Today's Message Index:
----------------------
1. 08:26 AM - Re: Grounding radio antenna and transponder antenna (user9253)
2. 08:28 AM - fuel transfer controller, revisited (Charlie England)
3. 08:31 AM - Re: fuel transfer controller, revisited (Charlie England)
4. 08:53 AM - Re: fuel transfer controller, revisited (user9253)
5. 08:59 AM - Re: Re: Grounding radio antenna and transponder antenna (Charlie England)
6. 10:03 AM - Re: fuel transfer controller, revisited (The Kuffels)
7. 10:57 AM - OOPS: Re: fuel transfer controller, revisited (The Kuffels)
8. 12:10 PM - Re: fuel transfer controller, revisited (Ernest Christley)
9. 12:16 PM - Re: Re: fuel transfer controller, revisited (Charlie England)
10. 12:29 PM - Re: fuel transfer controller, revisited (Charlie England)
11. 12:45 PM - Re: fuel transfer controller, revisited (Charlie England)
12. 01:09 PM - Re: Re: Grounding radio antenna and transponder antenna (Robert L. Nuckolls, III)
13. 01:09 PM - Re: Re: Grounding radio antenna and transponder antenna (Robert L. Nuckolls, III)
14. 08:07 PM - Re: Grounding radio antenna and transponder antenna (Argonaut36)
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| Subject: | Re: Grounding radio antenna and transponder antenna |
That copper tape does not do much good because it all goes in one direction. And
it is questionable if it is making good contact with the antenna mounting plate.
Here is a suggestion: Cut 4 pieces of coax each 22 or 23 inches long. Attach a
ring terminal to the shield of each coax (not the center conductor). Connect
one length of coax to each of the 4 antenna mounting screws using the ring terminals.
When the panel is mounted to the aircraft, arrange the coax ground plane
so that it extends outward in 4 different directions. Elastic cord attached
to the coax ends could help to position it.
This experiment is worth a try and will not cost much except your time.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=491361#491361
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| Subject: | fuel transfer controller, revisited |
Hi guys,
In my homebuilt project, I have aux tank(s) that must be pumped to the main
tank for engine supply, on an engine that uses automotive style high
pressure injection with a regulator return line to the main tank. (Personal
preference vs the complexity of a 4-selection duplex valve)
Thought I'd tap the brain trust for how best to execute an idea for an
automated fuel transfer controller. Liquid level controllers are readily
available now, but most I've found are almost 'too clever' for what I want,
using simple bare wire for probes in a water tank. What I'd like is a
controller that could look to the variable voltage seen by our typical fuel
gauges/EFISs from 'standard' Stewart Warner type resistive sensors for
level sensing, instead of separate probes, optical sensors, etc.
For my AFS engine monitor circuit, the tank sensor, according to AFS:
'It will be pulled up to ~4v. So with the 40-240=84 you will see 0.1
to 1.0V
.'
Since the sensor goes to 40 ohms at full and is referenced to ground, That
means 1.0 V at empty, and 0.1 V at full. ( I suspect that this is fairly
typical for gauges using SW resistive sensors.)
So my idea of an ideal circuit is this:
*An *adjustable* setpoint for pump turn-on, when voltage *rises* to say,
0.6V, and pump turn-off when voltage *falls* to say, 0.2V (to avoid
overfilling the tank). I'd consider the adjustable feature to be essential,
due to variations in float arms, tanks, supply voltage to the sensor/gauge
(might be 14V in some cases), etc. *A 'nice to have' additional feature for
others would allow inverting the voltage measurements, since some
installations might expect the resistive sensor to be at 240 ohms when full
.
Any thoughts on a simple circuit to do this? Every off-the-shelf controller
I've found uses switches, triggers, etc, instead of voltage comparators.
The two most common ICs are the LM324 (using one section as an oscillator
to generate a low voltage AC to excite the probes), and a 555 timer IC
(much simpler circuit, but no provision for voltage sensing for trigger).
