Looking for a cheap RF signal generator. - Page 1
Forum section: electronics / rf-microwave

author: Carrington
author_rank: Super Contributor
timestamp: August 10, 2018, 01:54:00 pm
content: I'm looking for a cheap RF signal generator, but I need/prefer one with a level accuracy of around +/-1dBm (or better), and low harmonics/spurious levels.And I don't want to spend much on it (400€ maximum).Something like this (SYM4400-USB) is ok for me:Website:http://www.ormelabs.com/en/?page_id=101Datasheet:http://www.ormelabs.com/pdf/SYM4400_eng.pdfThe SYM4400-USB is the best and cheapest I could find (325€).More info about it in attachments.By any chance, anyone here have one of these? What do you think about this one?Does anyone know of something better and at a similar price?I also found this other (ERASynth), better, but it is a bit pricey ($749).Website:http://erainstruments.com/Datasheet:https://github.com/erainstruments/erasynth-docs/blob/master/erasynth-datasheet.pdfMaybe I should look for a spectrum analyzer (new or old) but with generator.Any advice is welcome. Thanks.

author: bd139
author_rank: Super Contributor
timestamp: August 10, 2018, 05:54:01 pm
content: What sort of frequency range and power output do you need?For €400 look around for Marconi 2019A/2022 or any of the HP synthesised units. I’ve used all three and they’re pretty solid. The Marconi ones are easy to repair.

author: Mr Simpleton
author_rank: Unknown
timestamp: August 11, 2018, 12:25:16 pm
content: As you mention low harmonics... most of these "cheap" frequency generators are not applicable. These usually use a one-chip solution, and have none or very poor filtering on the output. As the signal coming from the chip is square wave or close to it, you will have very strong harmonics. Plus there is no amplitude control, so you may see quite a large variance over the frequency range.As suggested, a used Marconi or HP would do you vastly better.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 11, 2018, 12:51:37 pm
content: I agree, get an old, real, one!

author: Antonio84e
author_rank: Contributor
timestamp: August 11, 2018, 08:09:03 pm
content: If you are looking for cost competitive signal generator and spectrum analyzer... I´m wondering if something like the cost competitives VNAs from MegiQ could be of interest (some versions come with a generator port). I may be able to help you with your test equipment requirements, I rep various RF&Microwave vendors into UK and Spain mainly and have some very competitive solutions.to discuss in more detail, get in touch: aa@antaetech.com

author: Wolfgang
author_rank: Super Contributor
timestamp: August 27, 2018, 09:04:42 pm
content: Hi,when you are just working up to 60MHz, I used a RIGOL DG1062Z. The signal quality is a lot better than "real" RF models, they have two channels, arbitrary functions and they are cheap.https://electronicprojectsforfun.wordpress.com/test-equipment/test-equipment-measurements/rf-signal-generator-am-modulation-quality/

author: bd139
author_rank: Super Contributor
timestamp: August 27, 2018, 10:35:27 pm
content: Good recommendation. I use a 1022Z myself as a "most HF bands" generator and general signal source. Has two channels and can throw out known dBm into a 50 ohm load so with a step attenuator you can generate both the LO and RF signals going into a mixer for example. Plus it has a 200MHz counter in it that's not too bad. Also does sweeps and has a sync output so add a return loss bridge, power sensor and scope and you've got yourself a VSWR analyser.

author: Carrington
author_rank: Super Contributor
timestamp: September 01, 2018, 01:12:15 pm
content: Thank everyone for your time and answers.Maybe I will have to opt for another solution, leaving a bit aside, the spectral purity, but not its accuracy level.But I still without know what I'm going to do...Cheers.

author: rhb
author_rank: Super Contributor
timestamp: September 02, 2018, 12:24:48 am
content: If you can live with a maximum of 60 MHz, take a look at the FY-6600 thread. At low voltage levels, the spectral purity is quite good. The output op amp starts to distort above about 0.5 Vpp. People have done some pretty amazing hacks on them. Some of them are available in the FY-6800.However, customer support is non-existent. so if it quits working, as happened to me, you are pretty much on your own.