Topics

Type 184


Stephen
 

I have this Type 184 that I acquired a few months back from EBay.
After cleaning all the contacts and switches, it works fine. However, the last calibration stickers dates from 1982. So I assume it hasn’t been calibrated since.
Yesterday I checked the 10Mhz base frequency and found this:

https://groups.io/g/TekScopes/photo/251419/0?p=Created,,,20,2,0,0

Is it acceptable? It oscillates between 10000.024 to 10000.030 kHz

I don’t feel confident nor confortable touching it. Would you?


Tom Gardner
 

On 31/07/20 16:26, Stephen wrote:
I have this Type 184 that I acquired a few months back from EBay.
After cleaning all the contacts and switches, it works fine. However, the last calibration stickers dates from 1982. So I assume it hasn’t been calibrated since.
Yesterday I checked the 10Mhz base frequency and found this:

https://groups.io/g/TekScopes/photo/251419/0?p=Created,,,20,2,0,0

Is it acceptable? It oscillates between 10000.024 to 10000.030 kHz
There are two possible answers:

* is it with the published specification?
* does it do what you need it to do?


I don’t feel confident nor confortable touching it. Would you?
Yes I would, but I'm not you.

I have been /very careful/ not to physically touch some of the internal metalwork when plugged in, and only to bend some of the exposed wires after it has been /unplugged/ for at least a minute.

My attitude? If you are happy with it, then touching it can only make you less happy with it.


n4buq
 

Is your Hameg counter in calibration and, if so, for what accuracy is is spec'd?

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Stephen" <stephen.nabet@...>
To: TekScopes@groups.io
Sent: Friday, July 31, 2020 10:26:01 AM
Subject: [TekScopes] Type 184

I have this Type 184 that I acquired a few months back from EBay.
After cleaning all the contacts and switches, it works fine. However, the
last calibration stickers dates from 1982. So I assume it hasn’t been
calibrated since.
Yesterday I checked the 10Mhz base frequency and found this:

https://groups.io/g/TekScopes/photo/251419/0?p=Created,,,20,2,0,0

Is it acceptable? It oscillates between 10000.024 to 10000.030 kHz

I don’t feel confident nor confortable touching it. Would you?




Mlynch001
 

On Fri, Jul 31, 2020 at 10:26 AM, Stephen wrote:


s it acceptable? It oscillates between 10000.024 to 10000.030 kHz

I don’t feel confident nor confortable touching it. Would you?
In my opinion, Your counter could just as easily have an error and be reading slightly high. Without a verifiable standard to compare either instrument with, it is impossible to determine, I would leave it as is until you can find a reliable standard source.


--
Michael Lynch
Dardanelle, AR


Ken Eckert
 

From the manual:

2. Check Crystal Oscillator Frequency
a. Requirement-Frequency 1 0 MHz ± 1 00 Hz at ambient
room temperature. Crystal oven stabil ized. (Two hours
warm-up time after power is appl ied before crystal oven is
stabilized.)

On Fri, Jul 31, 2020 at 8:41 AM Tom Gardner <tggzzz@...> wrote:

On 31/07/20 16:26, Stephen wrote:
I have this Type 184 that I acquired a few months back from EBay.
After cleaning all the contacts and switches, it works fine. However,
the last calibration stickers dates from 1982. So I assume it hasn’t been
calibrated since.
Yesterday I checked the 10Mhz base frequency and found this:

https://groups.io/g/TekScopes/photo/251419/0?p=Created,,,20,2,0,0

Is it acceptable? It oscillates between 10000.024 to 10000.030 kHz
There are two possible answers:

* is it with the published specification?
* does it do what you need it to do?


I don’t feel confident nor confortable touching it. Would you?
Yes I would, but I'm not you.

I have been /very careful/ not to physically touch some of the internal
metalwork when plugged in, and only to bend some of the exposed wires
after it
has been /unplugged/ for at least a minute.

My attitude? If you are happy with it, then touching it can only make you
less
happy with it.




Stephen
 

On Fri, Jul 31, 2020 at 04:40 AM, Tom Gardner wrote:

There are two possible answers:

* is it with the published specification?
* does it do what you need it to do?>
Yes and yes.


Tom Gardner
 

On 31/07/20 17:05, Stephen wrote:
On Fri, Jul 31, 2020 at 04:40 AM, Tom Gardner wrote:

There are two possible answers:

* is it with the published specification?
* does it do what you need it to do?>
Yes and yes.
In that case the question becomes "what have I got to gain by fiddling with it?". That can be balanced against what you might have to lose. The balance seems easy :)

That presumes all the outputs work as expected, but that is very different to the frequency accuracy.


