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 1 
 on: Today at 04:18:24 PM 
Started by W3GMS - Last post by W3GMS
A good friend has started to evaluate several different SDR based receivers.  The latest one being looked at is the Airspy Discovery.  That RXis being benchmarked against the RSP1A.  Both manufactures recommend various SDR programs.  My question is, how much of the SDR baseline performance is tied into the particular software package used? 

I am very new to this SDR stuff, but am getting hooked on the technology based on some of the SDR sites online. 

Thanks!

Joe-W3GMS

 2 
 on: Today at 02:40:38 PM 
Started by W3GMS - Last post by KA0HCP
I've been following SDR's for work and personal interest for about 18 years.

The software is going to be less important to performance than the 1. Bit size of the digitizer (larger is better) 2. Architecture of the receiver 2.a.  Pre-digitizer methods, preamps, filtering.

1.  Digitizer chips are a key factor in the cost of any SDR.  Larger bit size is better as is speed.  Better performance rapidly increases in cost.  

2.  Architecture:  Is the signal largely processed by a dedicated radio-side chip like an FPGA or Video processor which will be faster (and a key cost factor) or is processing sloughed off on an external computer (common in early SDR designs and inexpensive sets).

3.  How does the signal get to the digitizer?   Direct Conversion is the ideal (holy grail) of SDR's since it eliminates devices which add distortion to the signal. However DC is limited by present technology level, primarily overload of the digitizer with resulting distortion, as well as digitizer chip cost.

-Bandpass/Hi/Lopass filtering of the raw RF is important.  Type and quality?

-Preamplification of signal?  Method, quality specs?

-Digitization methods:
A.  Local Oscillator with Mixer converts to from RF to IF input to digitizer.  Typical heterodyne technology with typical distortion, spurs, IF products.  Quality?
B.  Quadrature Detection: Splits signal wave into four sections feeds each individually to digitizers.  Better.

These are things to consider.  The technology is ever improving, so the best you can do is make a choice and jump in, knowing better radios are on the way.  bill

 3 
 on: Today at 02:24:22 PM 
Started by W3GMS - Last post by W1ITT
Performance depends largely on the type of A to D converter used.   Sixteen bits is going to have a higher dynamic range than cheap 8-bit dongles, but the dongles hold their own pretty well just the same.  A bandpass filter in the front end may make a difference in some environments. The mainline software is pretty much the same in performance and differs mostly in features and whiz-bangs from one to the next.  And some hardware will only work with some software, but most everything has at least a couple to choose from.
The good news is that, with the exception of the later FlexRadio editions, it's mostly all free and downloadable, so you can get what you need (want), put it on the same PC (not a lot of software is Mac friendly) and try it all with a few mouse clicks.  It's a pretty cool time for Amateur Radio when you can essentially get a new radio for free in a few minutes or less.
73 de Norm W1ITT

 4 
 on: Today at 02:08:14 PM 
Started by Steve - K4HX - Last post by W3GMS
Kudos for the visit and glad he and his wife are moving forward.   

You can't go back but you can learn from your mistakes.

Joe-W3GMS 

 5 
 on: Today at 02:04:22 PM 
Started by W3GMS - Last post by W3GMS
I meant to post this under the technical section!  Sorry about that....

A good friend has started to evaluate several different SDR based receivers.  The latest one being looked at is the Airspy Discovery.  That RXis being benchmarked against the RSP1A.  Both manufactures recommend various SDR programs.  My question is, how much of the SDR baseline performance is tied into the particular software package used?  

I am very new to this SDR stuff, but am getting hooked on the technology based on some of the SDR sites online.  

Here is one of the SDR's that is being evaluated: 

https://airspy.com/airspy-hf-discovery

Thanks!

Joe-W3GMS

 6 
 on: Today at 02:03:55 PM 
Started by k7mdo - Last post by KA0HCP
Very nice.  It is exciting reading about some of the venerable Nationals being restored.  I've got an unmolested 1935 HRO awaiting restoration.

 7 
 on: Today at 08:15:32 AM 
Started by WA2SQQ - Last post by WA2SQQ
I'm still in discovery mode on this. Just got my nanoVNA and I'm discovering what I've been missing! Just lining up all the winter projects! Share some feedback with us - please!

 8 
 on: Today at 05:34:55 AM 
Started by Steve - K4HX - Last post by W1RC
Update: I visited Mike K1EEE at the Elliott Hospital in Manchester NH on Tuesday August 13th.  He is recovering from his injuries and he is in good spirits.  He says his house is sold and he and Valerie will be relocating to VA as planned after he has recovered.

We did not discuss details of the accident........

73,

MrMike

 9 
 on: Yesterday at 09:35:41 PM 
Started by steve_qix - Last post by WBear2GCR

So Fred was on 3885...
...he's installed a receive ANT about 300ft to the rear of his property.
Says it dropped the noise floor substantially from before the solar
array, and he barely can hear the solar array.

Also, the permits that the installer got were not approved, so the array,
installed, is making power that the home owner does NOT get credit for!!

Seems like I see a lawsuit possibly in the home owner's future...

                 _-_-bear

 10 
 on: Yesterday at 09:29:44 PM 
Started by WA2SQQ - Last post by WBear2GCR


Thanks... wonder how it compares with LTSPICE...?

Downloaded it...

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