Tom,
That is really weird behavior. It should be linear.
What is the power level from the Flex for a full 20 watts output?
I am going to assume that the XV432 LEDs show you the proper power
output - if not, calibrate the LEDs at 20 watts output (Power Cal pot
in the left rear quadrant) so you can use the LEDs to monitor the output
while you temporarily move the Bird wattmeter between the Flex and the
XV432.
The only thing I can think of is that the Local Oscillator in the XV432
is dropping out. You can remove the top cover and monitor the DC voltage
at the test point near the front center. You will have to "catch it in
the act", so keep transmission times short to keep from overheating the
XV432.
There is one other potential problem, if you are using transverter IF
output from the Flex, and that is that some 432 MHz energy is getting
back into the Flex and "fooling" its power output mechanism into
"thinking" there is more 28 MHz drive than actually exists.
The answer to that problem is to insert a Low Pass Filter with a cutoff
somewhere between 30 MHz and 50 MHz between the Flex and the XV432.
73,
Don W3FPR
On 2/4/2013 3:15 PM, Tom Warren wrote:
I purchased this unit used ( nice workmanship) and it seems to work well
in all respects
except as noted below. I must add that the prior owner told me up front that
there
was an issue with its power. However, when I first put it online line it seemed
to work ok.
Originally I used it with my K2/100 to drive a Mirage D1010 (100w) in ssb
mode. As
time passed, the unit started to show signs of loss of power similar to a high
swr turn back
or high heat shutoff and I attributed it to a failing relay in the Mirage,
which I cleaned and the
system seemed to again work ok for a while. After a reoccurrence, I switched
to another rig
for my 432 activities and let the XV432 sit on the shelf while I mulled the
issue.
I now have a Flex 5000 online and in the process of interfacing the XV432
with good results
except for the old issue again and I'm determined to figure out the problem
since it really seems
to be the transverter and not the K2 or Mirage.
The setup;
Flex 5000
Single coax interface
RCA keyline
XV432
Bird 43 (25W slug)
Bird dummy load
Here's what I've found;
1) As I start the Flexs' drive, the XV432 output turns on at 0w then continues
to increase to 2.5w
then 'shuts off' and power drops to 0.
2) As I continue to increase the drive, the output power again turns on at
about 15w and increases to 20w +.
I've looked all over the internet for a similar problem but don't find
anything. Maybe someone out there
can point me in the right direction before really hitting the books and at my
age gray matter is in short supply ;0).
Thanks in advance for any help.
73
Tom
W4TMW
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