P.E.R.C. doesn't broadcast continuously in order to conserve power. With how fast it is approaching the target system, its going to have to be a little conservative with fuel to keep enough that it will be able to boost back up to its ramjet's cruising velocity if it needs to.

P.E.R.C. broadcasts on a cycle coprime with the frequencies of the radio broadcasts it has observed, to make sure that it will sometimes coincide with them and sometimes not. It thinks this has the best chance of being heard, because if radio waves only reach it according to a particular cycle, there may be some obstruction or phenomenon attenuating the signal which it will have to work around.

So P.E.R.C. broadcasts, and sleeps, and listens.

One of the frequencies it picks up is easier than the others to understand. There are occasional parts that are more complicated, but it mostly consists of one of a limited number of symbols, followed by a small number of much more restricted symbols, repeated on a several minute cycle.

The restricted symbols associated to a symbol usually correlate over repetitions.

After some thought, P.E.R.C. decides that the less restricted symbols are probably labels, and the restricted symbols are quantities associated with them.

It makes a little table, and runs it through the signal processors again in case this is a frame encoding for another message.

"POTATOES": 2.1 2.4 2.4 2.3 ...

"BARLEY": 0.7 0.7 0.8 0.7 ...

Most of the symbols have somewhat predictable patterns, with the associated quantities changing only slowly. Many of the quantities have a 24-hour sinusoidal pattern on top of a deeper 168-hour one.

Other symbols jump unpredictably, the signal processors unable to find any particular pattern. It could be an encrypted stream of some kind, but P.E.R.C. doesn't think those would be muxed in with the more predictable symbols.

After some thought, P.E.R.C.'s highest-probability theory is that this is a market ticker. P.E.R.C. invents a new symbol that it hasn't heard in any of the radio broadcasts, and adds another segment to its re-transmitted broadcasts.

"AJOETTEDAXDEL: 0.0 AJOETTEDAXDEL: 0.0 AJOETTEDAXDEL: 0.0 ..."

Hopefully that will communicate that it is willing to trade peacefully and give whatever assistance it can free of charge.

P.E.R.C. turns its attention to the other broadcasts, which seem a lot harder to figure out. There are a few different ways that the broadcasts vary:

- Timing and duration

- Signal strength

- Radio frequency

- Frequency of encoded data

- Set of symbols used

They are all correlated, although some more strongly than others. Usually, separate broadcasts on very nearby frequencies will share other characteristics.

P.E.R.C. briefly considers whether the broadcasts are also attempting very-low-frequency frequency modulation, as well as amplitude modulation, but ultimately discards the idea. Combined with the probably-analog signal modulation, P.E.R.C. thinks it might have found somewhere that has only recently discovered or re-discovered radio.

Since their broadcast frequencies are so unstable, that probably means that they don't have very good clocks. P.E.R.C.'s clock is nothing special, but it is rated to drift at no more than a few hundred nanoseconds per day.

P.E.R.C. adds a little "AJOETTEDAXDEL: (light (frequency <frequency>) (amplitude (λt. (* t (/ 9.192.631.770 (frequency <cesium-133>))))))" blurb to its information broadcasts, and then a one-second clock pulse on an adjacent frequency.

P.E.R.C. doesn't have much of a linguistic corpus to work with, but eventually it notices that some of the broadcasts reference each other by frequency! Using this, it's able to put together a message that (hopefully) indicates that its first contact package/general information frequency, its echo frequency, and its clock frequency are all affiliated.

"AJOETTEDAXDEL: your radio to 101.5 the. AJOETTEDAXDEL: your radio to 203.0 the. AJOETTEDAXDEL: your radio to 101.7 the." it sends.

Furthermore, it thinks its figured out some labels for the broadcasts! The market ticker is called CHURCH OF ABADAR, and it has bidirectional interactions with FREEDOM RADIO, which has a strikingly different pattern from the other broadcasts.

Most of the broadcasts have a single tightly-clustered set of characteristics (like pitch and within-symbol variations) that stays the same for the duration of one broadcast, but sometimes changes between broadcasts. Some of the broadcasts have two characteristic bundles that roughly alternate transmission.

But FREEDOM RADIO has one characteristic bundle that has been in every transmission so far, and each transmission usually features another, not-before-seen characteristic bundle. After a while, other broadcasts with the same pattern pop up, but FREEDOM RADIO is still the frequency with these characteristics most commonly referenced from other broadcasts.

Eventually, P.E.R.C. decides that it is not getting enough information to learn the whole language being broadcast, and it tries to see if it can figure out a greeting. Each broadcast seems to start in a different way. CHURCH OF ABADAR usually starts with "Good morning today's weather is". OPPARA CHARIOT RACING usually starts with "Good evening you're listening to the chariot races in oppara tonight we've got". FREEDOM RADIO starts with "This is Freedom Radio reporting live from an undisclosed location", and so on.

P.E.R.C. does some frequency analysis, and "Good", "is", and the station's name are all more likely to be part of the relatively unchanging start of a broadcast than other words. It isn't really sure of the syntax, though. It plays around with various possibilities like "Good is AJOETTEDAXDEL" or "Good AJOETTEDAXDEL is listening to", but none of them are sufficiently likely that it feels safe broadcasting them. It doesn't want to cause a misunderstanding.