Changing direction - ignition noise intractable #bitx40


Robert D. Bowers
 

I've given up on trying to use my Bitx40 as mobile.  Nothing I've done eradicates the ignition noise (and the alternator whine came back).  I've gone with direct power from the battery, extra grounding on the 'doghouse' of my van, plus extra grounding on the antenna base and vehicle frame.  I've tried filtering on the power, then multiple layers of filtering - then even a separate battery entirely (no connections to van).  I added chokes to the outside of the coax... trying to stop that as a source of entry.  I did find that the original grounding scheme for the doghouse (internal cover to the motor on a van - in my case a 90's GMC) was seriously insufficient and improving that reduced the ignition noise by probably 30db or so... but it's still way too loud to use the radio.  I even took the coax out of the van and ran it over to a table, where I had the radio.  As soon as the coax fitting touched the antenna connector, ignition noise.  (You could even faintly hear it with a piece of wire stuck in the antenna connector.)  At the same time, using an old TS-520 on my fan dipole, I could not hear the slightest bit of ignition noise, with the van parked only about 30-40 feet from the 40m portion of the antenna.  I could hear the contest, however.
                                                     
I'm really tickled with my BitX40... it's very sensitive and works pretty well (I haven't tried making contacts with it - yet, but the rx is good and filtering seems more than adequate).  What I did with it was put it in an old metal case (like a toolbox in a way), with battery, coax, and external noise filter/AGC.  It's pretty slick there - a complete portable kit in a box, as long as I have an external antenna along (a dipole would probably fight right in).    Someday I may try to shield the case that the radio came with... that might (or might not) be the problem.

I had to pull my 'good' radio (Alinco DX-70) from my shack for repairs, so I'm going to put it in place of the BitX40 in the van... it has a rock-crusher noise blanker and good filtering - once I get it back in operating condition. It should help a lot in solving the noise problem - maybe eliminate it. 

A couple of tips from this... first, the radio is awesome, but very sensitive to impulse-type noise.   The more barriers you can throw up between the noise source and the radio, the better!  That means chokes in the power line, filter caps, and so on - and if possible, shielded wires!  If I had the equipment (broadband spectrum analyzer), I'd characterize the noise - it may actually getting in somehow via a path besides the antenna and knowing the spectrum could give a clue as to how it gets in.  (I don't have a good bandpass filter right now, that might also be a trick to try.)

Second, if you're trying to go mobile, grounding grounding grounding!!!  While my best attempt (I don't have lots of time to throw at the radio) wasn't good enough, it might be good enough in another situation.  Ground everything you can... and don't just trust to bolted-together sheet metal (frame).  Also, usually drawing the power from a very low impedance source (direct to the battery) with good shielding and filters is the usual fix to the sort of noise I'm getting.  In this case, it wasn't enough.

So now I have an awesome portable (emergency) HF station, that works good - I just can't use it mobile in our van.  (Third tip: if it doesn't do what you'd like, find a use where it does!)


MadRadioModder
 

Have you tried it in a different vehicle…?

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 7:07 PM
To: BITX20@groups.io
Subject: [BITX20] Changing direction - ignition noise intractable #bitx40

 

I've given up on trying to use my Bitx40 as mobile.  Nothing I've done eradicates the ignition noise (and the alternator whine came back).  I've gone with direct power from the battery, extra grounding on the 'doghouse' of my van, plus extra grounding on the antenna base and vehicle frame.  I've tried filtering on the power, then multiple layers of filtering - then even a separate battery entirely (no connections to van).  I added chokes to the outside of the coax... trying to stop that as a source of entry.  I did find that the original grounding scheme for the doghouse (internal cover to the motor on a van - in my case a 90's GMC) was seriously insufficient and improving that reduced the ignition noise by probably 30db or so... but it's still way too loud to use the radio.  I even took the coax out of the van and ran it over to a table, where I had the radio.  As soon as the coax fitting touched the antenna connector, ignition noise.  (You could even faintly hear it with a piece of wire stuck in the antenna connector.)  At the same time, using an old TS-520 on my fan dipole, I could not hear the slightest bit of ignition noise, with the van parked only about 30-40 feet from the 40m portion of the antenna.  I could hear the contest, however.
                                                     
I'm really tickled with my BitX40... it's very sensitive and works pretty well (I haven't tried making contacts with it - yet, but the rx is good and filtering seems more than adequate).  What I did with it was put it in an old metal case (like a toolbox in a way), with battery, coax, and external noise filter/AGC.  It's pretty slick there - a complete portable kit in a box, as long as I have an external antenna along (a dipole would probably fight right in).    Someday I may try to shield the case that the radio came with... that might (or might not) be the problem.

