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Test equipment recommendations

Robert D. Bowers
 

That sounds interesting, and would be a worthwhile thing to have (even for someone new, if the software is relatively easy to use and understand).  I'm used to (in my head) "stitching together" the results from my dongle via GQRX, but having software to do it would be great!  (I picked up a broken sweep generator and fixed it, so I have that capability to a degree already, but at the same time that could help in some instances!)

Thanks for bringing that up!


On 5/18/20 11:37 AM, Scott McDonald via groups.io wrote:
Given the modeling comments I may regret suggesting this, but as lots of folks have some of the less expensive SDRs, the free software that stitches multiple frequency ranges together to perform as a spectrum analyzer is a pretty cool piece of test kit.

A bit of learning required, but being able to look at the spectrum from your transmitter, or the output of a mixer module, really can speed along learning radio.  Much more intuitive than a scope for RF stuff to me.

I'm most familiar with the free software available for the RSP series SDRs, and have used that with a cheapie noise generator for lots of filter analysis, and am very happy with it.  I believe there is similar software available for dongles as well.  Slower than a real spectrum analyzer for sure, and often some bugs and spurs, but pretty amazing for the price of a free download.

Worth a thought if you already have a cheapie SDR.  

I would NOT do it with a more expensive SDR unless you are darn careful tho :)

Cheers, Scott ka9p


-----Original Message-----
From: Robert D. Bowers <n4fbz@...>
To: BITX20@groups.io
Sent: Mon, May 18, 2020 9:41 am
Subject: Re: [BITX20] Test equipment recommendations

You talk about a steep learning curve for the NanoVNA and then suggest MODELING SOFTWARE?  You do know that doesn't make sense - it could overwhelm someone in a hurry?

Let a new ham learn what they want to learn and when they're ready to learn - in order to pass the test (unless it's really been watered down even more since I got my Extra) they have to have some understanding of the basics already.  You have to build on a foundation - not start erecting the superstructure while the foundation is still being poured!

I'd suggest rather than modeling software, using the ARRL Antenna book or something similar.  That's appropriate not only for someone new to radio, but also useful even for experienced hams.  It also helps to lay a good foundation that can be built on.

Modeling can come later - at their own pace and if they choose.  (The VNA also may be a bit much, although the more a learns, the more valuable such a tool becomes.  That's why a directional wattmeter/SWR bridge is suggested.  Start simple and build up.)


On 5/18/20 9:38 AM, flatpickn via groups.io wrote:
If your interest aligns with this:
The NanoVNA is a nice piece of equipment for not a lot of money. I have an H model.
It does have a steep learning curve which would be true of any VNA.
Build yourself a wire antenna. Make it cheap, use speaker wire from the hardware store. Download the free copy of Eznec and model the antenna in it. Use the Nano to tune it and compare it to the model.
When your done, you'd have a good fundamental  understanding of antennas, a beginning knowledge of antenna analysis,  and you'll know the vna well enough to tackle other vna work like evaluating baluns and circuit impedences.
There's plenty of resources on the internet to help you figure it out.

Mark Muller
 

One suggestion: perhaps obvious given the others, perhaps not. Maybe you are near some sort of ham club, or at least within driving distance. While there may be a prohibition on swap meets, maybe you can drive to another ham's house? If so, maybe you an join a local club online, and ask the club moderator to send out an email request to the members, to see if anyone has a working analog, or inexpensive digital scope sitting on the shelf that they want to sell; or perhaps someone in the club knows of one that might be for sale from a school or non-member. Let them know approximately what you want in the way of performance, and what you want to spend. Who knows what you might find??? 

Leo
 

Wow! A mountain of great advice - thank you all so much. 

i have a RTL SDR V3 dongle which works pretty well and covers HF without an up converter. I can see on its own it will be a great diagnostic tool. I’m not scared of electronics having tinkered for many years starting with an HAC single valve receiver and a very long wire - Radio Moscow, Radio Prague and Voice of America seemed to swamp everything else. 

I’ll probably put the ‘scope on the back burner again although there were some good suggestions I’ll be looking into.

For the rest I’ll research and built and hack and modify. As a career programmer I can Arduino and I expect this to be a mainstay. I’ve just received a SI5351 from China and I have an OLED display so you can guess what I’ll be making. I found an ARRL article (QST?) on hacking the Chinese version Forty-9er to use a VFO and I have that kit in my drawer so that’s going to be a project soon.
once again thanks for all of your advice.

 

Doug W
 

On Wed, May 20, 2020 at 05:14 PM, <ponton.leo@...> wrote:
For the rest I’ll research and built and hack and modify. As a career programmer I can Arduino and I expect this to be a mainstay. I’ve just received a SI5351 from China and I have an OLED display so you can guess what I’ll be making. I found an ARRL article (QST?) on hacking the Chinese version Forty-9er to use a VFO and I have that kit in my drawer so that’s going to be a project soon.
In addition to this list, it sounds like you would also enjoy https://groups.io/g/SoftwareControlledHamRadio

As for a scope, I picked up a Tektronix 2235 on ebay from a reputable seller for probably less than it cost to make the box it came in when it was new.
 
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www.bitxmap.com

Doug W
 

On Wed, May 20, 2020 at 05:44 PM, Doug W wrote:
In addition to this list, it sounds like you would also enjoy https://groups.io/g/SoftwareControlledHamRadio
I forgot to mention https://groups.io/g/HBTE
 
--
www.bitxmap.com

Jack, W8TEE
 

Hi Leo:

You may have to do some adjustments on the 49-er article as we used an AD9850 which generates a sine wave, where the Si5153 is square wave. Still, it's a fun project and works surprisingly well.

Jack, W8TEE

On Wednesday, May 20, 2020, 6:14:40 PM EDT, ponton.leo@... <ponton.leo@...> wrote:


Wow! A mountain of great advice - thank you all so much. 

i have a RTL SDR V3 dongle which works pretty well and covers HF without an up converter. I can see on its own it will be a great diagnostic tool. I’m not scared of electronics having tinkered for many years starting with an HAC single valve receiver and a very long wire - Radio Moscow, Radio Prague and Voice of America seemed to swamp everything else. 

I’ll probably put the ‘scope on the back burner again although there were some good suggestions I’ll be looking into.

For the rest I’ll research and built and hack and modify. As a career programmer I can Arduino and I expect this to be a mainstay. I’ve just received a SI5351 from China and I have an OLED display so you can guess what I’ll be making. I found an ARRL article (QST?) on hacking the Chinese version Forty-9er to use a VFO and I have that kit in my drawer so that’s going to be a project soon.
once again thanks for all of your advice.

 


--
Jack, W8TEE

Leo
 

Thanks for the heads up Jack. I hadn’t spied that you were the author of that article! It’ll be an interesting experiment that will hopefully contribute to my Intermediate licence. 

i snagged a scope for £50 - don’t know yet if it will work. I’ll also be building test equipment such as RF tracer, sig gen etc. I’m also planning a SWR / power meter with a stockton bridge and a nano. Fun fun fun.