TL;DR

The best ways to track offline conversions from radio combine dedicated call tracking numbers, short vanity URLs, memorable promo codes, CRM revenue matchback, as-run log analysis, branded search lift monitoring, and geo lift testing. No single method captures every conversion. Radio listeners often search the brand name instead of using the exact call to action, so the measurement system needs to account for both direct response and delayed demand. Build the tracking plan before the first spot airs.

What Is Offline Conversion Tracking for Radio?

Offline conversion tracking for radio ads is the process of measuring real-world actions that happen after someone hears a radio spot. Those actions include phone calls, booked appointments, quote requests, purchases, store visits, form submissions, app downloads, and branded searches. Because radio does not generate a click, advertisers need dedicated tracking tools to connect ad exposure to business results.

This is different from digital attribution, where a user clicks an ad, lands on a page, and converts in a measurable session. Radio creates demand that flows through multiple paths, many of them invisible to standard analytics platforms. A listener might hear a spot during their morning commute and not act until that evening. They might call a number, search the brand on Google, type the URL directly, or walk into a store and mention they heard an ad.

Radio still reaches 225.4 million U.S. listeners according to Nielsen data cited by the Radio Advertising Bureau. Nielsen’s Q2 2025 report shows radio accounts for 64% of daily time spent with ad-supported audio. The audience is there. The challenge is proving what that audience does after they hear the ad. Understanding why radio advertising works is the first step. Tracking the response is the second.

Why Radio Attribution Is Different From Digital Attribution

Radio is not untrackable. It is undercounted when advertisers rely only on last-click analytics. Here is why the gap exists.

There is no native click. Digital ads produce click IDs, session data, and cookie-based attribution. Radio produces memory, intent, and delayed action. The listener has to do something voluntary to create a trackable signal.

Response is often delayed. A Westwood One analysis of 17 AM/FM attribution studies found that evening dayparts often show a greater share of attributed web sessions because consumers have more free time and devices later in the day. Morning-drive exposure may not produce visible response until hours later. Source

Listeners search the brand instead of following the CTA. Practitioners on Reddit consistently report this frustration. One marketer testing radio for a subscription product noted that many users simply Google the brand after hearing an ad, making attribution feel fuzzy even when vanity URLs and promo codes are in place. Source

Last-click platforms steal the credit. When a listener hears a radio spot, remembers the brand, and later searches it on Google, that conversion often gets attributed to paid search, organic search, or direct traffic. Radio created the demand. Search captured it. But in standard analytics, radio gets nothing.

The effect can last weeks. Oxford Road’s study, based on $400 million in cumulative audio spend, found that audio’s impact on branded search can persist for weeks after the initial investment. Source

The answer is not to abandon radio measurement. The answer is to build a system that captures both the visible response and the invisible lift.

The 5-Layer Radio Conversion Tracking Stack

The best way to track offline conversions from radio is not a single tactic. It is a layered system. Think of it in five tiers:

1. Direct response capture (tracking numbers, vanity URLs, promo codes, SMS keywords)
2. Lead quality capture (call recording, call duration, disposition, missed-call alerts, CRM status)
3. Revenue matchback (connecting caller ID, email, promo code, or order ID to actual revenue)
4. Response lift signals (branded search, direct traffic, landing page visits, call spikes aligned to spot times)
5. Incrementality validation (matched-market tests, geo holdouts, time-based tests for larger campaigns)

Most articles about tracking radio conversions list tactics. This framework shows how those tactics work together. Each layer catches something the others miss.

Method 1: Dedicated Call Tracking Numbers

For most direct-response radio campaigns, call tracking is the first and most important measurement layer. The phone call remains the highest-intent conversion for categories like insurance, legal, healthcare, home services, financial services, and automotive.

The concept is straightforward. Assign a unique phone number to each radio campaign, station, market, creative, or daypart. That number forwards to the business’s main sales line. The tracking platform records which number rang, when, how long the call lasted, and whether it was answered.

CallTrackingMetrics defines tracking numbers as unique phone numbers used to attribute calls, texts, form submissions, and chats to individual marketing campaigns. For offline ads, the platform recommends setting up a tracking number at the level of granularity needed for decisions. Source

CallRail describes the mechanism simply: the platform procures a tracking number that forwards to the main business number, and statistics are available online in real time. Source

Practical setup tips

Use local numbers when local trust matters. A plumber in Houston benefits from a 713 area code. Use toll-free or vanity numbers when national reach and memorability matter. A national insurance advertiser benefits from a catchy 800 number that listeners can recall hours later.

