This appeal arises from sentences imposed on appellant following jury verdicts finding him guilty of assault and battery, aggravated assault and battery, and two counts of aggravated robbery. Four issues have been preserved for review: lengthy delay in bringing appellant to trial; refusal to suppress identification of appellant; refusal to permit impeachment of a Commonwealth witness by use of prior inconsistent statements; and admission of evidence of appellant’s prior criminal activities. For the reasons that follow, we affirm the judgment of the lower court.
A. SPEEDY TRIAL
On November 27, 1972, appellant and another were arrested for robbery of two gas stations. During the investigation of these charges, evidence was discovered linking the suspects to two prior robberies, on November 23, 1972, and they were charged with those offenses. At a preliminary hearing held December 22, 1972, the prior robberies were severed at appellant’s request, and the two defendants were tried for the gas station robberies. The prior trial concluded on May 17, 1973, at which time appellant request*96ed that the remaining charges be held in abeyance pending appointment of counsel for his co-defendant. Counsel was not appointed until March 11, 1975, but on December 13, 1974, appellant moved to dismiss the indictments against him on the basis that his right to a speedy trial had been violated. The court denied this motion on January 31, 1975, and the case was continued at that time, and a suppression hearing held on April 17, 1975. The motion to suppress was denied, and on April 21, 1975, trial was held before the court below and a jury. Appellant was found guilty, post-verdict motions were denied, and sentence was imposed.
Since appellant’s arrest antedates Pa.R.Crim.P. 1100, we must evaluate his speedy trial claim within the framework of Barker v. Wingo, 407 U.S. 514, 92 S.Ct. 2182, 33 L.Ed.2d 101 (1972). In Barker, adopted by our Supreme Court in Commonwealth v. Hamilton, 449 Pa. 297, 297 A.2d 127 (1972), the factors to be balanced in determining whether a particular defendant’s right to a speedy trial has been denied were delineated as follows: length of the delay; reason for the delay; defendant’s assertion of his right; and prejudice to the defendant.
Length of the delay, if sufficient, is a triggering mechanism requiring inquiry into the other factors comprising the balance. The 29-month period here while not requiring dismissal is sufficient to justify consideration of the remaining factors. See Commonwealth v. Coffey, 230 Pa.Super. 49, 331 A.2d 829 (1974) (25-month delay).
The second factor, the reason for the delay, requires close scrutiny. Initially, we note that appellant is responsible for six months of the delay from the time of arrest to the conclusion of the prior trial, as the result of his request that two of the charges be severed. Additionally, in May, 1973, appellant requested that the present charges be held in abeyance pending appointment of new counsel for his co-defendant. Original co-defense counsel did not withdraw until March 11, 1975, at which time new counsel was appointed. While most of this period of delay could arguably be attributable to appellant, we regard it at most as a neutral cause *97of delay. See Barker v. Wingo, 407 U.S. at 531, 92 S.Ct. 2182. Finally, from the time appellant moved to dismiss the indictments until trial was held, less than four months elapsed. Even if we were to conclude that the Commonwealth is responsible for this last delay, we would not hold the delay unreasonable on this basis alone, particularly in light of the facts that the Commonwealth was prepared to try all four robberies in May, 1973, and there is no evidence that any of the delay was a tactic on the part of the prosecution to prejudice appellant’s defense. See Commonwealth v. Coffey, 230 Pa.Super. 49, 54, 331 A.2d 829 (1974).
The third part of the balance is the defendant’s failure to promptly assert his right to a speedy trial. Appellant here failed to assert his rights for 25 months, and although he made two requests to dismiss the pending indictments against him, we note that he at no time requested that he be brought to trial. This factor weighs heavily against appellant in light of the fact he has some responsibility to assert a speedy trial claim, and the fact that “failure to assert the right will make it difficult for a defendant to prove that he was denied a speedy trial.” Barker v. Wingo, 407 U.S. at 532, 92 S.Ct. at 2193.
«The final factor to be weighed in the balance is the prejudice suffered by the defendant as the result of the delay. Appellant asserts here that the prejudice caused by the delay is twofold, in that he was prevented from presenting witnesses to describe the scene of the arrest because of the lapse of time, and he suffered oppressive pretrial incarceration.
At trial, appellant attempted to present witnesses to describe the scene of the arrest, and the court refused to admit their testimony, holding that any attempt to describe the area as it presently exists is irrelevant if it does not coincide with the description at the time of arrest. This ruling was a correct statement of the law. See Commonwealth v. DelMarmol, 206 Pa.Super. 512, 519, 214 A.2d 264 (1965). Furthermore, we are not persuaded that appellant’s defense was impaired by the delay in this case, in light of *98the fact that the same rule of evidence would apply to any ordinary delay between arrest and trial. In essence, causation between the delay in this case and the alleged impairment of appellant’s defense has not been proved.
