From: "Clemens Paul" <cpaul@gmx.net>
To: <rsgb_lf_group@blacksheep.org>
References: <CAKvcm2dbFX3d+jv04M_quU0Nwy=W-g5Jk5vxcN5SP87gg3PmzA@mail.gmail.com> <B507F4F2886F4488A919515FDD664BC3@gnat> <B4BD637350C7488DA8A8BAF58FC09D7D@AGB> <E2FD3CEF9D874A728D06769DF8C30AEA@Clemens0811> <511FF5F0.1080603@iup.uni-heidelberg.de> <A21617629C974A8A9FB8ECA987965146@Clemens0811>
In-Reply-To: <A21617629C974A8A9FB8ECA987965146@Clemens0811>
Date: Sun, 17 Feb 2013 10:46:33 +0100
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Subject: RE: LF: Re: how to increase the Q of my loading coil?
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Typo correction in the third line:
It must read **loaded** Q.

73
Clemens
DL4RAJ =20

>-----Original Message-----
>From: owner-rsgb_lf_group@blacksheep.org=20
>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Clemens Paul
>Sent: Sunday, February 17, 2013 10:30 AM
>To: rsgb_lf_group@blacksheep.org
>Subject: RE: LF: Re: how to increase the Q of my loading coil?
>
>Stefan,
>
>>So a high Q must be the goal, loaded or unloaded.
>
>Regarding unloaded Q I think there is agreement
>
>Regarding unloaded Q it depends HOW it is increased.
>As Jim has pointed out increasing unloaded coil Q also=20
>increases somewhat the overall system loaded Q by reducing=20
>circuit total R, this is perhaps what Graham was concerned about.
>But the benefit overweighs this small disadvantage.=20
>
>As a matter of fact with a matching network consisting of two=20
>reactive elements (L,C) or of one coil and an autotransformer=20
>as we have here it is not possible to choose a desired loaded=20
>Q (without the exception above).
>You get the lowest possible loaded Q anyhow and it is=20
>determined by the complex impedance of the antenna.
>But if you match with three reactive elements like a Pi- or=20
>T-Network then you can choose - within certain limits - the=20
>loaded Q by choosing the components values but it will be=20
>always higher than with two elements.
>High XL and XC components will result in a high loaded Q.
>In this case time the high loaded Q is detrimental for=20
>efficiency,losses and heat go up, so THIS way of increasing=20
>loaded Q should be avoided.
>
>The source resistance of a transmitter or a vector network=20
>analyzer decreases the overall loaded system Q which increases=20
>bandwidth.
>If you would feed the system by a voltage source the 3dB=20
>BW-points would coincide with a VSWR of 5,9.
>With a 50 Ohm source you have the 3dB points at a VSWR of 2,6.
>
>My apologizes if this all has been too long and boring. :-)
>
>73
>Clemens
>DL4RAJ=20
>
>
>
>
>
>
>>-----Original Message-----
>>From: owner-rsgb_lf_group@blacksheep.org
>>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of=20
>Stefan Sch=E4fer
>>Sent: Saturday, February 16, 2013 10:11 PM
>>To: rsgb_lf_group@blacksheep.org
>>Subject: Re: LF: Re: how to increase the Q of my loading coil?
>>
>>
>>Am 16.02.2013 11:10, schrieb Clemens Paul:
>>>   [...]
>>> The higher the *loaded circuit* Q the higher are the losses in all=20
>>> involved components including the coil due to increasing
>>circulating currents.
>>> Given a certain circuit increasing the Q of its components
>>always will
>>> reduce overall losses of that circuit.
>>>
>>> 73
>>> Clemens
>>> DL4RAJ
>>
>>...however if the transmit power is kept constant, then the radiated=20
>>power is higher, due to the higher currents through the radiation=20
>>resistance. Thus the losses must be lower here.
>>It is not a constant voltage source, at least Dimitris' class E PA=20
>>isn't :-) So a high Q must be the goal, loaded or unloaded.
>>
>>73, Stefan/DK7FC
>>
>>
>>
>>-----
>>E-Mail ist virenfrei.
>>Von AVG =FCberpr=FCft - www.avg.de
>>Version: 2013.0.2899 / Virendatenbank: 2639/6104 -
>>Ausgabedatum: 14.02.2013
>>
>
>
>
>
>-----
>E-Mail ist virenfrei.
>Von AVG =FCberpr=FCft - www.avg.de
>Version: 2013.0.2899 / Virendatenbank: 2639/6104 -=20
>Ausgabedatum: 14.02.2013=20
>
>