I will have to take a look at that.
I also just got some advice from a ham friend who is also an oscillator
expert. He suggested putting an LC parallel resonant circuit at 14 MHz in
series with the sense line.
So far I've not had any luck with resistors and a large size RF choke (the
one sold by Radio Shack I forget the size). My friend says that one reason
why a choke may not work is that the choke has capacitance between the
windings. This capacitance then acts as a pickup for the touch sensing line
and actually counteracts the effect of the choke. Perhaps this is why a big
size choke hasn't worked for me but maybe a smaller one will.............
73,
Jon
NA9D
-------------------------------------
Jon Ogden
Sales Engineer
Cain-Forlaw Company
847-202-9898 (Voice)
847-202-9896 (Fax)
jon.ogden@cain-forlaw.com
> -----Original Message-----
> From: scameron [mailto:scameron@austin.rr.com]
> Sent: Thursday, June 28, 2001 10:14 AM
> To: rfi@contesting.com
> Subject: [RFI] Re: Radio Frequency Interference (RFI) Digest V4 #56
>
>
>
> The only thing that has worked for me on our and a neighbor's
> touch lamps is a 120
> micorhenry RF choke in series with a 1.8k ohm resistor at the
> circuit board end of the
> sense lead.
> March 1988 QST Technical Correspondence page 42 had a nice
> article on this. 3 lamps were
> discussed. the cures:
> 1. A 4.7 millihenry, 100 milliamp RF choke in series with a
> 1.8k resistor. (this one
> worked for me)
> 2. Same as #1 plus 7 turns of the power cord on a 2.5 inch
> Amidon FT-240-43 toroid.
> Raising the resistor value above 1.8k to the highest value
> possible while still allowing
> touch operation will provides the highest attenuation.
> 3. A 9.4 millihenry RF Choke in series with a 3.3kohm
> resistor plus a Radio Shack power
> line filter.
> January 1986 QST had another article, saying a 100 microhenry
> RF choke in series with a
> 1.8kohm resistor worked.
> Skip W5GAI
> "Experiment trumps theory." -- Dave Leeson W6NL
> ------------
> "Radio Frequency Interference (RFI) Digest" wrote:
>
> > Radio Frequency Interference (RFI) Digest Tuesday, June 26
> 2001 Volume 04 : Number 056
> >
> > In this issue:
> >
> > [RFI] Touch Light Update #3
> > RE: [RFI] Touch Light Update #3
> > RE: [RFI] Touch Light Update #3
> > RE: [RFI] Touch Light Update #3
> > RE: [RFI] Touch Light Update #3
> > RE: [RFI] Touch Light Update #3
> > [RFI] Coffee Pot RFI!
> > Re: [RFI] Coffee Pot RFI!
> > Re: [RFI] Coffee Pot RFI!
> > Re: [RFI] Coffee Pot RFI!
> > [RFI] Touch Light Update #3
> >
> > See the end of the digest for information about rfi-digest
> >
> >
> ----------------------------------------------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 07:31:18 -0500
> > From: Jon Ogden <jon.ogden@cain-forlaw.com>
> > Subject: [RFI] Touch Light Update #3
> >
> > Hi all,
> >
> > Yet again another update to my under cabinet touch lighting
> situation.
> >
> > To refresh your memory, on 20m I am having problems with my
> RF turning the
> > lights on and stepping them through their various dimmer stages.
> >
> > The lighting system consists of a dimmer unit which
> contains the sensing
> > circuitry and a switching power supply unit which takes the
> AC voltage
> > output of the dimmer unit and steps it down to 12 V DC or less.
> >
> > Here is where I am now. I have successfully eliminated the
> interference on
> > all amateur bands from my lighting system when it is
> uninstalled. This
> > solution consisted of wrapping the cord going to the AC
> mains around a large
> > Amidon torroid (I forget the material number - but it's
> correct for HF) and
> > wrapping the cord going between the dimmer unit and the
> power supply unit
> > the same way. I've tested on all bands but 160M and I have
> no interference
> > to the light.
> >
> > I did not need any bypass caps or anything like I thought I might.
> >
> > The current unit I have been messing with gets mounted
> above a fan hood.
