My build of Jim's Antenna Analyser design:-

The details of the design I sought to be build can be found here:- A VHF/HF Aerial Analyser Jim Tregellas VK5JST

Other sources?

Rockby

Futrelec (maybe give trouble)

RS

I noticed that at VHF putting my hand near the circuit board would cause the frequency to drift, this is a disadvantage of using a free running oscillator.

I haven't used monolithic capacitor that have the correct lead spacing, but have tried to make the connections to the PCB as short as possible. I may have to replace with correctly spaced monolithic capacitors in the future of problems are caused. Jim has further details on this on his website.

I don't know if an antenna analyser circuit could be made up with a Si570, Si5351A or an ADF4351, which give out a square wave.

Sdr-kits.net have a USB kit that uses a Si570. The buyer selects a Si570 of a speed grade they want.

K5BCQ have 'AQRP Vector Impedance Analyser kit generates smith chart's etc.. Code doesn't seem to be available to continue progress of unit. Also a Si570 kit is available. http://www.qsl.net/k5bcq/Kits/Kits.html

Makis at www.sv1afn.com have PCB's with ADF4351 (PLL Synthesiser Module), that covers 35Mhz to 4400Mhz. The web-page states that KIT comes with all SMD components factory pre-soldered. The kit is price is 29 USD.

The SV1AFN design lab has a Si5351A clock generator module for sale. It is stated it can operate at a frequency between 8kHz to more than 150Mhz, price is 8.90 USD, and al SMD components pre-soldered.

The website also shows a DRA-818VHF module available with a board that has other parts such as audio amplifier and filter.

On the Internet there is VK3YY's analyser, which is a version of a HF analyser using a DDS and Arduino. The analysis of antenna is output on a computer connected via USB..

Fox delta have a 50Mhz Antenna analyser USB kit listed. www.foxdelta.com

There is also commercial made analyser made by manufacturers such as MFJ. There are USB interface types that go up to 70cm.

It is quite possible that the commercial designs are more accurate than the JST design.

Read some MFJ owner manuals to get an idea about the use of antenna analysers and limitations

www.3-mtr.info/manuals/MFJ ENTERPRISES/

The signal was high enough from the VK5JST design when running into a folded dipole to activate a local repeater a few kilometres away when tuned on it's input frequency.

This has also been done using a rubber duck antenna.

I'm not sure how a computer control aerial analyser works, but I guess it would quickly sweep a frequency range and show results. It is possible that a made up kit may by tuning of the dial go into the aircraft band and their may be other frequencies it may be noticed on, so I probably would be a could idea to note what the frequency displayed is, the aerial type and where the signal may go, to minimise problems.

The label says 132-170Mhz

If an aerial analyser went down to 132Mhz, this would mean it would extend a few megahertz into the aircraft band.

Due to the free running oscillator design that doesn't use a PLL to control drift and the lack of fine tuning of the variable capacitor, I have found that a way to get more precise tuning control if to vary the distance of an object above the unit that will effect the frequency of the unit, such part of my body e.g. arm, hand, then hold. Also placing he unit the lap will effect the frequency.

I didn't use monolithic capacitors with the correct with the correct spacing, I didn't put the lead flat on the board as I was unsure about the potential for shorts. I did reduce the length that the lead goes to the board. I may need to buy monolithic capacitors with the correct spacing, these aren't the most popular variety. I am not sure why the board was made to use a non standard spacing.

After building some section of the board, I read an update to the web-page. Someone had wrote in about some inaccuracies in the unit, a fix was to raise the height of some parts from the board. This meant I had to put some new ones in as the leads were now too short.

While doing some Internet searches using 'AD8307 Arduino',I found some ideas to use Arduino an AD8307 or another version that goes to a higher frequency together with a frequency synthesiser to make an analyser.

On the 'SV1AFN Design Lab' web-page some power detector's are listed. I have seen the AD8313 ('100 - 2500 MHZ / 18 - 50 - 100 mV/dB Voltage Output RF POWER DETECTOR'), ADL5513 ('1 MHZ - 4000 MHZ / 21 mV/dB Voltage Output RF POWER DETECTOR), AD8310 Fast RF Detector ('LF - 440 MHZ Very Fast (ASK/AM Demodulation Possible) RF Power Log Detector with 95 dB Dynamic Range'), ADL5519 Dual RF Detector ('1 MHZ - 10 GHZ max Dual RF Channel Log-Linear RF Detector - Use with a directional coupler and measure Return Loss, FWD power and RFL power')

So I guess an Arduino with USB connector could be wired to an ADF4351, together with a ADL5519 and a suitable directional coupler, code on the Arduino could sweep a frequency range and send the output from the ADL5519 to a computer via USB, to be displayed, or maybe send to a SD card with an add on board. A display could also be added to the Arduino. There's a website with French and English text that provides source code for an Arduino project to interface to a ADF4351 module. 'ADF4351 driven by an Arduino, March 7, 2016 , RF Generator 34.5 to 4400MHz, By Alain Fort F1CJN'

http://f6kbf.free.fr/html/ADF4251%20and%20Arduino_Fr_Gb.htm

http://f6kbf.free.fr/html/ADF4351_LCD_07032016.zip

ADF4351 MINI Module EXT REF; $29.00 USD

ADL5519 Dual RF Detector PCB Module; $39.00 USD

Directional coupler; up to a $100 or so, Jim has a design for a cheap VHF design, although I am thinking a metal box would be a good idea for it if operating near a radiating antenna.

USB Arduino clone about; $9

LCD display with buttons; about $5

Arduino Compatible Data , Logging Shield; Jaycar have one listed for $19.95

I mentioned to Jim via email, that Minikits have some DDS projects as well as there being DRA818 radio boards. Jim replied with “Did seriously consider DDS units but there are none currently available at reasonable cost which cover up to 170MHz. My design brief was to develop something which even youngsters can afford. Those who want HP standard instruments must pay the price.........:-)