¶ 1 In thеse consolidated appeals, four defendants challenge their convictions of various crimes, including corrupt organizations, conspiracy, drug charges and criminal use of a communication facility. 1 Appellants challenge the suppression court’s order denying the motion to suppress both wiretap evidence and physical evidence seized from the Doyen home. Appellants also claim error in compelling Gary Doyen and Glenford Thompson to proceed pro se, in denying a Batson challenge and in admitting certain testimony by Trooper Jose Torres. 2 We affirm.
¶ 2 The factual bаckground underlying the charges is set forth in the trial court’s Rule 1925 opinion: 3
In July of 1999, Trooper Jose Torres of the Pennsylvania State Police began investigating the drug trafficking activities of someone known at that time as “Glen.” Shortly thereafter, Trooper Torres identified “Glen” as defendant, Glenford Thompsоn. A few months later, Trooper Torres learned that Glen-ford Thompson received his drugs from defendant, Gary F. Doyen, who was the primary supplier of the narcotics sold by Thompson.
In February of 2000, the police obtained authorization to conduct electronic surveillance of Thomson and Doyen’s cellular telephones. The defendants changed cell phones several times during the course of the investigation. Each time they did, the police obtained a new authorization to conduct electronic monitoring on the new phones. During the course of the investigation, the police intercepted thousands of telephone conversations that showed defendants’ involvement with the distribution of marijuana in southeast Pennsylvania.
The police also utilized the services of confidential informants, conducted controlled buys, used visual surveillance, and employed other investigative techniques in order to ascertain the size of the organization, the amount of marijuana involved and the identity of the individuals involved in the distribution of marijuana. The police discovered that the defendants were part of a large-scale marijuana trafficking organizаtion that was responsible for distributing hundreds of pounds of marijuana every ten days to two weeks throughout Chester, Philadelphia, Montgomery and Dauphin Counties in Pennsylvania. Defendant, Gary Doyen, was the head of the organization. Defendants, Glenford Thompson and Errol Brown, were Gary Doyen’s principal аssistants. By the end of the police investigation, at least twelve individuals were linked to the Doyen drug organization.
Trial Court Opinion, 5/15/03, at 1-3 (footnotes omitted).
*1011
¶3 Appellants Gary Doyen
and
Glenford Thompson first argue that the suppression court erred in failing to suppress tape recordings and transcripts of intercepted telephone conversations obtainеd pursuant to wiretap authorization orders signed by Superior Court Judge Phyllis Beck. Appellants claim that the Commonwealth did not establish the authenticity of Judge Beck’s signature on the wiretap authorization and sealing orders. Appellants, however, neglect to mention that they never challengеd the signature of Judge Beck. In their Motion to Exclude and Suppress, Appellants asserted that the signatures of Judge James Cavanaugh, which appeared on other wiretap authorizations, were not authentic. Therefore, at the hearing on this motion, Judge Cava-naugh testified and authenticаted his signatures. Judge Beck did not appear at the hearing for the simple reason that her signatures were never challenged. Claims not raised in the trial court may not be raised for the first time on appeal.
Commonwealth v. Gordon,
¶4 Appellant Errol Brown also challenges Judge Beck’s signatures by contending that his priоr counsel was ineffective for failing to move to suppress the wiretap evidence that was obtained pursuant to authorization issued by Judge Beck. Pursuant to
Commonwealth v. Grant,
¶ 5 Appellants Lloyd Dоyen and Gary Doyen argue that the suppression court erred in failing to suppress evidence seized from their home at 5448 Merion Avenue. We summarize the court’s findings of fact in relation to this issue. The State Police obtained a search warrant which was executed shortly after 6:00 a.m. on April 5. They were accompanied by a Special Emergency Response Team (SERT). The lead vehicle was a SERT van with a public address system. For approximately one to two minutes before arriving at the house, a statement, “State Police, we are serving a warrant, 5448 Merion Avenue,” was cоntinuously transmitted over the public address system. This transmission was loud enough that a state trooper who was in a closed vehicle approximately 1000 feet from the residence could hear it. The announcement was repeated as the SERT team and State Trooper Greg Wert climbed thе stairs to 5448 Merion Avenue. Trooper Wert knocked and Corporal White yelled, “State Police, search warrant.” After a few seconds, the trooper forced entry with a ram.
¶ 6 Appellants contend that the police violated the so-called “knock and announce” rule set forth in Pa.R.Crim.P. 207. This rale states:
(A) A law enforcement officer executing a search warrant shall, before entry, give, or make reasonable effort to give, notice of the officer’s identity, authority, and purpose to any occupant of the premises specified in the warrant, unless exigent circumstances require the officer’s immediate forcible entry.
(B) Such officer shall await a response for a reasonable period of time after this announcement of identity, authority, and purpose, unless exigent circumstances *1012 require the officer’s immediate forcible entry.