Thanks for any thoughts,
Charlie
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| Subject: | Re: fuel transfer controller, revisited |
OOPS; forgot an important point:
Since the device will operate in parallel with an existing gauge (or input
to an EFIS), the voltage sensing circuit obviously needs to present a
relatively high impedance to avoid affecting the existing measurements.
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On Tue, Sep 17, 2019 at 10:25 PM Charlie England <ceengland7@gmail.com>
wrote:
> Hi guys,
>
> In my homebuilt project, I have aux tank(s) that must be pumped to the
> main tank for engine supply, on an engine that uses automotive style high
> pressure injection with a regulator return line to the main tank. (Person
al
> preference vs the complexity of a 4-selection duplex valve)
>
> Thought I'd tap the brain trust for how best to execute an idea for an
> automated fuel transfer controller. Liquid level controllers are readily
> available now, but most I've found are almost 'too clever' for what I wan
t,
> using simple bare wire for probes in a water tank. What I'd like is a
> controller that could look to the variable voltage seen by our typical fu
el
> gauges/EFISs from 'standard' Stewart Warner type resistive sensors for
> level sensing, instead of separate probes, optical sensors, etc.
>
> For my AFS engine monitor circuit, the tank sensor, according to AFS:
> 'It will be pulled up to ~4v. So with the 40-240=84 you will see 0.
1 to 1.0V
> .'
>
> Since the sensor goes to 40 ohms at full and is referenced to ground, Tha
t
> means 1.0 V at empty, and 0.1 V at full. ( I suspect that this is fairly
> typical for gauges using SW resistive sensors.)
>
> So my idea of an ideal circuit is this:
>
> *An *adjustable* setpoint for pump turn-on, when voltage *rises* to say,
> 0.6V, and pump turn-off when voltage *falls* to say, 0.2V (to avoid
> overfilling the tank). I'd consider the adjustable feature to be essentia
l,
> due to variations in float arms, tanks, supply voltage to the sensor/gaug
e
> (might be 14V in some cases), etc. *A 'nice to have' additional feature
> for others would allow inverting the voltage measurements, since some
> installations might expect the resistive sensor to be at 240 ohms when fu
ll.
>
> Any thoughts on a simple circuit to do this? Every off-the-shelf
> controller I've found uses switches, triggers, etc, instead of voltage
> comparators. The two most common ICs are the LM324 (using one section as
an
> oscillator to generate a low voltage AC to excite the probes), and a 555
> timer IC (much simpler circuit, but no provision for voltage sensing for
> trigger).
>
> Thanks for any thoughts,
>
> Charlie
>
>
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| Subject: | Re: fuel transfer controller, revisited |
Charlie, a search on the internet found this thread:
https://forum.allaboutcircuits.com/threads/voltage-controlled-switch.63998/
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=491364#491364
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| Subject: | Re: Grounding radio antenna and transponder antenna |
If the copper tape isn't soldered or otherwise electrically bonded to the
rest of the metal ground plane (panel), then it's not doing anything
productive. You could get what you were hoping for by using strips of
aluminum; even something really thin like strips cut from aluminum flashing
material. They could be riveted on one end to the aluminum doubler shown in
the pics, and glued with clear 'sensor safe' rtv to the plexi, and screwed
at the other end using the plexi mounting screws.
Having said that, the antenna still won't be centered in the ground plane.
You could add strips going the other direction using similar techniques.
The 'ideal' ground plane extends out from the base as far as the antenna
height. As few as 4 equally spaced radial arms can get the job done pretty
effectively.
Having said *that*, are you sure your problems are purely transmission
range? Tube/rag a/c are notoriously noisy in the cockpit. You may have as
much a problem with *audio* signal to noise ratio as with transmission
distance. Ability to accurately describe comm deficiencies is pretty rare,
even for controllers. If you think that could be a possibility, we can
expand on that.
Charlie
(sound tech in one of my previous lives)
On Tue, Sep 17, 2019 at 9:45 PM Argonaut36 <fmlibrino@msn.com> wrote:
>
> Thanks to both for the additional comments.