Appellant raises the additional claim of prejudice in his assertion that he suffered undue and oppressive pretrial incarceration, and irretrievably lost the opportunity for an earlier parole. Smith v. Hooey, 393 U.S. 374, 89 S.Ct. 575, 21 L.Ed.2d 607 (1969). We agree with the trial court that appellant suffered no undue anxiety or oppression as the result of the delay in this trial, considering the fact that appellant was not to begin his prior sentence for the gas station robberies until he served a prior sentence of four to six years on still another charge. In addition, we regard any possible prejudice suffered by appellant in this respect to be minimal. See Commonwealth v. Bailey, 463 Pa. 354, 344 A. 2d 869 (1975).
Although there was a relatively lengthy delay in this case, we are persuaded that much of it was either caused by appellant or the result of a neutral cause. Moreover, appellant failed to assert his rights for 25 of the 29-month period, and failed to demonstrate more than minimal prejudice resulting from the delay. Consequently, we hold that appellant was not deprived of his constitutional right to a speedy trial.
B. SUPPRESSION OF IDENTIFICATION
Appellant next contends that the court below erred in refusing to suppress lineup and preliminary hearing identifications obtained as the result of an illegal arrest. It is important to note here that this motion was originally made in May, 1973 at a suppression hearing held before appellant’s prior trial for the gas station robberies, and denied by Judge SHIOMOS. At the suppression hearing held before trial on the present charges, Judge GUARINO refused to allow relitigation of the legality of the arrest. In all fairness to appellant, we deem Judge SHIOMOS’ conclusions as to the legality of the arrest incorporated in Judge GUARINO’s *99findings, and will therefore review the arrest and identifications at this juncture.
At about 4:15 a. m. on November 27,. 1972, officer Theodore W. Black of the Philadelphia police was patrolling the 93rd District when he received a series of radio calls informing him that a gas station robbery had just occurred, involving two Negro males driving a brown Cadillac. Further radio information described the robbers,1 and stated that the pursued vehicle had been wrecked, and the two suspects were being pursued on foot. Officer Black proceeded to the scene of the chase, and near the area observed a Negro male, the appellant, who appeared to fit one of the radio descriptions. Black stopped appellant and asked his name; appellant responded: “Robert Jones.” At that time, the officer noticed a large bulge in appellant’s pocket, and proceeded to search him. The search revealed a large roll of paper money, whereupon Black checked the name “Robert Jones” over police radio and was directed to bring appellant in for investigation. Appellant was then taken to the area of the wreck in a police wagon, and from there to the scene of the crime. The gas station owner was unable to make an identification, and appellant was thereupon transported to police headquarters. While appellant was being processed, the police received information implicating appellant in two other robberies, and decided to conduct a lineup. At the lineup, appellant was identified by one of the prior robbery victims. Later at a preliminary hearing held on December 22, 1972, both victims of prior robberies identified appellant as the perpetrator. These identifications are presently before us.
The initial question for our determination is the legality of the arrest. The description given Officer Black was that one of the robbers had a dark complexion, was about 5'8" tall, and wore a black coat. Although the officer testified that appellant fit this meager description, and was walking quickly, we are not satisfied that these circumstanc*100es constituted sufficient probable cause. See, e. g., Commonwealth v. Richards, 458 Pa. 455, 327 A.2d 63 (1974). Furthermore, the arrest cannot be justified on the grounds that the officer searched appellant in the reasonable belief that he was armed and dangerous. Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968). When asked whether the bulge he saw appeared to be a weapon, Officer Black responded: “I didn’t know what it was.” N.T.S.H. p. 138. Further questioning elicited the information that the search was not a limited intrusion undertaken for the purpose of ascertaining the presence of weapons, but, in the officer’s words, “I went through the whole motion. I checked him from head to toe.” N.T.S.H. p. 138.
Despite this illegality, we cannot accept appellant’s contention that the identification evidence stemmed directly and immediately from the illegal search and was impermissibly tainted by it. The test that we must apply was set forth in Wong-Sun v. United States, 371 U.S. 471, 487-88, 83 S.Ct. 407, 417, 9 L.Ed.2d 441 (1963), where the Court said:
“We need not hold that all evidence is ‘fruit of the poisonous tree’ simply because it would not have come to light but for the illegal actions of the police. Rather, the more apt question in such a case is ‘whether, granting establishment of the primary illegality, the evidence to which instant objection is made has been come at by exploitation of that illegality or instead by means sufficiently distinguishable to be purged of the primary taint.’ ” (Citation omitted.)
