One thing I still find amazing, in these days where FM is predominantly the major mode outside of some commercial /aviation/military long range analogue comms setups and ham usage, and digital rapidly taking hold on more local FM radio territory services, how people still chased gain and try to tune setups for maximum grunt or max smoke as some in radio referred to it.
Actually, ‘max smoke’ is kinda appropriate given that eventually you either killed the PA through an extreme mismatch because your power meter showed a huge difference with what proved to be a highly ill suited and configured setup.
But, dare I say it, a lot of FM user ignorance about chasing max smoke is definitely an AM CB legacy that mislead a lot of FM CB users to go to ridiculous lengths to gain big outputs and heard with big signals simply never needed.
You see, with FM - once a SIG demodulates to a level where there’s no white noise present (‘fully quietened’ being the technical term for the state), the sender could add 3db of gain, 6db, or start messing with adding 30/50/100W amps and it benefits the reception in no positive way. In fact, you’ll just be creating a lot of grief with adjacent channel users and upping your normally minimal out of band harmonics hideously.
Add in overloading receivers and extra inherent noise/birdies that causes and you’ve just made matters worse as everyone in a fairly near range to you gets the same effect on their receiver you’re inflicting on the local station your in convo with.
On digital, the translation is an effect where clean within threshold reception and clean clear audio demodulated goes distorted and metallic again like happened when you have a poor SIG received by listener. It’s a similar effect to where on Sat receivers you got sparkles on the picture (analogue) and the degree of dark to light indicated how below threshold the SIG was or above threshold. Once you got it dialled in right, they were gone unless weather caused bad reception through SIG attenuation.
On digital sat, if you bring up the RSSI info, you’ll see it indicates an error rate and a type of SIG reading. What you’ll find is when the SIG is below threshold, the SIG strength indication isn’t necessarily telling you the info you need, it’s the Error rate that’s more telling. Once you have a low to nil error rate by optimal antenna setup, a tiny margin of extra SIG helps offset attenuation due to weather, but we are talking very little and big lumps of extra SIG unnecessarily gained just sends the Error Rate climbing again.
So whilst there’s some point to, for long range (especially over the horizon skip based sending), maxing out your ERP and getting the best reception you can drag out of a setup on AM/SSB, ■■■■■■ all for CW mostly as CW is a bit like FM in that once it’s distinguishable and easily read there’s little to gain from boosting reception methods, and nil effectively on FM and Digital Voice modulation based systems.
In fact, unnecessary use of amps can be as pointless as a high gain antenna which has big numbers but has a radiation pattern totally ill suited to your needs.
The only difference is excessive gain on a passive antenna is just that, any gain on an active antenna is double edged because the SIG level gain also has a worsening SNR to the mix. Amps, bilateral or unidirectional, add noise and artifacts into the chain, which is why amps should be used with care, and passive gain (inwards and outwards) should be your focus for inprovement along with finding an antenna system which has a Tx radiation pattern suitable for your needs if transmitting and even for RX only use, the right territory of antenna radiation pattern as it affects reception will always be better than forced amplified worsened quality RF.
We’ve all been there, most will never admit to it, but I doubt there’s a single radio enthusiast who didn’t get tempted by potential big dB claims and got disappointed and maybe even choked on a bit of white acrid ‘PA module/transistor’ death at least once. I’ve been there, I admit, thankfully it was a short lived spell during my excitement of my first CB rig, but I rapidly realised the truth and never looked back.
Realising the reality can save a lot of money, wasted effort and help keep you from frustration induced hair loss