Hi all, could use some pointers here on replacing L5/L7 on a V4 board. Not having a real spectrum scope, i am using the sdrplay with their spectrum scope software... Was using a RF sampler + 110db attn (HP 355d)
I got the following results...
? ? ? ? ? ? ? ? ? ? ?Spur? ? ? ? ? ? ? ? Spur? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Fundamental
Band .? ? ? ? ? Before? ? ? ? ? ? ?After replacement l5/l7 .? ? ? ? Before? ? ? ? ? ? ? After
80 .? ? ? ? ? ? ? ?-34db? ? ? ? ? ? ?-28db? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -57db? ? ? ? ? ? ?-65db
40? ? ? ? ? ? ? ? ?-19db? ? ? ? ? ? ?-13.5db? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?-65db? ? ? ? ? ? ?-70db
20? ? ? ? ? ? ? ? ?-28db? ? ? ? ? ? ?-33db? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -60db? ? ? ? ? ? -61db
10? ? ? ? ? ? ? ? ?-32db? ? ? ? ? ? ?-40db? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -65db? ? ? ? ? ? ?-63db
Looks like the main culprit is a decrease in output of the fundamental on 80 and 40 of 8db and 6db respectively.
So I am wondering...
1. Measurement error? (does the transceiver need to warm up for 30 minutes or more?)
2. Wrong part for L5/L7? Mine are orange, with markings of "A" and "T" and R68K 1145
3. One of the solder joints is poor
4. Inductor damaged during solderin g
?
Does the fact that 80/40 output reduced point the finger at either L5 or L7??
How did you bridge that gap, especially for L7. That seems to be a likely target for a cold solder joint.
Appreciate any thoughts and experiences here!
73
Mark
AJ6CU?
