6300 Odd RX behavior - noise floor/ RX gain drift

Hugh - VA3TO

My Flex 6300 just started exhibiting some strange behavior.
First the antenna tuner would not tune and the receiver seemed to be low on gain so I did a full reset. Now the tuner seems to be working better but the receive noise floor drifts and sometimes the gain just drops out completely. The receiver appears to recover somewhat after I transmit but then it eventually drifts and drops out again. Even after it recovers I perceive the gain to be lower than it was before the problem arose. The problem seems to be more pronounced on the lower bands (40/80m).  I checked my antenna using another radio and all seems well.
Any thoughts ?

Mike-VA3MW

Hi Hugh

It looks like you narrowed things down.  I am going to create a Helpdesk ticket for you but I'll leave this open for further discussion in case anyone else has thoughts.

Does it do the same on the other antenna?

Mike

Hugh - VA3TO

Hi Mike.
The other antenna is only good for a couple of the higher bands where the problem is not so apparent.

Hugh.

Mike-VA3MW

Hmmm. Ok, one more question, but it is a moot point. How about the xvtr port? I'm opening a help desk ticket for you.

Hugh - VA3TO

I haven't used the transverter port.  What should I try ?

Mike-VA3MW

Just see if you can receive normally. I'm still thinking what else could cause is. I opened a case for you as the support team has more experience in this area.

Bill English

Hugh, I have noticed something sort of like that on my 6300. On 20m the noise floor seems to have dropped off in comparison to the other bands. Signals seem OK, just the noise floor is very low. I would be interested in what they find on this.

Hugh - VA3TO

Hi Bill.
After further investigation I discovered that my Antenna 2 port is completely unusable. The internal tuner just will not tune and antenna on that port. I can tune an antenna on Port 1 but RX still seems down to me.  Sometimes the noise floor is low after the radio has been off or sitting in RX mode for a while but it improves after I transmit. I was going to open it up and replace the relays but it was suggested that I replace the ESD protection diode I.C.  That makes good sense as I think about it. I'm guessing that the TX RF charges up some caps and biases the diodes to conduct after TXing !?  I've ordered the part from Mouser and will give it a try.

As a sidenote, I find it disturbing that Flex will not release technical info like a schematic or even a parts placement map for anyone but them to effect repairs.  I'd like to hear the rationale for such protectionism.

Tim - W4TME

As a sidenote, I find it disturbing that Flex will not release technical info like a schematic or even a parts placement map for anyone but them to effect repairs.  I'd like to hear the rationale for such protectionism.

There is a valid business reason for this.  Some of the circuitry in the FLEX-6000s is fairly advanced for SDRs and we choose not to provide this information readily to the public for competitors to easily use.  Patents are not internationally enforceable; intellectual property is a little more secure.  If someone wants to reverse engineer our products, we are not going to make it easy.

Also, there are very few things on the radio that can be user replaced that does not require our factory calibration software to be run on the radio to properly recalibrate.  This software is not available to users.  So making component level changes without running the calibration software may end up doing more harm than good.

Hugh - VA3TO

Well, I'm not convinced that hoarding the hardware design will thwart any efforts to reverse engineer the hardware for those that really want to. The real magic is in the firmware. 

So then when is Flex going to set up a repair depot in Canada ?  The repair department at our local Radioworld in Toronto that sells Flex radios is apparently not equipped to do repairs on my radio. The cost of shipping to and from Flex from Canada, plus the cost of the repair starts looking pretty ugly.