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pa3arw(at)euronet.nl
Guest

Posted: Fri Jul 03, 2009 5:03 am Post subject: Interference Becker 4201 radio

Mark,



I finally made the time available to do the tests/modifications we have

talked about with respect to the interference on a Becker VHF radio in my

Yak52.



I installed the Lonestar P-lead filters on both mags. Found that both

screens of the p-leads are in perfect condition but installed the filters ,

just to make sure.

The screening can now be called perfect. I have made a special copper "plug"

to fill up for the thinner wires on the filters. The screens of the filter

wires have been soldered to those "plugs" and locked in the mags.

Everything has been fixed thoroughly and inspected for grounding.

All OK so far. Started the engine and found no difference on the VHF, i.e.

the interference is still there. That means: the squelch is opened by the

interference. Switching off the squelch it appears that there is no constant

noise level but more of a kind of rattling noise which opens the squelch.

Checked antenna...found no problem or loose wires. Swr is within the airband

1 : 1.5 max.



So in my humble opinion there is only 1 thing left: the interference is

going into the vhf via the power supply or the power is that "dirty" that it

is picked up by the vhf antenna.....



I know that the Becker gets its power via a dc-dc converter of some sort,

after all the Yak has 24v standard power. Is the 12 volts present on any

standard Yak or is there a built in down converter somewhere??

What is the "voltage adjustment" screw meant for in the front cockpit??



Did some tests with the GPS also. When the GPS is connected to the power

plug and switched on, the noise level on the VHF opens the squelch which

makes it unuseable in flight.

Switched off gps: noise is reduced but squelch is still opened 6 out of 10

sec. Disconnected power supply lead from GPS but kept it connected to the

plane, same result as GPS being switched off, i.e. the VHF is picking up

interference via its antenna but the noise is generated one way or the other

on the power bus??



I have come to a point of saturation in my mind about the cause of this.

Taking a scope into the cockpit is probably the only way to find out whether

there is any noise on the power bus.

Probably another way is to power the VHF via the cigarette ligher connector

with another dc-dc converter. Thus bypassing the present circuitry but still

using the power on board.



Any suggestions, thoughts are welcomed!



Hans

RA3326K

Mob: +31 653 286022

viperdoc(at)mindspring.co
Guest

Posted: Fri Jul 03, 2009 5:49 am Post subject: Interference Becker 4201 radio

Hans,

I also added a filter in line with the power supply from my converter to the

Becker radio. It to came from Lone Star Avionics.

http://www.lonestaraviation.com/product_details.asp?Product_Name=The

Eliminator. With the mag filters and the DC filter in line, the noise has

been pretty much eliminated.

The other place to check in your Tack generator shielding.

Doc



--

pa3arw(at)euronet.nl
Guest

Posted: Fri Jul 03, 2009 6:24 am Post subject: Interference Becker 4201 radio

Doc,



Yeah...I do have the in line filter as well as the capacitor for the

generator but did not install it yet. Have not found a place to install it

safely. I need to do that. I assume you installed it close to the busbar in

the area of the switches on the left side of the plane and then with a

shielded wire to the VHF??



What I don't understand though is why the Becker radio is so sensitive for

noise on the dc supply??



Hans



-----Oorspronkelijk bericht-----

Van: owner-yak-list-server(at)matronics.com

[mailto:owner-yak-list-server(at)matronics.com] Namens Roger Kemp M.D.

Verzonden: vrijdag 3 juli 2009 15:45

Aan: yak-list(at)matronics.com

Onderwerp: RE: Interference Becker 4201 radio




--> <viperdoc(at)mindspring.com>



Hans,

I also added a filter in line with the power supply from my converter to the

Becker radio. It to came from Lone Star Avionics.

http://www.lonestaraviation.com/product_details.asp?Product_Name=The

Eliminator. With the mag filters and the DC filter in line, the noise has

been pretty much eliminated.

The other place to check in your Tack generator shielding.

Doc



--

ChangDriver

Joined: 15 Sep 2007
Posts: 266

Posted: Sun Jul 05, 2009 4:07 pm Post subject: Re: Interference Becker 4201 radio

I too have a Becker in my CJ that is stone quite on the ground (at idle) and unusable in flight due to noise.  The Garmin SL-30 in the plane functions perfectly.  My Becker is fed by a King KR-22 24 to 12 VDC converter and I have converted from the stock generator to the B&C alternator.



