[Elecraft] Phase noise

Sun Mar 20 16:12:34 EST 2005

Hello Leigh!

It's easyer with top posting HI!

This is not a must mod but i need every dB vhen I am QRO with transverter on
144Mhz at +60dBm and stations 20 miles around me.
Yes You see a peace of bended cooper of 0.5mm placed over the half U1 and
entire U2 on KSB2.
There are three supports.
I steal the one end support on pin 4 of U2 wich is on GND.The cooper foil is
cutted and bonded a bit to touch only pin 4 of U2 and  not touch the other
pins of U2.
Then for support on the other side i drilled 1mm hole between U1 and C38
right in front of C38 to reach the ground on the other side of PCB (pay
attention on traces on the other side of PCB).I inserted the wire in the
hole and soldered it on the ground side (you must scratch a bit the green
stuff to get to the gnd foil).
Than i found some gnd on bottom side at the edge of PCB (near U1)
,scratched-solderd the wire, and bended the wire all over to reach the
cooper shield on the top.
It sits very well and is not isolated at the bottom (gap from pcb of
1mm).The solderd supports are keeping it in place without damage.Preform at
your own risk.

I am very bad in English writing :( so look well at the picture HI.
I think that K2 would be much better with a bit of internal shielding
between digital and analog parts and maybe with metal (not alluminium)
covers. Every PIC is possible source of birdies.
K2 is a little compressed box with lot's of fun packed in.And lot's of
reserve!

S55M-Adi

----- Original Message ----- 
From: "Leigh L Klotz, Jr." <Leigh at WA5ZNU.org>
To: "S55M" <s55m at siol.com>; "Elecraft" <elecraft at mailman.qth.net>
Sent: Sunday, March 20, 2005 7:46 PM
Subject: Re: [Elecraft] Phase noise

> Adi,
> It looks like you have a small piece of copper and two grounds, one
> taken from the far side of the processor and the other from somewhere
> behind that electrolytic capacitor.  Could you let us know if that is
> correct and which tie points you used?  Also, did you insulate the
> copper on the bottom or are you depending on wire stiffness to keep it
> from touching?
> 73,
> Leigh / WA5ZNU
>
> On Sat, 19 Mar 2005 4:12 pm, S55M wrote:
> > Hello everyone!
> >
> >> From one debate we went to two different ones.
> > While on the beginning we were talking about K2's TX noise and birdies
> > on
> > SSB now we are talking on another subject which is interference of
> > magnetic
> > fields on K2's behavior.
> > Let's see the noise and birdies problem first.
> > I found the surce of birdies is the clock signal (maybe the 4Mhz osc
> > itself
> > also contributes to this) on KSB2 wich goes from pin 14 on U1 to pin 2
> > of
> > U2.This signal is interfering directly to Q2 and some birdies are well
> > heard
> > on the band HI.
> > So what i tried to do is simply to shield a bit the path betwen the
> > U1+U2 to
> > Q2. The result is that the strongest bird (Fc 14.250MHz
> > Fbirdie14.148MHz
> > went down by 10dB (and i suppose all the others went down for the same
> > ammount) Maybe 10dB seams little but for me evry dB is important.
> > Picture of my KSB2 can be found at
> > http://www.s55m.com/teh/images/ksb2.jpg
> > Test eq:
> >
> > K2 itself TX output at transverter port (jumper W6) at +6dBm (for
> > birdies
> > without modulated signal but checked also with SSB modulation wich do
> > not
> > affect birdies as far away HI)
> > RX TS930S on CW 500Hz filter AGC OFF
> > NF Siemens U2032 Gerauschspannungmesser (psophometer) BW 300-3400 Hz
> > range -70 to +40dB
> >
> > 73's
> > S55M-Adi
> >
> > ----- Original Message -----
> > From: "S55M" <s55m at siol.com>
> > To: "Elecraft" <elecraft at mailman.qth.net>
> > Sent: Saturday, March 19, 2005 2:46 PM
> > Subject: [Elecraft] Phase noise
> >
> >
> > Hello again Elecrafters!
> >
> > Yes Fraser i saw Your comment but not the comments of others.We are
> > still in
> > very low number.
> > Seams that only Europians have the problems with "little" birdies and
> > noises.
> > And between Europians S5 is a little country with a lot of ham-radio
> > activity HI.
> > In what kind of place do we live is Bob asking?
> > In a place of 300*300 km (186*186 miles if You are more familiar with
> > that).
> > And during VHF ctests there are at least 10 stations with full legal
> > limit
> > power and "average" distance between them is abt 35 miles (worst case
> > 23
> > miles) what in terms of path loss is "only" -110dB in free space on
> > 144MHz
> > (there is a line of sight between us !!!).
> > Now all of us use "Javornik" 144/14Mhz transverters designed by S53WW
> > and
> > the situation is not so bad as before with all sorts of stuff.The only
> > important thing now is to have bullet-proof HF RX (K2 shurely is) and a
> > clean HF TX.
> > I will enjoy in comments.And i understand that is difficult to deal
> > with
> > the problem if you live in MBA (Mighty Big America).
> >
> >
> > S55M-Adi
> >
> >
> > P.S.
> > I was trying to send this several times to the list. Hope that it will
> > get
> > trough now.
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