On Jul 15, 7:18 pm, Art Unwin wrote:
On Jul 14, 3:10 am, derek wrote:

On Jul 14, 8:16 am, Art Unwin wrote

Hi Art
The details for the variometer would be of help if you could
oblige thank you.

Derek

If he hasn't got a variometer he can use his tuner as a substitute.
The SWR meter he is using is referenced to 50 ohms so his readings are
false.
When using twisted wire the impedance will go very much higher than
untwisted wire
at least one hundred times . The impedance of his antenna is probably
around the 300 ohm mark so he should
add a 6 or 9 to one transformer. As a furthur adjustment he can put
the up and down wires in parallell such that the 1100 feet of wire
which is two wavelengths of the top band when wound in series is now 1
wavelength and the impedance will change accoringly. So there are
options available which the ham can chose as well as changing
connections from series to parallel as well as the diferent places he
can add his tuner in the circuit. If he stands the wire tube antenna
upright say as a lamp shade so it appears unobstrusive the radiation
will be omni radial or partialy direcftional if he tilts it and if it
is low power DX that is his hobby then the lower lobe is at least half
of that of a yagi which in his circumstances it should be ideal.Since
the wire is close wound I am not sure of the power limitations but
with it being Hi Temp magnet wire with circuitry of a wavelength I
really don't see a guy in a nursing home having a problem
One thing I am not sure of is the nearnes of the point radiation
antenna with respect to personal health so he may well want to place
it outside say as a frost protector for a rose bush or the like
Regards
Art

On the suject of transformers. In the US somebody makes a pre packaged
transformer with five female coax conections depending on the ratio
required,
Since the frequency span is so large as well various locations it may
be that his ratio will land between 6 and 9 to 1
He may want to have ratios that are not as course. What he can do is
to have two rotating contacts ie minuits and hours instead of the
single one provided
On the female conectors you place a cent or copper disk in the centre
which is your contact The rotary cam that moves the contact around is
a 5 pointed star cam with slots from each point towards the center.
The outside of the star surface moves a pin around a fifth of the way
which is the distance between coax connector. So the switch does not
just float across the contact the pin which runs on the cam goes down
and up each slot which provides a stop of rotary motionwhile the
contact is made. I would not make this until the situation proves that
you need it but it does supply matches to with one ohm or so for the
intervening distance beteen 6 and 9 to one. One last thing , If power
is to be used by others on top band it is adviseable to gang two
toroids in parallel
to avoid saturation of the toroidal material. I added the above incase
other club members decide to copy with more favourable operating
conditions
Art
unwinantennas.com/