PoorBoys PentaScanner or Microtest??? 2

[jonnybb1]

Just wanted to see if anyone has any suggestions on purchasing an inexpensive scanner that does wiremappings, length, and line speed. Most of my clients don't require certification but I would like to be able to confirm an approximate speed for a given that might pushing the length boundaries.

Ok in other words, does anybody know the best to determine speed without spending $5000-$7900???
Jonnybb

 

[wires]

No handheld testers I know of can actually "determine speed" of a cable. There are essentially three types of testing that apply to wiring in the field:

1.Wiremap $50-$1000
These testers will at minimum show if a cable (assembly) has electrical continuity and which pin on one end of the cable is connected to which pin on the other end of the cable. As the price goes up additional tests like split pairs, length, cable ID, media ID and tone are added. Here is a fairly inexpensive "wiremap" type tester:

http://www.test-um.com/testum/product_detail.asp?itemno=TP500

My favorite in this category is:

http://www.flukenetworks.com/us/Cabling/Residential+and+Basic+Testing/MicroScanner+Pro/Overview.htm

2.Certification $1000-$10000
These testers can certify that a cable (assembly) can perform to a "certified" level like cat5. The PentaScanner is a example of a cat5 certification tester. It is being replaced by the OmniScanner as cat6 becomes more widespread. There are quite a few under $1000 PentaScanners on eBay these days as the industry upgrades.

3.Network tools $free-$$$$$$$$$$$$$
Once the cable is installed and tested there are a variety of hardware and software tools to test just about any parameter you can imagine. One nice handheld unit is the OptiView:

http://www.flukenetworks.com/us/LAN/Handheld+Testers/OptiView/Overview.htm

One inexpensive tool I use is ProvaGENc/s:

http://www.provanet.com/packet_generator_tts_page.htm

Like in the automotive world where there are all sorts of tools to adjust and test every part of the vehicle the only way to "determine speed" of a vehicle is to run it. A network (like a car) is built of many components so the final speed test is in the operation. A cable that does not meet certification may or may not affect network speed.

 

[phonebiz]

Just a point, but I have tested thousands of cables and have never had one fail a Cat 5 test unless the wire map was wrong.

 

[c0i0nes]

I agree with Phonebiz, if the wiremap checks out as OK, then 99% of the time the rest of the tests check out too. Logical really, with good quality cable, unless you have really abused the cable when laying it. The commonest exception is an intermittent fault in one of the RJ45 plug connections, often due to wire strain.

Paladin Patch-Check # 1529 tool costs about $50, and is easy to use with RJ45 and RJ11 terminated leads (you can use guaranteed patch leads to test socket - socket cabling wiremap and continuity).

The caveat is, just because the cable works, it doesn't mean it is working within specification, or could gain certification.

 

[fonedude]

When you start testing for Cat 5e and Cat6, there are a couple of things that will fail a cable that has a good wiremap. Near end cross talk and far end cross talk are 2. Sometimes these errors can be caused by squashing the cable, pulling the wire ties too tight, having the cable too close to a transformer, or having the cables submerged in water. But 99% of the time if wiremap is ok the cable will work. What the tester is testing is "overhead", which is that maximum capability of the cable. A Omniscanner runs 30,000 tests on a cable in a minute.

 

[daronwilson]

I've not used the Omniscanner for a year, moved to the Wirescope 350, but as I remember it does not test for headroom.

Basically there are particular parameters that the tester checks, and it checks those parameter at intervals in frequency between 0 and 100 Mhz for Cat5 and 5e. So the wire tester takes off and checks at say 1 Mhz, and it logs all the attenuation, NEXT, FEXT, ELFEXT, etc. Then it bumps up and up until it gets to 100 Mhz. When it has done all this, it compares the results with an internal table that is preset (and user modifiable) to see if the wire met the requirements for the Category that you are asking it to certify to.

