Topband: Spiderbeam Topband Mast suggestions

Sat Aug 24 16:06:24 EDT 2013

Hi, Regarding recent topic, Spiderbeam mast suggestions needed.

Please note, 
The September 2013 issue of Radio Society of Great Britain (RSGB) RADCOM contains an article by Steve Nichols G0KYA
on the Spiderbeam Model 160-18-4 WTH 160M Vertical.
Info on setting up, quality, and some idea on performance.

73
Phil G4LWB

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Message Received: Aug 24 2013, 05:01 PM
From: topband-request at contesting.com
To: topband at contesting.com
Cc: 
Subject: Topband Digest, Vol 128, Issue 25

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Today's Topics:

1. Spiderbeam mast suggestions needed (Jim Garland)
2. Vertical Antennas (Eddy Swynar)
3. Re: Spiderbeam mast suggestions needed (GeorgeWallner)

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Message: 1
Date: Fri, 23 Aug 2013 10:46:43 -0600
From: "Jim Garland" <4cx250b at miamioh.edu>
To: 
Subject: Topband: Spiderbeam mast suggestions needed
Message-ID: <002101cea020$5a04ba60$0e0e2f20$@miamioh.edu>
Content-Type: text/plain; charset="us-ascii"

Hi everyone,

I'm _finally_ trying to erect a decent vertical for 80m and 160m, and have
purchased a 26m (85ft) Spiderbeam mast. I'd really like to hear from guys
who have used this mast for these bands. I'll have about 60 120ft radials.
I've seen sheet from the manufacturer about using the mast as a monoband
160m shortened vertical. The diagram shows a wire wound aound the mast, with
4 7m wires near the top for a capacity hat, but wonder what other
configurations people have used? Also, if possible I'd like to be able to
use the mast on both 80m and 160m. It will located about 600 ft from my
house.

73,

Jim W8ZR

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Message: 2
Date: Fri, 23 Aug 2013 13:00:11 -0400
From: Eddy Swynar 
To: topband at contesting.com
Subject: Topband: Vertical Antennas
Message-ID: <278FD2D7-C0DE-4F58-A303-88B8BB9D7F99 at xplornet.ca>
Content-Type: text/plain; charset=us-ascii

Hi Guys,

While I most certainly agree with what others such as Tom (W8JI) might offer here as to the value of TRUE "A" vs. "B" comparisons when it comes to how effective an 
antenna may be, I won't let a little thing like expediency deter me from erecting---and using---a "...less than stellar" antenna...

Case in point: at our summer cottage (a two storey affair, with an upper balcony), I lashed together some aluminum tubing to tie to the railing on the second floor with 
bungy cord: I made up the balance of its length for a 1/4-wave 7-MHz vertical with a re-cycled old electrical extension cord dropped down from the aluminum, which 
terminates at the feed point some 3' above physical ground. I then unrolled 2 insulated counterpoise wires, 1/4-wavelength long, in opposite directions.

Surprisingly the doggone thing works very well into Europe, no doubt testament as to the effectiveness of the stations of our European friends(!) as much as anything 
else at this end of my QSOs...but the point is, it works quite well with just the 100-watts that I might pump into it from my now-ancient Yaesu FT-980 transceiver.

So don't despair, and---as the Nike slogan so aptly puts it---JUST DO IT!!!

~73~ de Eddy VE3CUI - VE3XZ

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Message: 3
Date: Fri, 23 Aug 2013 16:19:59 -0400
From: "GeorgeWallner" 
To: "Jim Garland" <4cx250b at miamioh.edu>, 
Subject: Re: Topband: Spiderbeam mast suggestions needed
Message-ID: 
Content-Type: text/plain;charset=utf-8; format="flowed"

Jim,

My home QTH and all my DXpeditions had SpiderPole 
verticals for 80 and 160 (and other bands). You have a 
wide range of options. A lot depends on how much work you 
are willing to do and how much efficiency you want to 
squeeze out of the system.

The simplest arrangement would be a low loss loading coil 
(around 60 uH) somewhere in the middle to resonate the 
antenna on 1.9 MHz. Use AWG #14 insulated wire for the 
whole length and fold it back at the tip to create a 30 cm 
(1 foot) diameter loop to reduce voltages on the tip and 
to add a little bit of top loading. Add an approximately 8 
uH inductor between the base and GND. You will find a 50 
ohm tap point on the inductor somewhere around the center. 
For the base inductor use 1/4 inch copper pipe or large 
diameter wire. For 80 m use a relay to switch in a 
suitable L matching network.

An alternative is to use an inverted L configuration. Use 
very thin wire for the horizontal section to reduce the 
side load as the tope part of the SpiderPole is very 
flexible. You may find that you can get decent SWR with 
the 50 ohm coax connected directly to the feed-point. 
(That would indicate a high ground system impedance and 
substantial losses, but...) Otherwise use a simple L 
network to match the coax to the feed-point. One word of 
caution, an inverted L that is resonant on 160 will have a 
very high reactive feed-point impedance on 80 and will 
also have a high radiation angle. You can use a shorter 
horizontal wire (around 8 meters) and two switchable 
matching networks, one for 80 and one for 160 m. An 
alternative to consider is to leave off the top two 
sections of the 26 m SpiderPole to create a stiffer pole 
which can hold more side load. The horizontal wire would 
have to be correspondingly longer but the improvement in 
mechanical strength would be well worth the slightly lower 
efficiency.

For something a lot more elaborate (and something that can 
cover all bands, check out the antenna used on VK9GMW. 
(http://vk9gmw.com/documents/VK9GMW_ANTENNA.pdf ) That 
antenna worked great because of the salt water, but with 
enough radials you could get good performance on land too.

For a permanent installation I strongly recommend that you 
paint the antenna once you got it working. Use flexible 
urethane paint. It will make it last 5 times longer. You 
should also have at least 3 guy ropes, attached somewhere 
around the middle. For ultimate strength, buy two poles 
and insert one inside the other. The antenna at my QTH has 
an 11 m tall 100 mm diameter aluminum tube with two 18 m 
SpiderPoles on top, for a total height of 29 m. No guy 
ropes. It works from 160 to 30 m via a tuner and has been 
up since 2009. (You can see a picture of this antenna on 
my QRZ.com page.)

GL and 73,

George,
AA7JV

On Fri, 23 Aug 2013 10:46:43 -0600
"Jim Garland" <4cx250b at miamioh.edu> wrote:
> Hi everyone,
> 
> I'm _finally_ trying to erect a decent vertical for 80m 
>and 160m, and have
> purchased a 26m (85ft) Spiderbeam mast. I'd really like 
>to hear from guys
> who have used this mast for these bands. I'll have about 
>60 120ft radials.
> I've seen sheet from the manufacturer about using the 
>mast as a monoband
> 160m shortened vertical. The diagram shows a wire wound 
>aound the mast, with
> 4 7m wires near the top for a capacity hat, but wonder 
>what other
> configurations people have used? Also, if possible I'd 
>like to be able to
> use the mast on both 80m and 160m. It will located about 
>600 ft from my
> house.
> 
> 73,
> 
> Jim W8ZR
> 
> _________________
> Topband Reflector

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