[Antennas] Antenna help needed, please

Wed Mar 30 23:01:56 EST 2005

Make sure IF YOU get permission to put antennas on the roof your INSURANCE
covers your butt...all it takes is ONE hole in their roof, etc and YOU are
liable for any damage to their AND any tennants property (Lawyers love to
sue over anything).
QRP is a good idea though it may still cause TVI on the right freqs......
A non penetrating mount is made out of flat plates with a vertical support
for dishes and welded together with at least 2 or more angle
connections/support....once in place on a flat section, any heavy weight can
be used to "hold" it in place...
But again, nothing is perfect!! Usually cinder blocks are used....with the
base of the mount having channels for the blocks to sit in snuggly....also I
have used cement bags thrown on the base and then punctured in many
places...1st rain adds wate and weight and when dry, its not going anywhere
:)

A Horiz loop is not good unless it is over a 1/4wave off the ground...in
this case, that's the roof! 5ft wont work at all and cause the loop to go
straight up as a cloud warmer....go with a vertical...Butternut or GAP or
similar....if the roof is all metal, you have your ground plane! But since
it probably is not, you need to put in at least 4 radials if you can. I
would see if there is a vertical pipe sticking up on the roof..if so, use
that as a mounting place for a lightweight multiband vertical....put the
base a few feet above the roof with a mast if you can...forget ladder line
in any case..
UNLESS you want to run a dipole off the roof to the ground as a sloper and
use ladder line to the center and use it as an allband dipole with a tuner.
BUT check your insurance and go SLOW with a SMALL foot print...the less that
is seen, the less management will hear about you and the safer you
are...once you leave, you need to make sure pictures, etc are taken to
protect you down the road..
Chris
WB5ITT
> -----Original Message-----
> From: antennas-bounces at mailman.qth.net 
> [mailto:antennas-bounces at mailman.qth.net] On Behalf Of Tim KD5CKP
> Sent: Wednesday, March 30, 2005 9:15 PM
> To: Antennas
> Subject: [Antennas] Antenna help needed, please
>>>> Hi folks,
> I'm in the process of getting permission/approval from my 
> landlord (Vanguard Properties) for my 1st floor apartment, at 
> (Crestwood Terrace) the 2 storys behind HEB, to put 
> antenna(s) on my (4
> unit) roof. The roof is flat, about 52'x26', with 4 heat pump 
> units on it. Top floor has new ~10' metal siding all the way 
> around and then bottom is brick.
>> I already know there is a "no holes/attachments to the 
> existing structure" rule. What I am considering is a base 
> plate of metal (unknown size) 3'x3' maybe, with a vertical 
> and perhaps a few radial wires off from it's corners for hf. 
> Perhaps another smaller one for vhf/uhf.
>> I would like to have a multiband vhf/uhf antenna 
> (maybe even one for future sat work?)
> Also 17m, 30m, and 40m hf capabilities. I figure I will have 
> to do verticles but I really don't think much over 10'-15' 
> will be allowed. 
>> Currently the equiptment I have is a 440mhz Midland and a 
> TS-430S (which may have bad finals?) I've just used it to SWL 
> with a MFJ 752B Audio filter. I wanted to go QRP 10w or less 
> as it might prevent any complaints of TVI (all units have 
> cable) and I can't the risk of afford any big guns stuff.
>> I always worked with inverted 160m vees and horizontal loops, 
> so I'm out of my knowledge level here, and that was 7 yrs ago 
> when I was last active. I had thought of a horizontal loop 
> around the top, maybe 5' off the roof level, but that entails 
> 4 supports. Also due to the metal siding I doubt I could use 
> ladder line to make it tunable?
>> Rear of HEB (50' nw of me) has transformers at 15' plus the 
> level with the roof. Lots of potential rfi on recieve end. 
> But using 100' of wire looped around my 1st floor bed room 
> ceiling doesn't seem to indicate much of a problem.
>> I understand there is an existing Satalite dish that was 
> allowed in the apt. complex and it (maybe) uses sandbags to 
> weigh its base down??
>> My questions are:
> If I get the ok for sandbags, what material can I use for 
> them that will not decompose under the westex sun? If the 
> sand blows away a couple of years from now .. not good.
>> What kind of hf antenna(s) (tunable from shack) could I use 
> for say 17m and 40m? I know sunspot cycle is going down and 
> it will be maybe 8 yrs before things get good again. As I 
> have emphazima I'm not sure I need to plan that far ahead ;-)
>> Any and all ideas and comments welcome. TIA
>> God Bless,
> Sam Morgan 
> --
> Linux _ the lifetime learning experience.
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