> I reply to the questions of Bob as follows:
> =A2 I do not have the old coax any more
> =A2 I have never used a hand-held radio in this airplane
> =A2 The radio performance is ok for Class D operations, but n
ot so
> good for Class B and Class C, when you need to communicate from further o
ut
> and clarity of communications is even more important
> =A2 As far as additional input, I can tell you that the radio
harness
> was replaced without appreciable changes
> I am posting a file that includes 2 pictures of my panel/antenna. The
> copper strips are just taped (not soldered) and there is no communing
> disk. The strips do not extend laterally, because of the limited width o
f
> the panel. I assumed that, as we normally fly towards the radio station
we
> are talking to, that would be kind of acceptable.
> Could you please make comments on my copper foil strips and elaborate a
> little further on how the set up described by Bob is in his book could be
> implemented on my panel (keeping the panel removable from the airplane)?
> Note: in my previous post with the dimensions of the ground plane I have
> just disregarded the copper foil strips and I have assumed that the secti
on
> of panel behind the plexigas window and the double plate work together as
a
> ground plane.
> Thanks
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=491345#491345
>
>
> Attachments:
>
> http://forums.matronics.com//files/pictures_196.pdf
>
>
===========
===========
===========
===========
===========
>
>
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| Subject: | Re: fuel transfer controller, revisited |
Charlie,
Believe your approach is too "clever". For example, your specifications ha
ve no way to turn off the pump when the aux tanks are empty and the mains a
re low. Nor is there any way to turn on the pump when the fuel sensor fail
s.
Suggest a simple push button activated timer circuit that stays on for abou
t 20% of the aux tank capacity is a simpler, more reliable approach. See t
he May issue of Kitplanes for a detailed description of such a circuit and
how to use it.
Or a simpler version of the same circuit can be found at the Glassair Owner
s Association website under the tag "fuel".
If you don't have access to these on-line drop me a note and I can email yo
u the source files.
I also have a manuscript for a gadget that correctly detects net fuel flow
in a return line installation. Cost: about $2.00 in parts plus the flow tr
ansducers.
Tom Kuffel
kuffel@cyberport.net
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| Subject: | Re: fuel transfer controller, revisited |
<< See the May issue of Kitplanes for a detailed description of such a cir
cuit and how to use it. >>
Should be: See the May 2009 issue of Kitplanes
Tom
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| Subject: | Re: fuel transfer controller, revisited |
Are the AUX tanks higher than the main?=C2- At the wing tips vs. root, f
or instance?
If so, get rid of the electronics completely.=C2- Put a float controlled
valve on port on the main tank, and have it fed from a low point on the AUX
tank.
On Wednesday, September 18, 2019, 11:29:11 AM EDT, Charlie England <cee
ngland7@gmail.com> wrote:
Hi guys,
In my homebuilt project, I have aux tank(s) that must be pumped to the main
tank for engine supply, on an engine that uses automotive style high press
ure injection with a regulator return line to the main tank. (Personal pref
erence vs the complexity of a 4-selection duplex valve)
Thought I'd tap the brain trust for how best to execute an idea for an auto
mated fuel transfer controller. Liquid level controllers are readily availa
ble now, but most I've found are almost 'too clever' for what I want, using
simple bare wire for probes in a water tank. What I'd like is a controller
that could look to the variable voltage seen by our typical fuel gauges/EF
ISs from 'standard' Stewart Warner type resistive=C2-sensors for level se
nsing, instead of separate probes, optical sensors, etc.=C2-
For my AFS engine monitor circuit, the tank sensor, according to AFS:'It wi
ll be pulled up to ~4v. So with the 40-240=84 you will see 0.1 to 1.0
V=C2-.'