Add call whisper. This is a brief audio message the agent hears before connecting with the caller, something like “this call is from the sports talk campaign.” It lets the team know the source before they say hello.

Record and score calls. Not every ring is a conversion. A 15-second hang-up is not the same as a qualified lead who books an appointment. Small-business owners and PPC practitioners on Reddit repeatedly emphasize that phone-call volume can include irrelevant calls, spam, and low-quality leads. The tracking system needs to separate signal from noise. Source

Track missed calls. A campaign might be working perfectly while the business loses response because nobody answers the phone. Missed-call capture and callback protocols turn lost leads into recovered revenue.

Do not use only the main business number as the radio CTA. If every channel points to the same number, there is no way to know whether calls came from radio, search, referrals, or repeat customers.

For advertisers running talk radio advertising or sports talk radio advertising, a unique number per host or show can reveal which placements actually drive qualified callers.

Example

A legal advertiser runs three stations in Los Angeles. Assign one tracking number per station for the first test. If call volume is high enough, split by daypart or creative in the next flight. Compare not just call count but qualified consultations and signed cases per station.

Method 2: Short Vanity URLs and Landing Pages

Some listeners will not call. They will go online. A short, memorable URL gives them a trackable path to the website.

The URL needs to be easy to hear once and type correctly. Avoid hyphens, confusing spellings, long paths, or words that sound like other words. Something like brand.com/radio or brand.com/save works well. Something like brand.com/special-radio-offer-2025 does not.

Redirect the vanity URL to a landing page with UTM parameters so the visit shows up correctly in Google Analytics. Google’s documentation explains that UTM campaign parameters added to destination URLs allow Analytics to identify which campaigns refer traffic. Source

Neil Patel’s guidance on offline campaign tracking recommends keeping these URLs short, logging where each URL is used, noindexing duplicate landing pages to prevent organic traffic from contaminating the data, and including a phone number on the landing page because offline audiences may prefer speaking with a person. Source

Key principles

• Make the landing page mobile-friendly. Most listeners will type the URL on a phone.
• Include the same phone number and offer mentioned in the radio spot. Consistency matters.
• Use one unique landing page per campaign, market, or offer when there is enough volume to justify the comparison.
• Remember that vanity URLs capture only people who type that exact URL. They miss everyone who searches the brand or goes to the homepage.

Example

For a first broad test, use brand.com/radio. For a market-level comparison, use brand.com/chicago or brand.com/houston. Only split further if the campaign has enough traffic to produce meaningful data.

Method 3: Memorable Promo Codes

Promo codes work well for ecommerce, subscription trials, and call-center orders where the agent can ask for a code during the transaction. The code needs to be short, phonetic, and easy to repeat. Think “RADIO,” “SAVE50,” “TALK,” or a station name. Avoid codes that are hard to spell or that listeners will confuse with other promotions.

The code should also be valuable enough to remember. A 5% discount is not worth the mental effort. A meaningful dollar amount, a free month, or a waived fee gives the listener a reason to hold onto the code.

The undercounting problem

Promo codes consistently undercount radio response. Customers forget the code. They search for other coupons at checkout. They call the main number instead of the tracking number and never mention the code. They convert days later through a different channel.

RioStack’s guide on offline conversion tracking notes that promo codes work only if customers remember to use them. Source Practitioners on Reddit echo this, pointing out that many users simply Google the brand after hearing a radio ad, bypassing the code entirely. Source

The solution is not to abandon promo codes. It is to use them alongside call tracking and branded search monitoring so the promo code captures some attribution while other methods capture the rest.

Tip for call-center businesses

Train phone reps to ask for the promo code but never block the sale if the caller does not have one. If the call came through a radio tracking number, the source is already known. The promo code is a bonus data point, not a gate.

Method 4: CRM, POS, and Call-Center Outcome Tracking

Counting calls is not enough. A radio campaign that produces 200 calls but only 8 sales is a different story than one that produces 80 calls and 25 sales. The goal is to connect radio response to revenue.