I had to pull my 'good' radio (Alinco DX-70) from my shack for repairs, so I'm going to put it in place of the BitX40 in the van... it has a rock-crusher noise blanker and good filtering - once I get it back in operating condition. It should help a lot in solving the noise problem - maybe eliminate it. 

A couple of tips from this... first, the radio is awesome, but very sensitive to impulse-type noise.   The more barriers you can throw up between the noise source and the radio, the better!  That means chokes in the power line, filter caps, and so on - and if possible, shielded wires!  If I had the equipment (broadband spectrum analyzer), I'd characterize the noise - it may actually getting in somehow via a path besides the antenna and knowing the spectrum could give a clue as to how it gets in.  (I don't have a good bandpass filter right now, that might also be a trick to try.)

Second, if you're trying to go mobile, grounding grounding grounding!!!  While my best attempt (I don't have lots of time to throw at the radio) wasn't good enough, it might be good enough in another situation.  Ground everything you can... and don't just trust to bolted-together sheet metal (frame).  Also, usually drawing the power from a very low impedance source (direct to the battery) with good shielding and filters is the usual fix to the sort of noise I'm getting.  In this case, it wasn't enough.

So now I have an awesome portable (emergency) HF station, that works good - I just can't use it mobile in our van.  (Third tip: if it doesn't do what you'd like, find a use where it does!)


Virus-free. www.avg.com

--

…_. _._


Mike Short <ai4ns.mike.spam@...>
 

Did you go to k0bg.com and do the bonding he recommended?
what case is your radio in? 
Is everything inside the radio grounded to a common ground? (Power, antenna, board, raduino, mic and key jacks, etc.)
his site has a section on ignition noise, spark plug wires, etc.
how is your antenna mounted?
do you have a common mode choke using the ferrite material and number of turns of coax through it?
where is this choke located?

mike


Mike Short <ai4ns.mike.spam@...>
 

Shielded cables are not the answer either.


Robert D. Bowers
 

No.  Our other car is too small.  There really isn't even room for a 2m in it - except maybe a ht.

On 3/31/19 8:14 PM, MadRadioModder wrote:

Have you tried it in a different vehicle…?

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 7:07 PM
To: BITX20@groups.io
Subject: [BITX20] Changing direction - ignition noise intractable #bitx40

 

I've given up on trying to use my Bitx40 as mobile.  Nothing I've done eradicates the ignition noise (and the alternator whine came back).  I've gone with direct power from the battery, extra grounding on the 'doghouse' of my van, plus extra grounding on the antenna base and vehicle frame.  I've tried filtering on the power, then multiple layers of filtering - then even a separate battery entirely (no connections to van).  I added chokes to the outside of the coax... trying to stop that as a source of entry.  I did find that the original grounding scheme for the doghouse (internal cover to the motor on a van - in my case a 90's GMC) was seriously insufficient and improving that reduced the ignition noise by probably 30db or so... but it's still way too loud to use the radio.  I even took the coax out of the van and ran it over to a table, where I had the radio.  As soon as the coax fitting touched the antenna connector, ignition noise.  (You could even faintly hear it with a piece of wire stuck in the antenna connector.)  At the same time, using an old TS-520 on my fan dipole, I could not hear the slightest bit of ignition noise, with the van parked only about 30-40 feet from the 40m portion of the antenna.  I could hear the contest, however.
                                                     
I'm really tickled with my BitX40... it's very sensitive and works pretty well (I haven't tried making contacts with it - yet, but the rx is good and filtering seems more than adequate).  What I did with it was put it in an old metal case (like a toolbox in a way), with battery, coax, and external noise filter/AGC.  It's pretty slick there - a complete portable kit in a box, as long as I have an external antenna along (a dipole would probably fight right in).    Someday I may try to shield the case that the radio came with... that might (or might not) be the problem.

