Telemetry

I've used telemetry on every one of my merlins. Merlins have a reputation of being easy loose, I'm sure much of this reputation came before the use of telemetry. I use my telemetry often, merlins are pursuit birds and can chase quarry for great distances and catch them. If you don’t use telemetry on your merlin then yes, I would agree that it could be very easy to loose. Not because it’s going to try to get away from you but because they are very gamey and obviously small. A merlin that chases a bird off in the distance and catches it can be tough to locate. I’ve found that a very small transmitter with a modest range is sufficient to prevent loss. You should use the smallest transmitter you can find. I recommend the LL Electronics Micro Merlin. I recently tried the Marshall Micro transmitter with good results, although I found the transmitter to be very unreliable.

In the early stages of flying I use a zip-tie to leg mount the transmitter to the grommet, after the jess is removed. I do this partly to hinder the merlin from catching game prematurely. I believe anything on a merlins legs hinders their footing and ability to catch game. When I'm ready for the bird to start catching game I neck mount my transmitters. This is far easier than you would expect. 

I use a #10 rubber band. I thread the rubber band through the transmitter and then back through itself. Tip: I lick the rubber band, so it slides better against itself, and pull it as tight as possible. I then place a small piece of food in the palm of my hand and stretch the rubber band around the tips of all five of my fingers with the transmitter dangling in the center gap of my fingers. (Your thumb will be going behind her head.) With the rubber band around my fingers I un-hood the bird, hold my opened hand in front of her and when she puts her head through the rubber band to take her tid-bit I close the rubber band around her neck. I've never had a bird object to this.  I had 1 merlin that would allow me to open the rubber band in my hand and just put it on her un-hooded head with out any food.

To remove the transmitter I use a small pair of blunt tipped "safety scissors". I find it easiest to hold the antenna between my gloved fingers so when the bird stands up straight it stretches the rubber band slightly. Then just snip one side of the band and it will slide off. I find this much easier to do while un-hooded. 

It may seem like much of this would be easier to do while the bird is hooded. However, I've found the opposite to be true. The hooded bird is jumpy when something touches her, or when she sees movement through the hood. It makes the whole process much more difficult. 

Receivers

I don't sell any telemetry on this site but I've used just about every receiver on the market. My favorite receiver for flying merlins is the Tracker Maxima. This unit is very small and compact while still being one of the most powerful on the market. It fits in your pocket and deploys easily.
www.trackerradio.com