In this case, the wreck of the getaway car led to discovery that the stolen Cadillac belonged to one Clarence Carter, and a wallet in the car belonged to one William Kellog. As previously discussed, Kellog identified appellant at the lineup; both Kellog and Carter identified him as the robber at the preliminary hearing. Identification evidence, however, will not be suppressed merely because it has derived from an illegal arrest. Commonwealth v. Garvin, 448 Pa. 258, 293 A.2d 33 (1972). As our Supreme Court indicated in Garvin, we cannot assume that but for the illegal arrest appellant *101would have remained at large indefinitely. “No law abiding society could tolerate a presumption that but for the illegal arrest the suspect would never have been required to face his accusors.” Commonwealth v. Garvin, 448 Pa. at 264, 293 A.2d at 37. The record clearly indicates in this case that Carter had ample opportunity to observe appellant when he was beaten and robbed, and made a positive, unwavering identification at trial. N.T. Trial, pp. 384-399; 438-499. Kellog, the other victim of a prior robbery, also got a good look at appellant’s face up close when he was robbed, and gave a clear and positive description at trial. N.T. Trial, pp. 1269-1284; 1287-1295. After reviewing the record in this light, we are satisfied that the in-court identifications by Carter and Kellog were based on personal observation during their robberies, and not the result of the exploitation of any illegality. The only effect of the arrest in this case was to hasten the inevitable confrontation between appellant and his victims, not to influence its outcome. Commonwealth v. Garvin, 448 Pa. at 264, 293 A.2d 33. Trial testimony* of the victims positively demonstrates that appellant’s arrest contributed neither to their knowledge as witnesses nor to the accuracy of their identifications. Consequently, we hold that the court did not err in refusing to suppress the identification testimony, when the testimony was sufficiently independent of the illegal arrest as to be unaffected by the “fruit of the poisonous tree” prohibition. Commonwealth v. Crutchley, 242 Pa.Super. 496, 364 A.2d 381 (1976).
C. IMPEACHMENT — PRIOR INCONSISTENT STATEMENT
Appellant next contends that the trial court erred in refusing to direct the court stenographer to read prior statements made by a Commonwealth witness under oath, for the purpose of impeaching the witness by prior inconsistent statements.
At the pretrial suppression hearing before Judge GUARINO, Detective West was questioned about the composition of the lineup, and testified as follows:
*102MS. CHRISTIE: Were you able, when you looked through the glass at the line-up participants, to see any part of the bodies of the participants below their waist — strike that. I should say, Detective when you looked through the glass at the line-up participants, were you able to see any portions of the body of these participants which were below the level of the table?
DETECTIVE WEST: Little if at all . . .” N.T.S.H. pp. 157-158.
And further,
MS. CHRISTIE: Did you have occasion to note any of the participants in the lineup at the time you looked through the screen which you’ve indicated was contemporaneously with the complainant, with their legs faced — the sides of their legs facing the screen?
DETECTIVE WEST: Not to my knowledge, no.
MS. CHRISTIE: As a matter of fact, did you have occasion to note at all in what direction the front of the legs of the police officer participants were facing? DETECTIVE WEST: No I wouldn’t — would have no reason to.
MS. CHRISTIE: As a matter of fact, did you have occasion to note at all whether or not you could see any stripes on the police officer’s trousers?
DETECTIVE WEST: I wasn’t even looking at his legs, at anybody’s.” N.T.S.H. pp. 161-162.
At trial, Detective West was again asked what portion of the participants in the lineup he could see below the table. He answered: “None.” N.T. Trial, p. 1239.
We discern no inconsistency between these statements, and therefore hold that the trial judge committed no error in refusing to allow the attempted impeachment. Detective West’s testimony was substantially the same on both occasions, thereby precluding impeachment by use of a prior inconsistent statement. A mere dissimilarity between the prior statement and the present testimony will not suffice; there must be a substantial inconsistency. See In re Silverberg, 459 Pa. 107, 117, 327 A.2d 106 (1974).
*103D. RADIO CALLS — PRIOR CRIMINAL ACTIVITY
Appellant’s final assignment of error contains the claim that the Commonwealth improperly presented evidence of appellant’s prior criminal activities, by repeated reference to radio calls broadcast to the police during pursuit of appellant. The problem arises from the fact that while appellant was being tried in this case for the November 23 robberies, the radio calls at issue were the result of 2 robberies that occurred on November 27. We are compelled to agree with the trial judge, however, that references in the record to these radio calls in no way implied prior criminal activity by appellant, and consequently did not prejudice him before the jury.2
Moreover, we are persuaded that testimony as to the radio broadcasts was not offered or admitted to prove the truth of the broadcasts, but rather to show the mental state of the police and explain their course of conduct. Under these circumstances, we find no error. See Commonwealth v. Sampson, 454 Pa. 215, 219, 311 A.2d 624 (1973); Commonwealth v. Jacobs, 445 Pa. 364, 367, 284 A.2d 717 (1971); Commonwealth v. Tselepis, 198 Pa.Super. 449, 452, 181 A.2d 710 (1962).
Accordingly, the judgment of sentence is affirmed.
CERCONE, J., concurs in the result. HOFFMAN, J., files a dissenting opinion in which SPAETH, J., joins. SPAETH, J., files a dissenting opinion in which HOFFMAN, J., joins. WATKINS, former President Judge, did not participate in the consideration or decision of this case.. Two Negro males, one 5'7", dark, wearing an earring; the other about 5'8", and also dark, and wearing a dark coat. N.T.S.H. p. 125.
. The trial court noted one reference to prior criminal activity when Officer Cheatham inadvertently referred to a holdup at Vare Avenue, the scene of the gas station robberies. We nevertheless agree with the trial judge’s characterization of this testimony as a spontaneous slip, and no basis for a new trial. Commonwealth v. Bunch, 454 Pa. 365, 311 A.2d 632 (1973). Furthermore, defense counsel declined the trial judge’s offer of a curative instruction. Lower Court Opinion at 15.