Roomcap - RBN - Comparison                                                                            
23 June 2014  (upd 27.7.2014)                                                                                                                                                         
Felix Meyer HB9ABX                                                                                                                                                            

ROOMCAP - Comparison
with using the RBN

Here follows the comparisons of the ROOMCAP with wire antennas.
This comparison have done during many years. However, many wrote,
that my announced measurings are not believed, because the
measurings were obtained in mode SSB, and the reading of the values
was done manually.     >>> Read about here  
Peoples, who did not beleaved the reports, see  here

>>>  27th July 2014:
In the last days I wrote some OMs to ask, if they are willing to help
to perform more, real transmits (with help of RBN and good antennas),
and to make pictures and to report.
They offered to assist in more simulations with better programs!!!
- Do they want to know the reality, or do they prefer
   fantasy, irreality or the unreality ?


Therefore, I have performed many measurings and comparisons
with help of RBN in mode CW.  I spent many months for that.
The transmissions was in automatic transmission, and automatic
measuring of the signal by RBN stations.
In each tests in all test sessions, and more than 25 RBN stations
within the whole of Europe, in the range between 140 km to 2500 km
did receive and analyse my transmissions.
Description of the RBN system  here 

The quality and performance of an antenna can be measured in
different ways:
- Measuring of SWR
- Measuring of the bandwidth with antenna analyser 
- Measuring of the field strength in the far-field, with precision instrument
- Measuring the signal at remote listeners through sky waves
The measured bandwidth of the Roomcap (2nd Gen):  here  and here 

The first 3 above parameters are important for each antenna,
however, this does not say how strong your signal arrives at distance.
Your signal can "vaporize" of your power in different ways:
- in the antenna itself
- in the ground through "ground current", ground resistance, flexion
- in the ionosphere in low flexion (depends of radiate angle!)

Only the real transmission to distance shows, how good is an antenna.

Here follows a few comparisons with RBN:        see  RBN


For the comparison with HB9ATX, using G5RV in 12m height, hunging free.
I was 200m next beside in the car.
During 1 hour we were sending alternating. HB9ATX obtained 3 reports, and HB9ABX
obtained over 150 reports from RBN. Both with 100 W in CW .
1. picture = G5RV,       2. picture = Roomcap 2.Gen,  pictures from RBN of this test.


Addition: A earlier comparison G5RV with Roomcap from VE3UNF  here  with picture antenna

Note: My position in the car on a city street, next to HB9BNK


Note the SNR scale : See the db distance from line to line.
Test began at 1800h, before was a test transmission while the car next to my house.

Note: Die CP-6 antenna on the roof, 14m above ground, all houses of same height, free round around.


What says these comparisons ?


When you see the dimension in comparing the Roomcap with wire antennas of 30m to 40m
length. The long wire antennas hanging free in the height - and the Roomcap with the 1m x 1m
radiator, 50cm above the car!

This a real Sensation,  why the antenna experts explained years ago, that this would never
be possible !!!
Here I bring the prove, because the automatic RBN measuring constitute a destinctly proof!

This is the future of the short wave antenna!

>>>   See the theory to this antenna  HERE  
>>>   See the calculation                    HERE

Here about the antenna simulation with EZNEC of Roomcap
Peter HB9PJT performed the antenna simulation, where he obtained his result:    

- Roomcap             =  - 11.4  dBi
- Dipole 15m high  =  + 5.43 dBi
- Titanex GP          =   -  9.7  dBi
The Roomcap is bad. See antenne simulation , I say only this one :
To delight about the beautiful curves, but there's nothing to do with reality!

Here are his results to see and to study  here
(ony in Germany).
(Peter meanwhile found out, that the Roomcap can not be defined in EZNEC. I use elements
that are not know by NEC ...  ... )