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Hi
I,ve been trying to use my r4a recently. The pulse noise has been strong, and the blanker does not seem to be helpful. IS the experience of others similar?
73s
David?
N9pvf
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I can talk about the R4B. The blanker works fine on ignition noise, which was what it was mostly designed for but does nothing for the grinding line noise that is much more common. I tested it using a Tektronix pulse generator. It does work but is not like the blankers found in some more modern receivers. The idea of the blanker is to prevent pulse noise like ignition noise from causing the AVC to reduce sensitivity. It also does not affect the sort of noise a conventional noise limiter of the sort found in boatanchor receivers will take out but the usual series valve limiter does not work for CW or SSB. I think there are after market noise removers that work pretty well.
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On 4/11/2021 5:09 AM, David Lipson via groups.io wrote: Hi
I,ve been trying to use my r4a recently. The pulse noise has been strong, and the blanker does not seem to be helpful. IS the experience of others similar?
73s
David
N9pvf
--
Richard Knoppow
1oldlens1@...
WB6KBL
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The Drake blanker is very effective...? Like Richard says it works great on ignition noise.
Back in the day it made the difference between being able to hear a station or not.
Now a days, there isn't much ignition noise anymore so it really doesn't do much.
73,
Gary
WB6OGD
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On 4/11/2021 7:36 AM, Richard Knoppow wrote: ?? I can talk about the R4B. The blanker works fine on ignition noise, which was what it was mostly designed for but does nothing for the grinding line noise that is much more common. I tested it using a Tektronix pulse generator. It does work but is not like the blankers found in some more modern receivers. The idea of the blanker is to prevent pulse noise like ignition noise from causing the AVC to reduce sensitivity. It also does not affect the sort of noise a conventional noise limiter of the sort found in boatanchor receivers will take out but the usual series valve limiter does not work for CW or SSB. I think there are after market noise removers that work pretty well.
On 4/11/2021 5:09 AM, David Lipson via groups.io wrote:
Hi
I,ve been trying to use my r4a recently. The pulse noise has been strong, and the blanker does not seem to be helpful. IS the experience of others similar?
73s
David
N9pvf
|
Don’t expect miracles with the NB ! It works on some noise and some it just don’t care! I would eliminate all noise in and around house first!
I run a Timewave dsp599 ( works on audio ) which makes the radio much better to listen to.
My R4C I don’t have a NB in it the first IF is to narrow for stock NB to work but using the Timewave , lightning isnt to bad and I don’t make any rf noise in house or if I do I can turn that light off Hihi
73s Byron AC9PA
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On Apr 11, 2021, at 11:20 AM, wb6ogd <garywinblad@...> wrote: ?The Drake blanker is very effective... Like Richard says it works great on ignition noise. Back in the day it made the difference between being able to hear a station or not. Now a days, there isn't much ignition noise anymore so it really doesn't do much. 73, Gary WB6OGD On 4/11/2021 7:36 AM, Richard Knoppow wrote: I can talk about the R4B. The blanker works fine on ignition noise, which was what it was mostly designed for but does nothing for the grinding line noise that is much more common. I tested it using a Tektronix pulse generator. It does work but is not like the blankers found in some more modern receivers. The idea of the blanker is to prevent pulse noise like ignition noise from causing the AVC to reduce sensitivity. It also does not affect the sort of noise a conventional noise limiter of the sort found in boatanchor receivers will take out but the usual series valve limiter does not work for CW or SSB. I think there are after market noise removers that work pretty well.
On 4/11/2021 5:09 AM, David Lipson via groups.io wrote:
Hi
I,ve been trying to use my r4a recently. The pulse noise has been strong, and the blanker does not seem to be helpful. IS the experience of others similar?
73s
David
N9pvf
|
David,
You can try a mod to permit an adjustment to the NB threshold, as per this suggestion:?
This allows an adjustable threshold, as per the original R-4 configuration. Might help.
Bob
K7CY
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On Apr 11, 2021, at 10:10 AM, AC9PA via groups.io <byroncordes@...> wrote:
? Don’t expect miracles with the NB ! It works on some noise and some it just don’t care! I would eliminate all noise in and around house first! I run a Timewave dsp599 ( works on audio ) which makes the radio much better to listen to. My R4C I don’t have a NB in it the first IF is to narrow for stock NB to work but using the Timewave ?, lightning isnt to bad ?and I don’t make any rf noise in house or if I do I can turn that light off Hihi 73s Byron AC9PA On Apr 11, 2021, at 11:20 AM, wb6ogd <garywinblad@...> wrote:?The Drake blanker is very effective... ?Like Richard says it works great on ignition noise.Back in the day it made the difference between being able to hear a station or not.Now a days, there isn't much ignition noise anymore so it really doesn't do much.73,GaryWB6OGDOn 4/11/2021 7:36 AM, Richard Knoppow wrote: ??I can talk about the R4B. The blanker works fine on ignition noise, which was what it was mostly designed for but does nothing for the grinding line noise that is much more common. I tested it using a Tektronix pulse generator. It does work but is not like the blankers found in some more modern receivers. The idea of the blanker is to prevent pulse noise like ignition noise from causing the AVC to reduce sensitivity. It also does not affect the sort of noise a conventional noise limiter of the sort found in boatanchor receivers will take out but the usual series valve limiter does not work for CW or SSB. I think there are after market noise removers that work pretty well.
