[Elecraft] XV432 - No intermediate pwr output

[Don Wilhelm]

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
>