Re: [softrock40] Re: Battery power for original SoftRock40 (ver4)?
Yes, there are always designers that cannot read the component datasheets
properly. It's always been like that and I'm totally convinced we will
continue to meet these illiterate engineers/designers.
However... running a kit from batteries, especially NiCad acks, makes it
important to be able to use all possible power before your voltage drops
to "unregulated". Even if 0.5V can be seen as a small voltage, it caneasily
be just these 0.5Volts where I have the batteries maximum capacity.
Also, I'd like to define the new type of mobile phones as RF devices... and
many of them use the LDO regulators.
Anyway, It never hurts to remind people to try to understand the components
they use but I disagree in using the argument as an excuse to continue to use
older generations of components unless there are special reasons for it. By
all means, oscillation can be one of them and if the designer can't make his
design stable - he have to accept a shorter battery life.
Now what, ham radio... Yeah, get your self a motor bike battery on 12V and
run your low power consuming homebrews with that. There are lot of new tasty
hermetically sealed lead/acid batteries nowadays, and they are cheap to!
On Saturday 02 December 2006 16:04, Graham Haddock wrote:
> Yes, there are multiple "low drop out" regulators available on the market.
> Make sure you read and understand the output ESR (Effective Series
> limitations that all of these regulators have. The majority of them can
> not tolerate a good RF type ceramic bypass capacitor on the output
> without oscillating. A nice 0.1uF ceramic chip cap has an ESR of
> 0.01 ohms. Most low dropout regulators will oscillate if the ESR
> on the output is below about 0.5 to 0.1 ohms. Since we are using them
> for RF applications, we have multiple low ESR ceramic caps everywhere in
> our circuits.
> There are some of the LDO regulators that are specifically rated for
> driving ceramic capacitors. Use those, and still beware the ESR
> You can stick a 78L05 in almost any circuit and it will most likely
> just work fine. The LDO's are much more application sensitive.
> --- Graham / KE9H
> Dan Andersson wrote:
> > There are a new "breed" of very low voltage drop regulators available
> > nowadays. It's time to retire the old faithful 7805's and the 78L05's,
> > especially if you run your gear on batteries.
> > These new chips are specially designed for mobile phone designs where
> > every
> > ounce of battery juice have to be squeezed out. And they are cheap!
> > It's especially important for this kind of designs that tend to be
> > replicated
> > globally, use the latest breed of components. That way you make it
> > easier for
> > the next generation of homebrewers to build your designs!
> > //Dan
> > --
> > Dan Andersson, M0DFI
> > dan@... <mailto:dan%40andersson.co.uk>
> > dan.andersson@... <mailto:dan.andersson%40ieee.org>
Dan Andersson, M0DFI
I just completed building a SoftRockLite for 30 meters.
It works amazingly well, and it worked the first time I turned it on.
So, thanks for your efforts and good work getting it out to us.
1.) In measuring the input impedance (with MFJ-259B) I note that the
series resonator on the antenna input came out tuned for about 10.9 MHz.
I assume that it should be centered on about 10.12 MHz or something down
Is there any reason that I should not re-trim the input resonator for
10.1 MHz and pick up a few more dB sensitivity?
2.) How high in frequency can the SoftRockLite design go? What limits the
upper frequency performance (assuming you adjust the input resonators)?
Is it the time skew between the Johnson counter 90 degree outputs?
Or the switching time of the switches?
3.) On the SoftRock V7 you went all the way up to 30 MHz, and generated
the 90 degree LO shift differently. The question I am asking is, how
90 degrees can the two LO inputs into the switches be, and still compensate
for it in the backend software? 2 or three degrees?
--- Graham / KE9H
- FYI, if you are shopping for a "modern" computer - this one followed
me home today:
Emachines T5216 Pentium D Processor 805 2.66GHz 512MB, 160GB HD, DVD+-RW
It has one parallel and one serial port along with two PCI slots (one
empty, one with a modem installed). No monitor, no printer.
$300 after rebate, ending 12/16.
I have a Rosewill 1P2S pci card on order to give it more ports. Don't
need the modem card, so can put the Delta-44 there.
Don't know what performance to expect as a dedicated SDR processor,
but probably pretty good per dollar.
- Status report:
I got the new computer configured with the Delta-44 and a cheapie
1P2S card and connected up the SDR-1000 to it an hour ago. Been
sitting here copying 75 meters since then .
As I expected, it is showing very low CPU utilization. Typically 2-4%
unless I switch on ANF or NR. It is dedicated to the SDR, so no
conventional software is running.
These are still on sale for a couple days more at CompUSA.
At 03:55 PM 12/12/2006, Jerry Flanders wrote:
>FYI, if you are shopping for a "modern" computer - this one followed
>me home today:
>Emachines T5216 Pentium D Processor 805 2.66GHz 512MB, 160GB HD, DVD+-RW
>It has one parallel and one serial port along with two PCI slots (one
>empty, one with a modem installed). No monitor, no printer.
>$300 after rebate, ending 12/16.
>I have a Rosewill 1P2S pci card on order to give it more ports. Don't
>need the modem card, so can put the Delta-44 there.
>Don't know what performance to expect as a dedicated SDR processor,
>but probably pretty good per dollar.
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