Showing posts from September, 2016

PLL ADF4351A Progrock QLG1 GPS

Meanwhile  some progress made
My Trimble GPSDO 10MHz output  30mV tt   amplified  a filter  followed by 3 stage amplifier
then shaped by hex inverting Schmitt trigger  74AC14
a reasonable clean signal at 1296.210
Shielding and grounding and a clean 5V power are important
the AM 350Hz hum side-bands are weaker
-60 dB at 144.550     -40dB 1296.210

The ADF4351  REF in seems to be a straight TTL input  without analog interfacing.
It  omits  a trigger circuit.  I had to  make that myself.
The specs only give the maximum signal level for this REF  nothing about the shape or minimum
usable  level.
It does not work with  a relative weak or  sinus shape 10MHz signal.
Some other types PLL chips seem to have no issue with the reference  level.

 2V / division    .5 uSec /devision  10MHz signal at the ADF REF input

test setup
 10dB / dev.

discrete 10MHz  booster  3 stage  and a band filter  after a lot of modifications this one can amplify the  30mV 10MHz Trimble out to 5V tt square wave  derived from …


Could only join  for a few hours  the CQWWRTTY  last weekend

DX was possible
CE3CT  40m
strong  XE2CQ 40m   (heard only  could not copy me or other EU callers )

VK3JA 40m    several JA at 21 MHz

A very strange issue with the K3 in RTTY at 15m
  the tx switched out / on   in a  slow sequence  after some cq  calling
a relay starts to click in a slow 1-2 second sequence  and the RF does interrupt to  complete zero.
The TX  led is on as normal.  And first off/on off/on and then  stays at  zero out.
No error message. no RFI effect observed .

This is only in RTTY and only 21MHz
It happend before only RTTY at 15m

It is not that the CAT RTS drops i monitored that  then the TX would go off as well.
it is an internal K3  issue since a relay click is heard at the moment the TX output is gone.

strange things  happen sometimes
Finally i tried to make a video clip of this strange behavior
This was happening all the time after a few cq's  or when i tried to respond to a caller.
But once the re…