Now, you could congifure your tester to scan up to say 300 Mhz, but, what would that do for you? There is no standard to compare it to for 300 Mhz, so how do you know if the attenuation, NEXT, FEXT, etc. are in compliance? We went through this waiting for Cat6 to come out, everyone guessed what the standard was going to be, and we tested to 250 Mhz or so to be sure we were above what the standard was going to require. However, until the standard for Cat6 was adopted, no one could tell for sure what the requirements were going to be. With the wirescope (and probably others) you could save all the test results, and then run them through again under the Cat6 requirements after the standard was adopted.

Overhead, to me anyway, is the distance between the top of your standard and the maximum the cable can do. So if you have 350 Mhz cable, and you are certifying it to Cat5e, you should have a 250 Mhz overhead in the bandwidth of the cable. Thats all, nothing more. When i look at plots produced by my wirescope, I get a plot for each test. So I can see that for NEXT, I have an overall 6dB difference between the standard limit and the performance of my cable. That difference is the NEXT overhead.

Now if the test fails on NEXT or FEXT, I don't agree that this is caused by a transformer in the area or submerging the cables in water. Being too close to a transformer will quite likely increase the Noise measurements, but NEXT is checked by transmitting a signal on one pair, and listening for THAT signal on an adjacent pair (Power Sum NEXT is listening for that signal on ALL adjacent pairs).

Anyway, there is no real substitute for a good wire scanner if you really want compliance. If you can't spend the $$$, the next best thing that I have found is the Siemon STM-8 Tester. It cost me about $230 I think, it checks a variety of wiring standards. What is real cool about this cheap tester is that is does continuity, then it does a 'transmission' test. The transmission test checks for split pairs, and oddly enough it works. So if you have the pairs split but still continuity, this tester will show you. For the money, this is one of the better deals.

Hope that Helps! It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[wybnormal]

For the poor mans scanner(?) check out this issue of Poptronics which has a *build it yourself* intelligent mapper. I plan to build one just to see how well it works as a quick and dirty checker.

http://www.poptronics.com/

It's a two parter.. so this is the first part.. 2nd is in Jan.

MikeS
Find me at

http://www.packetattack.com

"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu

 

[wires]

Is this the same item as in poptroncs?

http://www.a-and-t-labs.com/K10_Mapper8/

If so it looks like a fairly neat project. I am not so sure it will end up being cheaper than some of the items below. It all depends on your level of electronics assembly experience, how well you junk box is stocked and the value you assign to your time. I have always found building stuff (kits or my own projects) very rewarding, so cost savings have never been a key factor in deciding to tackle build-it myself project.

Here are some assembled units with similar functionality (wiremap but no pass/fail like the mapper8 above):

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2079666200

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1923731692

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2078086816

All of the above testers only do wiremap. They will not detect a split pair. Split pairs (a pair made up of wires not twisted together) seem to generate a fair number of the problems found in this forum. For a device to detect split pairs it costs a few more bucks:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2079209729

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2078728764

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2078934686

phonebiz - I too have tested thousands of cables. I have found plenty that passed wiremap but failed certification, including a good number of brand new "factory made" cables.

 

[skip555]

like daron said the siemans stm8 is a preety neat item for the money.

the only problem I have had with mine is my remotes are all starting to physicly come apart. Im down to two

 

[wybnormal]

Looks like the same unit. I have a fairly good stash of parts leftover from my days as a ET for Hughes and other projects. It's always fun to build something like this.. just to say you did build it. Peoples eyes get real big when you say that

MikeS
Find me at

http://www.packetattack.com

"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu

 

[networkstudent]

Hi Jonnyboy,

If you want an usefull scanner, cheap and usefull i'll recommend these:

For wiremapping, i can't imagine a better thing than Siemon's STM-8, is the hell of resistant and durable and still a very good tester, very usefull too.

If you want something above that without spending your next car, you can look for the HP J2263A scanner, is just the same as the microtest MT350, take a look at some auctions sites, it meassures lenght, scans for cable troubles, wiremaps, next @ 20mhz., and grades the cable up to cat5 at 20mhz, noise, etc.

Hope this helps

 

[jonnybb1]

Thanx for all the information!!

Sorry for the delayed response! (The holidays ya know!)

jonnybb1