I had to pull my 'good' radio (Alinco DX-70) from my shack for repairs, so I'm going to put it in place of the BitX40 in the van... it has a rock-crusher noise blanker and good filtering - once I get it back in operating condition. It should help a lot in solving the noise problem - maybe eliminate it. 

A couple of tips from this... first, the radio is awesome, but very sensitive to impulse-type noise.   The more barriers you can throw up between the noise source and the radio, the better!  That means chokes in the power line, filter caps, and so on - and if possible, shielded wires!  If I had the equipment (broadband spectrum analyzer), I'd characterize the noise - it may actually getting in somehow via a path besides the antenna and knowing the spectrum could give a clue as to how it gets in.  (I don't have a good bandpass filter right now, that might also be a trick to try.)

Second, if you're trying to go mobile, grounding grounding grounding!!!  While my best attempt (I don't have lots of time to throw at the radio) wasn't good enough, it might be good enough in another situation.  Ground everything you can... and don't just trust to bolted-together sheet metal (frame).  Also, usually drawing the power from a very low impedance source (direct to the battery) with good shielding and filters is the usual fix to the sort of noise I'm getting.  In this case, it wasn't enough.

So now I have an awesome portable (emergency) HF station, that works good - I just can't use it mobile in our van.  (Third tip: if it doesn't do what you'd like, find a use where it does!)


Virus-free. www.avg.com

--

…_. _._


Robert D. Bowers
 

1. Yes (nothing new there - I've been around radios since I got my ticket in 1980, have a general radiotelephone as well plus serviced radios, and am quite familiar with the sorts of issues that can arise).  2. The plastic case that it came in (I don't have anything else to use right now, unless I cobbled together something hideous) - the radio was given to me. 3. Yes - again, nothing new there. 4. The antenna is mounted on a back door (ONLY location possible), the door solidly grounded with braid strap to frame and panels, I mentioned the choke already.  A separate ground went from the frame (after checking the connections) to the radio... no difference.

I suspect that someone put non-resistive plugs and wires on it, and I will be looking at the charging system to see why I got the alternator whine, although scoping the 12v did not show noise.  (The alternator whine is weak and probably could be ignored, the ignition noise overwhelming even after all of that.)

I tried multiple locations for chokes (including two at the same time) - by the radio, by the tuner, and by the antenna (and both radio and antenna).  I also tried different materials - Ferrite, steel, iron powder.

I don't have the resources ($$$) to replace the plugs and wires, at least now.  It's a major job - you have to take the wheels off and remove the barriers behind the shock towers to get to the plugs - from the wheel wells.  Changing the wires is a bit easier, but pricey.

It's a good one, so to speak.  Fixing CNCs (at board level) rarely got this... "interesting".


On 3/31/19 9:06 PM, Mike Short wrote:
Did you go to k0bg.com and do the bonding he recommended?
what case is your radio in? 
Is everything inside the radio grounded to a common ground? (Power, antenna, board, raduino, mic and key jacks, etc.)
his site has a section on ignition noise, spark plug wires, etc.
how is your antenna mounted?
do you have a common mode choke using the ferrite material and number of turns of coax through it?
where is this choke located?

mike


MadRadioModder
 

The idea was to see if it was the 90’s vehicle that was the problem, not to leave it there permanently.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 10:14 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Changing direction - ignition noise intractable #bitx40

 

No.  Our other car is too small.  There really isn't even room for a 2m in it - except maybe a ht.

On 3/31/19 8:14 PM, MadRadioModder wrote:

Have you tried it in a different vehicle…?

