RAD Group co-founder (1949–2023). Built 17 companies from one Tel Aviv networking lab. Father of Israeli networking. RADVision, RADCOM, Silicom, Ceragon. The company-building machine that predated Israeli VC.
Zohar Zisapel (1949–2023) was the co-founder of the RAD Group — the Israeli networking and telecommunications conglomerate that produced 17 companies, multiple IPOs, and an entire generation of Israeli networking engineers. If Gil Shwed is the father of Israeli cybersecurity, Zisapel is the father of Israeli networking.
Zohar and his brother Yehuda Zisapel founded RAD Data Communications in 1981 in Tel Aviv. The company built data communications equipment — modems, multiplexers, access devices — for telecom carriers. From RAD, they spun out a constellation of companies: RADCOM, RADVision (acquired by Avaya for $230M), Silicom, Ceragon Networks, RADWIN, and others. The model was unique: build a technology inside RAD, spin it out as an independent company, give it its own management team, and let it grow — or fail — independently.
The RAD Model: Israel's First Systematic Company-Building Machine
The RAD Group was Israel's first systematic company-building operation — predating the VC-backed incubator model by a decade. The Zisapels funded early development internally, recruited engineers from the IDF's technology units, gave each spin-out operational independence, and maintained minority ownership positions. At its peak, the RAD Group companies collectively employed over 5,000 people and generated over $1 billion in combined annual revenue.
The model influenced an entire generation of Israeli entrepreneurs. Many of the engineers who built careers inside RAD Group companies went on to found their own startups. The RAD alumni network is one of the densest in Israeli tech — less visible than the Unit 8200 alumni network but arguably as influential in the networking and telecommunications infrastructure sector.
The Industrial Park and the Tefen Connection
The Zisapels built the RAD Group's operations in the Tel Aviv area but drew inspiration from Stef Wertheimer's Tefen industrial park model in the Galilee. Where Wertheimer built manufacturing parks in the periphery, the Zisapels built a technology conglomerate in the center — but the principle was similar: create infrastructure, recruit talent, spin out independent operations, and let the ecosystem compound.
Zohar Zisapel's Legacy After 2023
Zohar Zisapel passed away in January 2023. His death marked the end of a founding era in Israeli technology — the generation that built networking infrastructure companies before venture capital, before Unit 8200 became a brand, and before "startup nation" was a phrase. The RAD Group companies he co-founded continue to operate. The engineers he trained continue to build. The model he pioneered — systematic internal spin-outs — is now the standard playbook for Israeli technology conglomerates.
