Does gain apply to receive as well as transmit?

[NeoHam]

If so, in the same proportion?

 

[Beetle]

Generally, yes. I never heard a station from Europe until I installed a used triband beam on a used tower and worked England. Couldn't even hear him with my dipole; S6 with the beam.

(This was in 1960).

 

[W5LZ]

Antenna gain is reciprocal, works in both directions, receiving/transmitting. Except in a few cases which is a matter of the antenna characteristics. Some antennas work just great for receiving but don't work well for transmitting. those antennas are not common at all.
- 'Doc

 

[Se7en]

Antenna gain is reciprocal, works in both directions, receiving/transmitting. Except in a few cases which is a matter of the antenna characteristics. Some antennas work just great for receiving but don't work well for transmitting. those antennas are not common at all.
- 'Doc

So if a mobile mono band antenna has a gain of 10 on tx if uses to rx on the band it was designed for it will have gain ?

 

[wavrider]

So if a mobile mono band antenna has a gain of 10 on tx if uses to rx on the band it was designed for it will have gain ?

In theory yes, would be hard to make a HF mobile antenna with 10 DBD gain and drive down the road with it.

 

[KC9Q]

Yes, gain is reciprical in both directions. But, another thing to consider: Tx gain is figured differently than Rx gain. TX Gain equals 10 Log (Pout/Pin), whereas Rx Gain equals 20 Log (Vout/Vin). Thus, 3 dB of TX Gain will double the transmit power, however, 6 dB of gain is required to double received signal. Ever wonder why the S-Meter is 6 dB per S-Unit?

 

[W5LZ]

'wavrider's right. It's not difficult to find VHF/UHF (mobile or not) with gain. Hf antennas are another story, they are just larger/longer to start with and so even fixed gain antennas get sort of 'tall'/large'ish.
There are a few manufacturers who 'claim' their mobile antennas have gain. A loaded 10/11 meter vertical antenna for example. Sorry, they don't. They may be the electrical 'equivalent' in certain ways, but 'gain' ain't one of those ways.
- 'Doc

 

[Beetle]

Don't forget to specify "gain over what". My dummy load has several dB of gain relative to a dipole. It's negative gain, though.

 

[Robb]

The only REAL gain you are likely to see on an vehicle antenna, is if the antenna is for either the 2m or 70cm bands. Unless you put a 6m or 10m loop antenna on your car. If you do that; I wanna see pictures of it!

 

[Se7en]

The only REAL gain you are likely to see on an vehicle antenna, is if the antenna is for either the 2m or 70cm bands. Unless you put a 6m or 10m loop antenna on your car. If you do that; I wanna see pictures of it!

Check your inbox.

 

[WA8ZYT]

A Beverage antenna is one example of an antenna the works well for receive, but is more or less a dummy load for transmit, though some folks have had limited success transmitting on them.

 

[wavrider]

A Beverage antenna is one example of an antenna the works well for receive, but is more or less a dummy load for transmit, though some folks have had limited success transmitting on them.

Works "OK" for receive, sure does not have any gain, nor is it intended to as it is mostly a low band antenna. Sort of negative gain to receive those signals usually covered up by noise.