Problem with brand new Rigol DSA815-TG - Page 1
Forum section: electronics / testgear

author: OZ99DW
author_rank: Contributor
timestamp: August 03, 2015, 07:58:20 pm
content: Hello everyone.I have just bought a brand new Rigol DSA815-TG from a company in Germany.It seems not to be working correct.I get these readings (see picture) with following settings:Center Frequency 450 MHzSPAN 10 MHzATTENUATOR 0 dBREF Level -10 dBmPre Amp OFFRBW 1 KHzTracking Generator ONTG Level 0 dBm30 cm N-N RG223 from Generator Output til RF input.After a couple of minutes the Spectrum Analyzer starts to do calibration and then comes out with the message "intermediate frequency signal out of range"I have contacted the deal and he try to buy me of with the explanation that I overdrive the input with 0dBm input from the Tracking Generator.I hope some DSA815-TG owners have a comment..RegardsDanielOZ99DW

author: TheSteve
author_rank: Unknown
timestamp: August 03, 2015, 08:14:25 pm
content: I only had a DSA815 briefly but yours certainly does look defective to me. And there should be no way to damage the SA input with the TG output. 100% get it replaced.

author: dadler
author_rank: Unknown
timestamp: August 03, 2015, 08:30:36 pm
content: Concur, it is safe to feed the TG straight into the input without issue. The input can handle 20dBm.I think your unit is defective.

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 03, 2015, 08:52:04 pm
content: Is your dealer Batronix? =)

author: OZ99DW
author_rank: Contributor
timestamp: August 04, 2015, 04:29:37 am
content: Quote from: pascal_sweden on August 03, 2015, 08:52:04 pmYes its BatronixWhy ?

author: Bud
author_rank: Super Contributor
timestamp: August 04, 2015, 04:40:41 am
content: Why did you set reference level to -10dBm if you feeding 0dBm into input?Try increasing ref level.Now, in a normal spectrum analyzer this is never a problem (it does not cause overdrive) but with rigol morons you can never be sure.

author: TheSteve
author_rank: Unknown
timestamp: August 04, 2015, 04:44:10 am
content: Quote from: Bud on August 04, 2015, 04:40:41 amRigol may be a little odd at times but I can't see this being an issue - if he is feeding the tracking gen back into the input and his cable isn't bad we should be seeing a line that is very flat.

author: OZ99DW
author_rank: Contributor
timestamp: August 04, 2015, 05:59:10 am
content: Quote from: Bud on August 04, 2015, 04:40:41 amIts necessary to lower the noise when you are adjusting VHF/UHF duplex filters with a rejecting notch level of 90-110dB.Afterwards when you are going to blot the filter for documentation, you just normalize the spectrum analyzer and then is the reference level 0dBm with 0dBm TG input.I´m trying to do the same routine as in this videoThe guy in the video has no problems..

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 04, 2015, 07:01:57 am
content: Quote from: OZ99DW on August 04, 2015, 04:29:37 amI just wanted to know, and will follow-up how the dealer treats the issue.This will make me learn if I should buy from this dealer in the future.I haven't used this distributor myself, but a friend has.Given that you live in Scandinavia, you might have considered Instrumentcenter instead.They are present in Sweden and Denmark, and both country extensions are available for their website. They are smaller in size, and provide more personal service AFAIK.

author: pauln
author_rank: Contributor
timestamp: August 04, 2015, 07:08:33 am
content: Quote from: OZ99DW on August 04, 2015, 05:59:10 amI have just completed a diplexer tune following this exact video and it worked perfectly. A small point only, was that I could not get the screen image with both notches displayed despite many attempts. So have a screen shot of each instead.Paul vk4apn

author: OZ99DW
author_rank: Contributor
timestamp: August 04, 2015, 07:14:15 am
content: Quote from: pauln on August 04, 2015, 07:08:33 amThanks Paul vk4apnCould i ask you a favor ?Please take picture with the same settings as described in my first posting.73 deOZ99DWDaniel

author: OZ99DW
author_rank: Contributor
timestamp: August 04, 2015, 08:12:41 am
content: Quote from: pascal_sweden on August 04, 2015, 07:01:57 amOkay.I really regret that i did not bought at Instrumentcenter..The only reason is the was to high at Instrumentcent last i checked.. But now the price is the same..RegardsDaniel

author: pauln
author_rank: Contributor
timestamp: August 04, 2015, 09:19:19 am
content: Sorry!

author: OZ99DW
author_rank: Contributor
timestamp: August 04, 2015, 09:34:57 am
content: Quote from: pauln on August 04, 2015, 09:19:19 amThanks mateBig help..Hope other DSA815-TG owners would do the same..

