开云体育

Its not a hardware problem. The radio has been working fine until
recently when some software mods were made.
Use some sound deductive reasoning here. This problem did not exist a
month ago with any transceivers that were build. Then work was done
on the software in a mad dash to close it out for the next version of
the T41 book. All of a sudden, there are issues with most/ everyone's
radio. What conclusion and action would you take from that? Bobb
some hardware out of you radio?... or go back and check out an earlier
version of the software?
DR. WILLIAM J. SCHMIDT - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ VP2EHZ
Owner - Operator
Big Signal Ranch - K9ZC
Staunton, Illinois
Owner - Operator
Villa Grand Piton - J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com [1]
Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
email: bill@...
FROM: [email protected]
<[email protected]> ON BEHALF OF Rick Price via
groups.io
SENT: Saturday, March 22, 2025 3:14 PM
TO: [email protected]
SUBJECT: Re: [SoftwareControlledHamRadio] LPF-Control PCB TX Logic at
U3 & U7
Oliver, I was having some kind of feedback/oscillation problems a
couple of weeks ago and traced it back to the T/R switch also. The
relays and associated parts all checked out but, when I removed the
3-"0" ohm resistors that were there in place of the Low Pass Filter
(160M) and inserted the parts for the LPF the problem stopped. I
wanted to go back and remove the filter parts and place just two "0"
ohm parts at c14-c16 and a single cap at c-15 but never did.
Wondering if the oscillation problem boards have the "0" ohm resistors
and not the LPF filter in place. Maybe, I will try it later just
thought I would mention what I had, when you suggested a possible
feedback issue.
Rick, KN4AIE
-------------------------
FROM: [email protected]
<[email protected]> on behalf of Oliver KI3P via
groups.io <oliver@...>
SENT: Saturday, March 22, 2025 1:40 PM
TO: [email protected]
<[email protected]>
SUBJECT: Re: [SoftwareControlledHamRadio] LPF-Control PCB TX Logic at
U3 & U7
The situation I think we might have is that both TX_BPF_SEL AND
RX_BPF_SEL are HIGH during SSB transmit. This lets a little bit of the
transmitted signal leak through the TR switch back into the amplifier
input through the BPF selection stage, like this:
These two lines are controller by GPIO register bank A:
This register is set by the function call setBPFPath [2]; the code
there looks correct and unchanged. Scanning the code, it all appears
to be correct. Some judiciously placed statements like this will
confirm:
Debug("Set LPF GPA state: "+String(LPF_GPA_state,DEC));
The fix that I implemented (major change to radio layout) to cure the
short that caused the burning smell has created a display freeze
issue, so I'm not able to test this myself right now.
Links:
------
[1]
[2]

[3] /g/SoftwareControlledHamRadio/message/33179
[4] /mt/111571221/243852
[5] /g/SoftwareControlledHamRadio/post
[6] /g/SoftwareControlledHamRadio/editsub/243852
[7]
/g/SoftwareControlledHamRadio/leave/10484476/243852/1943518115/xyzzy