Defendant appeals her convictions for tape recording a police radio broadcast without the consent of one of the participants, ORS 165.540(1)(a),1 and for tape recording a conversation with police officers without specifically informing them. ORS 165.540(l)(c). We reverse the conviction for recording the broadcast but affirm the conviction for recording the face-to-face conversation.
Defendant had had unpleasant interactions with the police as a result of her attempts to help and counsel young people at the Eugene Mall, many of whom had records of delinquency. At about 2 a.m. on August 1,1987, Officer Shad-wick and at least one other officer stopped defendant and a juvenile in an alley in downtown Eugene. Defendant carried a police scanner and a tape recorder with which she had been taping police broadcasts. During the ensuing encounter with Shadwick, the recorder continued to run, recording the conversation. When Shadwick discovered the recorder, he arrested defendant for unlawfully obtaining contents of communications.
With respect to defendant’s conviction under ORS 165.540(1)(a), that section provides:
“Except as otherwise provided in ORS 133.724 or subsections (2) to (6) of this section, no person shall:
“ (a) Obtain or attempt to obtain the whole or any part of a telecommunication or a radio communication to which such person is not a participant, by means of any device, contrivance, machine or apparatus, whether electrical, mechanical, manual or otherwise, unless consent is given by at least one participant.”
ORS 165.540(4), however, provides:
“The prohibitions in paragraph (a) of subsection (1) of this section do not apply to the receiving or obtaining of the contents of any radio or television broadcast transmitted for the use of the general public” (Emphasis supplied.)
Defendant assigns as error that the court held that the police *260broadcast that she heard over the scanner, although accessible to the public, was not transmitted “for the use of the general public.”
No Oregon statute or case construes the phrase “for the use of the general public.” That language, however, is in the Communications Act of 1934 at 47 USC § 605. That section exempts transmissions, including radio signals, “for the use of the general public” from its prohibitions on intercepting and divulging radio communications. We read the federal cases to mean that the phrase refers to an electronic transmission in which the sender has no property or privacy interest, which he sends unscrambled and to which the public has free and ready access. See National Subscription Television v. S & H TV, 644 F2d 820 (9th Cir 1981); Chartwell Communications Group v. Westbrook, 637 F2d 459 (6th Cir 1980); Bubis v. United States, 384 F2d 643 (9th Cir 1967); Hoosier Home Theater, Inc. v. Adkins, 595 F Supp 389 (SD Ind 1984); United States v. Russo, 250 F Supp 55 (ED Pa 1966). In the absence of Oregon authority on the question, we give the same meaning to the phrase in ORS 165.540(4).2
We note that, under State v. Knobel, 97 Or App 559, 777 P2d 985 (1989), rev den 309 Or 522 (1990), the word “obtain” in ORS 165.540(1) (c) means to intercept a communication by means of a device. Presumably, “obtain” has the same meaning in ORS 165.540(l)(a). Because the scanner is a “device,” it would be a crime to use it merely to listen to a broadcast that is readily accessible and free to the public, even without tape recording the broadcast, unless the exception in ORS 165.540(4) prevents such an unreasonable result, which it does.
We hold that the trial court erred in its conclusion that the broadcast was not “for the use of the general public.” *261The police had no property or privacy interest in it. It is undisputed that it was transmitted on a frequency that was accessible to the public, who could listen without subscription, payment or other hindrance. The scanner that defendant used to receive the message was for sale at K-Mart and Radio Shack stores. Although the police intended that the broadcast be for police use, the message was not coded or scrambled, and the police knew that the public could listen to it. The public could understand the content of the message without the use of special equipment, even though police officers were identified by number rather than by name. The broadcast was “for the use of the general public” within the meaning of the exception in ORS 165.540(4). Defendant committed no crime when she tape recorded the police radio broadcast.
With respect to defendant’s conviction under ORS 165.540(l)(c), that section provides:
“[N]o person shall * * * [o]btain or attempt to obtain the whole or any part of a conversation by means of any device, contrivance, machine or apparatus, whether electrical, mechanical, manual or otherwise, if all participants in the conversation are not specifically informed that their conversation is being obtained.”
ORS 165.540(6) contains these exceptions:
“The prohibition in paragraph (c) of subsection (1) of this section shall not apply to persons who intercept or attempt to intercept with an unconcealed recording device the oral communications that are part of any of the following proceedings:
“(a) Public or semipublic meetings such as hearings before governmental or quasi-governmental bodies, trials, press conferences, public speeches, rallys [sic] and sporting or other events;
* * * *
“(c) Private meetings or conferences if all others involved knew or reasonably should have known that the recording was being made.”3
Defendant first argues that there was no evidence *262from which the trial court could find that she did not specifically inform Shadwick that she was recording the conversation. According to her, the tape recorder was in plain sight. Moreover, before the confrontation, fellow officers had told Shadwick that defendant was carrying a recorder. She argues that, because the circumstances show that Shadwick had reason to know that his conversation was being taped, he should be considered “specifically informed” under the statute.