(C) If the officer is not admitted after such reasonable period, the officer may forcibly enter the premises and may use as much physical force to effect entry therein as- is necessary to execute the search.
Although this rule is frequently referred to as “knock and announce,” the rule actually imposes no specific obligation to knock. Rather, the focus of the rule is on the announcement of identity, authority and purpose of the law enforcement officers seeking entry. The purpose of the rule “is to prevent violence and physical injury to the police and occupants, to protect an оccupant’s privacy expectation against the unauthorized entry of unknown persons, and to prevent property damage resulting from forced entry.”
Commonwealth v. Martinelli,
¶ 7 In the present case, however, the officers announced their identity, authority, and purpose fоr one to two minutes prior to arriving at the door and continued to announce as Trooper Wert climbed the steps and knocked on the door. Finding no Pennsylvania case with a similar factual situation, the Commonwealth has directed our attention to
United States v. Spikes,
¶ 8 Appellants Gary Doyen and Glenford Thompson contend the trial court erred in compelling them to proceed
pro se
at trial. Although an accused has a constitutional right to representation by counsel during trial, he may waive this right as long as the waiver is knowing and intelligent.
Commonwealth v. Monica,
(1) the defendant understands that he has the right to be represented by counsel, and the right to have free counsel appointed if he is indigent; (2) the defendant understands the nature of the *1013 charges against him and the elements of each of those charges; (3) the defendant is aware of the permissible range of sentences and/or fines for the offenses charged; (4) the defendant understands that if he waives the right to counsel he will still be bound by all the normal rules of procedure and that counsel would be familial' with these rules; (5) defendant understands that there are possible dеfenses to these charges which counsel might be aware of, and if these defenses are not raised at trial, they may be lost permanently; and (6) the defendant understands that, in addition to defenses, the defendant has many rights that, if not timely asserted, may be lost permanently; and that if errors occur and are not timely objected to, or otherwise timely raised by the defendant, the objection to these errors may be lost permanently.
Commonwealth v. Starr,
¶ 9 All four Appellants raise a Bat-son 5 challenge. During jury selection, the Commonwealth used a peremptory challenge to dismiss a juror who appeared to be of African-Ameriean-Hispanic descent. When the defense challenged this action, thе Commonwealth gave the following explanation:
[The juror], by the questionnaire he filled out, is not a high school graduate. He has a GED. He is young, and I think this is a very complicated case. His education.
The other reason was that when juror number 55, I was looking at the jury panel, juror number 55 ... had identified himself as a police officer, I noticed a visible look of disdain from [the juror]
It was brought to my attention by Trooper Torres that he was giving him dirty looks.
N.T., 4/12/02, at 108-9. The trial court found the prosecutor’s explanation credible and found as a fact that the juror was stricken “because of his age, education level, and an apparent dislike of police officers.” Trial Court Opinion, 5/15/03, at 29.
¶ 10 To sustain a challenge under
Batson,
a defendant must make a
prima facie
showing that the circumstances give rise to an inference that the prosecutor struck the prospective juror on account of race. Once a
prima facie
showing is made, the burden shifts to the prosecutor to articulate a race-neutral explanation for striking the juror. The court must then make the ultimate determination of whether the defense has carried its burden of proving purposeful discrimination.
Commonwealth v. Harris,
¶ 11 Finally, Appellants challenge the court’s decision to qualify Troop
*1014
er Torres to testify as an expert concerning the coded and guarded language used by drug dealers.
6
Admission of evidence is within the sound discretion of the trial court and will not be reversed absent an abuse of that discretion.
Commonwealth v. Begley,
¶ 12 Accordingly, as none of Appellants’ claims has merit, we affirm the judgments of sentence.
¶ 13 Judgments of sentence affirmed.
Notes
. Lloyd Dоyen was acquitted of corrupt organizations, possession with intent to deliver marijuana on April 5, 2000, and possession of drug paraphernalia on April 5, 2000.
. Appellants have filed one consolidated brief. Where an issue applies to fewer than all Appellants, we will so indicate in our discussion.
.Contrary to Pa.R.A.P. 2117, Appellants’ Statement of the Case does not contain "a closely condensed chronological statement, in narrative form, of all the facts which are necessary to be known in order to determine the points in controversy....” Pa.R.A.P. 2117(a)(4).
. Although we may address an ineffectiveness claim on direct appeal where the claim was raised post-trial and an evidentiary hearing was held,
Commonwealth v. Bomar, 573
Pa. 426,
.
Batson v. Kentucky,
. Apрellants Lloyd Doyen and Gary Doyen also set forth, as a separate argument, two particular portions of Trooper Torres’s testimony. However, this argument section contains no reference to any case law and it is not clear on what basis Appellants are challenging this testimony. See
Commonwealth v. Long,
