Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
Search
L506 Winding Gap Improves Filter Sweeps
|
I just finished building my second QMX+ and the 160m filter sweep had rather ugly oscillations on it.? L506 in the 160m filter has so many windings that the start and end windings had butted against each other likely adding some parasitic capacitance in parallel.? I found that by creating a small gap between the start and end winding the sweep greatly improved.? This also improved the sweeps on almost all other bands although to a lesser degree.? I went back to my first QMX+ (which did not have ugly oscillations on the 160m sweep) and added the gap and also noticed improvement in the sweeps on almost all bands.? Has anyone else experienced this?
Andy KY4DF |
|
Robert AD6XJ
I'm winding toroids, like we all are I suppose, for QMX+. L506 calls for 38 turns on T37-6. I can only fit 36. The post I've replied to here suggest a gap is desirable. Should I change to 30ga wire or to a T50-6 core or overlap the 28ga (0.33mm) in some fashion? I have both the larger toroid and the smaller wire in my parts stash.
I'm open to all helpful suggestions,
Tnx 73 AD6XJ Robert |
|
Paul
开云体育I was just able to get 38 turns. ?You really have to squeeze the wires together in the inside, even the slightest gap and they won’t all fit. ?I don’t think that an overlapped turn or two will make any difference however.On Sep 24, 2024, at 4:15?PM, Robert AD6XJ <91710robert@...> wrote:
|
|
Interesting, seems like it's a real squeeze! KitsandParts info shows 37 max turns on that size with 28 awg wire.
I'm putting together a QDX-M soon for 160m, and thinking of trying T50-2 for the LPFs.....In theory I'd only need 30 turns to be wound to the same inductance at the T37-6 with 38 turns.? (And the QDX-M has the room)
?
-Nate?
N8BTR |
to navigate to use esc to dismiss