Cables for my function generator? - Page 1
Forum section: electronics / testgear

author: Mustey
author_rank: Contributor
timestamp: May 08, 2020, 04:41:30 pm
content: I bought me a Siglent SDG 1032X.Pretty sure I don't need oneBut I am going to try and keep it relevant in my studies...It arrived with a power and USB cables. I would like to have some cables for connecting to my projects.1. I do have probes from my scope, but I have a feeling I am not supposed to use these as outputs from my gen?2. Can I call gen output cables "leads"? (Not a native English speaker)3. Any recommendations on which cables/leads to get? I am just starting to learn electronics and will be mostly inspecting basic components like caps, transistors, coils (to analyse stuff like high/low pass filters, modulation, etc...). I do want to do a little basic radio transmission (like one circuit talking to another circuit in the room) and micro-controllers (ATmega328, ESP32, etc...)4. I've read that "it depends if you do high frequency stuff". In this context (studying filters, radio and controllers), what is considered "HF"?Thanks

author: Grandchuck
author_rank: Super Contributor
timestamp: May 08, 2020, 05:03:56 pm
content: One possibility:https://www.amazon.com/AideTek-Mini-Grabber-Test-black/dp/B011GB13XO

author: RoGeorge
author_rank: Super Contributor
timestamp: May 08, 2020, 05:54:56 pm
content: You need to search for BNC 50\$\Omega\$ cables. Example:https://eu.mouser.com/Connectors/RF-Interconnects/RF-Cable-Assemblies/_/N-bsiqa?P=1z0x0emZ1yzsqvbZ1yzsqvaBe sure that are 50\$\Omega\$ and not 75\$\Omega\$. There are also plenty of 75\$\Omega\$ BNC cables on the market, too, but those are for video equipment interconnections. If the webpage doesn't specify the impedance, chances are those are video cables, I know because I bought a few of those, only to discover later they were 75\$\Omega\$ BNC to alligator cables. At low frequency, the cable impedance may not matter much, but why not buying the proper 50\$\Omega\$ cables from the very beginning.In an emergency you can use any other cables, too, including the oscilloscope's probes set on x1, but better keep the oscilloscopes probes for the oscilloscope.Later edit:Fun offtopic, the capital Omega letter is rendered differently when there is a space between the number and the symbol.50vs 50\$\Omega\$

author: bob91343
author_rank: Super Contributor
timestamp: May 08, 2020, 06:39:57 pm
content: I agree that some ordinary 50 Ohm cables are called for here. One needs a stock of various lengths as well as terminations in BNC or test leads. And yes, make sure you use RG-58/U for 50 Ohms.These cables will serve for other purposes, such as connecting counters, analyzers, and such. You will also be wise to obtain some adapters, such as female-to-female and to other connector series such as UHF, SMA, and N, and even T-adapters for connecting multiple instruments. Further, one or two 50 Ohm feedthrough terminations will be useful.

author: MarkF
author_rank: Super Contributor
timestamp: May 08, 2020, 08:07:03 pm
content: I bought this set of cables:https://www.amazon.com/Micsoa-Leads-Alligator-Clips-Oscilloscope/dp/B07FZV589P/ref=psdc_5011673011_t3_B011GB13XO

author: tautech
author_rank: Super Contributor
timestamp: May 09, 2020, 10:17:27 am
content: Quote from: MarkF on May 08, 2020, 08:07:03 pmMustey ^^^^ good value for money.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: May 09, 2020, 01:29:22 pm
content: I don't like the thick black BNC cables which are expensive and poor quality. Some of my test gear has other connectors like N-Type and 7mm. What I have done is buy converters to get everything to SMA female and then I have a stock of RG316 male SMA-SMA cables. I also have a few semi-rigid male SMA-SMA cables that are good for GHz frequencies.You might consider this as an option.

author: alm
author_rank: Super Contributor
timestamp: May 09, 2020, 04:21:59 pm
content: I would be worried about SMA connector mating cycles when using them for everyday, jellybean connections. Especially if you not being careful when mating them. You can also get BNC cables with RG316 (or RG174) if you prefer the thinner cables.Sure, BNC is not a good option for GHz frequencies, but the Siglent function gen is not going to get anywhere near that.Quote from: RoGeorge on May 08, 2020, 05:54:56 pmFor straight cables I would definitely stick to 50 Ohm. But for alligator clips I'm not sure if it makes much of a difference. The impedance mismatch at the point where the coaxial cable changes to two flying leads might very well swamp the mismatch between coaxial cable and function gen. But sticking to 50 Ohm cables certainly doesn't hurt.