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 7:07 PM
To: BITX20@groups.io
Subject: [BITX20] Changing direction - ignition noise intractable #bitx40

 

I've given up on trying to use my Bitx40 as mobile.  Nothing I've done eradicates the ignition noise (and the alternator whine came back).  I've gone with direct power from the battery, extra grounding on the 'doghouse' of my van, plus extra grounding on the antenna base and vehicle frame.  I've tried filtering on the power, then multiple layers of filtering - then even a separate battery entirely (no connections to van).  I added chokes to the outside of the coax... trying to stop that as a source of entry.  I did find that the original grounding scheme for the doghouse (internal cover to the motor on a van - in my case a 90's GMC) was seriously insufficient and improving that reduced the ignition noise by probably 30db or so... but it's still way too loud to use the radio.  I even took the coax out of the van and ran it over to a table, where I had the radio.  As soon as the coax fitting touched the antenna connector, ignition noise.  (You could even faintly hear it with a piece of wire stuck in the antenna connector.)  At the same time, using an old TS-520 on my fan dipole, I could not hear the slightest bit of ignition noise, with the van parked only about 30-40 feet from the 40m portion of the antenna.  I could hear the contest, however.
                                                     
I'm really tickled with my BitX40... it's very sensitive and works pretty well (I haven't tried making contacts with it - yet, but the rx is good and filtering seems more than adequate).  What I did with it was put it in an old metal case (like a toolbox in a way), with battery, coax, and external noise filter/AGC.  It's pretty slick there - a complete portable kit in a box, as long as I have an external antenna along (a dipole would probably fight right in).    Someday I may try to shield the case that the radio came with... that might (or might not) be the problem.

I had to pull my 'good' radio (Alinco DX-70) from my shack for repairs, so I'm going to put it in place of the BitX40 in the van... it has a rock-crusher noise blanker and good filtering - once I get it back in operating condition. It should help a lot in solving the noise problem - maybe eliminate it. 

A couple of tips from this... first, the radio is awesome, but very sensitive to impulse-type noise.   The more barriers you can throw up between the noise source and the radio, the better!  That means chokes in the power line, filter caps, and so on - and if possible, shielded wires!  If I had the equipment (broadband spectrum analyzer), I'd characterize the noise - it may actually getting in somehow via a path besides the antenna and knowing the spectrum could give a clue as to how it gets in.  (I don't have a good bandpass filter right now, that might also be a trick to try.)

Second, if you're trying to go mobile, grounding grounding grounding!!!  While my best attempt (I don't have lots of time to throw at the radio) wasn't good enough, it might be good enough in another situation.  Ground everything you can... and don't just trust to bolted-together sheet metal (frame).  Also, usually drawing the power from a very low impedance source (direct to the battery) with good shielding and filters is the usual fix to the sort of noise I'm getting.  In this case, it wasn't enough.

So now I have an awesome portable (emergency) HF station, that works good - I just can't use it mobile in our van.  (Third tip: if it doesn't do what you'd like, find a use where it does!)

 

Virus-free. www.avg.com


--

…_. _._


--

…_. _._


Adrian Chadd
 

Hm, has anyone done up a standalone noise blanker circuit? it sounds like inserting something in the IF chain may help substantially.

(I've seen plenty of them done in the IF chain in kenwood radios, but they're not small circuits..)

-adrian


Robert D. Bowers
 

That was my idea for down the road, when I've got far less pressure and a bit more time (finish my degree and find employment).

I've got some information (I forget how much) on the design of noise blankers.  I'd still be very interested in any other information, however!


On 4/1/19 12:08 AM, Adrian Chadd wrote:
Hm, has anyone done up a standalone noise blanker circuit? it sounds like inserting something in the IF chain may help substantially.

(I've seen plenty of them done in the IF chain in kenwood radios, but they're not small circuits..)

-adrian


Robert D. Bowers
 

I understood that.  The problem is, I'd have to move everything over to try to replicate the setup - and the car is a 90s version too!  :-\

(What I WILL try is firing up the van with the radios in the {metal} box as I've got them now... so the only line in is the antenna, and everything would be shielded.  I wouldn't want to run it permanently like that, however.)

On 3/31/19 11:57 PM, MadRadioModder wrote:

The idea was to see if it was the 90’s vehicle that was the problem, not to leave it there permanently.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 10:14 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Changing direction - ignition noise intractable #bitx40

 

No.  Our other car is too small.  There really isn't even room for a 2m in it - except maybe a ht.