 I have yet to make some tests to determine where the noise is coming from (power or antenna).  I will get to that in a week or so (other problems to solve first), hence, I am very interested in this discussion.



I wonder if the Becker was originally designed for gliders so there is no filtration on the power as it would be operating off a battery.  This could be one reason why this radio seems to be line noise sensitive.   I am also going to try and call Becker USA to inquire.



Craig W.

jan.mevis(at)informavia.b
Guest

Posted: Mon Jul 06, 2009 12:44 am Post subject: Interference Becker 4201 radio

I have a Becker 4201 radio in my Yak 50 (with  B&C alternator). The radio

works perfectly well, but I've also changed the audio wiring completely.

I've used RG400 antenna cable and have a Comant antenna instead of the

original Russian antenna (and a Dave Clark headset). 



IMHO, but I'm not an electronics expert, if you use western radio's, then

better change it ALL to avoid impedance problems etc. 



Before I had the American ignition wiring harness (Dennis' set) on my M14P

and I had more noise on my Russian BRIZ radio. That's why I installed the

Becker, and all the noise problems were solved. Since a year I have a new

engine, and did not change the wiring harness yet. So that is still the

original Russian. And the Becker 4201 still works very fine. So I'm inclined

to think that in my case the problem was cable-related.



Jan

YK50 RA2005K 



--

mark.bitterlich(at)navy.m
Guest

Posted: Mon Jul 06, 2009 10:34 am Post subject: Interference Becker 4201 radio

Lot's to talk about after reading your message.    



1.  Disconnect the antenna from the radio and see if the noise goes

away.  This test will tell us one heck of a lot.  Remove antenna at the

radio and turn squelch off and listen. 



2.  The voltage adjusting screw adjusts the bias voltage going to the

voltage regulator which controls the generator output voltage.  In other

words, it adjusts 28 vdc out of the generator.  It is a SMALL range of

adjustment.  BIG adjustments are made at the carbon pile regulator

itself.  



This statement is very perplexing: 



" When the GPS is connected to the power plug and switched on, the noise

level on the VHF opens the squelch which makes it unuseable in flight.



Switched off gps: noise is reduced but squelch is still opened 6 out of

10 sec. 



Disconnected power supply lead from GPS but kept it connected to the

plane, same result as GPS being switched off, i.e. the VHF is picking up

interference via its antenna but the noise is generated one way or the

other on the power bus??" 



First, just to be absolutely sure, remove the antenna coax at the radio

and run your GPS noise tests again.  



Next, make sure you test Dennis Savarese's idea about where the 12 volts

is coming from.  Is it coming from a DC to DC converter, or has some one

tapped one of two 12 volt batteries in series?  



Moving on:   



So you are saying... And please confirm this.... That when you hook the

GPS wiring to the aircraft, with the GPS completely removed and not

connected and NOT turned on or running by battery power, that merely

ADDING THE GPS WIRING ITSELF increases the noise to your radio?   And

there is NOTHING in that GPS cable at all other than some WIRE?  No

active elements like a little module or something like that?  Just some

WIRE?  Disconnecting the antenna makes this goes away, get less, stay

the same?  Squelch off.  



Where is your GPS power cable tapped into the aircraft wiring?  Is it

tapped to the same wiring the radio is using?  By that I mean, you have

12 volts going to the radio by some method or another... Have you tapped

that same 12 volts to power the GPS, or is it coming from a 28 volt wire

connected somewhere else in the aircraft?  



If you are 100% absolutely certain about that all this, as in.. It is

connected to the 12 volt source, it has no modules in it at all, it is

just a piece of wire.... If that is absolutely without a doubt what is

happening... Then there is simply no question that an external noise

source is COUPLING into the GPS wiring and then being fed into the

Becker via the power supply input wiring.  Period.  No other

possibility.  (again, the antenna checks withstanding) 



Based on that premise, I would then get a little 12 volt sealed battery.

Use it to power the radio.  Remove the aircraft as the power source.

Gell cell or something.  It can be very very small since we are not

going to transmit, and receive current draw is less than 100 mills or

so.  That's a guess, but it has to be pretty darn low.  The noise to the

radio should either go away, or change dramatically.  



Thinking out loud, it then appears to be the case that the Becker has

some design issues regarding rejection of external noise on the power

source wiring.  We then have a few ways to approach this. 



1. Replace the radio.  Yeah, I know that idea is less than good, but you

have to at least mention it. 

