If you are only a short stay Carp Angler, say 12 hours or so, is it really necessary to have Bite Alarms and if it is necessary, do they have to be the best that your money can buy ? What do you really get for your money ?
I would say that a 12 hour session is too long to stare at a float or bobbin without taking a bit of time out so yes, IMO a bite alarm would be a good idea. For non-predator fishing I just use a set of 3 simple 'roller-ball' alarms which I bought brand new with a digital receiver for £50 from Ebay in a lovely hard case, Dec 06! They are rock solid,have decent rod-resting groove, are non affected by rain nor weather and have served me proudly. There are loads on the net in a similar vein and for a similar price. I also always aim to keep the volume down as much as I can.
What does get my goat a little though, is guys fishing an extremely small tennis court size, 2ft deep commercial (where I take my two young nephews) with 3 rods on pods, brotels, bedchairs and the LOUDEST bite alarms money can buy. Honestly, even the two young boys laugh as morse code at 2,000,000 decibels is transmitted at 75 words per minute across the complex, as yet another 6oz pastie falls for one of these Chimp's ebay tied, critically balanced, incorporating a 4oz lead, Chod rig.