Stephen
 

On Fri, Jul 31, 2020 at 04:43 AM, n4buq wrote:


Is your Hameg counter in calibration and, if so, for what accuracy is is
spec'd?

Thanks,
Barry - N4BUQ
It should be, yes.

Translated from the manual:
Time lapse between 2 measures: >= 0.3s
Precision? +/- CMS +/- trigger error/N to the 3rd, + Time Base Error x Period.


Stephen
 

On Fri, Jul 31, 2020 at 04:44 AM, Mlynch001 wrote:


On Fri, Jul 31, 2020 at 10:26 AM, Stephen wrote:


s it acceptable? It oscillates between 10000.024 to 10000.030 kHz

I don’t feel confident nor confortable touching it. Would you?
In my opinion, Your counter could just as easily have an error and be reading
slightly high. Without a verifiable standard to compare either instrument
with, it is impossible to determine, I would leave it as is until you can
find a reliable standard source.


--
Michael Lynch
Dardanelle, AR
That’s pretty much what I thought too. Hence my hesitation to touch it.
And now that Ken mentioned it, the manual does indeed specify +/-100Hz.
And I’m off by about 30Hz. The couter can loose +/-1-10-7 / month. So even if the counter is slightly off, I should still be with specs, I guess.

PS: Did you receive my last email yesterday?


Stephen
 

On Fri, Jul 31, 2020 at 05:09 AM, Tom Gardner wrote:


On 31/07/20 17:05, Stephen wrote:
On Fri, Jul 31, 2020 at 04:40 AM, Tom Gardner wrote:

There are two possible answers:

* is it with the published specification?
* does it do what you need it to do?>
Yes and yes.
In that case the question becomes "what have I got to gain by fiddling with
it?". That can be balanced against what you might have to lose. The balance
seems easy :)

That presumes all the outputs work as expected, but that is very different to
the frequency accuracy.
Everything works. So you’re right. I have nothing to gain messing with it.

Although now that you mention it, I did notice some +DC offset when my scope is DC coupled...
Hmmmm...


Stephen
 

On Fri, Jul 31, 2020 at 04:51 AM, Ken Eckert wrote:


From the manual:

2. Check Crystal Oscillator Frequency
a. Requirement-Frequency 1 0 MHz ± 1 00 Hz at ambient
room temperature. Crystal oven stabil ized. (Two hours
warm-up time after power is appl ied before crystal oven is
stabilized.)
You’re correct. I had forgotten about the +/-100Hz.


Stephen
 

That settles it, I guess. I’m not touching the calibration on it.


Tom Gardner
 

On 31/07/20 17:25, Stephen wrote:
On Fri, Jul 31, 2020 at 05:09 AM, Tom Gardner wrote:

On 31/07/20 17:05, Stephen wrote:
On Fri, Jul 31, 2020 at 04:40 AM, Tom Gardner wrote:

There are two possible answers:

* is it with the published specification?
* does it do what you need it to do?>
Yes and yes.
In that case the question becomes "what have I got to gain by fiddling with
it?". That can be balanced against what you might have to lose. The balance
seems easy :)

That presumes all the outputs work as expected, but that is very different to
the frequency accuracy.
Everything works. So you’re right. I have nothing to gain messing with it.

Although now that you mention it, I did notice some +DC offset when my scope is DC coupled...
Hmmmm...
Ah. A perfectionist tweaker :)

A quick skim of the schematic makes me think I would expect to see offsets on the outputs.

It is a time calibrator, not an amplitude calibrator. I'd be satisfied if the peak-peak amplitudes are acceptably large.


Roy Morgan
 

The error reading you get from your counter seems to be on the order of one fifth of one thousandth of a percent.

The spec on the 184 is one thousandth of one percent.

So, IF the counter is dead on, the 184 error is well within specification. I offer two questions:

1) Is the counter dead on?

2) Why worry about it? Do you really need or want time marks to be accurate to one thousandth of one percent? (Another way to think about this is: how wide is the trace on a scope you might want to calibrate?)

Roy Morgan
K1LKY Western Mass

On Jul 31, 2020, at 11:52 AM, Ken Eckert <eckertkp@...> wrote:

From the manual:

2. Check Crystal Oscillator Frequency
a. Requirement-Frequency 1 0 MHz ± 1 00 Hz at ambient
room temperature. Crystal oven stabil ized. (Two hours
warm-up time after power is appl ied before crystal oven is
stabilized.)

On Fri, Jul 31, 2020 at 8:41 AM Tom Gardner <tggzzz@...> wrote:

On 31/07/20 16:26, Stephen wrote:
I have this Type 184 that I acquired a few months back from EBay.
...


