WTB(UK) RF DC Block and cables - Page 1
Forum section: electronics / general

author: trevwhite
author_rank: Frequent Contributor
timestamp: September 25, 2017, 07:40:26 pm
content: HiI have a SSA3021X on order along with a TEKBOX probe set. I am new to using a Spectrum Analyser and I read that a safe thing to do is use a DC Block to protect the SA input. I found one in RS but it was over £50. I found one on ebay, it was £5. I was wondering what is the normal price for a DC Block and where can I buy one that I can trust?A recommended seller of RF cables and accessories that I might need for the future would be helpful as well thanks.ThanksTrev

author: CJay
author_rank: Super Contributor
timestamp: September 25, 2017, 07:49:05 pm
content: Minicircuitshttps://ww2.minicircuits.com/WebStore/dc_blocks.html

author: tautech
author_rank: Super Contributor
timestamp: September 25, 2017, 07:54:05 pm
content: I worried about this too when I got my 3032X.I bought the UKitSSA3X accessory kit as a starter and except for some more adapters and some more SMA cables haven't needed anything else. Those Siglent supplied cables are characterised to 6 GHz.http://www.siglentamerica.com/prodcut-fj.aspx?id=5113&tid=227&T=2The SSA's have an input rating of +/- 50 VDC max and Over Voltage warning protection that I've only activated once when I had the inbuilt attenuator set to Off. User error.Research when I was looking indicated all the DC blocks available had the same 50V rating and I saw little need to double this up. In the 3000X thread there's some input from members about what accessories are useful.Starting here:https://www.eevblog.com/forum/testgear/siglent-ssa3000x-spectrum-analyzers/msg990874/#msg990874

author: 4CX35000
author_rank: Regular Contributor
timestamp: September 25, 2017, 07:56:15 pm
content: RF Shop in Lancaster.https://www.rfshop.co.uk/index.php/dc-blocks.html

author: trevwhite
author_rank: Frequent Contributor
timestamp: September 25, 2017, 07:59:03 pm
content: Great, thanks all.I also would like to do some tuning measurements with a RBSSA3X20 but I watched a review that said this kit was not particularly good. I think I read somewhere else that you can make them/buy them from Ebay cheap? Anyone had good experience with a cheap kit?Trev

author: tautech
author_rank: Super Contributor
timestamp: September 25, 2017, 08:09:18 pm
content: Quote from: trevwhite on September 25, 2017, 07:59:03 pmSpec says they're rated to only 2 GHz so maybe that's why they didn't get a good wrap.The bit I like about them is there's no additional cabling required, they connect directly to the TG and RFin ports.But yes, bought on their own (no SW option) they ain't cheap.There's a pic of one I got for a customer in the 3000X thread....comes in a nice padded soft case.

author: 4CX35000
author_rank: Regular Contributor
timestamp: September 25, 2017, 08:14:26 pm
content: You can buy reasonable second hand couplers on eBay for reasonable prices which will cover the frequencies you require. Also remember there are plenty of Mini-Circuits couplers on eBay which for fine for measurement purposes, once you calibrate it with the tracking generator.

author: trevwhite
author_rank: Frequent Contributor
timestamp: September 25, 2017, 08:18:27 pm
content: So can this type really be trusted?http://www.ebay.co.uk/itm/New-SMA-male-to-female-Stainless-steel-RF-Coaxial-DC-block-6000MHz-50ohms-Sag/281664186989?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3D4e0215a41efd4fe881ed726a23d2791d%26pid%3D100033%26rk%3D5%26rkt%3D8%26sd%3D253166369505&_trksid=p2045573.c100033.m2042

author: tautech
author_rank: Super Contributor
timestamp: September 25, 2017, 08:37:11 pm
content: Quote from: trevwhite on September 25, 2017, 08:18:27 pmDon't see much wrong with it.I've had some chats with member hendorog about this stuff, his comments were1: Metrology grade.2. Instrument grade <== This is what you are supposed to be using with your SA3. Standard grade4. These cheap ones off Ali-ExpressYou want to protect the SA connector if you can by not attaching anything too cheap and nasty to it.For adapters I've been looking at these:https://www.aliexpress.com/item/17-standard-N-type-to-sma-BNC-to-sma-TNC-to-sma-RF-connectors-adapter/32685053986.html?spm=2114.search0104.3.122.MKPdEV&ws_ab_test=searchweb0_0,searchweb201602_1_10152_10065_10151_10068_10084_10083_10080_10082_10081_10110_10137_10175_10111_10060_10112_10155_10113_10114_10154_438_10056_10055_10054_10182_10059_100031_10099_10078_10079_10103_10073_10102_10189_10052_10053_10142_10107_10050_10051-10050_10111,searchweb201603_1,ppcSwitch_5&btsid=315c910e-534c-429e-8338-00160209ae40&algo_expid=6e10298e-a857-473d-a389-0ae37d52c843-15&algo_pvid=6e10298e-a857-473d-a389-0ae37d52c843

author: 4CX35000
author_rank: Regular Contributor
timestamp: September 25, 2017, 08:54:51 pm
content: DC Block is nothing more than a capacitor in series with the spectrum analyser. You can buy those cheap versions if your certain the DC voltage your working with is reasonably low; but it also comes down to the performance regarding losses, frequency range and max DC voltage the capacitor can withstand. From what I can see you have no idea of the performance, as you have no idea who manufactured them (No data sheet), whilst the products from other manufacturers like JyeBao, Minicircuits and so on, you know the exact performance and max DC voltage of the DC Block.http://www.jyebao.com.tw/upload/DC-AMAF0-5G100V50.pdfhttps://ww2.minicircuits.com/pdfs/BLK-18+.pdf