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:
And another post from Raj, affirming that he was using a yellow S+M brand 1210 inductor.
Here, Raj says that TDK-EPCOS parts work as well (EPCOS was bought out by TDK):
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
480pcs inductor coil size 1210 1008 (24x20pcs) EPCOS TDK MURATA
B82422A3470J 47nH 1210 EPCOS 20pcs
B82422A3101K 100nH 1210 EPCOS 20pcs
NL322522TR120K 120nH 1210 TDK 20pcs
B82412A3181K 180nH 1210 EPCOS 20pcs
1008CS221XG 220nH 1008 COILCRAFT 20pcs
B82422A3331K 330nH 1210 EPCOS 20pcs
B82422A3471J 470nH 1210 EPCOS 20pcs
NL322522TR56J 560nH 1210 TDK 20pcs
B82422A3681K 680nH 1210 EPCOS 20pcs
NL322522TR82J 820nH 1210 TDK 20pcs
B82412A1102K 1uH 1210 EPCOS 20pcs
FSLM2520-1R5J 1.5uH 1008 TOKO 20pcs
B82412A1222K 2.2uH 1210 EPCOS 20pcs
NL322522T3R3J 3.3uH 1210 TDK 20pcs
B82422T1472K 4.7uH 1210 EPCOS 20pcs
B82412A1562K 5.6uH 1210 EPCOS 20pcs
NLV25T6R8J 6.8uH 1008 TDK 20pcs
B82422A1822K 8.2uH 1210 EPCOS 20pcs
NLV25T120J 12uH 1008 TDK 20pcs
NL322522T270J 27uH 1210 TDK 20pcs
NLV25T330J 33uH 1008 TDK 20pcs
NLV25T680J 68uH 1008 TDK 20pcs
B82422A1104K 100uH 1210 EPCOS 20pcs
NL322522T121J 120uH 1210 TDK 20pcs
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).