Actually 27.305 was a popular licensed business frequency during the 23ch days. I have an old Courier business band radio with that lone frequency in it. I would need to look into my Sams books to see what crystal frequencies that radio takes. The receive crystals in those old sets usually operate on another frequency in combination with another oscillator to bring it to the desired channel. Transmit crystals on the other hand in those old sets most often operate directly at the desired frequency. In other words, any 27.305 transmit crystal will most likely work. If that radio has a tunable receive like I think it does, it should tune that far up. In that case you needn’t worry too much about the receive part. I know that radio takes the larger HC-6/U holder type crystal, but a typical old school walkie talkie crystal will also work. At one time you could even buy adapters. If it were my set I would remove one of those small crystal sockets out of an old parts radio, and solder it on the back side of your radios socket. You can buy a set of walkie crystals for ch30 on Ebay for about $9. Like I said, I'm not certain if the receive crystal will work, that will depend on the radios particular mixing scheme, but its a fair bet the transmit crystal will work fine. I have a couple old Johnsons that are loaded with walkie crystals instead of the HC-6/U type. Their receive crystals are the typical 455khz down from the channel frequency, same scheme as most old school walkies.