On 3/31/19 8:14 PM, MadRadioModder wrote:

Have you tried it in a different vehicle…?

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 7:07 PM
To: BITX20@groups.io
Subject: [BITX20] Changing direction - ignition noise intractable #bitx40

 

I've given up on trying to use my Bitx40 as mobile.  Nothing I've done eradicates the ignition noise (and the alternator whine came back).  I've gone with direct power from the battery, extra grounding on the 'doghouse' of my van, plus extra grounding on the antenna base and vehicle frame.  I've tried filtering on the power, then multiple layers of filtering - then even a separate battery entirely (no connections to van).  I added chokes to the outside of the coax... trying to stop that as a source of entry.  I did find that the original grounding scheme for the doghouse (internal cover to the motor on a van - in my case a 90's GMC) was seriously insufficient and improving that reduced the ignition noise by probably 30db or so... but it's still way too loud to use the radio.  I even took the coax out of the van and ran it over to a table, where I had the radio.  As soon as the coax fitting touched the antenna connector, ignition noise.  (You could even faintly hear it with a piece of wire stuck in the antenna connector.)  At the same time, using an old TS-520 on my fan dipole, I could not hear the slightest bit of ignition noise, with the van parked only about 30-40 feet from the 40m portion of the antenna.  I could hear the contest, however.
                                                     
I'm really tickled with my BitX40... it's very sensitive and works pretty well (I haven't tried making contacts with it - yet, but the rx is good and filtering seems more than adequate).  What I did with it was put it in an old metal case (like a toolbox in a way), with battery, coax, and external noise filter/AGC.  It's pretty slick there - a complete portable kit in a box, as long as I have an external antenna along (a dipole would probably fight right in).    Someday I may try to shield the case that the radio came with... that might (or might not) be the problem.

I had to pull my 'good' radio (Alinco DX-70) from my shack for repairs, so I'm going to put it in place of the BitX40 in the van... it has a rock-crusher noise blanker and good filtering - once I get it back in operating condition. It should help a lot in solving the noise problem - maybe eliminate it. 

A couple of tips from this... first, the radio is awesome, but very sensitive to impulse-type noise.   The more barriers you can throw up between the noise source and the radio, the better!  That means chokes in the power line, filter caps, and so on - and if possible, shielded wires!  If I had the equipment (broadband spectrum analyzer), I'd characterize the noise - it may actually getting in somehow via a path besides the antenna and knowing the spectrum could give a clue as to how it gets in.  (I don't have a good bandpass filter right now, that might also be a trick to try.)

Second, if you're trying to go mobile, grounding grounding grounding!!!  While my best attempt (I don't have lots of time to throw at the radio) wasn't good enough, it might be good enough in another situation.  Ground everything you can... and don't just trust to bolted-together sheet metal (frame).  Also, usually drawing the power from a very low impedance source (direct to the battery) with good shielding and filters is the usual fix to the sort of noise I'm getting.  In this case, it wasn't enough.

So now I have an awesome portable (emergency) HF station, that works good - I just can't use it mobile in our van.  (Third tip: if it doesn't do what you'd like, find a use where it does!)

 

Virus-free. www.avg.com


--

…_. _._


--

…_. _._


Christopher Miller
 

If the engine itself is acting as a spark gap transmitter, you will need to put effort in to choking ignition wires etc. Just looking at the radio isn't going to solve a transmitter being next to the antenna. 


On Mon, Apr 1, 2019, 6:58 AM Robert D. Bowers <n4fbz@...> wrote:

I understood that.  The problem is, I'd have to move everything over to try to replicate the setup - and the car is a 90s version too!  :-\

(What I WILL try is firing up the van with the radios in the {metal} box as I've got them now... so the only line in is the antenna, and everything would be shielded.  I wouldn't want to run it permanently like that, however.)

On 3/31/19 11:57 PM, MadRadioModder wrote:

The idea was to see if it was the 90’s vehicle that was the problem, not to leave it there permanently.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 10:14 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Changing direction - ignition noise intractable #bitx40

 

No.  Our other car is too small.  There really isn't even room for a 2m in it - except maybe a ht.