2. Reduce the noise sources that are getting into the wiring.  That is

not going to be very easy.  You've already done pretty close to all that

can be done.  



3.  Best solution.  Use a TON of filtering on the input wiring to the

radio.  This filtering method has to be as close to the radio as

possible for obvious reasons.  This is probably going to have to be a

multi-layered approach, because we really do not have any hard ideas on

what the noise source frequency range is.   Of course, you have to know

right up front that EVERY SINGLE WIRE that goes to the Becker is going

to have to be shielded.  I mean every single one.  ANY wire that allows

noise to ride up and into the radio has to be considered.  



Most importantly, the power wiring needs to be shielded.  



You will need to make some kind of mount close to the radio and start

adding whatever filters you want to try.  I would try several approaches

just for the heck of it...  First would be a big cap, very close to the

radio, attached to 12 volts and ground.  22,000 mmf or so, at 50 volts.

You can start smaller and just see if it helps.  Even 5000 mmf should

tell you if it helps at all.  Torroidal chokes....   Commercial

through-line filters.  Etc.  



This is a tough problem.  I'm still thinking. 



On the other hand, if all this just stops dead when you disconnect the

antenna, the direction of attack changes dramatically.  



Mark Bitterlich 



P.s.  I don't think I'll buy a Becker.  



--

ChangDriver

Joined: 15 Sep 2007
Posts: 266

Posted: Mon Jul 06, 2009 11:55 am Post subject: Re: Interference Becker 4201 radio

I contacted Becker USA today at lunch and spoke with a tech for about 30 minutes on my noise issue.  Two things he mentioned to me.  First, the radio is TSOed so it was required to meet FAA specs.  many of the other small radios are not TSOed so the Becker seems to be the better choice from an environmental standpoint.  Second, the radio was indeed designed for gliders first.  Then modified for the FAA TSO requirements.



The tech is perplexed because my Garmin SL-30 has not one bit of noise and the power for the Becker is coming from a King KA-39 downconverter and this is the only thing on the converter.   The antenna for the SL30 and the Becker were swapped and the noise persisted.  His thought is that the RF section of the Becker is too sensitive and that it is picking up engine noise on the antenna.  He said the Becker is set up so that you can hear ATC from about 100 miles away (hence very sensitive).  He has asked me to remove the radio and send it back to them for RF interference testing.



Craig

mark.bitterlich(at)navy.m
Guest

Posted: Tue Jul 07, 2009 9:54 am Post subject: Interference Becker 4201 radio

Craig, 



I ran into this noise problem first with a Becker installed in a SU-26.

Then an SU-31.  Since then, at least two others.  There seems to be a

pattern developing here.  



Anyway, we are now moving into an area that I am qualified to talk

about.  



I do not agree with what the Becker "Tech" told you.  Of course, to be

honest, does anyone really expect a representative from any company that

makes a product to come right out and say: "Yeah, well we really screwed

up the design on that radio, don't buy it".  Umm.. Not likely.  In all

other respects it seems to be a great radio... It just seems to be very

susceptible to noise from on-board sources that normally do not effect

other radios in the same frequency range.    



TSO means Technical Standard Order, and while there are more than one,

the typical one used for radios of this type is: TSO-C169a. You can also

look at TSO-C37/38 series.  The 37/38 series is older and I am pretty

certain that is what it meets.  Let me check... Yep.. That is what it

meets.



In order to meet these Technical Standard Orders, certain "things" of

the radio must be checked.  No need for me to list every one of them

here as it would get very boring very quickly. 



That said... Guess what?  Resistance to noise coming in from the power

wiring is not checked at all and is not part of the TSO in any way.

"FAA Specs" do not in any way call for testing to determine any immunity

to noise coming in on the power wires.  Also, they do not test for noise

immunity in any way really.... Even coming in from the antenna.  They do

check for selectivity, sensitivity, power output, and a whole bunch of

other stuff, but not what we are talking about here.  Not really.  



Saying that the RF receive section of the radio is "too sensitive" is

horse manure.  These radios are designed to have the very best

sensitivity possible.  There is no such thing as "too much" per se.  The

receivers on these radios ARE tested IAW the TSO and they are checked

for being on freq. and from adjacent channel interference as well as

sensitivity.  Please note, in aircraft receiver testing, there is no

such thing as "too much sensitivity".  Radios on the bench are ALWAYS

tuned for best sensitivity.  Becker's spec on this radio is: 1.5 uV for

6 d (S+N)/N   This is pretty darn good.  Not freaking amazing mind you,

but pretty good.  Real old radios were about 2.5 uV, and anything under

2.0 uV is pretty much normal for modern radios.  Under the TSO, these

radios are normally only tested to be audible with 24 uv at 30%

modulation.  



