Hello Mark,
There is now an HF1, with a high first IF of 45 MHz and even a newer version
where i am working on with an if of 60 MHz, with better filters.
Regards Ben (in Turkije)
-------- Origineel bericht --------
Van:"Mark Smith (Redacted sender "smittyhalibut" for DMARC)"
<dmarc-noreply@xxxxxxxxxxxxx>
Verzonden:Mon, 25 Jul 2016 17:15:29 +0300
Aan:minima@xxxxxxxxxxxxx
Onderwerp:[minima] Re: for minima project
Forgive my ignorance. "The old minima project?" Is there a "new minima
project?"
This is the one I've been working off of:
http://www.phonestack.com/farhan/minima.html
Is there something else I should be looking at too, or instead?
-Mark
On Jul 25, 2016, at 5:33 AM, allison <ajp166@xxxxxxxxxxx> wrote:
On 7/25/16 4:19 AM, Computer Burgas wrote:
In old minima project, after series of tests I found that Si570 has too many
harmonics and frequency counter reported me them rather than the fundamental
frequency, which means that the mixer and quartz filter probably being down
work properly.
SI570 and the 5331 all provide a square wave output which is rich in
harmonics. The frequency counter may be
such that it has higher sensitivity at harmonic frequencies or your not
coupled adequately.
Also the cost of Si570 in ebay is 2-3 times higher than , for example -
AD9851. Moreover BFO also realized unstable frequency. I decided to work
towards replacing VFO and BFO with the 2 pcs of AD9851 DDS generators. So with
this I will get freq accuracy and easy programmability of LSB and USB in BFO
and VFO.
From cost perspective ok. However you need a micro to set it and DDS have
spurs. Minimally the DDS will require gain to drive the DBM adequately.
Old minima project will still require better filters and more of them to avoid
out of band unwanted signals.
Allison