On 3/31/19 8:14 PM, MadRadioModder wrote:

Have you tried it in a different vehicle…?

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 7:07 PM
To: BITX20@groups.io
Subject: [BITX20] Changing direction - ignition noise intractable #bitx40

 

I've given up on trying to use my Bitx40 as mobile.  Nothing I've done eradicates the ignition noise (and the alternator whine came back).  I've gone with direct power from the battery, extra grounding on the 'doghouse' of my van, plus extra grounding on the antenna base and vehicle frame.  I've tried filtering on the power, then multiple layers of filtering - then even a separate battery entirely (no connections to van).  I added chokes to the outside of the coax... trying to stop that as a source of entry.  I did find that the original grounding scheme for the doghouse (internal cover to the motor on a van - in my case a 90's GMC) was seriously insufficient and improving that reduced the ignition noise by probably 30db or so... but it's still way too loud to use the radio.  I even took the coax out of the van and ran it over to a table, where I had the radio.  As soon as the coax fitting touched the antenna connector, ignition noise.  (You could even faintly hear it with a piece of wire stuck in the antenna connector.)  At the same time, using an old TS-520 on my fan dipole, I could not hear the slightest bit of ignition noise, with the van parked only about 30-40 feet from the 40m portion of the antenna.  I could hear the contest, however.
                                                     
I'm really tickled with my BitX40... it's very sensitive and works pretty well (I haven't tried making contacts with it - yet, but the rx is good and filtering seems more than adequate).  What I did with it was put it in an old metal case (like a toolbox in a way), with battery, coax, and external noise filter/AGC.  It's pretty slick there - a complete portable kit in a box, as long as I have an external antenna along (a dipole would probably fight right in).    Someday I may try to shield the case that the radio came with... that might (or might not) be the problem.

I had to pull my 'good' radio (Alinco DX-70) from my shack for repairs, so I'm going to put it in place of the BitX40 in the van... it has a rock-crusher noise blanker and good filtering - once I get it back in operating condition. It should help a lot in solving the noise problem - maybe eliminate it. 

A couple of tips from this... first, the radio is awesome, but very sensitive to impulse-type noise.   The more barriers you can throw up between the noise source and the radio, the better!  That means chokes in the power line, filter caps, and so on - and if possible, shielded wires!  If I had the equipment (broadband spectrum analyzer), I'd characterize the noise - it may actually getting in somehow via a path besides the antenna and knowing the spectrum could give a clue as to how it gets in.  (I don't have a good bandpass filter right now, that might also be a trick to try.)

Second, if you're trying to go mobile, grounding grounding grounding!!!  While my best attempt (I don't have lots of time to throw at the radio) wasn't good enough, it might be good enough in another situation.  Ground everything you can... and don't just trust to bolted-together sheet metal (frame).  Also, usually drawing the power from a very low impedance source (direct to the battery) with good shielding and filters is the usual fix to the sort of noise I'm getting.  In this case, it wasn't enough.

So now I have an awesome portable (emergency) HF station, that works good - I just can't use it mobile in our van.  (Third tip: if it doesn't do what you'd like, find a use where it does!)

 

Virus-free. www.avg.com


--

…_. _._


--

…_. _._


Robert D. Bowers
 

That's true!  Problem is, I've not been able to figure out how this is happening.  (If it IS acting like a spark gap... the transmissions don't get into the TS-520 sitting beside my chair, with the antenna only 30-40 feet from the van.  Usually they scramble everything within a pretty good distance!)

Once I know how and why, the solution would (usually) be easy.  I'd like to stick a spectrum analyzer outside and inside the van... characterize that against the output of the radio.  Don't have one... yet.

On 4/1/19 10:14 AM, Christopher Miller wrote:
If the engine itself is acting as a spark gap transmitter, you will need to put effort in to choking ignition wires etc. Just looking at the radio isn't going to solve a transmitter being next to the antenna. 

On Mon, Apr 1, 2019, 6:58 AM Robert D. Bowers <n4fbz@...> wrote:

I understood that.  The problem is, I'd have to move everything over to try to replicate the setup - and the car is a 90s version too!  :-\

(What I WILL try is firing up the van with the radios in the {metal} box as I've got them now... so the only line in is the antenna, and everything would be shielded.  I wouldn't want to run it permanently like that, however.)