author: hendorog
author_rank: Super Contributor
timestamp: August 04, 2015, 10:25:39 am
content: What happens if you normalise it?Change this one setting from your original set:REF Level +10 dBmand then select normalise?After you normalise then change back to the previous setting.The key sequence is on this page:http://www.edn.com/electronics-blogs/emc-emi-rfi-esd/4396464/Using-a-tracking-generator" So to normalize the sweep, press TG > Normalize > Stor Ref. Now enable normalization by pressing TG > Normalize > Normalize On. You should now have a straight line sweep at the top of the display."

author: OZ99DW
author_rank: Contributor
timestamp: August 04, 2015, 10:36:12 am
content: Quote from: hendorog on August 04, 2015, 10:25:39 amStill same problem..Its not possible to Normalize it out..Sorry..

author: hendorog
author_rank: Super Contributor
timestamp: August 04, 2015, 10:59:08 am
content: QuoteDamn, sorry it was a long shot. Good luck and I hope you get a return out of them.

author: Jason_Zhang
author_rank: Newbie
timestamp: August 04, 2015, 01:39:09 pm
content: I think the message "intermediate frequency signal out of range" means the IF signal overload (because the input signal too large), you can try to reduce the TG level or increase the reference level(Set to 10dBm). The overload level doesn't damage the SA input.

author: OZ99DW
author_rank: Contributor
timestamp: August 04, 2015, 03:08:57 pm
content: Quote from: Jason_Zhang on August 04, 2015, 01:39:09 pmYou probably right.. But the thing is that the fail only is on the SA that I received..What should I use a SA to which gets laid down with 0 dBm from its own TG..

author: navzptc
author_rank: Contributor
timestamp: August 05, 2015, 11:50:18 am
content: No problems with my one using your parameters

author: Giorgio
author_rank: Contributor
timestamp: August 06, 2015, 04:18:08 pm
content: Sorry, no problem here too using your settings.Looks like a defective unit.BTW I found another problem with most of the 815-TG, if not all units:https://www.eevblog.com/forum/testgear/rigol-dsa815-tg-10-mhz-issue/

author: mcinque
author_rank: Unknown
timestamp: August 06, 2015, 05:51:32 pm
content: hmmm... same problem here. What's your calibration date? Mine is May 15, 2015edit: i get the UNCAL icon... it seems overloaded

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 06:39:26 pm
content: Quote from: navzptc on August 05, 2015, 11:50:18 amThanks for your reply..

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 06:40:56 pm
content: Quote from: Giorgio on August 06, 2015, 04:18:08 pmThanks for the reply.

author: mcinque
author_rank: Unknown
timestamp: August 06, 2015, 07:04:14 pm
content: so I own a unit like yours that its apparently defective.I noticed that if I put a 10db bnc attenuator on the tg output the problem disappear, so I guess that maybe can be something in the tg output limit?What's yout calibration date?And what the calibration dates of yours "not defective" units?

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 07:04:57 pm
content: Quote from: mcinque on August 06, 2015, 05:51:32 pmI'm sorry that you experience the same problem.Please try to do it same thing with full span and then with preamp on.I think the units calibration date was Mar 8, 2015I also get UNCAL icon, I think the problem is something which gets out of lock..

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 07:13:39 pm
content: A quick update.I sent back the defective unit to the dealer, and the dealer sent a new tested unit apparently without the problemBut the shipping company left en on my doorstep without my permission, and now its goneNow I going to by a used HP spectrum analyzer..

author: TomThomas
author_rank: Contributor
timestamp: August 06, 2015, 07:18:20 pm
content: Quote from: OZ99DW on August 06, 2015, 07:13:39 pmHi,does it act normally if you set the input attenuator to AUTO?brTom

author: mcinque
author_rank: Unknown
timestamp: August 06, 2015, 07:23:17 pm
content: Quote from: OZ99DW on August 06, 2015, 07:13:39 pmWHAT!??!!?!?!?!?p.s. I can saturate the input with 1.25V sinewave on the input with 0db attenuation, very far from the +20dB max input (wich should be 2.25V): I get immediately "out of range".There must be something on the input.

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 07:27:24 pm
content: Quote from: TomThomas on August 06, 2015, 07:18:20 pmYes it did.The last thing i noticed was that the problem chanced over the frequency span over time.Sometimes the problem was from 0 to 750 Mhz, and then 0 to 455 Mhz.Rigol Germany´s test unit was with same problem, so they thought it was normal function.I have lost al confidence to Rigol´s products.

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 07:31:27 pm
content: Quote from: mcinque on August 06, 2015, 07:23:17 pmYes yes.. The guy from DHL is not that clever..I'm starting to get tired..Which type of RF source did you use ?

author: TheSteve
author_rank: Unknown
timestamp: August 06, 2015, 07:38:18 pm
content: Quote from: OZ99DW on August 06, 2015, 07:13:39 pmI replaced my DSA815-TG with an Agilent N1996A, then enabled all features and bumped it from 3 to 6 GHz(with tracking gen!) - cost me the same money as the Rigol.

