FL3 auto notch sweeping sound?

[Clifford Novey]

Hello- 

I just got an FL3 delivered today. Powers up and everything works. The auto notch does indeed remove tones impressively. I do hear a sweeping sound with the auto notch left engaged as the manual suggests. This is in SSB mode monitoring on the headphone jack. Is this normal?

Thanks

Clifford

KK6QMS

[Nick B.]

That sounds correct to me. If you're comparing with  DSP notch filter there's a noticable difference as the old analogue filters in the datong aren't as steep on the slopes.

Nick.

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[Clifford Novey]

Here is what it sounds like: attached

off

ssb/pk - auto notch on/off

ssb

ssb w auto notch

[cas...@tbwil.ch]

Hi Clifford

A few years ago I changed radically my station with new rigs and did not include the Datong FL-3 any more. For sure I never heard such sweeping noise like your recording when I used to listen to SSB signals. In spite of Mr. Datong's saying in his short manual I used to switch off the Auto Notch, listen and when I had a disturbed station switched it in. To me the FL-3 with the Auto Notch was a real jewel compared to the FL-2 without the Auto Notch. With my TS-590SG I have had no need for it. The FL-3 is in fact a FL-2 with a second pcboard for the Auto Notch (model 710-0342).

By the way I had several Datong products and I never saw any serial number as you mention. Just his FL pcboards have a model number beginning with 710-xxxx.

73 de Jean-Claude, HB3YDH

[Nick B.]

Hi,

I'll have to get my FL3 hooked up again and test it. In the meantime, if you haven't already found them, the schematics and alignment manuals can be found over here -> https://sites.google.com/site/datongarchive/fl2-fl3/fl2-fl3-manuals

When the FL1 and FL3 were around in the early 1980's I recall a few people commenting that the auto-notch was better in the FL1 than it was i the FL3 (or ANF or FL2/A). Considering the age of any Dating equipment I'd consider one a restoration project as components may have aged, particularly the electrolytic capacitors.

Nice to see some activity on the group again!

73

Nick.

[cnovey]

thanks

pics-

https://forums.qrz.com/index.php?threads/datong-fl3-analog-multi-mode-audio-filters.546667/

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[cnovey]

Thanks very much. Let me know. I appreciate the help.

C

 

From: datong...@googlegroups.com [mailto:datong...@googlegroups.com] On Behalf Of Nick B.
Sent: Friday, December 09, 2016 11:52 AM
To: datong...@googlegroups.com
Subject: Re: [datong] FL3 auto notch sweeping sound?

 

Hi,

Nick.

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[cas...@tbwil.ch]

Hi Nick

May be you can add something about the FL-1 to your Datong website. I gathered these files a long time ago on Internet, the schematic and the operating instructions of the FL-1. Somebody drew it by analyzing the pcboard (nice work!). I had cleaned them somehow as I could. Mr. Datong was not keen to publish any schematic and even erased the IC denomination in his rigs. Also attached the product catalogue of Mr. Datong. I have no clue if he stopped his business because of age or if he died.

73 de Jean-Claude, HB3YDH

[Clifford Novey]

I have a friend in Leeds who applied for a job and met him. Apparently the British govt approached him and he has been doing govt contracts only ever since.

Clifford

[Nick B.]

Hi Jean-Claude,

Thanks for the details. I already have some FL1 information on the site https://sites.google.com/site/datongarchive/fl1/fl1-manuals

[cas...@tbwil.ch]

Hi Nick

Sorry I did not see your extra register for the FL-1.

By the way you have only the schematic of its small pcboard and mine is even better optimized. The schematic of the large pcboard is missing.

Have a nice Sunday.
Jean-Claude

[cnovey]

Hello- looking for suggestions-

 

I opened the unit tonight but the knobs almost felt glued on. The are right knob with the 6 pin pot broke the shaft- Grrr.

Knobs were so tight on the shafts the upper cutoff freq shaft broke off- ARGH! (far right knob) There was something akin to tree sap all over the shafts once knobs pried off. Bummed as it is a 6 leg pot not a more common 3 leg.

 

I do not see anything glaring. Unfortunately the schem part numbers are not screened on the PCBs. Wondering where you suggest I start. The 10uF on the i/o of the auto notch board? Somewhere else? Being able to shine a light through the PCB and follow traces is awesome.

 

Pics-

https://goo.gl/photos/p1cdob61w5dfsKwy9

 

Clifford

 

[cas...@tbwil.ch]

Clifford

You must be a strong man!....

From what I could gather it is a double potentiometer of 10Kohms (do verify the value on the potentiometer or measure both of them). If it indicates 10Kohm <A> it is a linear execution, if it indicates 10Kohm <B> it is a logarithmic execution. For the Datong it should be a <A>.. I do not know in which country you live. If it is in the USA, you will surely find such one at <mouser.com> or <digikey.com>.

With a desoldering pump or desoldering iron you shoud be able to unsolder the 6 pads without impairing the pads. Look carefully if by chance there are one or two more prongs than the six holding the potentiometer on the pcboard

Jean-Claude

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[Clifford Novey]

I do not understand <A> and <B> referenced in your description

Ya I had to pry them off which is why the shaft broke. Never seen anything like it.

73

C

[cas...@tbwil.ch]

Potentiometers were and are often used for audio volume in AF amplifiers. The human's ears do not ear sound in a linear fashion but in a logarithmic one. That's why there are also potentiometers (as B engraved) which have such a logarithmic carbon track. In other appplications than audio and hi-fi, linear carbon tracks (engraved as A) are used, that means the amount of carbon is equally spread over the 270 degrees of the carbon track.

Mostly the letters A and B are engraved or printed close to the ohm value, sometimes in bracket).

Jean-Claude

[cnovey]

Thank you very much for the info. All 3 are A type= linear.

C

 

From: datong...@googlegroups.com [mailto:datong...@googlegroups.com] On Behalf Of cas...@tbwil.ch
Sent: Sunday, December 11, 2016 11:29 PM
To: datong...@googlegroups.com
Subject: Re: [datong] FL3 auto notch sweeping sound?

 

Potentiometers were and are often used for audio volume in AF amplifiers. The human's ears do not ear sound in a linear fashion but in a logarithmic one. That's why there are also potentiometers (as B engraved) which have such a logarithmic carbon track. In other appplications than audio and hi-fi, linear carbon tracks (engraved as A) are used, that means the amount of carbon is equally spread over the 270 degrees of the carbon track.

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[cas...@tbwil.ch]

Hi Clifford

Where do you live that you can answer so quickly? Here I am in Switzerland, not very far from the German border (UTC+ 1 hour).

Have a look at the following link and read under <Resistance–position relationship: "taper">
https://en.wikipedia.org/wiki/Potentiometer

73 de Jean-Claude

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[cnovey]

Thanks-

I am in Los Angeles. 1230AM PST here now- time for bed.

73

Clifford