Jerry KE7ER, provides summary details on the two know spurs mods:
Raj VU2ZAP recommended mod:
Change out inductors at L5 and L7 with 1210 shielded surface mount inductors.
Here’s the post from Raj giving results for various inductor types at L5,L7:
https://groups.io/g/BITX20/message/60946
And another post from Raj, affirming that he was using a yellow S+M brand 1210 inductor.
https://groups.io/g/BITX20/message/60678
Here, Raj says that TDK-EPCOS parts work as well (EPCOS was bought out by TDK):
https://groups.io/g/BITX20/message/61261
Unfortunately, I don’t see any complete part numbers in any forum posts
from somebody who has verified with a spectrum analyzer that spurs were reduced.
I bought a similar assortment of TDK-EPCOS-Murata parts from ebay,
have not verified results with a spectrum analyzer.
The parts they actually ship may vary with the parts they can find.
But here’s what they shipped to me
Ashhar Farhan VU2ESE mod used in v5 µBITx:
The v5 µBITx provides a different method of fixing spurs on the v5 uBitx,
primarily the low pass filter at L31, L32, C205 near the first mixer.
That filter removes the 90mhz second harmonic coming out of the 45mhz IF amp. Other possibly significant changes on v5 with regard to spurs would be the BFR93W’s at Q20,21,22 (to replace the MMBT3904’s) and the move to 220 ohms at R26 (was 470).