> > The hood is basically a big stainless steel box (simplest
> way to describe
> > it). The lighting circuitry is mounted above it. The
> sensing line is then
> > attached to the metal hood. This way whenever the hood is
> touched, the
> > lighting system is activated. With the sensing line
> attached to the hood, I
> > get my 20m interference problem again. The hood is acting
> like a big
> > antenna. The hood is not grounded but isolated from DC ground since
> > grounding the hood when then ground the sense line and the
> switching would
> > not work.
> >
> > I've tried adding a .01 uF cap (and other values too) from
> the sensing lead
> > to ground. So far no matter what value I have tried,
> adding the cap ends up
> > loading the oscillator in the dimmer unit to the point that
> it is no longer
> > sensitive to touch. I've also tried winding the sensing
> line around a
> > torroid. If I get too many wraps, I again destroy the
> sensitivity of the
> > sensing line and it no longer does it's job. And anyhow,
> it still doesn't
> > stop my RF problem. I've tried resistors in series with
> the sensing line to
> > the hood. Above a few 100 Ohms and I lose my sensitivity
> just like with the
> > torroid.
> >
> > So far, I have found no good way to RF bypass the sensing
> line. What I want
> > to do is basically shunt all HF energy to ground on that
> line, but I can't
> > load down the line otherwise the sensing circuitry won't help.
> >
> > Does this make sense and does anyone have any ideas?
> >
> > Thanks es 73,
> >
> > Jon
> > NA9D
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 10:01:27 -0500
> > From: "EDWARDS, EDDIE J" <eedwards@oppd.com>
> > Subject: RE: [RFI] Touch Light Update #3
> >
> > > -----Original Message-----
> > > From: Jon Ogden
> > > Here is where I am now. I have successfully eliminated
> the interference
> > > on
> > > all amateur bands from my lighting system when it is uninstalled.
> > >
> > > The current unit I have been messing with gets mounted
> above a fan hood.
> > > The hood is basically a big stainless steel box (simplest
> way to describe
> > > it). The lighting circuitry is mounted above it. The
> sensing line is
> > > then
> > > attached to the metal hood. This way whenever the hood
> is touched, the
> > > lighting system is activated. With the sensing line
> attached to the hood,
> > > I
> > > get my 20m interference problem again. The hood is
> acting like a big
> > > antenna. The hood is not grounded but isolated from DC
> ground since
> > > grounding the hood when then ground the sense line and
> the switching would
> > > not work.
> > >
> > > I've tried adding a .01 uF cap (and other values too)
> from the sensing
> > > lead
> > > to ground. So far no matter what value I have tried,
> adding the cap ends
> > > up
> > > loading the oscillator in the dimmer unit to the point
> that it is no
> > > longer
> > > sensitive to touch. I've also tried winding the sensing
> line around a
> > > torroid. If I get too many wraps, I again destroy the
> sensitivity of the
> > > sensing line and it no longer does it's job. And anyhow,
> it still doesn't
> > > stop my RF problem. I've tried resistors in series with
> the sensing line
> > > to
> > > the hood. Above a few 100 Ohms and I lose my sensitivity
> just like with
> > > the
> > > torroid.
> > >
> > Have you tried a "micro" Henry choke on the sense
> line? Something
> > from 1-10 micro Henries is what is recommended. I don't
> think the resistor
> > is really needed since this is a very low current
> application (high current
> > would be bad for the human contact!). This is a very small
> inductance
> > (don't use the Radio Shack 100milliH choke!) and should not be much
> > reactance to the free running oscillator's sense line.
> >
> > Assuming the oscillator is around 170 Khz like most
> touch lamps (see
> > if you can find out), that would be only 11 ohms inductive
> reactance (for 10
> > microH) while providing 880 ohms at 14 Mhz; a factor of 80.
> Don't use 10
> > milliH since the inductive reactance to the sensing circuit
> at 170Khz would
> > be almost 11Kohm and probably would shut it down. If 10
> microH is too much
> > try 1 microH. That'd be only 1.1 ohms at 170Khz (assuming
> that is the
> > oscillator's freq!?). It may take experimenting with
> several values to get
> > it close. Also mount the inductor as close as possible to
> the circuit.