On 4/11/2021 5:09 AM, David Lipson via groups.io wrote:
Hi
I,ve been trying to use my r4a recently. The pulse noise has been strong, and the blanker does not seem to be helpful. IS the experience of others similar?
73s
David
N9pvf
|
I tried this on my R4B and found that while it worked it didn't make the NB any more effective on noise other than ignition noise. Ignition noise is rare these days, about the only time I hear it is from the gardener's mower. The threshold of the NB is such that it will prevent pulse noise from raising the AVC level, which is what is expected of it. Lowering the threshold much begins to produce distortion. There are more elaborate blankers that are more effective on power line noise but the best ones seem to be the digital processing ones that are external to the receiver.
?? The theory of the noise blanker is not as simple as it may appear. The idea is that the blanker will cut off the RF path during the pulse but the effect of the bandwidth on the noise wave form at both the sensing and control points is critical plus you don't want the blanker to cut off desired signals.
?? As a matter of comfort in listening a simple clipper on the audio may be helpful. While its best to have it on the input to the audio stage even a simple solid state diode clipper on the audio output may help with some types of power line noise. My experience with many old fashioned receivers with both series and shunt clippers is that they are at best illusory.
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On 4/11/2021 10:45 AM, Robert Berg via groups.io wrote:
David,
You can try a mod to permit an adjustment to the NB threshold, as per this suggestion: <>
This allows an adjustable threshold, as per the original R-4 configuration. Might help.
Bob
K7CY
On Apr 11, 2021, at 10:10 AM, AC9PA via groups.io <byroncordes@...> wrote:
?Don’t expect miracles with the NB ! It works on some noise and some it just don’t care! I would eliminate all noise in and around house first!
I run a Timewave dsp599 ( works on audio ) which makes the radio much better to listen to.
My R4C I don’t have a NB in it the first IF is to narrow for stock NB to work but using the Timewave ?, lightning isnt to bad ?and I don’t make any rf noise in house or if I do I can turn that light off Hihi
73s Byron AC9PA
On Apr 11, 2021, at 11:20 AM, wb6ogd <garywinblad@...> wrote:
?The Drake blanker is very effective... ?Like Richard says it works great on ignition noise.
Back in the day it made the difference between being able to hear a station or not.
Now a days, there isn't much ignition noise anymore so it really doesn't do much.
73,
Gary
WB6OGD
On 4/11/2021 7:36 AM, Richard Knoppow wrote:
??I can talk about the R4B. The blanker works fine on ignition noise, which was what it was mostly designed for but does nothing for the grinding line noise that is much more common. I tested it using a Tektronix pulse generator. It does work but is not like the blankers found in some more modern receivers. The idea of the blanker is to prevent pulse noise like ignition noise from causing the AVC to reduce sensitivity. It also does not affect the sort of noise a conventional noise limiter of the sort found in boatanchor receivers will take out but the usual series valve limiter does not work for CW or SSB. I think there are after market noise removers that work pretty well.
On 4/11/2021 5:09 AM, David Lipson via groups.io wrote:
Hi
I,ve been trying to use my r4a recently. The pulse noise has been strong, and the blanker does not seem to be helpful. IS the experience of others similar?
73s
David
N9pvf
--
Richard Knoppow
1oldlens1@...
WB6KBL
|
Like the others have said, the Drake NB was only designed for ignition noise for those that took these mobile.
I added a pre-wired BHI DSP noise reduction inside my MS-4 cabinet.? I hid the on/off and threshold buttons on the bottom so that it still looks entirely stock.? It is a bypass unit, and when switched off the normal Drake audio is passed directly through.? Engage the DSP, though, and it takes the noise reduction into the 21st century.? Highly recommended!
Eric
WK3B
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NM0S has designed a narrow 200 CW filter that has no ringing. ?
The QRP Labs QCX QRP rigs use that design and I can attest to the effectiveness of that CW filter. One of my many projects is to build that filter for my R-4B.
The Four ?State QRP group sell a kit based on NM0S’s?design. ?See?
That CW filter is way better than the DSP ?one in my ICOM 746 PRO!
--
73, Bernie. VE3FWF
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Well, at risk of seeming an amalgamation of a classic snake oil salesman and revivalist 'tent meeting' speaker, I can personally attest for Dave Cripe's HiPerMite audio filter. It first appeared in 73 magazine, was revised and has been a 4Square QRP kit for some time now.....
