Help Choosing a 100MHz Oscilloscope - Page 1
Forum section: electronics / general

author: nathanpc
author_rank: Unknown
timestamp: November 11, 2013, 11:40:18 am
content: Hello,Recently I started playing around with some RF circuits (I've always been intrigued by RF since I was a kid. It's amazing to be able to understand it now). I have aAgilent DSO1052B, which is just a rebadgedRigol DS1052, so I've thinking about getting a higher bandwidth oscilloscope (I think 100MHz is fine).First I thought about buying a handheld oscilloscope since it would have been easier to work with it anywhere in the bench, the nicest one that I found was theSiglent SHS810, but sadly since I live in Brazil its price would go up to almost $1000 due to import fees which makes it a bit too much for my hobby.So I started looking around for analog oscilloscopes, because they are fairly cheap compared to digital and because I really like the look of the waves in a CRT, or as Dave would call it "the analog goodness". I found a working (and calibrated, so the seller claims)HP 1740afor $364.95 and aTektronics 465bfor $475.08 in the brazilian version of eBay.So, I would like to know if it's really worth waiting for a while and buying a new digital oscilloscope or go with a good ol' analog one.

author: madshaman
author_rank: Frequent Contributor
timestamp: November 11, 2013, 12:01:45 pm
content: That's a bit pricey for that scope. Another thing about the HP scopes of that era is the form factor is (imho) inferior to Tek scopes.At 100Mhz I'd recommend a Tek 465 (although some will complain it's really old). At higher bandwidths, the 475 (200Mhz) and 485 (350Mhz) are options.Depending on availability, you've also got the much newest 2445 at 100Mhz, the 2236 is also nice.For the price you're thinking of paying you could probably find a Tek 2465.I'd do a lot of reading of the specs of the scope you're getting, there are many variants to both the HP and Tek scopes.If you're getting into RF, I'm not sure 100Mhz does entirely suit your needs; but you seem confident.

author: nathanpc
author_rank: Unknown
timestamp: November 11, 2013, 12:06:02 pm
content: Sadly here in Brazil the availability of scopes is very bad and the prices are extremely high. For example, I paid $431.46 for that Agilent scope because of the awful taxes in this country (just a taste, our import fees are at 80%).

author: GreyWoolfe
author_rank: Unknown
timestamp: November 11, 2013, 12:18:17 pm
content: I agree with Dave on the analog goodness. I would tell you to have one of each. I have a hacked Hantek DSO5102B, a BK Precision 5100 100 MHz combination analog and digitizing scope and a Tektronix 2235 100 MHz analog scope. I would recommend the Tektronix 2235. It is a nice basic 100 MHz scope and hopefully can be had for decent money. Of your two choices, I would go for the Tektronix. The HP was introduced in 1963 and has tubes or valves and the 465 is a 10 year newer design without tubes and might be easier to repair if needed. Good luck on your hunt for analog goodness.Tom, NW0LF

author: nathanpc
author_rank: Unknown
timestamp: November 11, 2013, 12:29:02 pm
content: I searched a bit more and I was able to find aTektronics 475for the same price of that 465.

author: Dawn
author_rank: Regular Contributor
timestamp: November 14, 2013, 06:26:25 pm
content: Another thing about the HP scopes of that era is the form factor is (imho) inferior to Tek scopes.It's interesting how some things are relative. I spent two years of my undergrad doing work-study doing maintainance on test equipment in physical science labs and professor's labs. You couldn't convince anyone in the sciences that TEK was better. It was all HP and back then the 1700 series were the desired scopes. 180 frames were also popular. I hear that changed over the years to LeCroy in most institutions.Over at the college of engineering, it was the opposite and all TEK. Compactness, mainframe style/plug-ins and many of TEK's cutting edge features weren't valued in the sciences as much as the egonomic and intuitive layout of the monolithic HP's, and they didn't go through new scopes ever few years, that's for sure. While there were a lot of 180's still around, the 1740 series had to be the most favored and retained long afterwards during my Grad years still in the private labs. My shop has an old HP-1707 on one bench that I've owned about 25 years and an ex-mil TEK-7603 that I bought like new in '91 on a cart. I work in RF and guess which gets used the most? Nothing wrong with the TEK, although, to me, it's a royal PITA to work with compared to the 1707, so have been most any older TEK scope I've worked with. TEK has always had the advantage technologically, but not for long. My Rigol is now seeing the lion's share of scope use in the shop although sometimes the analog is much better to work with.

author: nathanpc
author_rank: Unknown
timestamp: November 14, 2013, 07:15:14 pm
content: Sorry, I forgot to keep you guys updated. I bought the Tektronics 475 2 days ago. The seller said he'll put it in the mail today. It'll probably take 4-5 days for it to get here. I'll do the basic tests and update everyone.

author: ivan747
author_rank: Super Contributor
timestamp: November 15, 2013, 11:25:58 pm
content: Do tell us. I undestand scopes in Brazil are hard to get and expensive, it's great that you could get oneWhat was the price, may I ask?

author: nathanpc
author_rank: Unknown
timestamp: November 15, 2013, 11:30:50 pm
content: Quote from: ivan747 on November 15, 2013, 11:25:58 pm$475.08

author: nathanpc
author_rank: Unknown
timestamp: November 19, 2013, 11:48:29 pm
content: The oscilloscope arrived today. It's beautiful:Thankfully it was very well packaged, a lot of padding and extra padding for the front to protect it:The first thing I noticed was that sadly the A Trigger potentiometer was broken (probably happened during shipping):As a quick fix to test if the A trigger was working correctly I decided to open the case and connect the B (delayed) Trigger potentiometer to the A Trigger connector:It works like a charm for Channel 1, but for some reason it can't trigger on Channel 2.Another thing that I've noticed while testing it was that apparently Channel 2 (the shorter wave) is completely out of calibration and CH 1 is just slightly out (both channels were measuring the same signal):Another thing that I've noticed is that, only on Channel 2, the 20mV/div range is showing a very strange square wave instead of the triangle signal:In a resume I'll have to find someone that have one of those old potentiometer+switch part and wants to sell it to fix the broken one. I have no idea where to start on why Channel 2 isn't triggering (any ideas?), also is it possible that the CH2 gain potentiometers are that much out of calibration (it seems too much in my opinion)?