I have and disproved your methods, logic and resulting data.

Allison

I just installed an LM380 amplifier instead. Why an old '380? Because they are rated for 22 volts and I had a bunch. Found one with less than 5ma. quiescent current. Very quiet and just the right gain. Opened R71 to shut off the old amplifier. It is quite loud and proud. Now for a CW filter! 72, Don

Allison

i am not going to engage further in these semantic battles. I have produced data, discussion, and transparent methodologies. You have produced words. Your agenda does not seem to be in pursuit of actual guidance to the readers.?

Do do some work and produce some data. Until then, have a nice day.?

WA8TOD

开云体育

Well done Kees and thanks. I agree the moment has come to call "Time". Having the gerbers available will enable others to have boards produced if required, including future group buys.

73

Bill, VK7MX

Make sure all the wires actaully connect at both ends.? specifically the black brown and yellow.

There are a few other things it could be but one step at a time.? The fact ther eis some change suggests?
a missing wire and it can be at the connector end as well.

Allison

On Tue, Jul 31, 2018 at 02:46 PM, Warren Allgyer wrote:

The cables were normalized out of the equation by connecting them to each other before normalizing the circuit to "0". We had this conversation before

The rf path you normalised is the inner conductor and the inner shield.? Doesn't stop
or measure current flowing on the outer side of the shield.? ?Explain to me how the
RF on the outside of the shield is not a parasitic element in the transformer test system?

Again follow the current flow.? Its on the outside, as you are using the shield.? That outside shield has a finite inductance.


Allison

Your did not understand or you'd stop and fix your error.? Using? 2 meters of wire and calling that
common at RF is about as faulty as one can get.??

Repeating myself.?

The RF circuit for the antenna is from the wire to the coax as a counterpoise (NOT GROUND OR EVEN CLOSE).

You are not testing the antenna you are testing the matching system and including a few meters of wire the
shield of the coax.? Which believe it or not is trying to be an antenna even though it is small and terribly
mismatched.? ?If you can't accept that then, explain it?? ??

The rf circuit does not go to ground it goes though 2M of the coax shield to the other side of the circuit
and including your spectrum analyzer in the loop doesn't fix the error.??I has an effect and impacts the
magnitude of the result.

HINT: the biggest argument in End Fed antennas is the non-existence of shield currents. Why because
Kirchhoff's rules a proven set of theory say so.? We can only discuss their effect and magnitude.??


Allison

Warren doing it wrong and calling it good.....

"Oh stop.... please!"? To borrow your own line.

It is not the case for testing the transformer.? ? Your trying to make a case that is invalid.

Allison

Oh stop.... please!

I tested the transformers in an environment in which they would be used. The cables were normalized out of the equation by connecting them to each other before normalizing the circuit to "0". We had this conversation before. In this stream.

WA8TOD

Allison

I understand your point. 1) I was testing a known configuration of the transformer which joins the primary and secondary together on the low side. I could test the transformers with the low sides separated but that is not the configuration that is being sold. 2) There is no inductive connection on either side. The four grounds are common and the connections to and from the S/A are properly terminated transmission lines.

Please feel free to do your own test on any configuration you wish and share your results.

WA8TOD

I am using a LM386 with the V4 ubitx, works really well.

Philip G7JUR

That actually Gary N3GO that cooked that one.? I thought it a good idea too.

? ? All the good ideas in one place.

Allison

That and it makes the hunt the missing or extra { or } a lot easier as it likes to span files.
Annoying to say the least.

Allison

Yes, Allison's solution would certainly work. The single diode in series with R52 does cure the spurious TX output at the beginning of transmission. For discharging the TX line, just one of the 2N3904s and one resistor (half of Allison's circuit) would do the trick for the TX to RX transition.

As a followup to the keying shape issue, I found that changing C1 to 2.2 uF gives quite nice keying shape with about 3 ms attack and 6 ms decay, much better than the original 0.5 ms attack and decay that made it a key click machine!

73,
Bob N1KW

if any of you folks need a new pc, here is a very good deal..

If C52 and C64 are isolated by diodes then the RX and TX voltages will have no large capacitors to filter low frequency noises. ?It might not be a problem here but I've had a number of "unexplained" problems turn out to be a lack of sufficient filter capacity. ?

73,

Tom ?W1EAT

Its not obvious so I'll try to explain.

Lets say we have two transformers (any for the moment save for they are the same).

Also the transformer have a separated primary and secondary as that makes it easier to see.

So we hook them up back to back and hook the primaries to the tracking generator and the?
spectrum analyser input.? So far we have complete circuits that do not depend on any
circuit common or "ground".

For that case if I said the transformers did such and so we can see and evaluate it.

Now what if...? I break? the back to back connection for one lead and insert 2M
of wire nicely laid out on the bench would you be happy with that?? ? I know I would
not as that 2M of wire is about 2.6uH of inductance give or take.? So I'd expect the
trace to show some loss especially at 28mhz? especially since that 2.6Uh is about
480 ohms of reactance.? ?Please do not argue the amount of inductance its
magnitude is less important than the fact that its there at all.

So if I go back to the back to back original transformer and instead take the other
leads apart and connect them to the input side shield of the coax what have we?
THe secondary are connect together via a 2M lead that also includes the frame
of the SA.? ?But the SA is ground.... no it has a common, but ground is likely about
3.5ft under it or more and the lead getting it to that mythical point is 3.5ft long or more
with its inductance.? IF you go to the 3 wire cord its 3-6ft long to the safety ground
pin on the receptacle which is not RF ground so it does not help and likely adds
problems to ponder. So as we follow the current around the circuit we find we have
a 2M?loop again and that loop has an added unknowns in the middle.

Its very easy to do this and not realize there is more going on but it is far from complicated
only that there are many parts to it.? Solution is to fix the test to remove that potential error.

Allison

I found that by simply increasing C1 to 2.2 uF (just parallel the existing 0.1 uF cap) the keying shape is greatly improved with about 3 ms attack and 6 ms decay. That is much better than the key click machine it was originally with about 0.5 ms attack and decay times.

73, Bob N1KW