Stephen
 

On Fri, Jul 31, 2020 at 05:36 AM, Tom Gardner wrote:

Ah. A perfectionist tweaker :)
Yes, I am. I like precision. Maybe I do have an OCD. 😂

A quick skim of the schematic makes me think I would expect to see offsets on
the outputs.
Ok.

It is a time calibrator, not an amplitude calibrator. I'd be satisfied if the
peak-peak amplitudes are acceptably large.
Honestly, I haven’t had the time to check everything yet, but for what I’m using it for (mostly .1ms and 1ms time marks), it works like a charm.


Eric
 

Slight frequency oscillation is NORMAL and is called out in the calibration document. It is because the temperature variation of the ovenized crystal. the oscillation should coincide with the oven light cycling on and off. If you are warming up the 187 to calibrate something it needs a 2 hour warm up followed by the 30 minute ON warn up. The oven needs 2 hours to thermal soak the crystal.

Zen

On 7/31/2020 12:23 PM, Stephen wrote:
On Fri, Jul 31, 2020 at 04:44 AM, Mlynch001 wrote:

On Fri, Jul 31, 2020 at 10:26 AM, Stephen wrote:

s it acceptable? It oscillates between 10000.024 to 10000.030 kHz

I don’t feel confident nor confortable touching it. Would you?
In my opinion, Your counter could just as easily have an error and be reading
slightly high. Without a verifiable standard to compare either instrument
with, it is impossible to determine, I would leave it as is until you can
find a reliable standard source.


--
Michael Lynch
Dardanelle, AR
That’s pretty much what I thought too. Hence my hesitation to touch it.
And now that Ken mentioned it, the manual does indeed specify +/-100Hz.
And I’m off by about 30Hz. The couter can loose +/-1-10-7 / month. So even if the counter is slightly off, I should still be with specs, I guess.

PS: Did you receive my last email yesterday?


Stephen
 

On Fri, Jul 31, 2020 at 05:40 AM, Roy Morgan wrote:


The error reading you get from your counter seems to be on the order of one
fifth of one thousandth of a percent.
Yes, I think so.

The spec on the 184 is one thousandth of one percent.

So, IF the counter is dead on, the 184 error is well within specification. I
offer two questions:

1) Is the counter dead on?
It’s probably not “dead on”, but should be very close to it. It was last calibrated in 2010.


2) Why worry about it? Do you really need or want time marks to be accurate
to one thousandth of one percent?
No, you are right.

(Another way to think about this is: how
wide is the trace on a scope you might > want to calibrate?)
Good point.

Roy Morgan
K1LKY Western Mass

On Jul 31, 2020, at 11:52 AM, Ken Eckert <eckertkp@...> wrote:

From the manual:

2. Check Crystal Oscillator Frequency
a. Requirement-Frequency 1 0 MHz ± 1 00 Hz at ambient
room temperature. Crystal oven stabil ized. (Two hours
warm-up time after power is appl ied before crystal oven is
stabilized.)

On Fri, Jul 31, 2020 at 8:41 AM Tom Gardner <tggzzz@...> wrote:

On 31/07/20 16:26, Stephen wrote:
I have this Type 184 that I acquired a few months back from EBay.
...


Stephen
 

On Fri, Jul 31, 2020 at 05:48 AM, Eric wrote:


Slight frequency oscillation is NORMAL and is called out in the
calibration document. It is because the temperature variation of the
ovenized crystal. the oscillation should coincide with the oven light
cycling on and off.
I didn’t pay attention to that.

If you are warming up the 187 to calibrate something
it needs a 2 hour warm up followed by the 30 minute ON warn up. The oven
needs 2 hours to thermal soak the crystal.
Yes, I usually let it on and forget about it for 4 or 5 hours before I use it.

Zen


Stephen
 

So I guess that +27Hz / 10Mhz, after 40 years since it was last calibrated in 1982 says a lot about the build and design quality of this thing.


Dave Seiter
 

I know how you feel! I still have two GPSDOs and a couple of Rb units sitting around (just in case), but although having at least seven stable zeros is nice, it doesn't make the scope you're working on any more accurate.  Unsubscribing from Timenuts made my life easier...
-Dave

On Friday, July 31, 2020, 09:43:19 AM PDT, Stephen <stephen.nabet@...> wrote:

On Fri, Jul 31, 2020 at 05:36 AM, Tom Gardner wrote:

Ah. A perfectionist tweaker :)
Yes, I am.  I like precision.  Maybe I do have an OCD.  😂

A quick skim of the schematic makes me think I would expect to see offsets on
the outputs.
Ok.

It is a time calibrator, not an amplitude calibrator. I'd be satisfied if the
peak-peak amplitudes are acceptably large.
Honestly, I haven’t had the time to check everything yet, but for what I’m using it for (mostly .1ms and 1ms time marks), it works like a charm.