Every radio-generated call or lead should get a source field in the CRM. The minimum useful fields include: tracking number dialed, station or market, campaign name, date and time, caller ID, call status (answered, missed, voicemail), qualified or not qualified, appointment booked, sale amount, close date, and rep notes.

For ecommerce or retail, match the promo code, phone number, email, loyalty ID, or order ID back to the campaign. For phone-heavy businesses, call disposition is critical.

RioStack recommends including deal values in CRM integration because a $10,000 deal should get more credit than a $100 deal. Source Cometly’s guide on offline attribution methods recommends CRM integration and sales-team attribution for high-consideration purchases where the sale happens through conversations. Source

Example

A senior-care advertiser gets 120 radio calls in a month. Only 45 are qualified prospects. 18 book consultations. 6 become customers. The campaign should be judged on cost per qualified lead, cost per booked consultation, and cost per acquired customer. Not 120 calls.

This is where radio tracking turns from a reporting exercise into a revenue optimization tool. If one station produces fewer calls but a higher close rate, that station deserves more budget.

Method 5: As-Run Log and Response-Window Analysis

This is the radio-specific method that most generic offline attribution articles miss entirely.

An as-run log is the station’s record of exactly when each spot aired. It shows the date, time, program, and spot length for every airing. By comparing as-run times against call logs, web sessions, branded search queries, and form submissions, the advertiser can see whether response spikes align with spot times.

Westwood One describes a methodology using ad occurrence data, Nielsen impressions, DMA-level traffic analysis, attribution windows, and decay curves to connect radio airings to web response. Their analysis of 17 AM/FM campaigns found an average +14% lift in site traffic.

Response windows matter

Do not assume all radio response happens within minutes. Use multiple response windows: immediate (0 to 5 minutes), short (5 to 30 minutes), medium (30 minutes to 2 hours), same day, next day, and multi-week for longer-consideration products.

Morning-drive spots may trigger evening response. Westwood One’s data shows evening dayparts often produce a greater share of attributed web sessions because consumers have more free time and access to devices later in the day. Judging a morning schedule only by calls in the next five minutes will undercount its true impact.

What to compare

Once the as-run data is matched to response data, compare performance by station, market, daypart, format, show, host read versus produced spot, offer, and creative. If calls consistently spike within 10 to 20 minutes after a sports-talk host-read spot, keep that placement. If another station delivers impressions but no detectable response-window lift, renegotiate, revise the creative, or reallocate the budget.

For advertisers using remnant radio advertising, this analysis is especially important. Remnant buying trades some placement control for significant cost savings, so measuring response by station and daypart keeps the campaign performance-driven even when exact scheduling is less predictable.

Method 6: Branded Search and Direct Traffic Lift

This might be the most underappreciated method for tracking offline conversions from radio. Many listeners never use the tracking number, the vanity URL, or the promo code. They hear the spot, remember the brand, and search for it later. That search often shows up in analytics as organic traffic, paid search, or direct traffic, with no connection to radio.

Oxford Road’s “The Sound of Growth” study found that audio drove an average of 18% of clients’ branded search volume, with some brands seeing 40% or more driven by audio. A Westwood One/LeadsRx analysis of 17 AM/FM campaigns found an average +14% lift in website traffic.

The frequency data is even more striking. An iHeartMedia/LeadsRx auto-dealer study found that dealers running 10 AM/FM ads daily in a market saw a 12% site traffic lift, those running 20 to 29 ads daily saw a 23% lift, and those running 40 or more ads saw a 55% lift.

How to monitor branded search lift

• Track branded search impressions and clicks in Google Search Console.
• Run a branded paid search campaign and watch impression and click volume changes when radio starts and stops.
• Monitor direct traffic and homepage sessions in GA4.
• Compare DMA-level changes when radio runs in some markets but not others.
• Separate branded search from non-branded search in ROI calculations, or the search channel will overclaim demand that radio created.

Pierre Bouvard, a well-known audio advertising researcher, has argued on LinkedIn that branded search is one of the most effective ways to cut through audio attribution noise. The Oxford Road study supports this, showing that audio’s search impact can persist for weeks after the campaign ends. Source

Example

A campaign airs in Chicago and Houston but not in Dallas or Atlanta. If branded search volume increases 20% in Chicago and Houston while staying flat in Dallas and Atlanta, radio is likely the cause.

