[minima] Re: Minima PCB
- From: Sandeep Lohia <sandeeplohia12@xxxxxxxxx>
- To: minima@xxxxxxxxxxxxx
- Date: Mon, 1 Feb 2016 02:55:28 +0530
On 30/01/2016, Takis <sv3auw@xxxxxxxxxxxxx> wrote:
Hi ganque!Same here like Paul. I am waiting for a PCB to surface.I had even
sent Sandeep a contribution to purchase a batch of 3 by 3 PCBoards of the
earlier version but never received the Main Board.I can homebrew Minima,
Manhattan style, but I do like the neatness of a PCB.Well, any
news?!Takissv3auw/m0lpt
hi, sv3auw Takis from Greece / UK
hope by now you can understand,why didn't I send you Exciter boards.
however I did send digital controller VFO & programmer's 3 by 3 PCBs
to you, & it's snaps were also there in your blog...
HERES A COPY OF MAIL THAT I RECEIVED ON 31 MAY 2014 :
{ Hi Sandeep,
Yes, I will do that. Unfortunately I would only be able to do so on Tuesday.
Broadcast stations here in XX comes through OK, not real loud but I
can hear them. Unfortunately I have not been able to hear any SSB
signals yet. The audio amp works fine since the tones on 5/10/20MHz
will hurt your eardrums through headphones at full volume. I made the
mistake once, never again. I have also built the low pass filters
Manhattan style before using the components in the filter section.
Unfortunately I do not have a spectrum analyzer to check them but I
used an MFJ analyzer to see where the SWR climbed to infinity on the
filters. The filter was terminated with a 51 ohm resistor. The 0 to
15MHz low pass filter reached very high SWR at around 15.3MHz and
infinity at 16MHz otherwise it was less than 1.2:1 over the whole
range. Not the best approach but that is all I have.
Regards,
xxxxx ZL2 xxxx
followed by various other issues, even Farhan's frustrations with kiss-mixer.
& I was waiting for HF1 which he demonstrated in ham fest 2015
same design (like HF1 ) was discussed by me & Farhan on 18-01-2014
& here's a copy :
SANDEEP 18/01/2014 : 2nd IF in BITX
Almost all commercial Rigs uses 2 IF frequencies (2nd IF chain
something above 50Mhz)
highest possible IF so that our image frequency is as away from the
receiver passband as is possible, safely away from the 0-30 MHz
operating range. (as new born MINIMA says)
BITX front end will overload without BPF,
how about using a fixed frequency on VFO, & it's BPF approx 30Mhz.
Now we can use a 2nd IF chain ( with passive switching mixers like
74AC series of IC)
I have already used easily available cheap HC series it won't
overload, works even without BPF, rest ladder filter will do the job
(NE612 easily overloads, no signal heard if not used front end BPF)
but HC series had limitation till 20Mhz only, & needs more & more LO
drive as we increases frequency.
Idea is to make same existing BITX go multibander & general coverage
HF, without bag full of BPF coils...
FARHAN 18/01/2014 : Sandeep, it can be done. I had proposed this
scheme in a previous mail.
1. Use 60 MHz as the first IF. This needs a 50 mhz oscillator to bring
mix down to 10 mhz IF. 50 mhz crystals are routinely available.
.2. Change the bandpass filter to tune to 60 mhz.
3. Add the minima front-end. Just a single lpf at 30 mhz followed by
the two fet mixer then to the bitz board. The same arduino code will
work. Just modify it for 60 mhz IF.
- f
Sent from BlackBerry® on Airtel
SANDEEP : In my Yeasu FT70GH RX path : 1st mixer product = 47.055 Mhz...
& 2nd mixer product = 10.7 Mhz...
Filter= 10.7015USB or 10.6985LSB
RX = DC to 30Mhz...
But still 9 rows of triple tuned BPF used there???
--------------------------------------------------------
I was still getting orders for MINIMA PCB sets weekly DX ( there's a
very high demand, but I never made second run of boards, first
run was made only after Farhans approval & under his & Adrian's
guidance. yes those ( only PCB, not entire kit ) were made only for
educational purpose, non-profit ( under 2 dollar, shipping extra) as
to carry on further R&D, & some were successful too... some sets
were distributed also as free gifts including shipping charges. just
to promote the hobby.
Many illegal boards were made by some others on which Farhan strongly
whatever...
on my personal mai ( those asking me boards) I was requesting every
other, to wait a little for Farhan Sir's further updates...
no revision could have been done on PCB, until & unless done to
systematic by Farhan or any other expert. commonsense!!!
In the mean time I got married, & now a father to 2 months old son.
very little time for hobby, since XYL won't quit her job in nursing home. :(
& my call sign have also expired ( need to renew )
so M no more a ham :)
my friend Takis only your's PCB R due with me, no other can say so....
refunding via PAY-PAL will be a problem from here in India. RBI
don't allow us keep balance in PAY-PAL. however I can send U
components of equal amount, that U prefer Sir, 73's
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