No discussion would be complete without reviewing the old "Station Design
for DX" series in QST by Rockwell. This was great stuff, complete with
graphs of marginal cost of the next dB. His rules of thumb as I recall
were: better QTH and antennas get first priority since the dB improvements
work on both receive and transmit, followed by receiver improvements,
followed by power, followed by all else. My favorite example that someone
gave as a result of the discussion generated by this series was moving to a
new job that was only 5 minutes from home, which increased time available to
DX plus better response time from work to the shack if a needed new one came
on.
If you eliminate power by assuming everyone is already running 1500W, then
for DX it would be IMHO: get antenna up 1/2 wavelength or more, increase
boom length, then stack. On 80 and 160, multiple transmit antennas
(vertical, high dipole) and receive antennas (beverage, etc,) make a
tremendous difference from one day to another. For DXCC purposes, there
must be a factor for cost of hours spent at the radio, i.e., 25 hours a week
at a modest station will most likely get you more DXCC entities than 5 hours
per week at a super station.
It might be useful to have you describe exactly what you have got now, and
then the specifics can be taken into account in the recommendations.
In my case, I went for a good location, then for the most electrical bang
per wind load buck (reliability), on the theory that more hours spent
listening would do more good than hours spent in repair and maintenance.
Within those provisos, I went for covering multiple radiation angles via
switch able stacks rather than single long boom antennas.
73 and Good DX John N5CQ
-----Original Message-----
From: owner-towertalk@contesting.com
[mailto:owner-towertalk@contesting.com]On Behalf Of alsopb
Sent: Thursday, August 19, 1999 12:46 PM
To: towertalk@contesting.com
Subject: [TowerTalk] $/db
Guys,
It looks like many stations are pushing the
envelop on improvements that can be made to
achieve a better transimitted signal. I'd like to
try and quantify what that "extra 2 db" might
cost.
I'd like to hear what station improvements you
would make to pick up extra db's. The goal is to
identify the most cost-effective ones.
It is clear that this is probably band dependent.
It surely is station dependent.
Assume that you can run no more power. All "gain"
has to come from the output of the amp to the
ether. Assume only the HF bands and you're
primarily a DXer.
Examples might be:
1. Increase the number of radials on my 160 meter
inverted L from 8 to 60. Gain estimate 2 db (via
less ground loss), cost = $1000 cost/db =$500
2. Replace my 10 meter antenna RG8 feedline (300')
with LMR600 . Cost = $300, gain =2 db, cost/db =
$150.
3. Raise my 40 meter dipole from 40 to 70'.
Estimated gain at 25 degree radiation angle = 3db,
cost =$100 (tree climber), cost/db = $33.
4. Match antennas better and get rid of antenna
tuner. Cost = 0, gain = 1db.
Please give the old configuration and the proposed
improved configuration.
I think you get the idea.
I'll compile these with the hope that can help us
all identify incremental improvements that may be
useful at our station and what they might cost.
73 de Brian/K3KO
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|