Nick wrote:
I am wanting to experiment making vertical whips, end fed,...

End fed whips? Is there some other way they are fed? In the middle?
At the other end? Am I missing something (and at my age that is likely)?

Irv VE6BP

"Irv Finkleman" wrote in message
news:BW4ai.6472$xq1.1239@pd7urf1no...
Nick wrote:
I am wanting to experiment making vertical whips, end fed,...

End fed whips? Is there some other way they are fed? In the
middle?
At the other end? Am I missing something (and at my age that is
likely)?

Irv VE6BP

Good points guys...
( I guess a vertical dipole could be fed elsewhere ( centre / 1/3rd
of the way up etc.... )

I elaborate...

End fed half wave dipoles was the original intention, but as JS
remarked, an end fed 5/8ths
seems more interesting.....

One of my applications is for an aerial mounted on a motorcycle
windscreen, fed with
50 ohm co-ax for inter-bike comms... 70 cms (or possibly 2 mtrs)
but needs to be ground plane independent, hence the thought of a
half wave ...

Another is a 16 foot whip for 10 mtrs ....... probably mounted just
under the house gutter

I just want to make myself something for the interest rather than
buy something

Thanks,

Nick

"Nick" wrote in message
...

"Irv Finkleman" wrote in message
news:BW4ai.6472$xq1.1239@pd7urf1no...
Nick wrote:
I am wanting to experiment making vertical whips, end fed,...

End fed whips? Is there some other way they are fed? In the middle?
At the other end? Am I missing something (and at my age that is likely)?

Irv VE6BP

Good points guys...
( I guess a vertical dipole could be fed elsewhere ( centre / 1/3rd
of the way up etc.... )

I elaborate...

End fed half wave dipoles was the original intention, but as JS remarked,
an end fed 5/8ths
seems more interesting.....

One of my applications is for an aerial mounted on a motorcycle
windscreen, fed with
50 ohm co-ax for inter-bike comms... 70 cms (or possibly 2 mtrs)
but needs to be ground plane independent, hence the thought of a half wave
...

Another is a 16 foot whip for 10 mtrs ....... probably mounted just under
the house gutter

I just want to make myself something for the interest rather than buy
something

Thanks,

Nick


My trick for feeding a 5/8 is to wind the coil with an 1/8 wl of wire as a
starting point and then trim from there. Using the coil in seies with the
antenna with coax connected between the other end of the coil and the ground
plane(no taps, coil does not conect to ground). This provides a petty decent
match to 50 ohm coax that can be reined a bit by drooping your
counterpoise(radials).

Thanks for the last two very useful replies...

The desired location for the bike aerial is lower part stuck to the
inside of the screen with as much as high and above the screen as
possible.
The reasons for this are obviously its good to have it as high as
reasonably possible, but also to get it away from the QRM generated
by the electronics around the dash area.

Also, as we ride as a pair, one is always in front or behind the
other, so immediately there is the body mass in the way, screening
the signal. Now this doesn't generally matter as we are usually
withing 200 metres of each other and 1/2 watt at UHF is still full
strength signal, but when we get perhaps a few miles apart and are
in front / behind situation, the body is definitely attenuating the
signal significantly.

Generally one rides in front much of the time, so a rear aerial
gets round this, and a front aerial on the following bike is not
shielded by the riders body - I have both front and rear aerials
and I guess it would be good to have an antenna switch to select,
but BNCs and swopping is no trouble.

The other thing is that everything has to be waterproof where it
matters. I have been experimenting with hot melt glue to pot up
connections - anyone have experience of this as a good potting
agent ? I will put out a separate thread about this as its a bit
hidden in this thread..

Thanks again all - much appreciated

Nick