Thursday, July 1, 2010

I often take my 2-meter/ 70-cm H-T with me on hiking trips ...

Q D. Menkes, KF6IOL, asks, “I often take my 2-meter/ 70-cm H-T with me on hiking trips, but I find that it’s difficult to access repeaters when I am in fringe coverage areas. I’ve considered purchasing a 6-meter H-T in the hope that I might enjoy greater range, but I’ve been told that the effective range would be limited because such an H-T uses FM instead of SSB. Is this true?”

A There are several factors that govern an H-T’s effective communication range. One is the type of antenna you are using. Quarter-wavelength telescoping antennas, for example, are more efficient and vastly superior to the “rubber duck” antennas supplied with most H-Ts. Height is another important factor. Some hams have taken H-Ts to mountaintops and have communicated over 200 or 300 miles. The same H-Ts in the valleys below, however, could hardly get into the local repeaters.

When it comes to local/regional FM coverage, 6 and 2 meters are very similar. The reason that SSB outperforms FM on either band is because an FM receiver requires a much stronger signal to produce copyable audio. An SSB receiver, however, can produce copyable audio with much less signal energy. Therefore, you can achieve a greater effective range with SSB compared to FM.

From QST July 1999