> >
> > > So far, I have found no good way to RF bypass the sensing
> line. What I
> > > want
> > > to do is basically shunt all HF energy to ground on that
> line, but I can't
> > > load down the line otherwise the sensing circuitry won't help.
> > >
> > Perhaps you could use a capacitor to pass the 14Mhz
> on the hood to
> > ground while, at the right value could look like a higher
> reactance to the
> > sensing line's capacitance. Cap of 0.01 microF would give
> 1.1 ohms at 14
> > Mhz & 93 ohms at 170Khz. So connect the cap to the hood
> somewhere or at a
> > couple of places, then gorund the other end of the cap(s).
> >
> > The problem is that the sensing line is operating on a
> > "Change-of-Capacitance" to change the operating state. The
> 14Mhz bypass to
> > ground might desense the "sensing line" enough to kill it.
> I think that's
> > what you've found already. So we're back to getting the RF
> choke right.
> > This all depends alot on the free running oscillator's
> operating frequency.
> > Is it spec'ed anywhere?
> >
> > 73,
> > de ed -K0iL
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 10:23:11 -0500
> > From: Jon Ogden <jon.ogden@cain-forlaw.com>
> > Subject: RE: [RFI] Touch Light Update #3
> >
> > > Have you tried a "micro" Henry choke on the sense line?
> > > Something
> > > from 1-10 micro Henries is what is recommended. I don't
> > > think the resistor
> > > is really needed since this is a very low current application
> > > (high current
> > > would be bad for the human contact!).
> >
> > No I have not. I had assumed that the sense line wrapped
> around the torroid
> > would end up looking similar to using a choke in series in the line.
> > Perhaps I am mistaken. Ten turns of the wire around an
> FT-50B-77 (half inch
> > torroid using the 77 material) didn't do much to solve the
> problem. Maybe
> > it's not the same as a choke actually in series with the line.
> >
> > >> So far, I have found no good way to RF bypass the sensing
> > >>line. What I want to do is basically shunt all HF energy
> to ground on
> > that
> > >>line, but I can't load down the line otherwise the
> sensing circuitry won't
> > help.
> > >
> > > Perhaps you could use a capacitor to pass the 14Mhz on
> > > the hood to
> > > ground while, at the right value could look like a higher
> > > reactance to the
> > > sensing line's capacitance. Cap of 0.01 microF would give
> > > 1.1 ohms at 14
> > > Mhz & 93 ohms at 170Khz. So connect the cap to the hood
> > > somewhere or at a
> > > couple of places, then gorund the other end of the cap(s).
> >
> > Tried that. The .01 uF cap prevents things from working
> correctly. That's
> > 93 Ohms at 170 KHz and I think that it pulls the circuit to
> ground too much.
> > I think a much, much smaller cap will need to be used.
> > >
> > > The problem is that the sensing line is operating on a
> > > "Change-of-Capacitance" to change the operating state. The
> > > 14Mhz bypass to
> > > ground might desense the "sensing line" enough to kill it. I
> > > think that's
> > > what you've found already. So we're back to getting the RF
> > > choke right.
> > > This all depends alot on the free running oscillator's
> > > operating frequency.
> > > Is it spec'ed anywhere?
> >
> > Exactly. No, I don't have a spec on the oscillator
> frequency. I think I
> > will finally puy my O-scope to a useful purpose and try to
> measure it. Then
> > I can try to make some useful sense out of things.
> >
> > UGH! There has got to be a solution though. So close!
> >
> > 73,
> >
> > Jon
> > NA9D
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 11:17:34 -0500
> > From: "EDWARDS, EDDIE J" <eedwards@oppd.com>
> > Subject: RE: [RFI] Touch Light Update #3
> >
> > > -----Original Message-----
> > > From: Jon Ogden
> > > > Have you tried a "micro" Henry choke on the sense line?
> > > No I have not. I had assumed that the sense line wrapped
> around the
> > > torroid
> > > would end up looking similar to using a choke in series
> in the line.
> > > Perhaps I am mistaken. Ten turns of the wire around an
> FT-50B-77 (half
> > > inch
> > > torroid using the 77 material) didn't do much to solve
> the problem. Maybe
> > > it's not the same as a choke actually in series with the line.