Method 7: Customer Surveys and Intake Questions

Self-reported attribution is imperfect. Customers misremember, conflate channels, and sometimes just say whatever ends the question fastest. But intake surveys can reveal radio influence that call tracking and web analytics miss entirely, especially when customers walk in, call the main number, or mention the ad to a salesperson.

Add “What prompted you to call today?” or “Where did you first hear about us?” to intake scripts, online forms, and post-purchase surveys. Include specific options like “AM/FM radio,” “SiriusXM,” “heard a host mention it,” and the relevant station or show name.

Practitioners on Reddit describe “How did you hear about us?” as underused but powerful, while cautioning that customers may not distinguish channels perfectly. Source In another thread, a local business owner spending about $1,500 per month on radio reported that customers (usually age 40 and older) regularly came in and mentioned hearing the ad. Source

Use survey data as a supporting signal, not the primary attribution method. It is most valuable for categories where call tracking cannot capture every path, like retail walk-ins, referrals triggered by radio, or delayed conversions on the main phone number.

Method 8: Geo Lift, Matched-Market Tests, and Holdouts

For larger radio budgets, the cleanest proof is not a promo code or a tracking number. It is a controlled market test.

The concept: run radio in a set of markets, hold out similar markets where radio does not run, keep the rest of the media mix as stable as possible, and compare total results. Measure qualified calls, branded search, direct traffic, sales, revenue, and new-customer acquisition across both groups.

Cometly recommends geographic and time-based lift analysis for TV, radio, and out-of-home campaigns where direct response tracking is limited. Source Wayfair has published a framework for geo experiments that outlines three steps: define geo units, assign geos to treatment groups, and measure lift. Source

Practitioners on Reddit who deal with similar attribution challenges for CTV (another non-click medium) describe geo holdouts as the gold standard. One suggested using matched DMAs, holding out 20 to 30% of markets, running a 4 to 6 week pre-period, and measuring blended site revenue plus branded search lift while keeping other channels constant. Source

Example

Run radio in 8 similar DMAs and hold out 2 or 3 comparable DMAs. Use the top 100 U.S. radio markets as a starting point for identifying test and control markets with similar population, demographics, and baseline performance.

When to use this method

Matched-market tests require enough budget to create meaningful frequency in the test markets and enough patience to run a proper pre-period and test period. They are best suited for national radio advertising campaigns or multi-market rollouts where leadership needs proof beyond direct attribution.

A Note on QR Codes

QR codes work well for print, direct mail, event signage, and streaming display companions. For pure radio, they are not the primary tracking tool because listeners cannot see them. If the radio campaign has companion visual placements (social ads, direct mail, CTV), QR codes can be part of the broader tracking plan. But they should not be listed as a core method for audio-only campaigns.

Which Tracking Method Should You Use?

The answer depends on the business model, the budget, and the conversion path.

Situation	Best primary method	Supporting methods
Phone-driven local business	Dedicated call tracking number	CRM disposition, missed-call tracking, intake survey
National direct-response campaign	Toll-free or vanity number plus campaign-specific numbers	Promo code, call center outcome tracking, as-run analysis
Ecommerce or subscription offer	Promo code plus short URL	Branded search lift, post-purchase survey, geo test
Multi-market radio test	Market-specific tracking numbers	DMA branded search, matched-market lift
High-ticket B2B or healthcare	Call tracking plus CRM matchback	Sales-stage reporting, revenue value, survey
Host-read or talk radio	Unique number or offer per host/show	Call notes, creative comparison, response windows
Remnant radio campaign	Dedicated number by market/station	Frequent reporting, creative and offer testing

Small-budget radio advertisers often cannot achieve perfect statistical proof. Practitioners on Reddit acknowledge this openly. One commenter with both radio and business-owner experience said radio depends heavily on repetition and that measuring ROI on a small budget is hard, but they knew radio worked because business was consistently busier with it than without it. Source The practical goal for smaller campaigns may be directional confidence: more qualified calls, higher booked revenue, increased branded search, and better response in test markets.

How to Calculate Radio ROI

The basic formula:

Radio ROI = (Revenue attributed to radio, minus radio campaign cost) / radio campaign cost

But “revenue attributed to radio” requires the tracking stack described above. Break it down further:

• Cost per call = total radio spend / total calls from tracking numbers
• Cost per qualified call = total radio spend / qualified calls only
• Cost per booked appointment = total radio spend / appointments booked from radio leads
• Cost per acquisition = total radio spend / new customers from radio
• ROAS = total revenue from radio-attributed customers / total radio spend

For longer sales cycles, factor in lifetime value. A legal client, insurance policy, or medical patient may generate revenue over months or years. Judging radio ROI on first-transaction revenue alone undervalues the channel.