The clear language of the statute requires otherwise. In some circumstances, the legislature has permitted recordings to be made “if all others * * * reasonably should have known that the recording was being made.” See ORS 165.540(7)(c), formerly ORS 165.540(6)(c). Rather than using such language in ORS 165.540(l)(c), however, it has required that persons being recorded be “specifically informed.” The legislature clearly intended to require persons recording the conversations of others to give an unequivocal warning to that effect. Because defendant did not notify Shadwick that she was recording his conversation, she violated the statute. See State v. Knobel, supra.
Defendant also contends that the trial court erred in finding that she “knowingly” taped Shadwick’s words. According to defendant, she intended to record only police broadcasts on her scanner. She contends that, surprised by a sudden confrontation with the police, she left the recorder running and accidentally taped the conversation.
The trial court reasoned that defendant must have known that she was recording the conversation, because she had turned the recorder on to record the police broadcasts. It also found that she was not surprised by the appearance of the officers, because she had been monitoring their activities with her scanner. It inferred that, because defendant started the recorder and left it running, she knew that she was taping her conversation with the officers. The evidence was sufficient to support that inference.
The dissent argues that “the undisputed facts show the absurdity of applying the words of the statute to defendant.” 101 Or App at 266. There are two problems^kuth that position. First, we see nothing in the record to indicate that the argument on which the dissent relies was raised either below at the trial level or here on appeal. Accordingly, we *263should not consider it. State v. Stroup, 290 Or 185, 204, 620 P2d 1359 (1980). Second, even if we were to decide that the dissent’s proposed holding is so broad that nearly any argument would preserve it, it provides no basis upon which to exonerate defendant. The dissent’s explanation for how it reaches its conclusion is obscure, permitting any number of unfortunate interpretations of the statute.4 Although it suggests that it would be absurd to apply the plain meaning of the statute, it fails to explain why. In the absence of any valid constitutional challenge,5 our only alternative is to accept the legislature’s clear pronouncement that persons being recorded must be given an unequivocal warning.
Reversed on conviction for tape recording police radio communication; otherwise affirmed.
In 1989, the legislature amended ORS 165.540 by, inter alia, adding the exception discussed at n 2. The statutory provisions that we discuss were changed only in numbering, and we quote them as they read at the date of defendant’s conviction.
In 1989, the legislature enacted ORS 165.540(8), which provides:
“The prohibitions in paragraphs (a), (c), (d) and (e) of subsection (1) of this section do not apply to any:
“(a) Radio communication which is transmitted by a station operating on an authorized frequency within the amateur or citizens bands; or
“(b) Person who intercepts a radio communication which is transmitted by any governmental, law enforcement, civil defense or public safety communications system, including police and fire, readily accessible to the general public provided that the interception is not for purposes of illegal activity.”
Contrary to defendant’s assertion, mere encounters are not “meetings” within the meaning of ORS 165.540(7)(a), formerly ORS 165.540(6)(a). Defendant’s argument that her taping of the confrontation with police was exempt either as a “public or semipublic meeting,” or as a “private meeting or conference,” ORS 165.540(7)(c), formerly ORS 165.540(6)(c), is without merit.
According to the dissent:
“[B]efore the officers arrived, defendant had been recording the police broadcast for some time, the officers knew that defendant was using a scanner, and Shad-wick knew that defendant was carrying a tape recorder. While defendant was recording the police broadcast, the officers arrived uninvited and the tape recorder recorded the ensuing interrogation.” 101 Or App at 264.
<i* * * * *
“It is absurd to state that, in her situation, defendant was obliged specifically to inform the officers that she was tape recording the conversation. When the police stopped her and her companions, she was already recording what she heard on the scanner and, as the trial court found, that is why she had her recorder on ‘in the first place.’ She was not obliged to turn off the recorder or inform the officers that she was tape recording the broadcast. ” (Emphasis in original.) 101 Or App at 266.
What that language means is a matter of conjecture. The dissent may mean that defendant did not tape the conversation knowingly. If so, it has ignored the specific findings of the trial court. It could mean that the statute does not apply to defendant, because she was legally recording something else. If so, one could escape criminal liability simply by turning on the radio before taping a conversation. It also may mean that ORS 165.540(1) (c) does not forbid recording uninitiated conversations. However, the statute contains no such exception. Finally, it might mean that defendant would have turned the recorder off, had she had opportunity to do so. Again, however, that would contravene the trial court’s findings. Simply put, the dissent has not lucidly articulated any reason for holding that defendant did not violate ORS 165.540(1) (c) that does not either disregard the trial court’s specific findings of fact or carve unwarranted exceptions from the express coverage of the statute.
Defendant has argued that the term “obtain” renders both ORS 165.540(l)(a) and ORS 165.540(1) (c) unconstitutionally vague. She concedes, however, that construing the statute “to prohibit only the use of a device, contrivance, machine or apparatus to intercept a conversation in any form” eliminates any such vagueness problem. See State v. Knobel, supra, 97 Or App at 562. (Emphasis supplied.) There is no merit in her contention that “participants” is unconstitutionally vague. She specifically withdrew her contention that ORS 165.540(1) (c) is unconstitutionally over-broad.