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 07:48:44 pm
content: Quote from: TheSteve on August 06, 2015, 07:38:18 pmI will pick up an HP 8594E with all options tomorrow..

author: dadler
author_rank: Unknown
timestamp: August 06, 2015, 07:51:23 pm
content: Are you out the cost of the DSA815, or will DHL refund you?There is a thread about DHL and its questionable practices in the for sale forum, making me doubt how easily they pay insurance claims...

author: OZ99DW
author_rank: Contributor
timestamp: August 06, 2015, 08:00:54 pm
content: Quote from: dadler on August 06, 2015, 07:51:23 pmI hope that DHL will refund my loss.. I will meet them with claim of compensation for lost income, I was supposed to deliverer 10 UHF duplex filter tomorrow..

author: mcinque
author_rank: Unknown
timestamp: August 06, 2015, 08:53:29 pm
content: Quote from: OZ99DW on August 06, 2015, 07:31:27 pmQuote from: OZ99DW on August 06, 2015, 07:31:27 pmWell... not properly a RF source, I used an arb function gen with a 1s sine sweep from 4.5 to 5.5 MHz (as the tracking gen output for that settings), with the same amplitude of the TG. I measured first the TG output and then reproduced the same values with the fgen (set to 50Ohm load, of course).

author: Pinkus
author_rank: Frequent Contributor
timestamp: August 07, 2015, 08:40:50 am
content: Quote from: OZ99DW on August 06, 2015, 08:00:54 pmQuote from: OZ99DW on August 06, 2015, 07:13:39 pmWell, DHL isnotyour business partner. They won't provideyouany money.Yourdealeris your partner and as you did not receive the unit (though it is not their fault) THEY are responsible. And THEY do need to claim a compensation at DHL. And THEY do need to send you a new unit.And yes, it is a pity for the dealer. It is not their fault and probably they did not pay extra insurance to DHL, thus they will only receive 500 Euro maximum from DHL. But this is live, that why they make money on the units ... and sometimes you loose some.

author: pascal_sweden
author_rank: Super Contributor
timestamp: August 07, 2015, 08:50:15 am
content: Quote from: TheSteve on August 06, 2015, 07:38:18 pmI guess you mean a second hand Agilent N1996A?

author: Gunb
author_rank: Regular Contributor
timestamp: August 07, 2015, 09:17:02 am
content: Quote from: pascal_sweden on August 04, 2015, 07:01:57 amHi there,I've bought a few devices (all Rigols) from Batronix in Germany. I'm very satisfied with their delivery time as well as support.Maybe it would be interesting for youKind regardsGunb

author: TheSteve
author_rank: Unknown
timestamp: August 07, 2015, 03:54:15 pm
content: Quote from: pascal_sweden on August 07, 2015, 08:50:15 amAbsolutely, but used Agilent seems to beat new Rigol.

author: G0HZU
author_rank: Super Contributor
timestamp: August 07, 2015, 07:03:22 pm
content: Quote from: OZ99DW on August 04, 2015, 10:36:12 amI'm slightly confused here...I've never used a Rigol 815 but I've used lots of decent lab analysers. Some of them won't allow this combination of settings because it is not a good idea to expect to be able to put +0dBm (let alone +10dBm) into the analyser with 0dB front end attenuation selected and then go on to make valid measurments of a typical spectrum input. So even the combination of 0dBm ref level and 0dB attenuation is deemed illegal in some analysers and it won't allow the user to punch in these settings without overriding the user input in some way.However, I think the Rigol has more loss in the various switched stages between the input and the first mixer plus it has a permanent fixed attenuator here even with the 0dB setting on the front panel.So you might be able to put 0dBm into it at 0dBm attenuator setting but it is going to be marginal. At some point the analyser will have an overload warning trip and maybe it is somewhere around 0dBm with 0dB attenuation.So it may be normal for some analysers to 'just' get away with this and some not. But it's not a typical way to set up an analyser anway.I'm not sure this behaviour is classed as a fault. I'd class it as unsympathetic settings by the user with unrealistic performance expectations from the analyser (at these settings) rather than a fault.

author: mcinque
author_rank: Unknown
timestamp: August 08, 2015, 09:08:01 am
content: You could be right.But then why pauln, Giorgio and navzptc don't have the issue with the same settings (and the same device)?

author: iDevice
author_rank: Regular Contributor
timestamp: August 09, 2015, 07:11:30 pm
content: Just reading this and wonder why anyone with Spectrum analyzer experience didn't react earlier in this thread...Like GOHZU just said, feeding 0dBm into an analyzer with 0dB attenuation is asking for trouble.There is a high risk to overload the mixer.I don't know at what level the Rigol overloads but by reading this thread with some devices overloading and others not, my guess is that it should be around this level and the dispersion between devices (internal losses) makes this "problem" apparent or not.Anyway, when using an analyzer with a 0dBm feed, the attenuator should be at minimum of -10dB...