> > >
> > I'm not sure how to calculate the inductance of the
> FT-50B-77.
> > Anyone know if it's the same as the FB-(77)-1024 listed in
> the ARRL RFI
> > book? And if so, what are the "A-sub-L v Mix No." values
> listed in table
> > 2.2? Seems to indicate nanoHenries. So then FB-77-1024 is
> 5600 nanoH or
> > 5.6 microH? For how many turns? One? So many questions!
> If it is one
> > then would've been 10 times 5.6 for 56 milliH. That might
> be too much
> > inductance and reactance for the sensing line. But this is
> all a complete
> > guess without the answers to my questions.
> >
> > An actual inductance value for the FT-50B-77 would
> be helpful to
> > know for sure.
> >
> > 73,
> > de ed -K0iL
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 11:35:34 -0500
> > From: Jon Ogden <jon.ogden@cain-forlaw.com>
> > Subject: RE: [RFI] Touch Light Update #3
> >
> > According to the Amidon literature I have in front of me,
> the FT-50B-77 has
> > a value of 2160 mH per 1000 turns. So that would mean that
> 10 turns is
> > 21.60 mH. So that's way to big. However, it still didn't
> stop the 20M RF
> > from messing with things.
> >
> > You'd think it would since it's a rather large impedance at
> 14 MHz, but it
> > didn't.
> >
> > 73,
> >
> > Jon
> > NA9D
> >
> > - -------------------------------------
> > Jon Ogden
> > Sales Engineer
> > Cain-Forlaw Company
> > 847-202-9898 (Voice)
> > 847-202-9896 (Fax)
> > jon.ogden@cain-forlaw.com
> >
> > > -----Original Message-----
> > > From: EDWARDS, EDDIE J [mailto:eedwards@oppd.com]
> > > Sent: Tuesday, June 26, 2001 11:18 AM
> > > To: 'Jon Ogden'; 'RFI'
> > > Subject: RE: [RFI] Touch Light Update #3
> > >
> > >
> > > > -----Original Message-----
> > > > From: Jon Ogden
> > > > > Have you tried a "micro" Henry choke on the sense line?
> > > > No I have not. I had assumed that the sense line
> wrapped around the
> > > > torroid
> > > > would end up looking similar to using a choke in series
> in the line.
> > > > Perhaps I am mistaken. Ten turns of the wire around an
> > > FT-50B-77 (half
> > > > inch
> > > > torroid using the 77 material) didn't do much to solve the
> > > problem. Maybe
> > > > it's not the same as a choke actually in series with the line.
> > > >
> > > I'm not sure how to calculate the inductance of the
> FT-50B-77.
> > > Anyone know if it's the same as the FB-(77)-1024 listed in
> > > the ARRL RFI
> > > book? And if so, what are the "A-sub-L v Mix No." values
> > > listed in table
> > > 2.2? Seems to indicate nanoHenries. So then FB-77-1024 is
> > > 5600 nanoH or
> > > 5.6 microH? For how many turns? One? So many questions!
> > > If it is one
> > > then would've been 10 times 5.6 for 56 milliH. That
> might be too much
> > > inductance and reactance for the sensing line. But this is
> > > all a complete
> > > guess without the answers to my questions.
> > >
> > > An actual inductance value for the FT-50B-77 would
> be helpful to
> > > know for sure.
> > >
> > > 73,
> > > de ed -K0iL
> > >
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 12:06:31 -0500
> > From: Jon Ogden <jon.ogden@cain-forlaw.com>
> > Subject: RE: [RFI] Touch Light Update #3
> >
> > I made a mistake here. The inductance is proportional to
> the square of the
> > turns.
> >
> > Amidon uses the following formula:
> >
> > Turns = 1000 * Sqrt(desired L (mH)/Al)
> >
> > Where Al = the inductance value at 1000 turns specified by Amidon
> >
> > So in my case I have 10 turns. Al = 2160
> >
> > So the correct amount of inductance is .216 mH or 216 uH.
