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QCX 40 meter TI inductances

Al Lipinski
 

My reason for asking about the actual inductance for TI is to find out if the number of winds is the priority or is the actual inductance.??
Is it better add or subtract a winding in order to get a more accurate inductance measurement?.?



--
Al Lipinski



 

I'd think C1 has enough range to tune the winding it is in parallel with.
Otherwise, if anything is critical, it might be the ratios between the various turn counts.
So just build it to the specified number of turns.


On Sat, Feb 2, 2019 at 04:27 PM, Al Lipinski wrote:
My reason for asking about the actual inductance for TI is to find out if the number of winds is the priority or is the actual inductance.??
Is it better add or subtract a winding in order to get a more accurate inductance measurement?.?
?
 

I wound mine based on the specified inductance value and didn¡¯t have any problems. I¡¯m sure more people wound thiers based on the number of turns and everything probably worked out fine for them also.?

Curt M.
 

Actually I take that back. L1-L4 I wound based on their inductance value. I wound T1 based on the number of turns.?

Curt M.
 

Is it better add or subtract a winding in order to get a more accurate inductance measurement?.
Al,

If your inductance meter is accurate wind it for inductance.
That should give first-time results but still be prepared to adjust turns, correct operation is what you aim for.

73 Alan G4ZFQ
 

Jerry makes a good point. S3 is the reasonant circuit with C1. If the C1 plates are around half mesh when peaked the turn count and inductance are correct. Primary, S1& S2 windings work simply in tramsformer mode, a turns-per-volt situation. S1 & S2 need enough turns to provide adequate signal level to the IQ Detector, and need to be of equal level. S1 determines the input signal level from the ant to the tuned circuit. So, turns count on S3 is inductance-critical, the rest are turns-critical.
--
> I finally got it all together...now I can't remember where I put it<

VY 73,
Wes

AE6ZM

Sierra Vista, AZ

?
 

If there's anything critical here, it's that S1 and S2 into that FST3253 give symmetric signals.
So if you feel inclined to worry about something, make sure the S1 and S2 windings
are wound equally tight, with equally long leads going into the board.

So long as C1 can peak the received signal, I would not worry about how close to half-meshed it is.

Jerry


On Sun, Feb 3, 2019 at 08:03 AM, Wes wrote:
S3 is the reasonant circuit with C1. If the C1 plates are around half mesh when peaked the turn count and inductance are correct. Primary, S1& S2 windings work simply in tramsformer mode, a turns-per-volt situation. S1 & S2 need enough turns to provide adequate signal level to the IQ Detector, and need to be of equal level. S1 determines the input signal level from the ant to the tuned circuit. So, turns count on S3 is inductance-critical, the rest are turns-critical.
 

If there is any reactance to the loads on S1 and S1, it will be coupled into the S3 tuned circuit, affecting the resonant frequency.? I assume that these reactances are minimal and fairly stable, and already accounted for in the design L/C values.? Antenna reactance will probably be the most prominent of these, which will transfer through the input filter section, but since the S3 tuned circuit is fairly heavily-loaded (and thus broadly-peaked) the tuning shouldn't be that critical.
--
Paul Elliott - WB6CXC
 

I had to add 6 turns.? Joe W3TTT

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