Creative Affects Tracking (Not Just Analytics)

Radio attribution is partly a creative problem. If listeners cannot remember the brand name, the phone number, the URL, or the offer, the measurement system will undercount response no matter how good the analytics setup is.

Westwood One’s LeadsRx analysis found the highest-performing ads mentioned the brand within the first five seconds. Veritonic recommends four to six brand mentions in a 30-second spot. Source

Pierre Bouvard echoed this on LinkedIn, arguing that weak audio attribution is often a creative problem. His recommendation: audit every spot for a “brand early and often” standard, meaning the brand name appears in the first two seconds and at least five times in a 30-second ad. Source

A creative checklist for trackability:

• Mention the brand within the first five seconds
• Repeat the brand name four to six times
• State one clear call to action (call, visit, use code)
• Use a phone number that is easy to remember
• Use a URL that is short and phonetically unambiguous
• Repeat the CTA at the end of the spot
• Avoid competing CTAs (do not give a phone number, a URL, a promo code, and a text keyword all in the same 30-second spot)

For help producing direct-response radio creative that is built for measurability, explore Berk Marketing’s radio advertising services. Berk handles scripting, voiceover, and production alongside media buying and call tracking setup.

Common Mistakes That Kill Radio Tracking

1. Using only the main phone number. There is no way to separate radio callers from other sources.
2. Counting every call as a conversion. Spam, wrong numbers, and unqualified inquiries inflate the count.
3. Ignoring missed calls. The campaign may be generating demand that the business is failing to capture.
4. Using long or hard-to-spell URLs. Audio URLs must be understood in one hearing.
5. Running different offers without clean labels. If every spot has a different message but the CRM just says “radio,” optimization is impossible.
6. Judging radio only by same-day results. Radio often creates delayed search, calls, and conversions.
7. Letting paid search take all the credit. Branded search may be the capture mechanism, not the demand source.
8. Not requesting as-run logs. Without actual spot times, there is no way to connect response spikes to specific airings.
9. Changing too many variables at once. If station, offer, creative, daypart, and market all change simultaneously, nobody can tell what worked.
10. Stopping too early. One or two weeks may not reveal the real response pattern. Frequency builds over time, and so does measurable lift.

Pre-Launch Tracking Checklist

Build this before the first spot airs. If you are working with rapid-launch radio campaign best practices, this checklist becomes even more important because speed without tracking is just fast spending.

Before the campaign

• Define the conversion hierarchy: call, qualified call, appointment, sale, revenue, lifetime value
• Assign tracking numbers by campaign, station, market, or creative
• Create a short vanity URL and landing page with UTM parameters
• Create one memorable promo code if the offer supports it
• Build CRM fields for campaign, market, station, show, creative, and outcome
• Set up call recording and transcription (where legally appropriate)
• Train sales and call-center staff on source-tracking questions
• Get as-run reporting expectations in writing from stations or networks
• Establish baselines: normal call volume, branded search volume, direct traffic, form fills, sales, revenue, and close rate
• Decide reporting cadence: daily during launch, weekly for optimization, monthly for ROI review

During the campaign

• Monitor calls by tracking number daily
• Review missed calls and callback times
• Score calls for quality and outcome
• Compare station, market, and daypart response
• Track branded search and direct traffic lift in Google Search Console and GA4
• Watch landing-page visits and conversion rates
• Review sales outcomes in the CRM, not just lead counts
• Flag creative or offer variations that outperform

After the campaign

• Match leads to closed sales and revenue
• Calculate cost per qualified call, cost per booked appointment, cost per acquisition, and ROAS
• Compare test markets against baseline or holdout markets
• Identify which placements should be renewed, cut, renegotiated, or scaled
• Update the next script based on call transcripts, objections, and response patterns
• Keep successful tracking numbers active long enough to catch delayed response

How Berk Marketing Helps Track Radio Response

Berk Marketing is a direct-response radio and TV advertising agency that specializes in remnant radio buying, which can save advertisers roughly 40 to 70% or more versus standard rate-card prices. The agency plans, buys, and produces campaigns across local and national AM/FM, SiriusXM, and select TV platforms.

