and out a cap. I am having a difficult time trying to Find one in a TO-92 package with a good enough Ft. Does anyone know where I could go to get this? or perhaps suggest a better device for me to use than an NFET.


While NFET is a good choice I would not limit myself to a specific type of package to allow more flexibility. Thre are many types of packages available besides TO-92.

Here are number of TO-92 NFET transistors from Vishay-Siliconix:

http://www.vishay.com/docs/70237/70237.pdf

Quote:
I posted this in the amateur radio forum first but I noticed it is pretty much a dead forum so I reposted it here. If a moderator wants to delete one of them please delete the other one.


posts with topics which are relevant to the Forum are not deleted.

I am moderating this forum for almost 2 years now and have met here people with reach knowledge from whom you can only learn.

Good luck

-IR







Posted  11/12/2012
Custom Search
More than 10,000 searchable pages indexed.

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeKirt Blattenberger... single-handedly redefining what an engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5th MOB: My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website