[VHFcontesting] A suggestion for ERP-based Entry Classes

[Zack Widup]

On Sun, 14 Dec 2003, Dana Rawding wrote:

> 1) How do you account for a log periodic?  Say I want to get my feet 
> wet as a rover so I grab my FT-897 and a pair of KMA 4113's (50-1300) 
> there would be a total of 60 elements.  Seems unfair that it would 
> potentially push me into a high ERP class.

Good point.  Log periodics don't have the gain of a narrowband yagi.  That
gets complicated.

> 
> 2) Say at my home station I run 110 elements on 1296 MHZ w/ 100W, but 
> only 5 elements on 50 MHz with 150W and 13 el on 144 MHZ with 150W.  My 
> 1296 station may put me in high ERP, while my 2m & 6m station is far 
> from high ERP.  I'd probably opt not to run 1296 at all rather than be 
> forced to compete against the big guns in New England.
> 

That's a good question.  The number would surely change for each band.
There are other factors involved, too. For example, I'm usually
QRP-portable on a hilltop.  The hill gives me a height advantage over
many other people right away.  But the power level puts me at a
disadvantage.  It also gets frustrating to a small extent because I hear
many people I can't work.

But let's say I'm using a 6-element beam on 144 MHz that has a gain of
about 10 dBd, an 8-element beam on 222 MHz that has a gain of about 13 dBd
and a 12-element beam on 432 that has a gain of about 14.5 dBd.  I have a
24 element loop yagi on 1296 that has a gain of about 16 dBd.  All of
these are driven with 8-10 watts.  The numbers are going to be quite
different for each band.

> 3) How do yo account for dishes?  Rather than run 110 elements on 1296 
> maybe I'd be better off dusting off that old TVRO dish in the back 
> yard?  I don't have $100's of dollars of test equipment to calculate my 
> ERP.  Is my math of what I think my ERP is going to be enough?

Another good question. There are simple formulas that will give you a
ballpark figure for gain of a dish.  But it's probably not what you
actually get because the type and position of feed has much effect.  For
instance, I have a 2 X 3 foot rectangular dish fed with a WA3RMX feed for
2304, 3456 and 5760.  It's by far not an optimum feed for each band but
it's simple and easy to make and use.  The gain should go up for each
higher band, but the feed loses efficiency, particularly on 5760.  My gain
calculations don't really mean a lot in this case.  And I DON'T have
thousands of dollars to build an antenna measuring field.  Probably most
of us don't.

> 
> 4) Feed lines and preamp/transverter noise figures make a big 
> difference.  Why should they not be included in the calculation?

Yes, you have to hear someone in order to work him/her. Maybe we can get
1/2 a point for hearing another station but not working him? [JOKE]  As I
mentioned above, I can have a great receive system with low-noise receive
preamps and low-loss feedlines, but if I hear the other station S5 who is
running 400 watts, he's probably not likely to hear my 10 watts at all
(been there, done that, way too often.)  :-(

> 
> I personally think that going to an ERP based class system would be 
> very confusing.  In order to make sure no one exploits a big loop hole 
> the rules would get VERY complex.  Also not all of us aspire to be a 
> big gun.  I already have K1UHF, K1TEO and W1QK all within 40 miles of 
> me.  The last thing I need is a half dozen more big guns in the area.
> 

I usually don't have anyone within 100-150 miles of me on bands 222 and up
except when the rovers happen to make it into my area.  If you want to
move out here, you'd be away from the big guns.  :-)

> Just some Sunday morning thoughts,
> Dana  N1OFZ
> 

I see this can get complicated.  We could REALLY get complicated and do
away with all the different entry classes altogether and instead use a
factor to try to equalize your score on each band based on the system
performance of your station on each band.  But I think I'd rather
forget all that and just get out and operate!

73, Zack W9SZ
EN50vc Urbana, IL

> On Dec 14, 2003, at 8:09 AM, Ev Tupis (W2EV) wrote:
> 
> > (Element count) x (RF Output) = Entry Category is a great way to 
> > categorize our
> > efforts without compromizing our future by encouraging less 
> > band-participation
> > or band-reporting.