I am a slender fellow, about 185 centimeters tall. I wonder if I can
use _myself_ as a monopole antenna for a wearable QRP station.
(Transmitter in shirt pocket, handheld straight key, and self as
antenna.) What is my impedance likely to be?

--
-30-

On Jul 30, 7:34 pm, Anonymous wrote:
I am a slender fellow, about 185 centimeters tall. I wonder if I can
use _myself_ as a monopole antenna for a wearable QRP station.
(Transmitter in shirt pocket, handheld straight key, and self as
antenna.) What is my impedance likely to be?

Zero or infinite, take yer pick . . .

--
-30-

w3rv

"Anonymous" wrote in message
...

I am a slender fellow, about 185 centimeters tall. I wonder if I can
use _myself_ as a monopole antenna for a wearable QRP station.
(Transmitter in shirt pocket, handheld straight key, and self as
antenna.) What is my impedance likely to be?

--
-30-

Rather like one of Radium's queries, but I'll bite...

This is an interesting question because it serves to demonstrate just how
many variables are involved.

Your height would probably be best used as a quarter wavelength vertical
radiator, so frequencies around 40 MHz would seem to fit the bill.

How do you intend to couple the RF to the radiating element? Dry skin has a
relatively high resistive value although once into the squishy stuff inside
your body, resistance values fall dramatically. Are you at all worried about
how much current passes through or over the radiating element? Brings a new
meaning to the term skin effect. At 40 MHz most of the RF will want to flow
around the outside of you.

What form of insulation/isolation is used from the ground? Rubber soled
sneakers, rubber boots, platform heels? What sort of ground plane will be
used. Standing on the ground would be very different to standing on a metal
roof or sheet of corrugated iron.

What local objects or obstructions are likely to be in the vicinity?

Off the cuff, I would guess an impedence of around 1 kilohm at 40 MHz would
probably be a ball park figure. You would radiate some signal but on any of
the amateur bands I would not expect a transmission range of better than
line of sight at any frequency.

Reception of signals would be okay. Receiver front ends generally have a
high impedence so your body would make a much better match to the receiving
side of the system. Receivers are also set up to receive signals in the
microvolt range, so very little in the way of an antenna is needed. This is
why you can generally pick up stuff on a radio receiver just by touching the
centre pin of an antenna socket even when the antenna itself is
disconnected.

In reality, a four foot telescopic antenna will make a far better
transmitting and receiving device than your body at pretty much any
frequency, even without any form of matching. Use one of the ferrite toroid
miracle whip designs published on the Internet to provide a half way decent
impedence match and you could work thousands of miles under the right
atmospheric conditions.

So in theory, it is possible to use your body as an antenna. In practice, it
is inadvisable to use your body for transmitting due to the potential for
causing possible physiological damage and it will be very inefficient. Using
your body as a receiving antenna does work in theory and in practice and is
unlikely to have any harmful effects.

Mike G0ULI

In article , Mike Kaliski
wrote:

How do you intend to couple the RF to the radiating element? Dry skin has a
relatively high resistive value although once into the squishy stuff inside
your body, resistance values fall dramatically.

I hadn't given that much thought. Perhaps a salt-water soaked sponge
under one of my feet, while wearing waterproof boots.

Reception of signals would be okay. Receiver front ends generally have a
high impedence so your body would make a much better match to the receiving
side of the system.

Interesting. Perhaps I could make some sort of a small vertical
transmit antenna to wear on a hat or helmet, then, instead of using
myself. Maybe a baseball batting helmet would be stable enough to
support a few pounds of antenna without flopping around like a soft
hat.

The idea of a wearable station just grabbed me this evening. Just as a
novelty, I wouldn't expect to work DX with it.

Thanks for your response.

--
-30-

Anonymous wrote:
I am a slender fellow, about 185 centimeters tall. I wonder if I can
use _myself_ as a monopole antenna for a wearable QRP station.
(Transmitter in shirt pocket, handheld straight key, and self as
antenna.) What is my impedance likely to be?


Will you be wearing an aluminum top hat?
Where will you be sticking the coax connector?
What grounds have you for doing this?

Irv VE6BP (the devil makes me do it!)

But, end fed, you'll only be half an antenna. What's the other half?

Maybe you can figure out a way to gamma feed yourself as a vertical dipole.

Roy Lewallen, W7EL

Anonymous wrote:
In article , Mike Kaliski
wrote:

How do you intend to couple the RF to the radiating element? Dry skin has a
relatively high resistive value although once into the squishy stuff inside
your body, resistance values fall dramatically.

I hadn't given that much thought. Perhaps a salt-water soaked sponge
under one of my feet, while wearing waterproof boots.

Reception of signals would be okay. Receiver front ends generally have a
high impedence so your body would make a much better match to the receiving
side of the system.

Interesting. Perhaps I could make some sort of a small vertical
transmit antenna to wear on a hat or helmet, then, instead of using
myself. Maybe a baseball batting helmet would be stable enough to
support a few pounds of antenna without flopping around like a soft
hat.

The idea of a wearable station just grabbed me this evening. Just as a
novelty, I wouldn't expect to work DX with it.

Thanks for your response.

Actually, people do it all the time. Every time someone picks up an HT
with a whip shorter than a half wavelength, he's just as much a part of
the antenna as the "antenna". In fact, it wouldn't surprise me to find
that the person holding the HT is radiating more than the "antenna".

Roy Lewallen, W7EL

Irv VE6BP (the devil makes me do it!)

Irv, down on your knees and bow your head... I want 40 CQ's at 160
meters at high noon and a dozen QRZ's on 10 meters at midnight as
penance, for that... Shame on you...

denny / k8do

JFI

I remember when I was involved in a coverage test prediction for a VHF
(149MHz) paging service, a persons body was said to increase the
received signal to the pager. I think I remember 6dB over just putting
the unit on a 4ft stick!.

The pager unit itself of course didn't have a antenna anywhere near that
of a half wave. I think we used 0dB gain (implying a 6dB loss in the
pager by itself) but my memory is kind of foggy on this..

Maybe loose coupling and not worrying about your Z is the way to go. You
could always vary the dielectric between your radio and skin if you want
to experiment! Just rub on more suntan lotion and watch a beacon on the
S meter! grin

Cheers Bob VK2YQA

Anonymous wrote:
What is my impedance likely to be?

"Denny" wrote in message
ups.com...


Irv VE6BP (the devil makes me do it!)

Irv, down on your knees and bow your head... I want 40 CQ's at 160
meters at high noon and a dozen QRZ's on 10 meters at midnight as
penance, for that... Shame on you...

denny / k8do

Very interesting thread, with the aluminium top hat and/or vertical
telescopic antenna mounted on a baseball helmet we should have a certain
lightning victim very shortly.

Mike./vk6mo.