I built mine and use it on many of my rigs as an external audio filter - on the R4C (even with its own filter), TR-4Cw (with and w.o its own filter), my R-390A etc. It is great. In fact, IMHO even though the one I built I did it as the zero-gain setup... I find that with my R-390A I don't have to have the RF and Audio gain pots nearly so high.. the filter seems to 'gain' the signal, FWIW, in an exemplary way. IMHO.
Additionally, my TR-7 has been put aside for now until I surrender the funds to buy a? new Noble CW filter to replace the Drake CW filters (which seem to have aged out and become hollow and ring-y in my hearing opinion... the HiPerMite made it work quite nice though).
Strongly recommended. I am not a salesman nor tent speaker and never have played one on TV nor radio..... :)
Brian VE3HI
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In line audio filters are a wonderful tool. I have two different DPS boxen that I regularly use that are frankly amazing. But you have to be aware of their limitations. They won't help with strong adjacent signals that are pumping your ACG or worse. 73 -Jm NU0C On Mon, 12 Apr 2021 09:31:12 -0700 "Brien Pepperdine" <busybrian@...> wrote: Well, at risk of seeming an amalgamation of a classic snake oil salesman and revivalist 'tent meeting' speaker, I can personally attest for Dave Cripe's HiPerMite audio filter. It first appeared in 73 magazine, was revised and has been a 4Square QRP kit for some time now..... *
* I built mine and use it on many of my rigs as an external audio filter - on the R4C (even with its own filter), TR-4Cw (with and w.o its own filter), my R-390A etc. It is great. In fact, IMHO even though the one I built I did it as the zero-gain setup... I find that with my R-390A I don't have to have the RF and Audio gain pots nearly so high.. the filter seems to 'gain' the signal, FWIW, in an exemplary way. IMHO.
Additionally, my TR-7 has been put aside for now until I surrender the funds to buy a? new Noble CW filter to replace the Drake CW filters (which seem to have aged out and become hollow and ring-y in my hearing opinion... the HiPerMite made it work quite nice though).
Strongly recommended. I am not a salesman nor tent speaker and never have played one on TV nor radio..... :)
Brian VE3HI
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Since all filtering is at 50KHz...? and 50KHz is nearly just high audio...
I wonder is an audio filter could be modified to work at 50KHz.? Inject it before the AVC and
it could be a modern rig...
73,
Gary
WB6OGD
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?Hello Ten Tec had a NB board that was a optional on the Scout . Have seen it used in a R4C . Worked better than stock but not great.? ? Have also seen R4B with tx filters installed it worked but didn’t compare it to anything .Hihi? ? As far as audio filters used up at 50k hey you could play with it !? ?I type probably 100 words why not to but deleted it Hihi? ? If I had a R4B which had noise outside of house and I couldn’t fix the problem. I would and do use two antennas and change phase on them . ?MFJ and DX Engineering make a box for that . It works better than any NB I have ever used but it mainly only works on one noise ?that you tune out.? ?Don’t chop up the Drake Hihi just add some modern accessories!? I was always told your antenna is your first noise filter!? ?73s Byron AC9PA?
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On Apr 13, 2021, at 9:04 AM, wb6ogd <garywinblad@...> wrote: ?Since all filtering is at 50KHz...? and 50KHz is nearly just high audio...
I wonder is an audio filter could be modified to work at 50KHz.? Inject it before the AVC and
it could be a modern rig...
73,
Gary
WB6OGD
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KNB2_KNB2 K2 Noise Blanker Option?×?1
Dave and Elecraft K2 Customer Support
After installation remarks for the Elecraft KNB2 Noise Blanker in
my Elecraft K2.? November 1, 2020? ?1300Z? 7.03000 MHZ
The KNB2 noise blanker very effectively removes "popcorn static" in
both narrow and wide pulse width modes. Also, both levels of low or high threshold removed the
static pulses.? Signal levels of the pulses are S9 plus in the Off
mode. Zero On.
I believe the source of the pulses are High Voltage power lines
that are located less than one mile away.? These are the lines
with the 100 ft. towers.
Thanks to Burdick and Swartz for designing a superior product.
Ken N4SO
David,?? You have old technology, and this one for the Elecraft K2 is very effective for High Voltage power lines.? I do not know
the source or meaning of your "pulse noise".? You want narrow and wide pulse width modes in a noise blanker.? Mine is completely effective.
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Gentlemen:
Thanks for your comments and suggestions. I bought a BHI noise away, but it appears to have been reworked, and the power-connection broke ( diode cracked). I'm hesitant to try that brand again.
When it did work (intermittently) the noise reduction was acceptable, but the output volume weak,
David
N9PVF
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Gary WB6OGD
Ham Radio
Jim Shorney