Tracking is built into the process, not bolted on afterward. Berk offers CALL TRACK setup with source attribution, toll-free and local number integration, missed-call capture, and ROI visibility. Campaigns can launch in as little as 24 hours, with creative production handled in-house.

The agency’s approach centers on high-frequency campaigns that drive calls and leads, which aligns directly with the frequency-driven results from the Westwood One research: more daily spots in a market produce measurably higher website traffic lift.

If you want a direct-response radio campaign where the phone rings and the response is tracked from day one, contact Berk Marketing for a free consultation and rate quote.

Related Terms

• Call tracking: Using unique phone numbers to attribute calls to specific marketing campaigns.
• Vanity URL: A short, branded web address used in offline media to drive trackable online visits.
• Promo code attribution: Tying a specific discount or offer code to a campaign to measure redemptions.
• As-run log: A station’s verified record of when each ad spot actually aired.
• CRM matchback: Connecting leads or callers in a CRM system back to their original marketing source and eventual revenue.
• Branded search lift: The increase in search queries containing a brand name during or after an advertising campaign.
• Geo lift test: Comparing results in markets where advertising ran against similar markets where it did not run, to measure incremental impact.
• Direct response radio: Radio advertising designed to produce an immediate, measurable action such as a phone call, website visit, or purchase.
• Remnant radio advertising: Purchasing unsold radio inventory at discounted rates, often enabling higher frequency at lower cost.
• Daypart: A segment of the broadcast day (morning drive, midday, afternoon drive, evening, overnight) used for scheduling and performance analysis.
• DMA (Designated Market Area): A geographic region defined by Nielsen for measuring media audiences and advertising performance.
• Incrementality: The additional conversions or revenue caused by an advertising campaign that would not have occurred without it.

FAQ

What is offline conversion tracking for radio ads?

It is the process of measuring real-world actions (calls, appointments, sales, store visits, branded searches) that happen after someone hears a radio spot. Because radio does not produce a click, advertisers use dedicated phone numbers, vanity URLs, promo codes, CRM data, as-run logs, and lift analysis to connect ad exposure to business results.

What is the best way to track calls from radio ads?

Assign a dedicated tracking phone number to each radio campaign, station, or market. The number forwards to the main business line. The tracking platform records call volume, timing, duration, and source. Add call recording and disposition scoring to separate qualified leads from noise.

Should I use a different phone number for each radio station?

If the campaign runs enough volume to make station-level comparison meaningful, yes. For smaller tests, one number per market or per campaign may be sufficient. The right level of granularity depends on the budget and the volume of calls.

How do I track radio listeners who search my brand instead of using the URL?

Monitor branded search impressions and clicks in Google Search Console and Google Ads. Compare branded search volume in markets where radio runs versus markets where it does not. Watch for lifts that correlate with campaign start dates, frequency increases, or market additions.

What is an as-run log and why does it matter?

An as-run log is the station’s verified record of when each spot actually aired, including date, time, program, and duration. By matching as-run times against call logs, web traffic, and search data, the advertiser can identify which stations, dayparts, and shows produce the strongest response.

How long should I track response after a radio spot airs?

It depends on the product. For impulse or urgent-need categories, most direct response happens within minutes to hours. For higher-consideration purchases (insurance, healthcare, legal, financial), response can trickle in over days or weeks. Oxford Road’s research shows audio’s effect on branded search can last for weeks. Use multiple attribution windows rather than a single cutoff.

Can radio conversions be imported into Google Ads or Meta?

Yes. Google Ads supports offline conversion imports using conversion timestamps and, with enhanced conversions for leads, hashed customer data like email addresses for improved matching. Source Meta replaced its older Offline Conversions API with the Conversions API in May 2025, which supports events from physical stores, phone calls, and offline sources. Source These imports help digital bidding algorithms account for offline value, but they require clean CRM data and consistent upload processes.

Are QR codes useful for radio campaigns?

Not as a primary tracking method for audio-only placements, because listeners cannot see or scan a QR code while hearing a radio ad. QR codes can add value when the radio campaign has companion visual placements like direct mail, social ads, event signage, or streaming display. For pure radio, stick with phone numbers, spoken URLs, and promo codes.