[Elecraft] Oscilloscopes (WAS: spectrogram)

[Alexandra Carter]

Yes, but in actuality, you can very often pick up a good 465 or 475 for 
$100 or so, take it home, clean it up, and it will work for you for 
years. That's hard to beat. 73 de Alex NS6Y.

On Jan 23, 2006, at 8:36 PM, Don Brown wrote:

> Hi
>
> Be careful buying older Tek scopes. Many of the repair parts are not
> available any more. You may get lucky and never need to repair one of 
> these
> scopes but many of the parts were proprietary made custom for Tek or 
> in the
> case of some of the IC's and CRT's were made only by Tek in there own 
> fab. I
> worked for Tektronix for many years as a field maintenance instructor 
> in the
> test and measurement division. My specialty was the 7000 series and the
> portable scopes among others. The reason the 7000 series is so cheap 
> on Ebay
> is the problem of getting repair parts. The most common problem is 
> with the
> cam switches and attenuators in both the 7000 and the 465 and 475 
> scopes.
> The 485 is even a generation earlier than the 465 or 475 so I would 
> not ever
> consider one these scopes unless it had a good CRT, is in excellent
> condition and was virtually free. It also takes a real expert and some
> special equipment to properly tweak a 485 so it will meet specs. The 
> 7000
> series may be OK if you can buy two for a few hundred dollars. The 
> second
> one for parts. I have a friend with a cal lab that has a warehouse 
> full of
> broken 7000's that he uses for parts to keep the stuff he has under
> contract. Tek has a policy that they do not guarantee parts support 
> seven
> years after a product is discontinued. The 465, 475 and most of the 
> 7000 has
> exceeded that by two and the 485 by three
>
> However I personally own a 2465 and can highly recommend it. It is 400 
> Mhz
> four channel with both 1 meg ohm and 50 ohm inputs with dual timebase. 
> This
> was the last of the really great analog scopes Tek made. This scope 
> sold for
> over $5000 in the mid 80's and was worth every penny. I have seen them 
> on
> Ebay for well under $1000 (I paid $800 for mine a couple of years ago) 
> I
> know that is a lot of money to spend on a scope used for hobby work 
> but a
> new scope with much less capability will cost as much or more.
>
> Ron Is correct on the bandwidth specification. Scopes are rated at 3 
> db down
> at the rated bandwidth. This means a 100 MHz scope can measure a one 
> volt pk
> to pk 100 MHz sine wave at .707 volts and still be in spec. Also the 
> probes
> are rated at a max bandwidth as well. If you use a 100 MHz probe on a 
> 200
> MHz scope then you will only have a 100 Mhz bandwidth at best
>
>
>
> Don Brown
> KD5NDB
>
>
>
>
> ----- Original Message -----
> From: "Alexandra Carter" <alexandracarter at sbcglobal.net>
> To: "Ron D'Eau Claire" <rondec at easystreet.com>
> Cc: <elecraft at mailman.qth.net>
> Sent: Monday, January 23, 2006 9:13 PM
> Subject: Re: [Elecraft] Oscilloscopes (WAS: spectrogram)
>
>
>> Tektronix 475, baby! The 465 is OK, and the 485 a real 400MHz work of
>> analog scope art I hope to own someday. Then if you're really serious
>> you have a 7000-series mainframe and a lot of plugins hehe.
>>
>> A really good tutorial on scopes is Tektronix's The XYZ's Of Using A
>> Scope which they used to give out, now you can download it from the 
>> net
>> and the recent versions have a bunch of stupid stuff about their
>> digital scopes - they tell such beautiful lies, stick to analog.
>>
>> 73 de Alex NS6Y.
>>
>> On Jan 23, 2006, at 7:06 PM, Ron D'Eau Claire wrote:
>>
>>> Jim, AB4CZ gave you an excellent summary.
>>>
>>> If you think you'd like to use the 'scope for general bench work to
>>> look at
>>> waveforms, etc., on HF gear, then look for one with at least a 200 
>>> MHz
>>> bandwidth. ...........If you try to observe signals on a narrower
>>> bandwidth oscilloscope, the
>>> higher-frequency information is simply lost.....
>>> At today's Hamfest prices, the price difference between a basic
>>> waveform
>>> monitor and a good general purpose scope is often small....,
>>> Ron AC7AC
>>
>> _______________________________________________
>