> >
> > 73,
> >
> > Jon
> > NA9D
> > - -------------------------------------
> > Jon Ogden
> > Sales Engineer
> > Cain-Forlaw Company
> > 847-202-9898 (Voice)
> > 847-202-9896 (Fax)
> > jon.ogden@cain-forlaw.com
> >
> > > -----Original Message-----
> > > From: Jon Ogden [mailto:jon.ogden@cain-forlaw.com]
> > > Sent: Tuesday, June 26, 2001 11:36 AM
> > > To: 'EDWARDS, EDDIE J'; Jon Ogden; 'RFI'
> > > Subject: RE: [RFI] Touch Light Update #3
> > >
> > >
> > >
> > > According to the Amidon literature I have in front of me, the
> > > FT-50B-77 has
> > > a value of 2160 mH per 1000 turns. So that would mean that
> > > 10 turns is
> > > 21.60 mH. So that's way to big. However, it still didn't
> > > stop the 20M RF
> > > from messing with things.
> > >
> > > You'd think it would since it's a rather large impedance at
> > > 14 MHz, but it
> > > didn't.
> > >
> > > 73,
> > >
> > > Jon
> > > NA9D
> > >
> > > -------------------------------------
> > > Jon Ogden
> > > Sales Engineer
> > > Cain-Forlaw Company
> > > 847-202-9898 (Voice)
> > > 847-202-9896 (Fax)
> > > jon.ogden@cain-forlaw.com
> > >
> > > > -----Original Message-----
> > > > From: EDWARDS, EDDIE J [mailto:eedwards@oppd.com]
> > > > Sent: Tuesday, June 26, 2001 11:18 AM
> > > > To: 'Jon Ogden'; 'RFI'
> > > > Subject: RE: [RFI] Touch Light Update #3
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Jon Ogden
> > > > > > Have you tried a "micro" Henry choke on the
> sense line?
> > > > > No I have not. I had assumed that the sense line wrapped
> > > around the
> > > > > torroid
> > > > > would end up looking similar to using a choke in series
> > > in the line.
> > > > > Perhaps I am mistaken. Ten turns of the wire around an
> > > > FT-50B-77 (half
> > > > > inch
> > > > > torroid using the 77 material) didn't do much to solve the
> > > > problem. Maybe
> > > > > it's not the same as a choke actually in series with the line.
> > > > >
> > > > I'm not sure how to calculate the inductance of the
> FT-50B-77.
> > > > Anyone know if it's the same as the FB-(77)-1024 listed in
> > > > the ARRL RFI
> > > > book? And if so, what are the "A-sub-L v Mix No." values
> > > > listed in table
> > > > 2.2? Seems to indicate nanoHenries. So then FB-77-1024 is
> > > > 5600 nanoH or
> > > > 5.6 microH? For how many turns? One? So many questions!
> > > > If it is one
> > > > then would've been 10 times 5.6 for 56 milliH. That might
> > > be too much
> > > > inductance and reactance for the sensing line. But this is
> > > > all a complete
> > > > guess without the answers to my questions.
> > > >
> > > > An actual inductance value for the FT-50B-77 would
> be helpful to
> > > > know for sure.
> > > >
> > > > 73,
> > > > de ed -K0iL
> > > >
> > >
> > > --
> > > FAQ on WWW: http://www.contesting.com/FAQ/rfi
> > > Submissions: rfi@contesting.com
> > > Administrative requests: rfi-REQUEST@contesting.com
> > > Questions: owner-rfi@contesting.com
> > >
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 18:23:27 -0700
> > From: "Mike Lazaroff K3AIR" <k3air@arrl.net>
> > Subject: [RFI] Coffee Pot RFI!
> >
> > Here's a great (and true!) story about our FD operation this year:
> >
> > When operating 80m phone, all of a sudden we were
> overwhelmed with 40 db
> > over 9 buzzing QRM up and down the band. The noise was
> barely audible on
> > 40m, and not at all on the other bands. It just appeared
> suddenly, so we
> > figured somebody turned on something that didn't like 80m.
> We checked our
> > power supplies, laptops, etc., figuring it had to be one of
> them. Nope.
> >
> > After checking all around the campsite, we discovered that
> when the coffee
> > pot in the "dining area" was turned on, the RFI appeared.
> When it was off,
> > the RFI was gone.