On 3/31/19 11:57 PM, MadRadioModder wrote:

The idea was to see if it was the 90’s vehicle that was the problem, not to leave it there permanently.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 10:14 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Changing direction - ignition noise intractable #bitx40

 

No.  Our other car is too small.  There really isn't even room for a 2m in it - except maybe a ht.

On 3/31/19 8:14 PM, MadRadioModder wrote:

Have you tried it in a different vehicle…?

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Robert D. Bowers
Sent: Sunday, March 31, 2019 7:07 PM
To: BITX20@groups.io
Subject: [BITX20] Changing direction - ignition noise intractable #bitx40

 

I've given up on trying to use my Bitx40 as mobile.  Nothing I've done eradicates the ignition noise (and the alternator whine came back).  I've gone with direct power from the battery, extra grounding on the 'doghouse' of my van, plus extra grounding on the antenna base and vehicle frame.  I've tried filtering on the power, then multiple layers of filtering - then even a separate battery entirely (no connections to van).  I added chokes to the outside of the coax... trying to stop that as a source of entry.  I did find that the original grounding scheme for the doghouse (internal cover to the motor on a van - in my case a 90's GMC) was seriously insufficient and improving that reduced the ignition noise by probably 30db or so... but it's still way too loud to use the radio.  I even took the coax out of the van and ran it over to a table, where I had the radio.  As soon as the coax fitting touched the antenna connector, ignition noise.  (You could even faintly hear it with a piece of wire stuck in the antenna connector.)  At the same time, using an old TS-520 on my fan dipole, I could not hear the slightest bit of ignition noise, with the van parked only about 30-40 feet from the 40m portion of the antenna.  I could hear the contest, however.
                                                     
I'm really tickled with my BitX40... it's very sensitive and works pretty well (I haven't tried making contacts with it - yet, but the rx is good and filtering seems more than adequate).  What I did with it was put it in an old metal case (like a toolbox in a way), with battery, coax, and external noise filter/AGC.  It's pretty slick there - a complete portable kit in a box, as long as I have an external antenna along (a dipole would probably fight right in).    Someday I may try to shield the case that the radio came with... that might (or might not) be the problem.

I had to pull my 'good' radio (Alinco DX-70) from my shack for repairs, so I'm going to put it in place of the BitX40 in the van... it has a rock-crusher noise blanker and good filtering - once I get it back in operating condition. It should help a lot in solving the noise problem - maybe eliminate it. 

A couple of tips from this... first, the radio is awesome, but very sensitive to impulse-type noise.   The more barriers you can throw up between the noise source and the radio, the better!  That means chokes in the power line, filter caps, and so on - and if possible, shielded wires!  If I had the equipment (broadband spectrum analyzer), I'd characterize the noise - it may actually getting in somehow via a path besides the antenna and knowing the spectrum could give a clue as to how it gets in.  (I don't have a good bandpass filter right now, that might also be a trick to try.)

Second, if you're trying to go mobile, grounding grounding grounding!!!  While my best attempt (I don't have lots of time to throw at the radio) wasn't good enough, it might be good enough in another situation.  Ground everything you can... and don't just trust to bolted-together sheet metal (frame).  Also, usually drawing the power from a very low impedance source (direct to the battery) with good shielding and filters is the usual fix to the sort of noise I'm getting.  In this case, it wasn't enough.

So now I have an awesome portable (emergency) HF station, that works good - I just can't use it mobile in our van.  (Third tip: if it doesn't do what you'd like, find a use where it does!)

 

Virus-free. www.avg.com


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Tim Gorman
 

If the ts-520 doesn't pick up the ignition noise and the bitx-40 does
then it is shielding in the radio's that are the difference. A hole
cut in the front panel for an lcd is a *big* hole for ignition
noise to enter the radio, for instance.