=C2- =C2-
Since the sensor goes to 40 ohms at full and is referenced to ground, That
means 1.0 V at empty, and 0.1 V at full. ( I suspect that this is fairly ty
pical for gauges using SW resistive sensors.)=C2-
So my idea of an ideal circuit is this:=C2-
An *adjustable* setpoint for pump turn-on, when voltage *rises* to say, 0.6
V, and pump turn-off when voltage *falls* to say, 0.2V (to avoid overfillin
g the tank). I'd consider the adjustable feature to be essential, due to va
riations in float arms, tanks, supply voltage to the sensor/gauge (might be
14V in some cases), etc. A 'nice to have' additional feature for others=C2
- would allow inverting the voltage measurements, since some installation
s might expect the resistive sensor to be at 240 ohms when full.
Any thoughts on a simple circuit to do this? Every off-the-shelf controller
I've found uses switches, triggers, etc, instead of voltage comparators. T
he two most common ICs are the LM324 (using one section as an oscillator to
generate a low voltage AC to excite the probes), and a 555 timer IC (much
simpler circuit, but no provision for voltage sensing for trigger).
Thanks for any thoughts,
Charlie
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| Subject: | Re: fuel transfer controller, revisited |
On 9/18/2019 10:52 AM, user9253 wrote:
>
> Charlie, a search on the internet found this thread:
> https://forum.allaboutcircuits.com/threads/voltage-controlled-switch.63998/
>
> --------
> Joe Gores
>
Thanks for the link, and the reminder. I've been away from active
electronics work for so long, I'd completely forgotten about comparator
circuits. I'll do some more research on that path; I'd like to have
independently adjustable trigger points via trim pots, and a variation
on that circuit might allow it. The site looks like it could be useful
for a variety of other projects, as well.
Charlie
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| Subject: | Re: fuel transfer controller, revisited |
On 9/18/2019 12:00 PM, The Kuffels wrote:
>
> Charlie,
> Believe your approach is too "clever". For example, your
> specifications have no way to turn off the pump when the aux tanks are
> empty and the mains are low. Nor is there anyway to turn on the pump
> when the fuel sensor fails.
> Suggest a simple push button activated timer circuit that stays on for
> about 20% of the aux tank capacity is a simpler, more reliable
> approach. See the May issue of Kitplanes for a detailed description
> of such a circuit and how to use it.
> Or a simpler version of the same circuit can be found at the Glassair
> Owners Association website under the tag "fuel".
> If you don't have access to these on-line drop me a note and I
> canemail you the source files.
> I also have a manuscript for a gadget that correctlydetects netfuel
> flow in a return line installation. Cost: about $2.00 in parts plus
> the flow transducers.
> Tom Kuffel
> kuffel@cyberport.net <mailto:kuffel@cyberport.net>
Hi Tom,
I appreciate the warning, since any of us can get lost in the weeds (get
too clever). In this case, though, I already have a 'no fuel present'
optical sensor in the supply line to the transfer pump(s). I was afraid
my initial narrative would get so long that I didn't try to describe
every detail; only the specific function that I'm having trouble
finalizing. I also intend manual switch control to both stop and start
transfers if problems develop.
Thanks for the link to the Glassair site for the timer circuit; a simple
timer has always been 'plan B'. I do have a subscription to Kitplanes
(all homebuilders should, in my opinion), so I'm good there. I'd love
to see your return flow compensation circuit, though it's not an issue
for this particular installation (flow sensor is downstream of the
regulator bypass). I'd be *really* excited if you could do it for $2
without the need of an extra $150 flow sensor. :-)
If you don't mind sending it, my email address is
ceengland7@gmail.com.
Thanks,
Charlie
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| Subject: | Re: fuel transfer controller, revisited |
Not high enough to matter; it's an RV-7 with 'wet wing' leading edge
tanks outboard of the mains. About 3 lbs weight gain total for the tanks
themselves & fuel lines, plus the weight of redundant Facet transfer
pumps in the fuselage.
The -7 is acro-qualified, but not with fuel weight in the outboard
sections of the wings. I've probably seen all the various tank building
and transfer methods, and none of the passive transfer methods I've seen
so far give me any confidence in being able to positively empty the aux
tanks and know that no fuel will get back out there even when the main
is full. The passive methods of transfer that I've seen also depend on
the cap on the main tank being totally fuel tight (not a universal
certainty with Van's caps) because the higher aux fuel will try to exit
the main's cap when both are full. In addition, some of the schemes
depend on re-arranging the vent system so that the main's vent ties to
the aux outlet, and the aux supplies the vent for the whole system. I
can't get comfortable with messing around with the vent system, either,
regardless of acro issues.
