The mosquito repeller is actually chemical rather than electronic. I tried electronic many years ago without success, and most Internet reviews said they don't work. While searching I found this chemical device called a ThermaCell.
ThermaCELL Mosquito Repellent
It uses a small butane catridge to heat the insecticide. I was really skeptical but decided it was worth a try. At our first camp (where the mosquitoes were the worst) I set it on our table in the kitchen area. My hope was to help the cooks survive while the rest of us were hanging out in the screen tent.
It takes 15-20 minutes for it to make a noticable difference, but it did seem to help. We had a very gentle breeze that kept shifting directions. After finishing dinner, when I exited the screen tent I was surprised that there were very few mosquitoes anywhere near the kitchen. If you walked 10 feet in any direction they would be thick, but if you walk back to the kitchen, there weren't many bugs.
To further test the device, the next morning I placed it near our port-a-potty which was near the river where the bugs were even worse. After about 30 minutes you could visit the toilet without getting eaten alive. I was impressed.
You can buy them at most sporting goods stores. I picked mine up at WalMart. I just bought a refill kit so I will be ready for our Lodore trip in a few weeks.
We also tried a new repellent with good results. In the past I have found that nothing works except DEET. DEET is still perhaps the best protection, but you shouldn't put it on clothing since it attacks fabric and plastic. In fact my glasses now have nice etch marks on the ear pieces, which I think was caused by DEET.
We tried a bottle of Bite Blocker Bio UD (which we also got at WalMart). My wife learned about it on a TV show. You can spray this on clothing, so we decided to test it out. It has some oder, but not too bad. It worked well and it was everyone's first choice until it ran out. Everyone liked being able to spray their shirts, pants, and socks.