If you have a big metal box the radio and a small 12v battery could be
put in with a short piece of wire for an antenna, it would be
interesting to see if the radio still picks up the ignition noise. You
might have to turn the volume up loud to hear the radio outside of the
box!

tim ab0wr

On Mon, 1 Apr 2019 11:14:11 -0400
"Robert D. Bowers" <n4fbz@...> wrote:

That's true!  Problem is, I've not been able to figure out how this
is happening.  (If it IS acting like a spark gap... the transmissions
don't get into the TS-520 sitting beside my chair, with the antenna
only 30-40 feet from the van.  Usually they scramble _everything_
within a pretty good distance!)

Once I know how and why, the solution would (usually) be easy. I'd
like to stick a spectrum analyzer outside and inside the van...
characterize that against the output of the radio.  Don't have one...
yet.


Jerry Gaffke
 

Lack of shielding could be part of the problem.

Another big difference is that the Bitx40 (and uBitx) have most of their
rx gain after the demodulator, in the audio amps.  
So more sensitive to power supply noise.

Jerry


On Mon, Apr 1, 2019 at 06:18 PM, Tim Gorman wrote:
If the ts-520 doesn't pick up the ignition noise and the bitx-40 does
then it is shielding in the radio's that are the difference.


Vic WA4THR
 

I may have missed the comment, but does the noise get in to your BitX40 with the antenna disconnected? On my mobile setup I found the BitX40 was very sensitive to noise on the 12v power line, but adding a noise filter on that line completely cured it and I have enjoyed making 40m contacts while underway. Another ham made this inexpensive filter for his BitX40 and it solved a noise problem he had.

https://www.worldwidedx.com/threads/building-a-simple-alternator-whine-ignition-filter.31492/


=Vic=


Curt
 

Robert

I would not give up completely on this.  Since the BITX uses very little current - why not operate it from a gel cell battery while mobile.  The battery can be charged at home on a wallwart, or in the car when not using the rig.  Yes problem avoidance but it may work. You might also add a dipole or end fed halfwave (these can be homebrewed, rather easily at QRP) to you stash for portable operation in a park.  Take care on your journey.  

Curt


Lee
 

Back in my 70s CB days a friend had a Datsun 240Z that had terrible noise.  Using braid from coax to make jumpers we bonded the hood and fenders to the firewall and the doors to the body.  On some cars we only had to bond the hood.  We think it acted like a repeater for engine noise instead of shielded it.
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Lee - N9LO  "I Void Warranties"

 


Robert D. Bowers
 

(Laugh!) I remember something just like that... but I think it was actually from the late 60s (in an old QST if I remember right) so it couldn't have been about a 240Z.

On 4/2/19 8:46 AM, Lee wrote:
Back in my 70s CB days a friend had a Datsun 240Z that had terrible noise.  Using braid from coax to make jumpers we bonded the hood and fenders to the firewall and the doors to the body.  On some cars we only had to bond the hood.  We think it acted like a repeater for engine noise instead of shielded it.
--
Lee - N9LO  "I Void Warranties"

 


Robert D. Bowers
 

I've tried it - I moved the radio to a steel toolbox (actually -I think- a film carrier like a tool box), with the noise filter, radio, and gel cell.  As soon as I attached the coax, ignition noise drowning out anything else.  (Engine off, I was receiving signals, but it clearly wasn't as sensitive as my shack's dipole.)

It seems as if the entire van is acting like an antenna for the noise, but it wasn't transmitting strong enough to reach my shack!

If I could get my hands on a spectrum analyzer that covers HF, I might be able to characterize the noise and figure out how it's being such a problem - and from that find a way to stop it. Most of the gear I could use is well outside my price range, however.


On 4/2/19 8:06 AM, Curt via Groups.Io wrote:
Robert

I would not give up completely on this.  Since the BITX uses very little current - why not operate it from a gel cell battery while mobile.  The battery can be charged at home on a wallwart, or in the car when not using the rig.  Yes problem avoidance but it may work. You might also add a dipole or end fed halfwave (these can be homebrewed, rather easily at QRP) to you stash for portable operation in a park.  Take care on your journey.  

Curt


Evan Hand
 

If you happen to have an SDR dongle there is free software that would help in this instance. 

FYI, I have not tried to use it for this type of application, so I would not run out any buy one just for this.

73
Evan
CA9TU