The alternative engine is a radical enough change, so I tried to keep
the actual fuel delivery path as close to 'stock' as possible, with the
only mod to the fuel delivery main tank being its return line.
Charlie
On 9/18/2019 2:07 PM, Ernest Christley wrote:
> Are the AUX tanks higher than the main? At the wing tips vs. root,
> for instance?
>
> If so, get rid of the electronics completely. Put a float controlled
> valve on port on the main tank, and have it fed from a low point on
> the AUX tank.
>
> On Wednesday, September 18, 2019, 11:29:11 AM EDT, Charlie England
> <ceengland7@gmail.com> wrote:
>
>
> Hi guys,
>
> In my homebuilt project, I have aux tank(s) that must be pumped to the
> main tank for engine supply, on an engine that uses automotive style
> high pressure injection with a regulator return line to the main tank.
> (Personal preference vs the complexity of a 4-selection duplex valve)
>
> Thought I'd tap the brain trust for how best to execute an idea for an
> automated fuel transfer controller. Liquid level controllers are
> readily available now, but most I've found are almost 'too clever' for
> what I want, using simple bare wire for probes in a water tank. What
> I'd like is a controller that could look to the variable voltage seen
> by our typical fuel gauges/EFISs from 'standard' Stewart Warner type
> resistivesensors for level sensing, instead of separate probes,
> optical sensors, etc.
>
> For my AFS engine monitor circuit, the tank sensor, according to AFS:
> 'It will be pulled up to ~4v. So with the 40-240 you will see 0.1 to
> 1.0V.'
>
> Since the sensor goes to 40 ohms at full and is referenced to ground,
> That means 1.0 V at empty, and 0.1 V at full. ( I suspect that this is
> fairly typical for gauges using SW resistive sensors.)
>
> So my idea of an ideal circuit is this:
>
> *An *adjustable* setpoint for pump turn-on, when voltage *rises* to
> say, 0.6V, and pump turn-off when voltage *falls* to say, 0.2V (to
> avoid overfilling the tank). I'd consider the adjustable feature to be
> essential, due to variations in float arms, tanks, supply voltage to
> the sensor/gauge (might be 14V in some cases), etc. *A 'nice to have'
> additional feature for others would allow inverting the voltage
> measurements, since some installations might expect the resistive
> sensor to be at 240 ohms when full.
>
> Any thoughts on a simple circuit to do this? Every off-the-shelf
> controller I've found uses switches, triggers, etc, instead of voltage
> comparators. The two most common ICs are the LM324 (using one section
> as an oscillator to generate a low voltage AC to excite the probes),
> and a 555 timer IC (much simpler circuit, but no provision for voltage
> sensing for trigger).
>
> Thanks for any thoughts,
>
> Charlie
>
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| Subject: | Re: Grounding radio antenna and transponder antenna |
At 10:57 PM 9/17/2019, you wrote:
>If the copper tape isn't soldered or otherwise
>electrically bonded to the rest of the metal
>ground plane (panel), then it's not doing
>anything productive. You could get what you were
>hoping for by using strips of aluminum; even
>something really thin like strips cut from
>aluminum flashing material. They could be
>riveted on one end to the aluminum doubler shown
>in the pics, and glued with clear 'sensor safe'
>rtv to the plexi, and screwed at the other=C2 end
>using the plexi mounting screws.=C2
>
>Having said that, the antenna still won't be
>centered in the ground plane. You could add
>strips going the other direction using similar
>techniques. The 'ideal' ground plane extends out
>from the base as far as the antenna height. As
>few as 4 equally spaced radial arms can get the job done pretty
effectively.=C2
Actually, there's a relatively simple experiment
that can be conducted. 4 radials ~1" wide, extending
from the antenna base and simply taped to the outside
surface of the a/c will emulate an excellent ground
plane. It does not need to be electrically bonded to
the airframe. Where it is in close proximity to the
airframe, there will be significant electro-static
coupling to the airframe. I'd make them 24" long or
so. Length not critical when so closely coupled to
the a/c skin. Here's a tape suited to the task of
temporary attachment to the airplane.
