The SARK-110

Calibration loads and repair service for the SARK-110 antenna analyser

About The SARK-110

I became aware of this remarkable analyser through the generosity of a close friend, whose gift was very much appreciated.


The SARK-110 is a shirt-pocket sized device with a competence that punches way above its weight. Unlike much of the competition, its menu system is virtually intuitive to use. Additionally, the user manual is comprehensive, explaining clearly the SARK-110’s extensive range of functions. This is entirely due to its exceptional designer, Melchor Varela EA4FRB, who, in addition to having produced such a competent device, is always willing to listen to and add new features as suggested by users. I know, because I suggested an enhancement and within a short time, it was there!

There’s a calibration system called OSL, that is run so that the connecting lead – often referred to as the pigtail – is ignored in all measurements and calculations. Initially, the loads I used for this OSL (Open, Short, Load) calibration were whatever fell to hand, but it was soon apparent that the SARK-110 deserved better. There was also the question of detector calibration. Was it set up with precision loads by the contracted manufacturer, Seeed Studios (yes, Seeed with three e’s)? What about occasional re-calibration to assure ongoing accuracy? Seeed Studios, located in China, handle the manufacture and direct sales of the SARK-110, see and search for SARK-110. The units are made to a very high standard and priced in USD, making it easy to purchase through PayPal. In Europe, Martin Lynch and Sons has EU-wide distributorship, however, direct purchases can still be made from Seeed Studios.

I made a decent set of loads for myself, then for friends and then a set was sent to Melchor, inviting him to check them over, as his opinion was greatly valued. After testing them, Melchor suggested that a set of affordable loads could be of interest to many SARK-110 users, as he’d had many enquiries.

After some thought, I decided to make up a few sets of loads to see if there is interest in them, so the following sets of calibration loads are offered.


Resistive loads are made from thin film SMT resistors of 0.1% accuracy. The short circuit loads are made with copper foil thoroughly soldered to the plug. The loads are completely screened but are not waterproof. As the SMT resistors are very small and of a low wattage, the calibration loads should not be subjected to electrical or electronic abuse.

There are nine components in the set that includes three BNC loads for OSL calibration; an Open, a Short and a Load of 50 ohms. These are used at the end of a female BNC-terminated pigtail lead, in accordance with User Manual Appendix D.


An MCX male to SMA female adapter is included for direct attachment to the SARK-110 for detector calibration using the SMA loads of Short, 50 ohm, 100 ohm and 200 ohm, as detailed in User Manual Appendix F. Additionally, an SMA open circuit has been included to complete a set of SMA OSL loads where pigtail leads with female SMA terminations are used. Once again, User Manual Appendix D applies for OSL calibration.


The loads are hand-assembled to a high standard using quality materials and it takes several hours to assemble a set. If demand should exceed supply, then a list in strict chronological order of requests to will be compiled and serviced in that order. It might mean a bit of a wait because I won’t cut corners……

The cost of a set of these loads is £40 plus shipping.

The price increase is because components I use are bought on dollar prices and Brexit has caused the pound value to drop against the dollar. There have been some small price increases on the components too. That is a big rise for people who use the pound as their currency but it represents only about a $4 increase in price to any other country.

I also offer an economical repair service here in the UK for SARK-110 owners. The SARK's designer, Melchor Varela, EA4FRB, is fully aware of this and is happy about it.

73, Dave Lankshear, G3TJP, QTHR


Firmware updates are easy to apply and are free for the life of the product.

See Firmware Updates

I could bang on about its features, but it would be far better for you to download and browse the manual from Melchor’s website.

See Manual Downloads

Contact SARK-110

All queries and placement of orders should be addressed to