Searching \ for '[EE]: RF amp' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/io/serials.htm?key=rf
Search entire site for: 'RF amp'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: RF amp'
2002\06\21@163404 by Dale Botkin

flavicon
face
Wow, thought I sent this the other night.  Guess my carefully typed reply
got eaten by Outlook.  That'll teach me to stray form the One True Path.
<grin>

Jim asked:

>Stability? (Will output always see 50 +j0, built-in VSWR protect, etc)

Needs short/open VSWR protection (protection from "stupid user tricks" and
abuse).

>BW? (1 MHz, 10 MHz)

No big deal.  Xmitter will be fixed 174.something MHz.

>Efficiency?

Not terribly important while on primary 13.8V power.  On backup (4.5
NiCd) more efficiency is better.

>Temp range?

Outdoor temp range, say -20 to +40 C.

>Expected life-time?

Indefinite, at least 3-5 years I'd guess.  They'll be potted and mounted
in more or less protected locations, the metal enclosure can be used as a
heat sink.  Heat should not be a big issue as transmit time will be very,
very short - 5% duty cycle when active with short (250ms or less) burst
data transmissions.


Dale

{Original Message removed}

2002\06\21@164843 by Brendan Moran

flavicon
face
----- Original Message -----
From: "Dale Botkin" <spam_OUTdaleTakeThisOuTspamBOTKIN.ORG>
To: <.....PICLISTKILLspamspam@spam@MITVMA.MIT.EDU>
Sent: Friday, June 21, 2002 1:32 PM
Subject: [EE]: RF amp

> > Yeah, yeah...  no applause, please, just somebody send me a design for a
> > VHF (174MHz) RF power amp giving 4W out from 100mW in, costing less than
> > $2 for parts in qty. 500, using as little board space as possible and
> > running off 13.8VDC or 3-4 AA NiCD batteries...  actually I think I have
> > something workable, but only testing will tell for sure.

I know the feeling.  Here's my RF woe:  relatively low frequency, but high
sensitivity amp having:

Operation at roughly 15MHz
30dB of gain
0.5dB noise figure
1-10 kohm input impedance, 50ohm output impedance
BW of roughly 100kHz
Lesser than -40dBm input
Operation off a 15V supply.

Here's the clincher:  It can't have any magnetic components.

As with you, I think I have something that will work, but only more testing
will tell, since we're basically forced to use active components well
outside their design frequency (the GaAs FET I'm using is 450MHz to 6GHz or
so)

--Brendan

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\21@173059 by Dave Tweed

face
flavicon
face
Brendan Moran <bmoranspamKILLspamMILLENNIUM.CA> wrote:
> As with you, I think I have something that will work, but only more testing
> will tell, since we're basically forced to use active components well
> outside their design frequency (the GaAs FET I'm using is 450MHz to 6GHz or
> so)

OK, I have to ask: Why does your FET have a *lower* frequency limit?

-- Dave Tweed

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\06\21@175605 by Brendan Moran

flavicon
face
> Brendan Moran <.....bmoranKILLspamspam.....MILLENNIUM.CA> wrote:
> > As with you, I think I have something that will work, but only more
testing
> > will tell, since we're basically forced to use active components well
> > outside their design frequency (the GaAs FET I'm using is 450MHz to 6GHz
or
> > so)
>
> OK, I have to ask: Why does your FET have a *lower* frequency limit?

You know?  I keep asking myself that, but, hey, that's what they told me.
I'm not an RF engineer, I like digital systems, myself, but I'm stuck with
this project, so I'm doing what I can.

I think the problem is in stability.  When you look at the k-factor which is
derived from the S-parameters, k peaks in about the middle of the frequency
range (the higher k is, the more stable the amplifier is) that it was
designed for.  They haven't even listed S-parameters below 500kHz.

I actually talked to Agilent about this one, and they're the ones that told
me about the minimum frequency restriction (aside from the datasheets, of
course)  I'm using the ATF-33143 for the active component.

I still just don't get *minimum* frequency restrictions on a component...

--Brendan

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


More... (looser matching)
- Last day of these posts
- In 2002 , 2003 only
- Today
- New search...