[UK-CONTEST] CQWW SSB 10m SO Unassisted : G3ZQH

Tue Oct 30 20:04:14 EDT 2012

Dave I am afraid Contesting is even more demanding than Dxing. Take for
example trying to work a ZL on 20m today either SP or LP the required wave
angle is 3 degrees.  Your antenna at about 14m high has a gain of about
-1dbi at 3 degrees, over flat ground.
	It may be the case that you can work one but the basic figures do
not make it easy. Every potential Dxer or Contester should examine the facts
about their location and optimise antennas to suite it. My suggestion to
anyone thinking of spending any money on a station, is first of all spend
money on Software, and model any considered antenna and its terrain BEFORE
buying anything. See how any antenna interacts with others and get a feel
for how it will perform before doing anything for real.
	I would not consider putting up any antenna without first spending a
lot of time checking the likely results beforehand.
73 Clive GM3POI  

-----Original Message-----
From: UK-Contest [mailto:uk-contest-bounces at contesting.com] On Behalf Of
G3ZQH
Sent: 30 October 2012 19:48
To: uk-contest at contesting.com
Subject: Re: [UK-CONTEST] CQWW SSB 10m SO Unassisted : G3ZQH

Sorry about the bad format of the antenna data- it looked fine when I sent
it! Tried to reformat it below, but not sure if this will be successful...

I worked lots of E EU of the back of my hexbeam when beaming towards US so
maybe that is an advantage!  When I check F/B on receive with the hexbeam it
is about 4-5 S points on 10m using my FT1000MP. I was thinking about
contesting not just DXing, where you might need some higher angle radiation
as well as low angle. Nevertheless very interesting comparison with Mike
G3SED’s 2el.  No chance of 75 ft here, but could risk another few metres on
the Tennamast stub mast to get the hexbeam up to about 50-55ft.  Point taken
about the narrow lobes on the 5-el- perhaps this is where the SteppIR
reversible mode comes into its own. Not used one- but this seems quite a
neat trick.

73 Dave G3ZQH

Ø  The lower noise floor on the 4 ele Yagi is due to it's better F/B, 

Ø  narrower forward lobe but mainly due to the lack of side nulls on the 

Ø  Hexbeam.

Ø  Clive is right, If you hear Mike SED on the higher bands then you may 

Ø  know he uses an optibeam, but with only 2 elements on 10M (actually 2 

Ø  elements on all 5 bands) but its up at 75ft. Mike is only 9 miles away 

Ø  and we are always comparing with stations at the other end. On 10M Mike 

Ø  is neck and neck with my 5 ele @45ft on 90% of the stations. 

Ø  Unfortunately planning restrictions, a 21ft wide garden, and overhanging 

Ø  tree branches limit what I can do here so the 5 ele is the biggest 

Ø  antenna I can get up for 10M for my everyday DXing, the problem when 

Ø  using that in a contest is the narrow forward lobe, deep side nulls and 

Ø  25dB F/B. When beaming to the West Eastern Eu can be barely readable but 

Ø  swinging the beam round they can be 9+. Great for point and shoot, not 

Ø  so good for multiplier hunting. I have a dipole at 90deg on the sub Rx 

Ø  which helped in CQWW but I need to dig out my 10M 5/8 vert which is 

Ø  corroding in the grass somewhere, that is a more effective mult finder.

Ø  Darren G0TSM

On 30/10/2012 13:39, Clive GM3POI wrote:
> Forget about minor differences in alleged gain of the different antennas,
and think in terms on Wave angle required at the wanted frequency. For
example 10m is roughly half the angle of that required at 20m typically
often below 5 degrees. This is the only real DX performance to worry about,
fractions of a db are meaningless. Far better to have a 2el 10m yagi at 70ft
than a 6el at 30ft and you can make a 2el 10m yagi for next to nothing.
> 73 Clive GM3POI
> 
> -----Original Message-----
> From: UK-Contest [mailto:uk-contest-bounces at contesting.com
<http://lists.contesting.com/mailman/listinfo/uk-contest> ] On Behalf Of
G3ZQH
> Sent: 30 October 2012 07:52
> To: uk-contest at contesting.com
<http://lists.contesting.com/mailman/listinfo/uk-contest> 
> Subject: Re: [UK-CONTEST] CQWW SSB 10m SO Unassisted : G3ZQH
> 
> Thanks for info on hexbeam vs Yagi.  Interesting that the noise level was
lower with the Yagi- possibly as a result of the higher angle lobe that
appears on the hexbeam at around 50’ height.
> 
> I have pasted in a table I put together a couple of years ago when I was
looking for best value for a 5-band directional antenna. It is interesting
to see that with these inevitably compromised antennas there is generally
fairly poor performance on 10m particularly F/B ratio. The SteppIR in 2- or
3-el format is actually worse than the hexbeam on 10m F/B!
> 
>   
>                              SteppIR 3 el   SteppIR 2 el   Optibeam 10-5
G3TXQ hex        Spiderbeam
> Max. Element length (m)      10.97           10.97          7,70
6.6             10
> Boomlength (m)               4.9            1.44           3.75
6.6             10
> Turning Radius (m)           6               5.61          4.3
3.3            5
> Weight (kg)                  19             13.6           14
10              11.5
> Windload (sq ft)             6.1             4.0           3,2
6.0             3.8
> Gain dBd 20                  4.9            4.2            4.2
3.2             4.5
> Gain dBd 17                  5.5            4.2            4.4
3.2             3.2
> Gain dBd 15                  5.7            4.1            4.2
3.5             4.7
> Gain dBd 12                  6.2            4.0            4.4
3.0             3.0
> Gain dBd 10                  6.3            3.8            4.8
3.6             4.9
> F-to-B dB 20                 21              18             22
22              15
> F-to-B dB 17                 20             19             17
19              20
> F-to-B dB 15                 27             13.7           15
16              20
> F-to-B dB 12                 21             13             15
13              10
> F-to-B dB 10                 11             9.3            20
16              18
> Price £                      1500           1100           1000
500             450

_______________________________________________
UK-Contest mailing list
UK-Contest at contesting.com
http://lists.contesting.com/mailman/listinfo/uk-contest

=======
Email scanned by PC Tools - No viruses or spyware found.
(Email Guard: 9.0.0.2308, Virus/Spyware Database: 6.20830)
http://www.pctools.com/
=======