> >
> > We survived just fine without (hot) coffee.
> >
> > Anyone else ever experience this???
> >
> > 73 and hope everyone enjoyed Field Day,
> > Mike K3AIR
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 20:10:03 -0400
> > From: "K4LDR" <k4ldr@hitter.net>
> > Subject: Re: [RFI] Coffee Pot RFI!
> >
> > Ahoy there Mike:
> >
> > That is really gud RFI experience and info to know and
> maintain in our
> > mental file. What
> > brand/model coffee pot was that? If u tell us, that wud be
> a great service
> > to readers and it may well save some teeth gnashing at a future
> > time.
> >
> > 73, Pete K4LDR Citrus County, FL
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 20:32:54 EDT
> > From: W2YR@aol.com
> > Subject: Re: [RFI] Coffee Pot RFI!
> >
> > - --part1_69.174003b8.286a83b6_boundary
> > Content-Type: text/plain; charset="US-ASCII"
> > Content-Transfer-Encoding: 7bit
> >
> > Mike,
> >
> > You asked if anyone else experienced anything like this?
> Well, at N2MO in
> > Spring Lake, NJ our field day microwave oven generated lots
> of hash on the 20
> > meter band. Thankfully, it was only short duration till
> another member
> > finished cooking his meal!
> >
> > 73,
> > John - W2YR
> >
> > - --part1_69.174003b8.286a83b6_boundary
> > Content-Type: text/html; charset="US-ASCII"
> > Content-Transfer-Encoding: 7bit
> >
> > <HTML><FONT FACE=arial,helvetica><FONT SIZE=3>Mike,
> > <BR>
> > <BR>You asked if anyone else experienced anything like
> this? Well, at N2MO in
> > <BR>Spring Lake, NJ our field day microwave oven generated
> lots of hash on the 20
> > <BR>meter band. Thankfully, it was only short duration till
> another member
> > <BR>finished cooking his meal!
> > <BR>
> > <BR>73,
> > <BR>John - W2YR</FONT></HTML>
> >
> > - --part1_69.174003b8.286a83b6_boundary--
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 21:37:43 -0400
> > From: Pete Smith <n4zr@contesting.com>
> > Subject: Re: [RFI] Coffee Pot RFI!
> >
> > At 06:23 PM 6/26/01 -0700, Mike Lazaroff K3AIR wrote:
> > >
> > >Here's a great (and true!) story about our FD operation this year:
> > >
> > >When operating 80m phone, all of a sudden we were
> overwhelmed with 40 db
> > >over 9 buzzing QRM up and down the band. The noise was
> barely audible on
> > >40m, and not at all on the other bands. It just appeared
> suddenly, so we
> > >figured somebody turned on something that didn't like 80m.
> We checked our
> > >power supplies, laptops, etc., figuring it had to be one
> of them. Nope.
> > >
> > >After checking all around the campsite, we discovered that
> when the coffee
> > >pot in the "dining area" was turned on, the RFI appeared.
> When it was off,
> > >the RFI was gone.
> > >
> > >We survived just fine without (hot) coffee.
> > >
> > >Anyone else ever experience this???
> >
> > Sounds like a close cousin to the electrically-heated dog dish we
> > discovered at a neighbor's house.
> >
> > 73, Pete N4ZR
> > No, no ... that's WEST Virginia
> >
> > ------------------------------
> >
To: <rfi@contesting.com>
> > Date: Tue, 26 Jun 2001 23:36:48 -0400
> > From: Palomar Engineers <Palomar@compuserve.com>
> > Subject: [RFI] Touch Light Update #3
> >
> > F50B-77 is 2400 mH/1000t so the 10 turns is 216 uH. But 77
> material is
> > quite lossy at 14 MHz and inductance is too high anyway.
> Better to use
> > about 15 turns on a T50-6 to get 1 uH with good "Q". -- If
> you are stuck
> > with the F50B-77 just slip it over the wire (one turn) to
> suppress the 14
> > MHz. -- Jack, K6NY, Palomar Engineers
> >
> > ------------------------------
> >
> > End of Radio Frequency Interference (RFI) Digest V4 #56
> > *******************************************************
> >
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>
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>
>
>
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