Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
RF TRANSMITTER LAYOUT - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: RF TRANSMITTER LAYOUT Posted: Fri Jul 25,
2008 2:45 pm
Joined: Sun Jun 22, 2008 3:57
i am a beginner to CAD. i have designed
a layout for a rf video tx circuit. i am enclosing the schematic and
layout. please tell me if there are any errors. i used a longer trace
to connect L2 to T1. will it have any effect on L2 inductance? please
give me suggestions on how to make it better. [img][img]http://img93.imageshack.us/img93/7151/rflayoutsd4.th.jpg[/img][/img]
Post subject: Posted: Mon Jul 28, 2008
Joined: Fri Feb 17, 2006 12:07 pm
Location: London UK
A track length of
about 35 mm and 0.5mm wide (estimates from your pdf file) will add about
0.4 microhenry to L2.
I gave you an extensive reply to this design
on June 30th. Was this understood and followed?
of the RF side of the circuit should be ground on both sides of the
PCB, with pads for components. Conventional LF electronic layout, as
done by software, leads to many problems at RF. Much of this is due
to narrow track widths give rise to higher radiated fields and so increase
the RF coupling into parts that should not be coupled to. Thus the true
schematic model with narrow tracks would have many many mutual inductances
that give rise to spurious genrated frequencies. Best avoided.