Total posts : 45366
Greg,
Percentagewise, the drift I cited for the Ramsey FM-25A is (200/90900000) x 100% = .00022% which is better than commercial radio standards (.005% for two way) and is well within broadcast FM standards. 200 Hz. may sound like a lot, but considering the carrier is around 91 MHz. it is negligible.
On AM the situation is different since a drift exceeding 20 Hz. will be audible if co-channel signals are present. Percentage wise, at 1640 kHz. this is (20/1640000) x 100% = .0012%, much greater than the percentage drift I have seen on either unit.
It is also worthy to note that I was able to net the FM carrier to within +/- 1 Hz. (my counter resolution) initially and a 200 Hz. carrier error in the FM band is insignificant.
Neil
