Low Cost Signal Generator (35Mhz-4.4Ghz) for antenna testing


I am interested in buying a low-cost Signal Generator to test antennas.

I found four (4) different types. Dont know which one to purchase.
All four are based on the chip ADF4351 or its older version ADF4350

Has any one used these?
Any advice which one is better, and why?

Type 1:
35Mhz to 4.4Ghz
ADF4351 development board × 1
CY7C68013A base board × 1


Type 2:
35Mhz to 4.4Ghz
ADF4351 development board x 1
High Speed USB2.0 Dashboard x 1


Type 3:
35Mhz to 4.4Ghz
1 X 35M-4.4G signal source signal generator/simple spectrum.
1 x USB Cable.
2 X SMA cable.


Type 4:
137Mhz to 4.4Ghz
ADF4350 development board 0.137-4.4G 137M-4.4G signal generator



Tweaking of Groundplane (Spider) Antenna
New model of BG7TBL noise source
New model of BG7TBL noise source

Directional Coupler for Antenna Testing
This item is required in addition to the RF Signal Generator.

800-2500MHz 15db Cavity Directional Coupler, N type



The coupler looks good but maybe one like this would be better for a low powered signal source.
Not sure about the signal generator, its a bit expensive for my tastes .
I found the cheap ebay noise source quite effective but it definitely needs a small $3 fan, I can understand why yours expired from over heating as mine runs crazy hot without it.
Maybe running at less than 12v volts would help, must try one day.


1. How to measure return loss of a 978 MHz antenna (and 1090 MHz antenna as well)

2. Directional Coupler Basics & how to sweep SWR of an antenna | Return Loss | VSWR

Instead of the costly professional Signal Generator and Spectrum Analyzer in above videos, following low-cost hardware & software can be used.

ADF4351 Signal Generator
Directional Coupler.

(1) RTLSDR Scanner

(2) SDR#
Download from Official Site (Air Spy):
http://airspy.com/download/ (Did not install on my Win XP. Says “Not a valid win32 application”).

Download from alternate site (adafruit):
http://adafruit-download.s3.amazonaws.com/sdrsharp-5-19-2014.zip (Somewhat older version, but works ok)



The Antenna Test Rig using ADF4351 Signal Generator, Directional Coupler, and LNA.

Coutesy: Richard Lee of Planefinder forum

Richard Lee’s ADF4351 (encased) Antenna Test Rig #1

LNA, 35 dB, 40 Mhz to 2.5 Ghz

LNA in Richard Lee’s Antenna Test Rig #2



Has anyone used any of these Signal Generators?