Make no mistake though.... DE-TUNING a radio to make it LESS sensitive

will indeed help you to get rid of noise of this type.  So will turning

it off.  DE-TUNING is in fact turning the receiver OFF... Just a little

bit at a time.  



If you want to check out what the tech said yourself, it is pretty darn

easy.  All you need is a good signal generator with a step attenuator

built in.  Simply connect the sig-gen to the antenna connector and turn

the squelch on the radio off.  Put both on the same freq.  Set for AM

modulation with a 1 Khz tone modulated at 80%.  Turn the sig-gen output

down until you can just barely hear the tone in your headset.  Record

the reading.  Now do the same thing again with your other radio...

Record THAT reading.  Compare which receiver is more sensitive and by

how much.  If you connect right at the radio, the readings will probably

be within 1 or 2 dB of each other.  Any radio repair shop can do this

for you .. And it should not cost very much.  It will only take about 10

minutes.  If you have even a WHIFF of suspicion that the KA-39 might be

causing noise, just replace it with a little lantern battery for a few

minutes.  The radio in receive mode only draw around 70-100 mills, or

say about 1/10th of an amp.  Not much.  See if your noise goes away.  It

would be a very interesting test to hear about really.  



Bottom line, I could honestly talk for hours about how noise like this

can get into a radio.  The first test is ALWAYS to remove the antenna

completely and see if the noise goes away completely.  If it does, then

it obviously is noise that is getting into the radio via the antenna or

coax.  The approach to fixing the problem ALWAYS starts with knowing the

answer to that question first. 



If it is indeed noise that is getting into the radio from the antenna,

then it does not always have to be noise that is RECEIVED in the normal

fashion.  It can be noise that is getting by the front end first

bandpass filter by cross coupling between stages for example.  This

comes down to DESIGN.  Not something being "too good for your airplane",

like "too much sensitivity".  If the SL30 had just SOME noise... Even

just a little... And the Becker had MORE noise.... I would not be so

sure about this.  But, you have stated that the SL30 is dead quiet.

This goes along with what I have seen too.  



But again.... if the SL30 has NONE... I mean NONE AT ALL (and the SL30

is a darn good radio) and the Becker is overwhelmed with noise, AND it

is for sure coming in the antenna, AND you have swapped antennas.... It

comes down to the Beckers design and is next to impossible to cure,

unless you try very hard to eliminate the noise at it's source.  That

then becomes a matter of tracing the noise down to the source, and then

taking steps that hopefully will keep it from radiating. This can be a

royal pain in the tail. But it can be done.  If your noise is coming in

from the antenna, that is pretty much what you are left with.  



Nothing wrong with sending the radio back though. 



Note:  At 13,000 feet, I can talk to ATC 100 miles away with the stock

Russian radios.  I talk to New Bern tower from Norfolk all the time.

The most important things to get range out of ANY radio is short coax,

good coax, good antenna, and lots of altitude.  



Mark Bitterlich

   



  



--

viperdoc(at)mindspring.co
Guest

Posted: Wed Jul 08, 2009 5:53 am Post subject: Interference Becker 4201 radio

Han's,

This is a problem that I have with my 50. There are three connections on the

filter. One goes to ground, one to the DC power supply and the other to the

power supply in line to the Becker Radio. I simply inserted the filter into

the power supply line from the DC converter to the radio. I have my Buss Bar

wired so the com switch takes 24 volt current to the DC converter first with

obviously the outline from the converter carrying 12 volt current to the

Becker. 

Agree, do not know why the Becker is so sensitive to RF noise. I even

changed out the radio for another Becker I had on the shelf. They both did

the same thing. The filters have helped immensely.

Doc



--

pa3arw(at)euronet.nl
Guest

Posted: Wed Jul 08, 2009 6:14 am Post subject: Interference Becker 4201 radio

Doc,



I'm going to try to install the in line filter during the coming weekend. I

wanna have this solved. In the meantime, thanks to Dennis, I found that the

Becker 12v is connected directly to the series connection wire of the 12v

batteries, i.e. there is no DC-DC converter used and this means that the

"dirty" power from the generator will go unfiltered in to the Becker.

