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eHam Forums => Elmers => Topic started by: AF5CC on March 12, 2013, 07:30:36 PM



Title: Rigs with good noise blankers
Post by: AF5CC on March 12, 2013, 07:30:36 PM
I have a really bad noise on 17m (and sometimes other bands) that really makes it hard to hear signals at times.  It sounds like some sort of electrical crud from consumer electronics, or something like that.  It might be powerline noise, but I really don't think so.  Anyways, I know the best solution is to remove the source of the noise, but that isn't always possible. 

What rigs have good noise blankers that take out electrical types of noise?  I know the Yaesu FT100D is pretty good at it.  What other rigs have you used that worked good.  The FT100D is getting kind of hard to fine used nowadays.

Any suggestions or experiences would be most welcome!

John AF5CC


Title: RE: Rigs with good noise blankers
Post by: W9PMZ on March 12, 2013, 07:34:57 PM
Icom7000


Title: RE: Rigs with good noise blankers
Post by: M6GOM on March 12, 2013, 07:52:04 PM
Icom7000

Seconded. My Icom 7000 NB is better than my Kenwood TS590. I think most 7xxx series Icoms are good. Flex also seems to have a very very good NB.

Alternatively look at something like a MFJ 1026 and put it inline.


Title: RE: Rigs with good noise blankers
Post by: VA2FSQ on March 12, 2013, 11:18:57 PM
Yes the MFJ or the DX engineering NCC-1.  Here's my experience
http://va2fsq.com/wp-content/uploads/2013-Jan-15-20-43-43.avi

 Best noise blanker around!


Title: RE: Rigs with good noise blankers
Post by: HB9PJT on March 13, 2013, 03:25:47 AM
Kenwood rigs have very good noise blankers. Look here for the TS-590: http://www.youtube.com/watch?v=opHgOxl7Ojk

73, Peter - HB9PJT


Title: RE: Rigs with good noise blankers
Post by: SWMAN on March 13, 2013, 03:59:54 AM
The NB button on my Kenwood TS-570 does nothing at all. It is the exactly the same with it on or off. That is my only complaint with my 14 year old 570.
Jim. 73. W5JJG


Title: RE: Rigs with good noise blankers
Post by: K0OD on March 13, 2013, 04:05:07 AM
Quote
"the best solution is to remove the source of the noise,"

I'd rate buying a new radio as the worst solution for dealing with the noise. What happens if that new $2,000 radio is even worse?

How long have you had the noise?  How close are you to your neighbors. Have you checked everything within your control?  Have you tried DFing it?  What antenna do you use on 17? The list could go on and on.

My longtime experience is that most noise problems like that eventually go away on their own. There are other bands, too.   



Title: RE: Rigs with good noise blankers
Post by: W1JKA on March 13, 2013, 04:14:06 AM
  ICOM-7200 Check the reviews,first rig I've had that both NR and NB actually work.


Title: RE: Rigs with good noise blankers
Post by: AA4PB on March 13, 2013, 05:15:37 AM
It depends very much on the waveform shape of the noise signal. A noise blanker can be quite effective against one noise source and worthless for another. My IC756PRO noise blanker will completely kill the power line noise on one day and do nothing the next day - depending on the weather factors that affect the arcing out on the power pole. I'd hesitate to buy a transceiver based on someone else's experience against his particular noise source.



Title: RE: Rigs with good noise blankers
Post by: NK7Z on March 13, 2013, 05:19:06 AM
756 PRO II or 756 PRO III NB is good...  Also, the Yaesu FT-900 has a really solid NB in it as well...


Title: RE: Rigs with good noise blankers
Post by: WA3SKN on March 13, 2013, 06:38:55 AM
Actually, you will find that most of the rigs have adjustable parameters for the noise blanker... deep in the bowels of the menu systems.  And the noise type encountered determines how well the default values work!  But it is best to find the source and fix it rather than use the noise blanker, if possible.
73s.

-Mike.


Title: RE: Rigs with good noise blankers
Post by: AF5CC on March 13, 2013, 07:23:04 AM
  ICOM-7200 Check the reviews,first rig I've had that both NR and NB actually work.

I was going to ask about the Icom 7200, as I think it uses the same NB as the 7000 (which others suggested) and it is a little cheaper than the 7000, appears more rugged and easier to use.  So it does a good job on noise?

