24 Raoul Wallenberg Street, Building C, Tel Aviv 6971920 Israel

1. Mr. Zisapel is a physician at Tel Aviv Sourasky Medical Center. The business address of Mr. Zisapel is 24 Raoul Wallenberg Street, Tel-Aviv, 6971920 Israel. 2. Ms. Zisapel is a writer. The business address of Ms. Zisapel is Vitkin 3, Apartment 5, Tel-Aviv 6347403, Israel.

During the past five years, neither Mr. Zisapel nor Ms. Zisapel has been convicted in any criminal proceeding (excluding traffic violations or similar misdemeanors).

During the past five years, neither Mr. Zisapel nor Ms. Zisapel has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction as a result of which such person was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding of any violation with respect to such laws.

Mr. Zisapel and Ms. Zisapel are each citizens and residents of Israel.

The Reporting Persons acquired the securities reported on this Schedule 13D in connection with the illness and subsequent death of their father, Zohar Zisapel, co-founder, member of the Board of Directors and major shareholder of the Issuer, which occurred on May 19, 2023. On May 18, 2023, Zohar Zisapel transferred without consideration 50% of the ownership interests in each of Michael & Klil Holdings (93) Ltd. and Lomsha Ltd. to each of the Reporting Persons, through which the Reporting Persons each hold an indirect ownership interest in an aggregate of 271,074 Ordinary Shares of the Issuer and shared voting and dispositive power with respect to an aggregate of 542,147 Ordinary Shares of the Issuer as the 50% owners of such entities. A probate was issued by the Israeli Registrar for Matters of Succession on August 4, 2023, according to which Zohar Zisapel's assets were divided 50% to Mr. Zisapel and 50% to Ms. Zisapel. Following the completion of certain transfer requirements, the Reporting Persons now own an aggregate of 2,294,738 Ordinary Shares of the Issuer effective as of March 25, 2026 (including options to acquire 4,497 Ordinary Shares exercisable currently or within 60 days of March 25, 2026). No funds or other consideration was used by the Reporting Persons to acquire the shares subject hereof, and no funds or other consideration were borrowed or otherwise obtained for the purpose of acquiring, holding, trading, or voting the shares subject hereof.

On March 25, 2026, the Reporting Persons together with Value Base Ltd. ("Value Base"), sent a letter to the Board of Directors of the Company (the "Demand Letter") requesting that the Company convene a special meeting of the Company's shareholders (the "Special Meeting") pursuant to the relevant provisions of the Israeli Companies Law, 5759-1999, and the Company's Amended and Restated Articles of Association (the "Articles"). Pursuant to the Demand Letter, the agenda for the Special Meeting would be to (i) amend the Articles to provide that the Board of Directors shall consist of not less than three nor more than seven directors (instead of nine), (ii) amend the Articles to provide that directors may be elected at any general meeting of shareholders (instead of only at the annual general meeting), (iii) amend the Articles to provide that the tenure of any directors appointed by the Board of Directors to fill vacancies prior to the Special Meeting shall terminate upon the conclusion of the Special Meeting, (iv) remove the following directors from the Company's Board of Directors, effective as of the conclusion of the Special Meeting: Rami Schwartz, Rachel (Hili) Bennun, Oren Most, Yaron Ravkeie and Andre Feutch, (v) nominate for election by shareholders the following candidates for the Board of Directors: Liat Aaronson, Tomer Jacob and Guy Levit (the "Candidates") and (vi) approve compensation, exemption, indemnification and insurance for the Candidates at levels commensurate with those currently provided to existing directors. A copy of the Demand Letter is filed herewith as Exhibit 99.2. Except for the Demand Letter, there is no other agreement between the Reporting Persons and Value Base regarding any cooperation, joint ventures, commitment to vote together or any other agreement of any kind concerning the Company's Ordinary Shares. The Reporting Persons hold the securities described in this Schedule 13D for investment purposes and they intend to review their investments in the Issuer on a continuing basis. The Reporting Persons seek to enhance Issuer value and may take such actions with respect to their investment in the Issuer as they deem appropriate in light of the circumstances existing from time to time, including without limitation, engaging in communications with management and the board, engaging in discussions with shareholders of the Issuer or other third parties about the Issuer and the Reporting Persons' investment in the Issuer, or with regard to any material changes to the Issuer's business, corporate governance, corporate structure, or potential transactions. The Reporting Persons may acquire additional securities of the Issuer, or retain or sell all or a portion of the securities then held, in the open market or in privately negotiated transactions. Other than as described above, the Reporting Persons do not currently have any plans or proposals that relate to, or would result in, any of the matters listed in Items 4(a)-(j) of Schedule 13D, although, depending on the factors discussed herein, the Reporting Persons may change their purpose or formulate different plans or proposals with respect thereto at any time.