I did some measurements here at my company and found the Becker to be a poor

performer from an RF point of view, but there is nothing I can do about that

then buy myself another one from a different brand that is.... 

However, before I get to that point I'll try a real dc-dc converter in

combination with the Lonestar in-line filter.



I'll keep you guys posted on the progress.



Hans Oortman, MBA, Ph.D.

CEO

STN BV



-----Oorspronkelijk bericht-----

Van: owner-yak-list-server(at)matronics.com

[mailto:owner-yak-list-server(at)matronics.com] Namens Roger Kemp M.D.

Verzonden: woensdag 8 juli 2009 15:46

Aan: yak-list(at)matronics.com

Onderwerp: RE: Interference Becker 4201 radio






Han's,

This is a problem that I have with my 50. There are three connections on the

filter. One goes to ground, one to the DC power supply and the other to the

power supply in line to the Becker Radio. I simply inserted the filter into

the power supply line from the DC converter to the radio. I have my Buss Bar

wired so the com switch takes 24 volt current to the DC converter first with

obviously the outline from the converter carrying 12 volt current to the

Becker. 

Agree, do not know why the Becker is so sensitive to RF noise. I even

changed out the radio for another Becker I had on the shelf. They both did

the same thing. The filters have helped immensely.

Doc



--

viperdoc(at)mindspring.co
Guest

Posted: Wed Jul 08, 2009 9:56 am Post subject: Interference Becker 4201 radio

Hans,

Thanks and good luck.

Doc



--

mark.bitterlich(at)navy.m
Guest

Posted: Wed Jul 08, 2009 11:20 am Post subject: Interference Becker 4201 radio

It seems there are two different things going on here.  I get the idea

from Craig that he is saying it is coming in from the antenna coax. 



I get the readback from you Doc, that it is clearly coming in on the DC

supply line.  If it is coming in from the DC supply line, the fix is

easy and very do-able.  If it is coming in from the antenna, it gets

much more complex.  



Which one is it?  



Antenna noise? 



Power input noise? 



Both?  



Mark Bitterlich



P.s.  Hans, CLEARLY filter the DC input.  Fact is, it worked for Doc,

and that can not be refuted.  

 



--

mark.bitterlich(at)navy.m
Guest

Posted: Wed Jul 08, 2009 11:34 am Post subject: Interference Becker 4201 radio

Just a note to Hans and anyone else.  



What Hans found (thanks to Dennis for remembering to check for it) is a

12 volt radio connected in-between two 12 volt batteries connected in

series to provide 24 volts.  



Actually Hans, doing it that way does allow the battery to act as a

fairly good filter (of sorts) to generator noise, and it still does not

explain in any way why connecting your GPS cable did what it did.  That

little phenomenon is another strong bit of evidence that the Becker

noise is all coming in from the DC power line and not the antenna.  



That aside, hooking any 12 volt accessory up like this is very do-able,

and will work just fine, for awhile.  



What eventually happens is that you end up putting more load on one

battery than the other one as they are operated.  Eventually, the one

battery won't charge quite as perfectly as it should.  This can be very

hard to detect, because your cockpit meter is looking at BOTH of them

and not just the one that is powering your radio, or whatever else.

Eventually, the batteries start to charge unevenly, and the voltage on

the one supplying the 12 volts starts to fail faster than the other one.

The end result is unpredictable voltage to the "12 volt device(s)".

This can damage them.  Not right away.  It takes awhile.   



Another thing that can happen is that as you put on a heavy 28 volt

load, the voltage in the middle of the 2 batteries goes even more off,

again giving the potential for voltages being present that you would

never use intentionally, and that you know very little about.  



If you change the batteries regularly, you can get away with this

approach, but it really is a bad design choice.  



As Hans has noted, the best choice is to use a DC to DC converter, that

runs off of 28 volts, and steps down to 12 volts.  It also then is a

good idea to put a line filter and a good sized cap on the output line

for further filtering.  Then put a switch on the INPUT to this DC to DC

converter to allow it to be turned OFF when you want it to be.  Or have

it wired to a circuit breaker.. Whatever.  



Mark Bitterlich





--

jan.mevis(at)informavia.b
Guest

Posted: Wed Jul 08, 2009 11:49 am Post subject: Interference Becker 4201 radio

I have a DC-DC- convertor on the battery, and NO filter on the 12 volts line

to the radio. The Becker 4201 on my Yak 50 works perfectly well.