73 John AF5CC


Title: RE: Rigs with good noise blankers
Post by: AF5CC on March 13, 2013, 07:25:41 AM
It depends very much on the waveform shape of the noise signal. A noise blanker can be quite effective against one noise source and worthless for another. My IC756PRO noise blanker will completely kill the power line noise on one day and do nothing the next day - depending on the weather factors that affect the arcing out on the power pole. I'd hesitate to buy a transceiver based on someone else's experience against his particular noise source.

Yes, isn't that the truth!  The NB in my Icom 706 original actually does really good on the noises that show up on 2m, 12m, and 15m.  Almost completely remove it. Doesn't do much of anything on the 17m noise.

73 John AF5CC


Title: RE: Rigs with good noise blankers
Post by: K8AC on March 13, 2013, 07:47:14 AM
There are many good noise blanker implementations, dating back to the Drake TR7, that are fairly effective at minimizing various types of impulse noise.  But, one thing that few understand or mention - there are side effects that can be rather unpleasant. Typically, with the NB activated on a band with many strong signals, you'll hear phantom signals that you might think are splatter caused by a dirty transmitter, but the signals are actually being produced in the receiver as a result of the NB being on.  There just isn't any free lunch - the best thing to do is to try and get the noise source eliminated.  Second best approach may be to use one of the noise cancellation devices such as the MFJ-1026 which can be effective in the right circumstances.  But if the noise is coming from multiple directions, that method may not produce good results.

73, K8AC


Title: RE: Rigs with good noise blankers
Post by: NR4C on March 13, 2013, 08:10:19 AM
It depends on exactly what type of noise you are trying to get rid of.

Several good solutions have already been described, but it's better to get rid of the noise, and often cheaper as it may be someone else's real problem.  Buying a new rig should be the last resort, unless of course this is your way of getting past the finacial manager (spouse) in which case i'll shut up.

Many recent rigs have good NB circucits and most offer some adjustments, to handle different types of noises.

Try before you buy.

...bill  nr4c


Title: RE: Rigs with good noise blankers
Post by: W8JX on March 13, 2013, 08:51:20 AM
The NB button on my Kenwood TS-570 does nothing at all. It is the exactly the same with it on or off. That is my only complaint with my 14 year old 570.
Jim. 73. W5JJG

It is only effective against certain type of noise pulse. Try the NR1 as it has 10 levels. The 480 has excellent noise reduction/blankers. It has a DNL, a NB  and two NR's and all are adjustable and DNL and NB can be used with NR1 or NR2.


Title: RE: Rigs with good noise blankers
Post by: W1JKA on March 13, 2013, 08:51:33 AM
Re; AF5CC  Reply #11

Yes, and as others have said the parameters are adjustable and results are dependent on any particular EMF or other electrical noise issues at your QTH.Definitely rugged with moisture resistant membrane behind all panel controls.Nice mid priced all round rig with simple no hassle menus and operation.


Title: RE: Rigs with good noise blankers
Post by: WB2WIK on March 13, 2013, 09:23:43 AM
I'd always spend the time and effort to find the noise source and see if I can kill it at the source.

Of course, nowadays it's very possible for there to be numerous noise sources.  Anything with electronics in it can be a noise source.

If it peaks on 17m, that may be because your antenna works best on 17m.  Although there are exceptions, most noise sources are at lower frequencies but generate a lot of harmonics so by the time you get up to HF or above, they appear to be just broadband sources.  Sometimes, they're periodic in nature which can make them easier to pin down.

Blankers can be helpful, but not nearly as nice as eliminating the source -- and eliminating the source might be cheaper!


Title: RE: Rigs with good noise blankers
Post by: AD4U on March 13, 2013, 09:50:41 AM
Since I am a boat anchor ham I cannot comment on the newest DSP based noise blankers.  However the older and most effective noise blankers actually "blank" the entire receiver (including the desired signal) for the duration of the noise pulse(s).  On the other hand noise limiters "clip" the noise peaks instead of blanking the receiver.  IMO they are about as useless as a screen door on a submarine.  

If you have lots of noise pulses, your receiver will be blanked a lot which will reduce the intelligibility of the desired signal as well as creating distortion and introducing phantom signals within the receiver passband.  It is a trade off.

