Hello,
Looks like my cut and paste didn't work. So, I'll type the sheet........
We would advise that there are several factors which should be taken into
consideration in connection with Noise Blanker operation.
First of all, it is normal for a blank noise pulse to turn off the receiver for
the duration of the pulse. This makes a hole in the received envelope. If the
noise has a definite frequency rate, the signal will appear to be modulated at
the noise frequency. The noise blanker is the most effective on noise pulses
of very short duration with a relatively long time between pauses. A prime
example of this type noise is that which is generated by automobile ignition
systems. It is least effective with noise pulses of relatively long duration
with short spacing in between pulses: an example of this is atmospheric noise.
There are occasional conditions when an adjacent signal which you cannot hear
in the R-4A output, will operate the noise gate and produce distortion. The
reason for this is that the bandwidth of the noise blanker IF following the
passband tuner is considerably wider than the passband filter itself. This
broadness is a prime requirement for noise blanker operation.
It should be kept in mind that the noise blanker is not needed and therefore
should not be used, if the noise which you hear is equal to or less than the
strength of the received signal. However, if the noise exceeds the strength of
the received signal, the noise blanker will be a definite advantage and should
be switched on.
If after the above suggestions, you feel that your noise blanker is operating
improperly, write in more detail concerning your observations and we will try
to of additional assistance.
R L DRAKE COMPANY
Service Department
67/3
________________________________
From: Bill Frost <[email protected]>
To: Drake List <[email protected]>
Sent: Monday, April 15, 2013 7:12 PM
Subject: Re: [Drakelist] Drake 2-C noise blanker
Hello to the Group,
While looking up information on the 2-NB for Ken, I found this sheet on noise
blanker operation. This was written for the R-4A noise blanker, but someone
wrote 2-NB on the sheet, so ....... This was written back in March of 1967,
most likely by an engineer for the service department, but not for me, as I was
on the R-4A production line as a tester.
73, Bill
From: Eric Webner <[email protected]>
To: Charles Ring <[email protected]>
Cc: Drake List <[email protected]>
Sent: Monday, April 15, 2013 3:10 PM
Subject: Re: [Drakelist] Drake 2-C noise blanker
Charles,
A large part of it depends on whether your 2-C suffers from the type of noise
(pulse type) that the noise blanker can help with. I have bad power line noise
at my QTH that a blanker won't touch.
73,
Eric Webner K4FAN
The DStar FAN Club
On Apr 15, 2013 3:04 PM, "Charles Ring" <[email protected]> wrote:
Is a schematic and parts list available for the 2NB? Any possibility of
duplicating it? How well does it work, in other words would it be worth the
effort?
>.
>73 de W3NU
>
>
>
>
>On 4/15/2013 0942, Ronald Baker wrote:
>
>I have pictures of the 2C and all the accessories on my Drake Website.
>>Here is the link to that page:
>>
>>http://www.wb4hfn.com/DRAKE/DrakeEquipmentPictures/Equip_2C.htm
>>
>>Maybe once a year you may see the 2NB noise blanker listed on eBay, but they
>>are very rare.
>>
>>The one’s I have seen sold on ebay range from $100 to $140.
>>
>>73, Ron / WB4HFN
>>
>>
>>
>>Sent from my old computer that I purchased new before the Dead Sea got sick.
>>
>>
>>From:[email protected] [mailto:[email protected]]
>>On Behalf Of Bill Frost
>>Sent: Monday, April 15, 2013 7:42 AM
>>To: Drake List
>>Subject: Re: [Drakelist] Drake 2-C Question
>>
>>Hello Ken,
>>
>>The 2-NB noise blanker, for the 2-C receiver, originally sold for around
>>$27.00 and was a plug in option. If you Google Drake 2-NB you should get a
>>link to Universal Radio site with a picture and description of the 2-NB.
>>There were not to many manufactured, so they are quite rare.
>>
>>73, Bill wd8dfp
>>
>>________________________________
>>
>
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