https://tinyurl.com/y3wrc7kx
I've used this stuff to run ribbon cable through
the baggage door seal, down the side of the fuselage
and past the entry door seal to bring investigatory
signals from the hell-hole of a Beechjet into the
cabin.
This tape would work fine for the experimental ground
plane installation as well.
>
>
>Having said *that*, are you sure your problems
>are purely transmission range? Tube/rag a/c are
>notoriously noisy in the cockpit. You may have
>as much a problem with *audio* signal to noise
>ratio as with transmission distance. Ability to
>accurately describe comm deficiencies is pretty
>rare, even for controllers. If you think that
>could be a possibility, we can expand on that.=C2
Excellent point! There was a list-thread on
this very topic way back when . Turns out
that transmission intelligibility was
completely dependent on the noise cancelling
quality of microphone . . . I'm embarrassed
for not to have recalled this.
Before hammering on the antenna installation,
do try another mic/headset combination. They
are not all the same . . . particularly
with respect to cancelling low frequency
'buffeting' kinds of noise common to airplanes
where creature comfort is rather far down on the
list of design priorities.
Is it just your transmitted signal that's
deficient . . . or both transmit and receive?
This brings up the point that few users
of two-way radios have the experience and vocabulary
to describe poor signal quality. For example,
you can have a strong radio frequency signal
that is dead quiet when not talking but the
audio is weak/distorted. This is ALWAYS an
audio/microphone problem. You can have
a marginal radio frequency signal (just
beginning to present 'popcorn' noises
when not talking and uncharacteristically
poor audio when adding voice modulation.
Then there's the truly weak-signal which
can be a combination of radio/coax/antenna
issued. Years ago, I asked a reader to
send me a recording of his received signal
as heard on the ground . . . his problem
turned out to be in the audio system causing
a badly under-modulated transmitter.
Charlie's memory jog suggests an
important avenue of investigation
that supercedes fiddling with the antenna.
Bob . . .
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| Subject: | Re: Grounding radio antenna and transponder antenna |
At 10:25 AM 9/18/2019, you wrote:
>
>That copper tape does not do much good because it all goes in one
>direction. And it is questionable if it is making good contact with
>the antenna mounting plate.
>Here is a suggestion: Cut 4 pieces of coax each 22 or 23 inches
>long. Attach a ring terminal to the shield of each coax (not the
>center conductor). Connect one length of coax to each of the 4
>antenna mounting screws using the ring terminals. When the panel is
>mounted to the aircraft, arrange the coax ground plane so that it
>extends outward in 4 different directions. Elastic cord attached to
>the coax ends could help to position it.
>This experiment is worth a try and will not cost much except your time.
That would work too . . . the same tape could
be used to hold it against the skin.
Bob . . .
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| Subject: | Re: Grounding radio antenna and transponder antenna |
Thanks to All for the interesting comments and suggestions.
In this post I would like to address the comments of Charlie on noise in the cockpit.
I need a little more time to write a second post on the antenna solutions
that have been proposed for testing (coax and external copper foil). I may
have a couple of questions.
Yes, the problem is not just range. It is also noise. ATC says that my transmissions
are weak and with a lot of static noise, but still acceptable. As I
wrote in an earlier post, that is not the case if I go to Class B or C airspace
and I need to call from far out.
My impression is that I receive better than I transmit. The noise level in the
cockpit is very high and when I press the push-to-talk button, the static noise
that I hear in the sidetone is louder than my voice.
I use what is considered a very good noise canceling microphone that I periodically
replace. My understanding is that the noise wears out the microphone. I
have also flown with a Bose headset; transmissions were better, but only marginally.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=491384#491384
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