Leo wrote:

...
Sorry, can't add to the knowledge base on this one - I'll ask around,
though!

73, LA

73, Leo

http://www.outbackerantennas.com/

JS
--
http://assemblywizard.tekcities.com

On Mar 4, 8:42�am, John Smith I wrote:
Leo wrote:

* ...

Sorry, can't add to the knowledge base on this one - I'll ask around,
though!

* 73, LA

73, Leo

http://www.outbackerantennas.com/

Thanks for pasting the link, JS, you beat me by an hour...:-)

Outbacker NA is based in Kentucky and seems to carry all
the Aussie verticals of that brand. I'm considering that sort
of multi-band antenna for a home station...not that it matters
a great deal here since the paths north to east require NVIS
type sky-burning. Mobile will probably be 6m-2m-70cm in a
triband whip (probably Diamond) with a Diamond motorized
hatchback-lip mount that allows lowering it inside the
garage. "Stealth antenna" sort of thing...:-)

Haven't heard a lot about them "furrin ay-tennas" (like
Australia is a "foreign land?") fur dem pickups in da woods
of Kain-tuckie. Over on www.antennex they've been
described in much detail by Aussie amateurs who thought
much of them in Aussie-land outback territory.

A curiosity is how to get an effective ground plane for a
home installation that does NOT involve sticking a lot of
radials into the ground. Sprinkler pipe is all PVC so that
will not do. There's no NEC version modeling program
that can simulate the row of tall cypresses where the
intended location of a vertical would be (in between two
of the spaced cypresses). [just planning ahead...]

No sweat on a VHF-UHF home antenna...enough vent
pipes (metal) to mount them on. For "stealth" I can do
the Ventenna thing and cover the vertical VHF-UHF with
PVC pipe of large diameter.

73, LA

wrote:

...

No problem Len.

But, make sure you purchase an antenna capable of BIG power. First time
you burn up one of those antennas with one of those BIG ruskie
leen-e-airs--kinda hurts

JS


--
http://assemblywizard.tekcities.com

On Mar 4, 11:54�am, John Smith I wrote:
wrote:

* ...

No problem Len.

But, make sure you purchase an antenna capable of BIG power. *First time
you burn up one of those antennas with one of those BIG ruskie
leen-e-airs--kinda hurts

Since I'm not contemplating any "big russkie linears" or even
US-made (or branded) on HF, not a problem here.

However, "BIG" to me is about 10 to 40 KW RF Output.
That is not allowed in US amateur radio regulations. It
is also beyond the RF Exposure limits for us urban city
dwellers. Now, not all my neighbors aren't the best of
folks but I ain't wanting to create crispy critters next
door...

73, LA

wrote:

...
That is not allowed in US amateur radio regulations. It
is also beyond the RF Exposure limits for us urban city
dwellers. Now, not all my neighbors aren't the best of
folks but I ain't wanting to create crispy critters next
door...

73, LA


Reminds me of the story of the guy in NY or there'bouts, took a high
powered microwave, cut and built a horn antenna out the door and aimed
it into the neighbors apt. (obviously, he didn't like the neighbors.)
The neighbors were afflicted with all sorts of strange medical
problems--until he was caught.

You should be able to find pics on the net ...

JS
--
http://assemblywizard.tekcities.com

wrote:

...

Well, anyway, if not for these six fingers, I don't think exposure to rf
is all that dangerous. grin

Actually, I did hear tell of guys up in alaska working on radar, decades
ago and before microwave ovens, they found holding their hands over the
slits in waveguides "warmed" their fingers--then some started ending up
with pains in their hands--cooked partially fingers are painful!

I have never heard of HF causing any medial problems which can be proved
to relate. However, UHF and beyond is quite different ...

JS
--
http://assemblywizard.tekcities.com

On Mar 4, 3:09�pm, John Smith I wrote:
wrote:

*...

Well, anyway, if not for these six fingers, I don't think exposure to rf
is all that dangerous. *grin

Actually, I did hear tell of guys up in alaska working on radar, decades
ago and before microwave ovens, they found holding their hands over the
slits in waveguides "warmed" their fingers--then some started ending up
with pains in their hands--cooked partially fingers are painful!

I have never heard of HF causing any medial problems which can be proved
to relate. *However, UHF and beyond is quite different ...

Ahem...take a look at the chart in Part 97. Maximum
allowed power before having to do an "evaluation" is
500 W at 40m but it drops down linearly to 50 W at
10m. All bands at VHF at 50 W. At UHF it is 70 W
at 70cm and rises to a maximum of 250 W at 13 cm
and holds there on up to maximum frequency of
anyone's allocations.

When I was at Fort Monmouth Signal School in '52
and taking the radar systems introductory class,
cadre used to put a wad of steel wool on the end of
a bamboo pole and hold it in front of a 1 MW peak
search radar. Steel wool blazed! One of the wesen-
heimers made a remark about "it was dangerous to
steel wool" with much ha-ha-ing from the group. The
next day we got a demo with a slab of outdated
(uncut) bacon. Instant fried bacon. Wisenheimer
shut up. Search radar was somewhere in S Band
or 2 to 4 GHz. (microwave ovens are 2.4 GHz)

When I worked at Hughes Aircraft Co., El Segundo,
CA division, one of the airborne radar final check-out
guys got one hand slightly fried from playing around
with adjustments with the (F-94?) radar. Wore a
large bandage for about two months after returning
from a medical leave of about a month. That was '57
to '59 time period. Peak powers ain't something to
fool with, not up-close and personal to the RF source.

On the other hand, the tower monkeys who service
the TV and FM towers on Mt. Wilson overlooking
L.A. aren't shielded and seem to survive. Was an
article about them in L.A. Times about a half year
ago. TV and FM sit right in the most sensitive
frequency region for RF Exposure. Go figure...

73, LA

wrote:

...

Len:

I always wanted a KW amp.

Finally the old guy who assisted me into radio broke down, brought out
the greenlee punches, drills, hacksaw, ceramic sockets, tubes and we
constructed one, I certainly could NOT have done it with out his
assistance. We scavenged old military gear I had accumulated and stuff
he had for wide spaced (HV) variable caps, hv transformer, filter caps,
chokes, resistors, plate coils, etc.

In the end, it was rather large, plenty of space to work on stuff in
there, and even room for an old LARGE muffin fan.

My shack, back then was the basement of my parents home. It got cold
down there in the winter, those tubes filaments (10amps at 2.5v if I
remember correctly X 2, PLUS the plate dissipation when xmitting)
provided some nice warmth (plates would glow a nice dim/dull red when ya
got long winded and peaked her for max tube capacity)--I sat on the
expanded metal case of that amp which sat upon a low stool, and enjoyed it!

Later had three boys. Only bothersome thing is that third eye in the
middle of their foreheads ... ROFLOL!

Comeon', ya can't kid a kidder!

Actually, that is a true story ... well, except for the third eyes.

HF just doesn't excite the molecules in the body to the degree necessary
to do damage (well, a 10kw-100KW I might begin to worry about.)

VHF I would be cautious of, but then I think 50w is conservative and low
here, UHF and above I have NO doubt about ... HF is about as dangerous
as high powered audio freqs, excepting ones ears.

JS
--
http://assemblywizard.tekcities.com