Leaderboard

You do, but the insertion loss is caused by the fact that the "V" notch trough isn't the only factor. The insertion loss comes from what the filter is doing to the pass frequency, which on these small units is going to be much higher at a 5 MHz split than a 10 MHz split. So while you're filtering out 462.xxx MHz in the notch, you're also losing power on 467.xxx MHz due to the curve to the right. Basically you're too close to the notch, and you're losing some power there. This is also why the duplexers are marked with a high and low side, as the configuration of that curve to the left or right depends on which side you're on. Normally the insertion loss is small, like 1 to 1.5 dB on a good duplexer, but you don't have that low of curve to contend with in those cases. So to avoid this, you can either tune the V lower in frequency (which isn't great, as you're losing isolation) or you can try to make it a little shallower as long as you're still getting adequate isolation. Since it's a low power transmitter, you don't need -90 dB but the more isolation, of course, the better. It's just a balancing act to notch as much as you can without negatively impacting the frequency you want to pass. I had to retune the duplexers that came in an engineering sample I received of these repeaters, as they were tuned for 453 and 463 MHz. For one, I had to swap the high and low sides since they were set up with RX on 453 and TX and 463, which was an issue with the short SMA jumpers they included. Then, I had to retune the duplexers to the GMRS band and be careful to not impact the pass side too much. Keep in mind I'm no expert, my background is software not RF design or Electrical Engineering. I know just enough to be dangerous and convince myself I'm right most of the time. ?

Ok, let's try to keep this in scale. If one were to renew for $70 the day before the new price went into effect. The total extent of the "damage" would be $3.50 per year over the 10 year life of the license. That is $ 0.0095 per day, $0.067 per week, or a whopping $0.29 a month.