Garmin Forerunner 305 Handheld GPS Receiver

I have had my Forerunner 305 for almost 3 weeks now. Previous to this I used a Polar S150 (wired bike mount) for several years and a entry level Polar before that, so I am used to basic heart rate monitor but not advance data recording or GPS.

I have tested the Forerunner 305 running, biking and swimming and have been generally very impressed.

General: The concept of acquiring satellites before I get going took a little getting used to. After the first couple of times I generally get satellite acquisition within about 30 seconds as long as I am outside or in my enclosed front porch. I set the unit down so that it is completely stationary while acquiring satellites. I get spotty to no reception indoors. The heart rate monitor functions well in comparison to my Polars. I have only had erratic heart readings at the end of one bike ride (fixed by adjusting the strap), which is better performance than I generally would get with the Polars (Except for Swimming, see below). The grade measurements are so erratic as to be totally useless. I have had the grade measurement vary from 8% to 25% back down to 5% within one minute of sustained climbing on the bike. I believe this is due to a poor averaging algorithm (2 point average as opposed to smoother averages involving more points). This is something I intended to test once I figure out how to access the raw data. Data recording is interesting, but is highly dependent on the software used to analyze it. Training center software is decent but unsophisticated (lack of user configurable option is disappointing in a $300+ product). Motion Based has been fun to use, especially the map player. As noted in a previous post of mine errors in distance calculations arise due to Motion Based insistence on connecting erratic track points recorded when you are standing still.

Running: To this point I have done about half a dozen runs of 3-3.5 miles each on a couple of different courses. Mostly I run on trails with trees (no real leaves as of yet) with some street and open field running mixed in. Generally in the trees I average an accuracy of about 25 ft, which I consider to be pretty good. The tracks and distances are both reproducible to within this approximate 25 ft range. I have found the "instantaneous" pace to be somewhat erratic but generally within approximately 5% of the short term mean. The auto stop feature (I have it set to stop if pace falls below 30 min mile) working decently on the run but occasionally does not register that I am stopped. Overall I am very excited to easily track my running distance and have a pretty good idea of my pace.

Biking: Used for approximately 10 bike rides both on and off road. Despite some concerns that the antenna faces the wrong way when mounted on the handlebars (I mount mine by wrapping the monitor around a piece of foam) I generally get great GPS reception on the bike. Accuracy is generally about 15 ft on open road and 25-30 ft.on trails. The speed and distance seems to be very accurate and the precision (reproducibility) is within 1%. The auto stop feature works extremely well on the bike, starting and stopping the unit within 1 second. The one down side is that the buttons you are most likely to use for cycling are on the side of the unit (the up/down and occasionally the mode button).

Swimming: I have only tested in an indoor swimming pool, hoping to be able to record my heart rate. Unfortunately, unlike my Polar S150 the heart rate signal cannot be measured in the water. I did these tests with the receiver under my swim cap, which was pretty comfortable and I could access the buttons easily. There may be more utility for swimming in open water.