Mr. Zisapel beneficially owns 1,147,369 Ordinary Shares of the Issuer, consisting of (i) 874,047 Ordinary Shares held directly by Mr. Zisapel, and (ii) 271,074 Ordinary Shares that are held indirectly by Mr. Zisapel through his 50% ownership in each of Lomsha Ltd., an Israeli company, and Michael & Klil Holdings (93) Ltd., an Israeli company and (iii) options to acquire 2,248 Ordinary Shares exercisable within 60 days. Based on 16,405,788 Ordinary Shares of the Issuer issued and outstanding as of October 20, 2025, as reported in Exhibit 99.1 to the Issuer's Form 6-K filed with the Securities and Exchange Commission on October 29, 2025, the Ordinary Shares beneficially owned by Mr. Zisapel represent approximately 7.0% of the Ordinary Shares of the Issuer issued and outstanding, and, together with the Ordinary Shares beneficially owned by Ms. Zisapel, as described below, represent approximately 14.0% of the Ordinary Shares of the Issuer issued and outstanding. Ms. Zisapel beneficially owns 1,147,369 Ordinary Shares of the Issuer, consisting of (i) 874,047 Ordinary Shares held directly by Ms. Zisapel and (ii) 271,074 Ordinary Shares that are held indirectly by Ms. Zisapel through her 50% ownership in each of Lomsha Ltd., an Israeli company, and Michael & Klil Holdings (93) Ltd., an Israeli company and (iii) options to acquire 2,249 Ordinary Shares exercisable within 60 days. Based on 16,405,788 Ordinary Shares of the Issuer issued and outstanding as of October 20, 2025, as reported in Exhibit 99.1 to the Issuer's Form 6-K filed with the Securities and Exchange Commission on October 29, 2025, the Ordinary Shares beneficially owned by Ms. Zisapel represent approximately 7.0% of the Ordinary Shares of the Issuer issued and outstanding, and, together with the Ordinary Shares beneficially owned by Mr. Zisapel, as described above, represent approximately 14.0% of the Ordinary Shares of the Issuer issued and outstanding. Mr. Zisapel has sole voting and dispositive power over 1,730,029 Ordinary Shares mutually held by the Reporting Persons in security bank accounts, and has shared voting and dispositive power over an aggregate of 542,147 Ordinary Shares owned by Lomsha Ltd and Michael & Klil Holdings (93) Ltd., in each of which Mr. Zisapel owns a 50% interest. Ms. Zisapel has sole voting and dispositive power over 1,730,030 Ordinary Shares mutually held by the Reporting Persons in security bank accounts, and has shared voting and dispositive power over an aggregate of 542,147 Ordinary Shares owned by Lomsha Ltd and Michael & Klil Holdings (93) Ltd., in each of which Ms. Zisapel owns a 50% interest. Because the Reporting Persons named in this Schedule 13D may be deemed to constitute a "group" for purposes of Section 13(d) of the Securities Exchange Act of 1934 (the "Exchange Act"), each of Mr. Zisapel and Ms. Zisapel may have shared voting and dispositive power over, and therefore may be deemed the beneficial owners of, an aggregate of 2,294,738 Ordinary Shares. According to information provided by Value Base, as of the date on the cover of this Amendment, Harmony Base, Limited Partnership (the "Limited Partnership") is the direct holder of 865,009 Ordinary Shares, representing approximately 5.27% of the number of Ordinary Shares outstanding; Value Base Hedge Fund Ltd. (the "General Partner") acts as general partner to the Limited Partnership; Value Base is the controlling shareholder of the General Partner; Mr. Victor Shamrich and Mr. Ido Nouberger control Value Base; and each of the General Partner, Value Base and Messrs. Shamrich and Nouberger may be deemed the beneficial owner of such Ordinary Shares. If the Reporting Persons named in this Amendment and Value Base were deemed to constitute a "group" for purposes of Section 13(d) of the Exchange Act, each of the Reporting Persons and Value Base may be deemed to share the power to vote, or direct the voting of, and share the power to dispose of, or direct the disposition of, the 3,159,747 Ordinary Shares held in the aggregate by the Reporting Persons and Value Base, which would represent approximately 19.26% of the number of Ordinary Shares outstanding. However, each of the Reporting Persons specifically disclaims beneficial ownership of the securities reported herein except to the extent of his or its pecuniary interest therein. Neither the filing of this Amendment nor any of its contents shall be deemed an admission that the Reporting Persons are, for purposes of Section 13(d) of the Exchange Act, the beneficial owners of any securities of the Issuer he or it does not directly own, or that a group exists for purposes of Schedule 13(d) of the Exchange Act or for any other purpose, and each Reporting Person and Value Base disclaims the existence of any such group.

The information set forth in Item 5(a) is incorporated herein by reference.

During the last 60 days, the Reporting Persons have affected the following transactions in the Ordinary Shares of the Issuer: None.

The information set forth in Item 4 is incorporated herein by reference.

99.1 Joint Filing Agreement 99.2 Letter dated March 25, 2026 to the Board of Directors of Radcom Ltd.