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Inexpensive Scope for Troubleshooting QMX


 

Can anyone tell me if this inexpensive scope would be capable of signal tracing on the QMX?



The problem I am having with the QMX build is that I am getting zero power out on transmit.? I have already done some troubleshooting measuring voltage and resistance, but I feel to go further I need some capability.

I know I will have to be careful not to hook up directly to power out or I will kill the scope, but I will figure that out.

Thanks so much in advance for any advice you can offer about this.

Mike
KC2EHR


 

It may well work for this and as a 'learner' you can probably kill it and still smile later

but . .?

The first law of electronics is that any piece of cheap test equipment will soon be replaced by a better one you can trust more?


 

I'd go for the Siglent?SDS1202X-E.? ?You won't out grow it.

Peter ve3poa?


 

Hi
I would say yes, it will do what you need.? You will be able to see the presence of a signal, the shape of the waveforms and the relative amplitude of the signal as you trace it through the transmitter path.? From the video, it doesn't seem too good at absolute magnitude of a signal but that doesn't really matter.? It seems to get frequency pretty well and amplitude to within about 30%.? I think its good enough, I would happily use it.? The features and menus seem a bit complicated for me.? I prefer simple things.? Having two channels is good because you can use it to see phase differences between two signals, which is handy.? Be careful with the probe.? The clippy bit should pull off to reveal a needle end and you can paint it with liquid insulation to minimise the risk of touching anything you don't intend to.??

Cheers
Peter, GM0EUL
??


 

Thankfully the complex maths-like functionality of many modern scopes will go unused by 95% of the owners. I remember when the Tektronix 465 was considered a hot-scope
--
Tisha, AA4HA


 

I have a Tektronix 485 which WAS the hot scope at the time. I still use it when my Siglent 1202X-E is having problems with the signal. I also have the P9201 900 MHz FET probe for much less signal loading than the standard probes. Needs to get power from the 485 which has two power jacks for just that.
Gary
W9TD


 

Michael,

An oscilloscope will be a great addition to your work bench. A quality instrument should serve you well for decades to come. My Tektronix 2465 has been a great performer for me for 30 years now.

While you are shopping/deciding, consider another little tool that will also prove to be extremely useful to you.

A simple RF voltage probe that attaches to your DMM can be purchased as a kit for about $15. A perfectly suitable one can be made from junkbox parts. Consisting of only a capacitor, a resistor and a diode, it is a very quick project? but very handy to have in the workshop!

JZ


On Sat, Mar 30, 2024, 9:04?PM Gary W9TD <w9td@...> wrote:
I have a Tektronix 485 which WAS the hot scope at the time. I still use it when my Siglent 1202X-E is having problems with the signal. I also have the P9201 900 MHz FET probe for much less signal loading than the standard probes. Needs to get power from the 485 which has two power jacks for just that.
Gary
W9TD


 

I must agree with you about the 465.? I had one on a cart that I used nearly daily for 20 years.? Even when I had a Tek 7904 with all sorts of plugins, it was just too big for my shack workbench, so the 465 was never far away.
Mark K9TR


 

Thanks to everyone for your input.

I have decided to go forward with the?FNIRSI DPOX180H shown in the video - on order and should be here Friday.

It seems like the right price as a starter scope and as someone said, it may not be the last one I ever buy.
?