Hi Curt, if these are the values of an unmodified unit, some bands were clearly out of spec but not terrible. My ver 3 board without the Axicom relays was worse. Coilcrafts are good stuff, I have some tunable but had a too low inductance so I used two small green white toroids (rated for 50-200Mhz) I had spare, it works well for me. The only worry for me was the 12mhz fixed spur which I hadn't addressed directly, but in my case it seems very low almost unnoticeable.
Il 09/mar/2019 22:41, "Curt via Groups.Io" <wb8yyy=
[email protected]> ha scritto:
Iz
while I am a decent operator - SO2R is way over my head.?
I am using the same LC design as v5.? the inductors were found in a junkbox - they are coilcraft (and not a small footprint) so I imagine them to have a reasonable Q.? I modeled them with a Q=70 -- it provides the rejection I need assuming filter lands reasonably well on frequency.? I need about 10 dB to clean up.? okay here are my stock values for spurs --
| Band |
CW |
SSB |
type |
| 80 |
-41 |
-45 |
? |
| 40 |
-30 |
-42 |
harmonic |
| 30 |
-30 |
-30 |
harmonic |
| 20 |
-49 |
-48 |
? |
| 17 |
-45 |
-42 |
? |
| 15 |
-43 |
-35 |
mixer |
| 12 |
-47 |
-33 |
mixer |
| 10 |
-55 |
-34 |
mixer |
I have a relay daughter board and the LC filter installed.? I don't have a spectrum analyzer but we measure them at our club session, I am confident on the lower band harmonics but uncertain on the upper band spurs.?
Now my rig is a bit haunted -- it does not like the 45 MHz bidi messed with on the antenna side.? anything too close to the amplifier messed with 7 MHz CW.? first I tried a xtal filter that our club kitted.? bad.? I put the LC in the v5 position -- bad also.? so it is moved closer to the antenna, only in the transmit path - 40m CW is good again.?
I am happy enough with the uBITX v4.? I figured out why none of the AGC circuits were working - I was putting them in series with the volume control, they need to be in parallel.? (I went to EE school to mess up simple things like this, glad my boss isn't on this list!).?
My theory on v5 was that it would push the spurs around, not necessarily cure them all.? Let's see as more are measured.?
Thanks for text.? 73
Curt
