Coupling box & attenuator
|
« Back ·
1 ·
Next »
|
|
|
Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5389
|
This is from a request from a post re11-20 Kriesler.
There really is not much to this black box as it's main function is to direct traffic by taking the outputs from the sig gen & distributing them, to mainly BNC so that they can couple via coax so there is no signal radiating everywhere. Box is metal because of RF
The sig gen I have is a clone of an LSG-11 and I have one of those and it's original box. The main difference between the LSG & Clone is that one (LSG) has a 0.001 cap before its attenuator & that causes the counter grief, when it cannot get enough input. That is another reason for the black box.
It puts the counter before the cap that has to be added to the clone but on the LSG reduces the signal needed by the counter. It would be nice to have a generator with a counter that does not need some of this. But when the OP is around 0.1V, or more & you need micro volts & DC blocking, you need to attenuate.
The sig gen can be modulated from an external source but I found that as it outputs audio I could use that on the CRO's external sync to give a more stable picture. I prefer the CRO during alignment as it is more sensitive & can see distortion, as well as being a great signal tracer when things go pear shaped.
As will be seen RF in goes direct to the counter, which should not be calibrated with the "tone" on .. Then there is the DC blocking cap, followed by the next stage of attenuation. Note there are two outputs for that. viz BNC & banana plug.
Marc
|
|
|
|
Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6761
|
|
|
|
|
Location: Central Coast, NSW
Member since 18 April 2014
Member #: 1554
Postcount: 215
|
Very tidy Idea Marc
Lot less clutter with leads and only what you need to be handling available
(apart from the fact no spurious signal floating about or reduced chances of)
When I was looking for a Sig Gen I did find a Fet based instrument as a project at a UK forum on Radio
Someone actually took that and added a frequency counter to it
https://yo4hhp.wordpress.com/2011/10/31/simple-rf-generator/.
(the original link to the design is off that page )
Id hardly call it a precision lab instrument as it stands but you just cant seem to buy these things here new any more (unless you want to pay through the nose for something thats way over kill)
What you could buy wasn't much more then that anyway from memory from the likes of DS etc
I did find a Loadstar that had a frequency counter rather then the dial..evolutionary step I suppose but the US price was like $300 plus and I think these are an obsolete item anyway
For valve gear I guess they dont have to be super high grade lab test gear just an accurate stable signal and with an accurate counter you got what you need, apart from how you might want to organise the Attenuation etc
I think some have modified the 324 with BNC so they can feed a counter
I like your Box idea thought, save modding equipment and brings things together neatly
Thanks Marc for sharing that
|
|
|
|
Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5389
|
Just for valve radio, alignment I would agree that if the generator is as I said, its good enough with the frequency counter calibrating it.
Do note that you can get & I have "double adapters for BNC. The Fluke counter is actually being fed by the thick wire going to the right. Apart from wire, that mostly uncapped duct is there to hold tweezers chopsticks, scissors, probes & anything else that fits in the grooves.
Happy its of use ..... can inspire others
Marc
|
|
|
|
Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6761
|
that mostly uncapped duct is there to hold tweezers chopsticks, scissors, probes & anything else that fits in the grooves
I did note that useful idea, too.
|
|
|
|
Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5389
|
Duct is handy: It keeps wire under control. There is wider fully capped duct on the shelf edge above the computers and it carries wires for printers, scanners, hubs, & corded rat, preventing them from being a massive tangle behind the screens & stress relieving wires from an engine that is actually on a shelf to keep it off the bench & above the floor dust.
Best to be misconstrued, radio quote of the day, when money was supposed to be mentioned; Claimed "Aluminium & Copper were flat"?
Marc
|
|
|
|
Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7395
|
double adapters for BNC
Before Cat5/6 cable was commonplace, local area networks were half-duplex and wired in coaxial cable. These tees were quite plentiful because one was needed at each computer on the network. If an electronics shop isn't handy and you know an IT guru, he may have some lying around.
‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...
|
|
|
|
Location: Somewhere, USA
Member since 22 October 2013
Member #: 1437
Postcount: 896
|
Hi, Can you provide any info on the Siggen including year?
I will have an opportunity to buy the exact same one (upgrade from Leaser LSG-11).
|
|
|
|
Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5389
|
Electrically, the only difference between the TED-20 & the LSG -11 is the output arrangement. Same valves same Colpitts oscillator.
I have the paperwork for both, which I made sure Kevin Chant also has. According to my paperwork I bought it new 22nd August 1975.
LSG is probably of the same vintage, I rescued it with original box at a car swap meet. It has been overhauled.
Marc
|
|
|
|
Location: Somewhere, USA
Member since 22 October 2013
Member #: 1437
Postcount: 896
|
Thanks, I thought it might be solid state. There's a massive ugly difference with regard to mine.
Image Link
I have cleaned it up and painted it, but it still won't be near as nice as the one on offer.
|
|
|
|
Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5389
|
Yes, same as... I did repair & sort out the cable on this one as it was 2 wire & its a metal case. Compared to the photo & the fact this one was in its own box mine is an A category.
Marc
|
|
|
|
Location: Central Coast, NSW
Member since 18 April 2014
Member #: 1554
Postcount: 215
|
|
|
|
|
Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5389
|
I was going to post a reply earlier but the system fell over?
My general comment is that I would love one of those things, but unless you are doing stuff that needs lots of decimal places, or the high frequencies that the cheap jobs struggle with with the valves used and the under voltage, used by LSG & Mine. You really can't justify it if the unit is stable with a good wave form and you already have a frequency counter to set it with.
And again, to the point of pedantic ....... do not use modulated signal when calibrating with the counter. The one I use is a Fluke 1912A
Marc
|
|
« Back ·
1 ·
Next »
|
You need to be a member to post comments on this forum.
|