As posted by many, by far the best approach is to identify and reduce or eliminate the noise source(s).  Maybe one day there will be a smart noise blanker that can distinguish between noise and the desired signal.  But I don't think that day has arrived.  Today there is no free lunch.

Dick  AD4U


Title: RE: Rigs with good noise blankers
Post by: K1TWH on March 22, 2013, 12:45:40 PM
__If you cannot find the noise source, I'd vote IC-7000, then IC-7200.  Of the radio's I've used, these two were able to address a large number of differing noises while impacting the desired signal as little as possible.  Being able to configure both noise amplitude and blanking width seems to help.  The IC-7000 has a wider "roofing" filter which would allow the DSP a better view of pulse noise as it has not been stretched by a 'narrow' filter.   Of course a wider filter also means strong signals within +/- 10 to 15KHz may impact your reception, but I don't see this all that often on my IC-7000.
__If there is one primary noise source , a noise phasing device like the ANC-4 or MFJ-1026 can be very helpful, but if you are plagued by many sources this is a dead end street.
Best wishes on less QRM,    Tom WB1FPA


Title: RE: Rigs with good noise blankers
Post by: K6AER on March 25, 2013, 08:54:12 AM
Some folks have problems with noise blankers and don’t realize that not all noise sources are removable. Pulse noise is relative easy to remove with the new DSP functions in the radio. This is because the noise source has a signature that repeats itself and has a relative long interim of audio between the narrow pulse width.  White Gaussian noise has no signature and is very broad in band width. AS a result it seems that the high frequency is reduced and add little to the recovered audio.

If your noise is from a specific source you can use RF interference noise cancellation but it requires sampling the RF source in some way. This is phase/amplitude inversion and can reduce the noise up to 30 dB. It is frequency sensitive and will have to be adjusted for each frequency.

Getting your antenna as high and far as possible from the noise source is also helpful. In addition using an antenna with a pattern null in the direction of the noise location will also reduce the noise level.


Title: RE: Rigs with good noise blankers
Post by: N6AJR on March 25, 2013, 12:22:55 PM
ten tec does well, and on the lower bands a magnetic loop is great for rx.  (Like the pixel technologies loop) also see if you can locate and fix the noise.


Title: RE: Rigs with good noise blankers
Post by: WB9YCJ on March 27, 2013, 06:58:02 PM
VERY IMPRESSIVE IC-7700 Noise Blanker ......

http://www.youtube.com/watch?v=KnBkr_Io3KE


Dont cry, see if this NB is offered in lower priced Icoms.


Title: RE: Rigs with good noise blankers
Post by: AF5CC on March 28, 2013, 11:44:30 AM
That is impressive. Wonder if the same NB is in the Icom 7200, I hear it is supposed to have a good noise blanker as well.

John AF5CC


Title: RE: Rigs with good noise blankers
Post by: K6AER on March 28, 2013, 01:15:10 PM
I just thought of another thing to realize about noise blanker operation in many older and newer radios.

Older radio mostly have only a single level of noise blanker operation and when applied, like a hammer, can provide as much artifact as the noise they are removing.

New blanker circuits can also adjust the timing, width and depth of the blanking signal. When combined with a good DSP system they can not only make the noise disappear but will also aid the RF gain in setting the proper level for the incoming signal.

My current SUV has coil over plugs and a nonmetal hood. The ignition noise was very intense.  My IC-706MK II G and the FT-100D did a reasonable job of removing the ignition noise but it was far from perfect.  On advice from other hams using the IC-7000 I bought the radio at HRO and installed into the SUV.

The ignition interference disappeared completely. I was able to adjust the depth of the blanking for minimum effect on the recovered audio.  In addition the ANR (Automatic Noise Reduction) also reduced the background hiss withy out reducing the audio highs. I was dumbfounded how far the DSP in these little radios have come.

Bottom line is you can have mobile operation without turning your engine wiring into a shielded airplane ignition system


Title: RE: Rigs with good noise blankers
Post by: AF5CC on March 28, 2013, 02:58:11 PM
So of the older rigs did have adjustable NBs.  I know the Icom 740 and 745 did, as well as the Kenwood TS140/680. It does seem, though, that newer radios are using digital based NBs which might work better.

John AF5CC