Grant xl noise blanker design

[nfsus]

I think I'd like to build a noise blanker like the one in the old grant xl radios. Does anyone have a good idea of figuring out the circuit? I suppose the schematic would be a place to start.

 

[nomadradio]

the schematic would be a place to start.

Yep.

What radio do you want to add this to? The tapoff point for the blanker's input, and the 'clamp' spot where the main signal gets blanked have to be timed correctly. The noise pulse gets delayed differently inside the blanker circuit than it does passing through the main receiver's circuits. The trick is to make the blanking pulse on the circuit's output arrive at the same time the noise pulse is passing through that part of the main receive circuit.

Too early or too late and it becomes less effective.

73

 

[nfsus]

I've got a radio that the nb sucks rear ninny. Was considering adding one to it.

 

[walterjn]

I've got a radio that the nb sucks rear ninny. Was considering adding one to it.

I think he means what make and model...
Would help to let you know where to wire it in...

 

[BC Coyote]

Just buy an MFJ-1026. Works the exact same way as the old-school noise blankers did and you won't have to hack your radio!
I use one daily and it will easily take 9S of powerline hash down to less than 1S unit. Important: MFJ-1026 is only as good as it's noise pickup antenna. Don't bother with the supplied rod.......put up a loop or something outside and the unit shines.

 

[nfsus]

Ive played with the noise eleminators. Works alright for base but looking for a mobile idea. I have one in the mobile but it's just not very mpressive. My base I use a 100ft longwire for the noise antenna. On the mobile it's a 4'whip

 

[BC Coyote]

Yeah, phase cancellation type noise eliminators WILL NOT work in a mobile environment, for the simple reason that when you are in motion, so too are are the phases of a signal, so there's simply no way you can find a null point to cancel the noise.

 

[unit_399]

NFSUS -
If you are talking about the NB circuit in the ORIGNAL 858 Grant, here is a schematic of the circuit and a circuit descripition The NB in the 858 radios was on a seperate circuit board, and if you can get hold of one, it would put you way ahead of the game. Plus . . . they were pretuned at the factory. Maybe a forum member has one you could have out of an old junker. If you can't find one, I'll send you one, but coming from Colombia takes time.. Let me know in a PM.
Anyway good luck. 73.
- J.J. 399

 

[nfsus]

Iv

Yeah, phase cancellation type noise eliminators WILL NOT work in a mobile environment, for the simple reason that when you are in motion, so too are are the phases of a signal, so there's simply no way you can find a null point to cancel the noise.

Yeah I've spun my fingers thin trying. Hahahaha

 

[nfsus]

NFSUS -
If you are talking about the NB circuit in the ORIGNAL 858 Grant, here is a schematic of the circuit and a circuit descripition The NB in the 858 radios was on a seperate circuit board, and if you can get hold of one, it would put you way ahead of the game. Plus . . . they were pretuned at the factory. Maybe a forum member has one you could have out of an old junker. If you can't find one, I'll send you one, but coming from Colombia takes time.. Let me know in a PM.
Anyway good luck. 73.
- J.J. 399

View attachment 68965

Reading this I would need to use this on a radio that uses a 7.8 if frequency. Correct?

 

[nfsus]

Basically I want to eliminate the noise pre radio. The rx stages of the radio does nothing for me if it's just amping the racket modern tech produces. It's just a thought

 

[unit_399]

Yes. 7.8 if

 

[nfsus]

Welllll crap wrong if. Thought that'd be the case. Hang on ill post something I found in one of my books

 

[nfsus]

This anl seems to serve as a nb as well? Itsin the am side but whatbif you moved it to the ssb side?