VHF some questions

ChapOfDRyans

i was just wondering could you install a vhf in your car and is that legal,also would the antenna be the same size as a cb radio one if so how much do they cost.

how much would a base unit be a resonably good one

fatboymsport

are you on about a vhf scanner or transciver???

the antennas for vhf are usuall a lot shorter than cb.

what do you plan to do with this unit.

ChapOfDRyans

i have a uniden usc230 which is handheld but i was wondering could you hook this to a bigger antenna like the cb one to get a better range

watty

Aerials are best at specific lengths.

1/4ths of 11m is nearly 3m, over 8ft.

5/8ths of 11m is nearly 21ft.

At 1.1m, 270MHz (top of VHF...)
1/4 is 30cm.. nearly 1ft
5/8 is about 2ft

At 3M, 100MHz, 3 times bigger.

CB aerials often have a loading coil at base to allow them to be physically shorter than 1/4 wave. (such as 6ft rather than over 8ft).

A VHF aerial depending on exact part of band is more car aerial sized. It will work less well if too big.

For 2m / 145Mhz & 70cm/435MHz you can get a dual band aerial that at UHF is two 1/4 waves stacked for more gain and one VHF aerial. Watson W770 is one model. Comet, Diamond and MFJ make them too.

It will work as reasonable scanner aerial from 80MHz to 800MHz.

A quad band 10m, 6m., 2m, & 70 is not as good. The more bands the aerial can transmit on the less wideband for receive as it is more narrow resonant on each band.

I found that a dual band 10/6m and separate dual band 2m/70cm works much better than a triple or quad band of supposed similar gain.

With an Aerial Tuner the Comet 10m/6m (28MHz & 50MHz) works from 160m to 4m (1.8Mhz to 70MHz) for transmit. Also works on CB with no tuning.


So to cover 25Mhz to 87 MHz scanner use a 10m/6m dual band whip
and to cover 87MHz to 500MHz use a 2m/70cm whip for your scanner.

You can get a dual band tetra magmount aerial, it will do 300Mhz to 1200MHz well, peaks at 450Mhz & 900MHz.

A good Phone aerial will do 900Mhz to 2.4Ghz (peak at 900, 1800 & 2100MHz).


my car has on occasion resembled a metal porcupine.

ChapOfDRyans

so the there are differant aerials for differant bands not just a one 4 all

i have a 60cm whip on my scanner and picks up anything over 89mhz but there is a freq around 84mhz which always active but its just crackling noise does that mean its in use just i cant pick it up

watty

It could be interference from a Flat panel TV, laptop, anything..

Any aerial, even a piece of wire will pick up a little on any frequency. But the correct aerial works 4 to 1000 times better.