Perhaps one major difference: I have a B&C alternator and thus electric

voltage regulator ? Is it possible that this generates far less noise than

the Russian generator and Russian voltage regulator ?



Jan

YK50

RA2005K



--

mark.bitterlich(at)navy.m
Guest

Posted: Wed Jul 08, 2009 12:21 pm Post subject: Interference Becker 4201 radio

Jan, it is very likely with that model that you have installed a big

filter capacitor with the system.  Big Blue thing.  Usually comes with

the over-voltage protection kit for the small B&C.  Do you have the 10

amp PMG model, or the 35 amp with a field wire?  



Don't limit it to just the generator versus alternator Jan.  No one has

yet determined the exact source for all this noise that everyone is

reporting.  Doc has installed filters that help, but that does not

really identify what is causing it.  It may help in determining how it

is getting INTO the radio.  Craig seems to indicate it is coming in the

antenna.  Doc seems to indicate it is coming in via the power wiring.

No one really knows what is making the noise to begin with. 



Consider yourself lucky. 



Mark Bitterlich



P.s.  Install the digital tach using the P lead connections and see what

happens.   



--

viperdoc(at)mindspring.co
Guest

Posted: Wed Jul 08, 2009 1:51 pm Post subject: Interference Becker 4201 radio

Mark,

Mine was power input noise. Changing the antenna coax did nothing for it.

Doc



--

dsavarese0812(at)bellsout
Guest

Posted: Wed Jul 08, 2009 2:32 pm Post subject: Interference Becker 4201 radio

I believe Doc's solution was a combination of the DC power  line filter AND the P-lead filters.  If I remember correctly, first  the DC filter was installed which reduced the noise level substantially.   Then the P-lead filters were installed and with the combination of both types of  filters, the noise has been basically eliminated.

 Dennis

 [quote]   ---

nc69666(at)aol.com
Guest

Posted: Wed Jul 08, 2009 9:57 pm Post subject: Interference Becker 4201 radio

Guys, I have a inexpensive and very reliable solution to you clean 12 Volts power needs. About 13 years ago when I wanted 12 Volts in my CJ I went to the local Ham Radio Store, and purchased a DC power converter, it is manufactured by Astron, it converts 24V to 12V, 20 amps output, extremely reliable and very highly filtered, I have never had any noise or interference in my 12 V electrical supply, radios are happy as can be, it gives you all the 12 V you should ever need.  The cost at that time was about $85.00..  Very simple solution..  Best of Luck.



Gary Gabbard



Las Vegas, NV



CJ, N22YK





--

jan.mevis(at)informavia.b
Guest

Posted: Wed Jul 08, 2009 11:12 pm Post subject: Interference Becker 4201 radio

That's correct, Mark! It's the small 10 amp model, and I have a big

electrolytic capacitor behind the rectifier/regulator.



Jan



--

pa3arw(at)euronet.nl
Guest

Posted: Wed Jul 08, 2009 11:13 pm Post subject: Interference Becker 4201 radio

Guys,

  

 This is what I did: I purchased a good DC-DC converter and  will install that in the next few days. In addition to the converter I'll  install the Lonestar Eliminator power line filter in line with the output from  the converter. This combination should eliminate any noise on the dc line to the  4201. 

  

 Just out of  technical curiosity I checked the Lonestar filter on a HP Network Analyzer and  found that the Eliminator is basically a High Pass Filter. (See attached plot)  

 Any frequency below 3.5 Mhz is cut off with at least 40dB.  This means that any ingition noise is cut off very well. It also means that it  will "stop" the 60KHz oscillation frequency of my DC-DC converter reaching  the Becker radio. Technically it should work...now I'll install it and w'll see  what happens....

  

 I'll keep you all posted!.

  

 Hans 

 RA3326K



   Van: owner-yak-list-server(at)matronics.com  [mailto:owner-yak-list-server(at)matronics.com] Namens A. Dennis  Savarese

Verzonden: donderdag 9 juli 2009 0:28

Aan:  yak-list(at)matronics.com

Onderwerp: Re: Interference Becker  4201 radio

 

 I believe Doc's solution was a combination of the DC power  line filter AND the P-lead filters.  If I remember correctly, first  the DC filter was installed which reduced the noise level substantially.   Then the P-lead filters were installed and with the combination of both types of  filters, the noise has been basically eliminated.

 Dennis

 [quote]   ---

Plot_Lonestar_Eliminator.bmp

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