author: Mustey
author_rank: Contributor
timestamp: May 09, 2020, 06:04:02 pm
content: Ah, you guys in the USA have more choice, at a lower price!Amazon UK doesn't have any cheap stuff - but I am thinking I'll go with a reasonable brand from a specialized electronics shop because I've been stung before (fake resistors).

author: Mustey
author_rank: Contributor
timestamp: May 09, 2020, 06:05:52 pm
content: Knowing the 50Ω stuff definitely helped, thank you!I hope that's pretty much all there is to it (unlike scope probes that have a frequency rating as well).

author: nctnico
author_rank: Super Contributor
timestamp: May 09, 2020, 06:31:48 pm
content: Quote from: alm on May 09, 2020, 04:21:59 pmI second the suggestion to buy RG316 or RG174 BNC cables which are very thin and easy to work with. I also cut them up to have open ended cables to solder them to a circuit. I usually buy these kind of cables from RF Supplier (https://www.rfsupplier.com/). They are cheap enough to consider them consumables.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 09, 2020, 06:32:22 pm
content: Quote from: Mustey on May 09, 2020, 06:05:52 pmCoaxial cables have many other ratings, too, e.g. maximum frequency, losses, velocity factor, etc. just that for your generator and your application (SDG 1032X, max 30MHz, no high power, not metrology only learning) almost any 50 ohms BNC cable will work just fine.

author: eplpwr
author_rank: Regular Contributor
timestamp: May 10, 2020, 01:14:44 pm
content: Quote from: Mustey on May 09, 2020, 06:05:52 pmI've bought a couple of cables from:https://www.koax24.de/en.htmlThey are not especiallly cheap, but have a large assortment and can do custom cables to order; I ordered some BNC-to-BNC (male both ends) with the Hyperflex 5 cable, since I have many other rather stiff coax cables. Also, this was the first place in Europe where I could find good triax cables (just the cable without connectors).I do not have any business interest in the mentioned company, just a happy customer.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: May 10, 2020, 03:27:59 pm
content: I have both RG58 and RG316 cables, if it is your first set of cables, I prefer RG58 because it can stand up to a lot more abuse.I only use Pomona for my cables (as long as they make what I am looking for), their RG58 is built so tough that if you accidentally pull on it, you will likely break the Siglent before the cable. I have never had a single failure with Pomona in decades.

author: Hydron
author_rank: Super Contributor
timestamp: May 15, 2020, 07:39:31 am
content: Quote from: NoisyBoy on May 10, 2020, 03:27:59 pmI'm guessing you've never used their standard multimeter leads then, they are guaranteed to fail where they enter the probe handle due to ~zero strain relief on a very flexible cable. The super pointy tiny probes have different issues due to poor internal connections. A real shame as there's really nothing quite the same available elsewhere for the super pointy small ones, and the bigger ones are otherwise nice too and reasonably priced if you avoid the fluke branded versions.

author: sequoia
author_rank: Unknown
timestamp: May 21, 2020, 06:54:31 pm
content: Quote from: MarkF on May 08, 2020, 08:07:03 pmAbove ones seem to be out-of-stock, so I ordered following "Proster" leads to try out:https://www.amazon.com/gp/product/B07K2MVB2D/[$12.99 currently]For the money quality is pretty good, thin and flexible 50\$\Omega\$ coax, markings on the cable: ML SYV-50-2-41(specs seem to be these:http://www.lianstar.com/en/SYV-50-cable.php)

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: May 24, 2020, 03:12:05 pm
content: You can make your own cables. I use RG 223 coax and good old fashioned Clamp connectors. There are various kinds of connectors. Stay away from the "screw on" typeHere is a link to you tube with a couple of videos on some RF BNC connectors by a real RF engineerhttps://www.youtube.com/user/w8bya/videosWally

author: james_s
author_rank: Super Contributor
timestamp: May 24, 2020, 04:20:22 pm
content: I make my own cables these days. I bought 50' of RG316 from an ebay seller and a bunch of different crimp connectors. Got a ratcheting crimp tool and a couple of die sets, that was around $40 and now I can make nice clean RF cables of any sort I please.