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 Leader signal generator
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 Return to top of page · Post #: 1 · Written at 8:15:23 AM on 21 December 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2149

What settings do I use for the broadcast band I know the frequencies can vary from set to set but its the settings on the generator itself I am wanting to know. I was offered a brand new digitech oscilloscope still in its box on the weekend and thought it's about time I experimented with aligning.


 
 Return to top of page · Post #: 2 · Written at 10:11:39 AM on 21 December 2021.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

I am familiar with LSG-11 and mine is a clone of one. I have the instructions for both. I would caution you to overhaul it as I consider them dangerous. I have a spare one here that needs a transformer. I have major overhauled a few.

These were made in two different factories and some have "oil filled caps". They are as bad as waxed paper caps. On those I have met two wire mains cables with caps (0.001uF) of dubious integrity mains to the metal case & chassis. That I consider less than safe: Irrespective of why they did it.

These I would consider "Entry level" when compared to what SC produced, recently. I nobbled mine & run audio output to the oscilloscope, being used as sync. That proves more stable. You can "Zero beat" (heterodyne) the thing against a quartz crystal, but essentially I have little (proven) confidence in the dial calibration. I set mine with a Fluke counter, or originally an old DSE / EA kitset one.

With both counters, setting with tone / modulation ON, will guarantee it to be set off frequency. Leader has a blocking cap (0.001uF) in the out put (cathode follower). However, the bias destroying attenuator is not blocked. The clone has no blocking & I built a "Black (metal) Box" to couple the Generator, Counter and Oscilloscope together and attenuate & block DC. That eliminates a mass of wires going all over the place.

The range switch is little different than a SW set Band "B" is the one with 455kHz. I do have a pic of an LSG-11 and its original box, this I nabbed at car swap meeting. Restored it to working order & moved it on (with box) Antiques are more valuable with there original box.


 
 Return to top of page · Post #: 3 · Written at 11:18:42 AM on 21 December 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2149

Its actually the LSG-11 that I have but no instructions band B is some of the info I was looking for.
Oh and it has been recapped recently I just haven't used it a great deal.
So I'm guessing A is longwave , B is mw and the rest are shortwave ?


 
 Return to top of page · Post #: 4 · Written at 12:19:24 PM on 21 December 2021.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 543

No, it does not work like that.
It’s a broad spectrum frequency generator, divided in to segments.
From around 100 kilohertz to 300 Megahertz.
So, from very low frequencies, ie airport beacons way up to the higher VHF television frequencies.
As per the LS11 Leader generator.
I have and am still using mine 50 years down the track of being new.
It’s had several overhauls though.
JJ


 
 Return to top of page · Post #: 5 · Written at 12:41:39 PM on 21 December 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2149

The oscilloscope I got is a digitech QC1932 and at $120.00 still in its box I had to grab it. So I will buy the HRSA book on receiver alignment and will attempt to teach myself how to do it.


 
 Return to top of page · Post #: 6 · Written at 12:52:28 PM on 21 December 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2149

Ah Thanks Johny I'm starting to understand it more. Its less of a mystery now lol.


 
 Return to top of page · Post #: 7 · Written at 1:00:21 PM on 21 December 2021.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 543

BTW the scope would be very handy, but not essential for normal radio type alignment.
Just be careful when “probing” valve equipment, as the protection on this digital scope will not save the smoke from escaping.
If you want to ring me sometime Carl, will be able to give you a crash course for the LS11.
Can be used as an AM modulator by driving it with your own audio, enabling it too be “heard” by all your radios in close proximity.
JJ


 
 Return to top of page · Post #: 8 · Written at 1:06:19 PM on 21 December 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2149

Thankyou Johny I was thinking of ringing you or Marcc it wont be till after christmas . I have a lot of downtime at my day job so I have time to study these things but alas private phone calls are a no no lol. Can you email me your number please.


 
 Return to top of page · Post #: 9 · Written at 9:32:01 PM on 21 December 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2149

Um correction guys its actually a LSG10 not 11. But it does work.


 
 Return to top of page · Post #: 10 · Written at 9:42:53 PM on 21 December 2021.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 543

Almost exactly the same coverage.
Just a little older.
JJ


 
 Return to top of page · Post #: 11 · Written at 8:28:02 AM on 22 December 2021.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2149

Yes Johnny I had a 5 minute look at it last night when I got home. The explanation you and Marcc gave me has really helped clear up some confusion.

This is the oscilloscope I got for $120 originally $539 so I believe I got a great deal.

https://www.jaycar.com.au/25MHz-dual-trace-digital-storage-oscilloscope/p/QC1932


 
 Return to top of page · Post #: 12 · Written at 10:04:33 AM on 22 December 2021.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

I have managed to collect three Oscilloscopes. An old Heathkit OS-1 with its paperwork, a BWD 539C dual trace and a Digitec 1910. Interesting that when the Digitec runs out of puff the Heathkit looses resolution but keeps going (VHF TV Valves like 6BL8).

Whist not essential they are a time saver with signal faults. The most bizarre being an effort looking for where the signal got lost in an a severely hacked STC 59 Chassis: Nasty surprises. Oscilloscope & Signal Generator are a formidable combination with signal. I do have the specs for LSG-10, so I have actually fixed one between now & 1967.

The STC when I went looking had a secondary oscillation up front caused by factory lead dress and the signal after sorting those two issues was getting murdered by the plate detector. Very clear on the Oscilloscope. Set has no AGC (Autodyne) The local / DX switch was missing. That got replaced and a 68pF cap added to reduce signal when switched in on a strong station. I ended up changing the bias on 6D6 (IF) after having to rebuild the bias chain, from -3 to -4.5V and that sorted it out.

A classic example of where at least two faults were eliminated due to initial spotting with the CRO. When aligning with a CRO if there is distortion you are liable to see it: Then you use the CRO as the signal tracer to see where its origin is.

Not a useless toy. I do have a "Rider" Book on them & one called "101 uses for an Oscilloscope" Not the same as the book (real) "101 uses for a "Dead Cat". Here, environmental vandalism, is owning a cat.

Marc


 
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