[Boatanchors] Inexpensive Scope Probes

[J. Forster]

Looking at RF waveforms with a 'scope is not very useful. Even at 10 MHz,
you need a least 100 MHz 'scope to see much of anything.

FWIW,

-John

===============

> At my age $100 for another scope is a luxury! I can do most of what I need
> to with the 35MHz scopes. And I can use a RF probe on the VHF/UHF stuff
> because I am not really interested in the RF waveform.
>
> And the way ham radio seems to be going here I really need to find
> something
> else to occupy my time.
>
> Bob Macklin
> K5MYJ
> Seattle, Wa.
> "Real Radios Glow In The Dark"
> ----- Original Message -----
> From: "Carl" <km1h at jeremy.mv.com>
> To: "Bob Macklin" <macklinbob at msn.com>; "rbethman" <rbethman at comcast.net>;
> "BOATANCHORS" <boatanchors at mailman.qth.net>
> Sent: Wednesday, February 09, 2011 9:42 AM
> Subject: Re: [Boatanchors] Inexpensive Scope Probes
>
>
>> With a 465 available for $100 these days why bother? Bench and rack
>> analog
>> models to 300-400MHz are now selling for less than the probes.
>>
>> Carl
>> KM1H
>>
>> ----- Original Message -----
>> From: "Bob Macklin" <macklinbob at msn.com>
>> To: "rbethman" <rbethman at comcast.net>; "BOATANCHORS"
>> <boatanchors at mailman.qth.net>
>> Sent: Wednesday, February 09, 2011 11:45 AM
>> Subject: Re: [Boatanchors] Inexpensive Scope Probes
>>
>>
>>>I bought mine from Pomona. since I only have 35MHz scopes they work very
>>> well.
>>>
>>> I have been thinking of making a VHF/UHF converter to use ahead of the
>>> 35MHz
>>> scopes so I use the scopes on  VHF and UHF gear.
>>>
>>> Bob Macklin
>>> K5MYJ
>>> Seattle, Wa.
>>> "Real Radios Glow In The Dark"
>>>
>>>
>>> ----- Original Message -----
>>> From: "rbethman" <rbethman at comcast.net>
>>> To: "BOATANCHORS" <boatanchors at mailman.qth.net>
>>> Sent: Wednesday, February 09, 2011 8:36 AM
>>> Subject: Re: [Boatanchors] Inexpensive Scope Probes
>>>
>>>
>>>>I don't know how long it has been since you were in the Navy.  If you
>>>> are like a large number of us, it has been a couple or more decades
>>>> since we left the military.
>>>>
>>>> I would "normally" agree that non-spec items are to be shied away
>>>> from.
>>>>
>>>> I went ahead and bought the same ones that are being offered
>>>> currently.
>>>> (It is 2011 now....)
>>>>
>>>> I attached these new ones to the dual channel inputs, along with an
>>>> Honest to goodness Tektronix Probe.
>>>>
>>>> Both got fed a 38.8 MHz PLL circuit test point.
>>>>
>>>> I swapped them back and forth from ch1 to ch2.  Running my hands over
>>>> them, and even twisting them around each other resulted NO CHANGE in
>>>> waveform.  The same result even when wrapped under the chassis of the
>>>> mainframe of the Tek 5440.
>>>>
>>>> They also compensate very well.
>>>>
>>>> Since I'm savings significantly, I'll go ahead an use them.  *IF*
>>>> there
>>>> is an "unseen" difference on traces, when one is laid over the other,
>>>> it
>>>> has got to be about 1% or less.
>>>>
>>>> I think they are more than usable for Amateur Radio.  The larger
>>>> number
>>>> of us are working on our own equipment.  We don't have a need for NIST
>>>> traceability.
>>>>
>>>> You'll find the nuts and bolts you buy are loaded with "forgeries",
>>>> and
>>>> that they will NOT hold the same torques.  I worry more about that
>>>> when
>>>> I start to bolt together 400 pound or greater pieces of gear.
>>>>
>>>> YMMV.
>>>>
>>>> Enjoy,
>>>> Bob - N0DGN
>>>>
>>>> On 2/8/2011 11:25 PM, Glenn Little WB4UIV wrote:
>>>>> While in the navy, we ordered a Tektronix scope probe.
>>>>> Due to competitive bids and "specs" we received a knock off probe.
>>>>> When I attempted to measure a clock waveform in a computer with the
>>>>> prescribed scope and this probe, the waveform would change depending
>>>>> on where along the lead you placed your hand or the position of the
>>>>> lead relative to the chassis of the computer.
>>>>> The next order was specified "do not substitute" and we did receive a
>>>>> genuine Tektronix probe.
>>>>> There was no problem measuring the clock waveform with this probe.
>>>>>
>>>>> Buyer be ware with cheap probes.
>>>>> Probably useable for audio, but very questionable above a few
>>>>> MegaHertz.
>>>>>
>>>>> It all depends on how much you want to trust the waveform displayed
>>>>> on the scope to be an accurate representation of the measured
>>>>> circuit.
>>>>>
>>>>> Just my experience.
>>>>> I will only use quality probes.
>>>>>
>>>>> 73
>>>>> Glenn
>>>>> WB4UIV
>>>>
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>>
>
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