New program SELFRES2.exe
--------------------------------------
Input data :

Length and diameter of solenoid.
Number of turns.
Conductor diameter
Length of line in which the coil is inserted.
Testing frequency.

Output data :

Coil self-capacitance.
Coil self-resonant frequency.
Choke impedance vs frequency.
Insertion loss of choke in dB.

Performance is based on a choke wound with coaxial cable of the same type as
the transmission transmission line in which it is inserted. Conductor
diameter is that of the coax outer. It behaves a single wire. Coax inner
diameter is of no consequence.

Choke insertion loss is a measure of the reduction in power radiated from
the feedline. But, despite the attention it attracts, actual power radiated
from the feedline WITH the choke will never be known because the power
radiated WITHOUT the choke is indeterminate.

SELFRES2 is 51 K-bytes. Download from website below in a few seconds. It is
not zipped-up and will run immediately.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Reg Edwards wrote:

New program SELFRES2.exe
--------------------------------------
Input data :

Length and diameter of solenoid.
Number of turns.
Conductor diameter
Length of line in which the coil is inserted.
Testing frequency.

Output data :

Coil self-capacitance.
Coil self-resonant frequency.
Choke impedance vs frequency.
Insertion loss of choke in dB.


Reg, please could you make the terminating impedance a user variable
too? (There's space for just one more parameter.) That would allow choke
performance to be calculated for the standard test conditions of 50 ohms
source and 50 ohms termination.

Real-life source and load impedances are, as you say, indeterminate (or
largely so). However, there still needs to be a standard test
environment for comparing published data for different chokes, and
comparing predictions against measurements. 50-50 meets that need.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

"Ian White, G3SEK" wrote

Reg, please could you make the terminating impedance a user variable
too? (There's space for just one more parameter.) That would allow choke
performance to be calculated for the standard test conditions of 50 ohms
source and 50 ohms termination.

Real-life source and load impedances are, as you say, indeterminate (or
largely so). However, there still needs to be a standard test
environment for comparing published data for different chokes, and
comparing predictions against measurements. 50-50 meets that need.

====================================

Ian,

Done!

It took 7 hours including updating program notes, local records, website,
making backups, notifying customers and writing this message. I spent an
hour testing for and removing a dozen or so bugs inevitably introduced by
modifications more involved than you perhaps realise. Normally this takes a
week or two but its only a hank of cable and a residual bug won't amount to
very much. ;o)

It added about 1.5 K-bytes to the source code. It has improved the screen's
appearance. The extra facility will add to a user's interest in a choke's
behaviour.

Thanks very much for your suggestion.

I changed the program's name. Download SELFRES3 now.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Reg Edwards wrote:
Ian,

Done!

It took 7 hours including updating program notes, local records,
website, making backups, notifying customers and writing this message.
I spent an hour testing for and removing a dozen or so bugs inevitably
introduced by modifications more involved than you perhaps realise.

I fully realise that any software modification will be more involved
than I realise.

Normally this takes a week or two but its only a hank of cable and a
residual bug won't amount to very much. ;o)

It added about 1.5 K-bytes to the source code. It has improved the
screen's appearance. The extra facility will add to a user's interest
in a choke's behaviour.

Thanks very much for your suggestion.


Thanks very much for making the staff work overtime!

I changed the program's name. Download SELFRES3 now.

Done - it looks good. Thanks again, Reg.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

On the suggestion of Ian White, G3SEK, program SELFRES2 has been modified by
the addition of an extra operating facility.

The terminating impedance at the other end of the line from the coaxial
choke, which was fixed at 20 ohms, can now be varied between 1ohm and 1000
ohms from the keyboard.

The name has been changed to SELFRES3 and is now available from website
below. If you have already downloaded the earlier version which is no longer
available, overwrite it with SELFRES3.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Reg Edwards wrote:

On the suggestion of Ian White, G3SEK, program SELFRES2 has been modified by
the addition of an extra operating facility.

The terminating impedance at the other end of the line from the coaxial
choke, which was fixed at 20 ohms, can now be varied between 1ohm and 1000
ohms from the keyboard.

The name has been changed to SELFRES3 and is now available from website
below. If you have already downloaded the earlier version which is no longer
available, overwrite it with SELFRES3.
----
.................................................. .........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. .........



Thanks Reg. As a programmer of the older sort, I appreciate the effort.
Seems to operate well.

tom
K0TAR

"Reg Edwards" wrote in message ...
New program SELFRES2.exe
--------------------------------------
Input data :

Length and diameter of solenoid.
Number of turns.
Conductor diameter
Length of line in which the coil is inserted.
Testing frequency.

Output data :

Coil self-capacitance.
Coil self-resonant frequency.
Choke impedance vs frequency.
Insertion loss of choke in dB.

Performance is based on a choke wound with coaxial cable of the same type as
the transmission transmission line in which it is inserted. Conductor
diameter is that of the coax outer. It behaves a single wire. Coax inner
diameter is of no consequence.

Choke insertion loss is a measure of the reduction in power radiated from
the feedline. But, despite the attention it attracts, actual power radiated
from the feedline WITH the choke will never be known because the power
radiated WITHOUT the choke is indeterminate.

SELFRES2 is 51 K-bytes. Download from website below in a few seconds. It is
not zipped-up and will run immediately.
----
.................................................. .........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. .........

Wunnerful! another gem from The Reg. I took the revised version out
for a couple test drives and it's very nice. As usual.

However I have an ongoing problem of a very practical nature involving
how to "wind" a true solenoid from coaxial cable. Turns out that at
the moment I'm pondering how to build as lightweight as possible
chokes made from RG-58 coax for 30, 20 and 2M dipoles. Does anybody
around here know how to fabricate a proper coax solenoid without
having to resort to some beastly heavy coil form like PVC pipe? How do
ya wind one which holds its shape out in the WX without a coil form?
Is there some magic goop out there which can bond the turns together
or what?

w3rv

Ian White, G3SEK wrote:

I fully realise that any software modification will be more involved
than I realise.


This is a great quote, Ian!

- Mike KB3EIA -