Radio
Channels
|
Club Member's Frequency Assignments
|
| Skipper |
CH |
Skipper |
CH |
| open |
61 |
Philip |
76 |
| open |
62 |
open |
77 |
| *conflict
(86) |
63 |
Steve |
78 |
| Pip |
64 |
open |
79 |
| open |
65 |
open |
80 |
| open |
66 |
open |
81 |
| open |
67 |
Bouy Boat |
82 |
| (Sean) |
68 |
open |
83 |
| open |
69 |
open |
84 |
| Jeff |
70 |
open |
85 |
| open |
71 |
Gary |
86 |
| Steve |
72 |
*conflict (64) |
87 |
| open |
73 |
open |
88 |
| Cliff |
74 |
open |
89 |
| open |
75 |
open |
90 |
| 27 MHz Band |
| open |
A1 |
open |
A4 |
| open |
A2 |
open |
A5 |
| open |
A3 |
open |
A6 |
| Bill |
DSM |
John |
DSM |
| Bob | DSM |
| |
|
This
list is to serve as a handy reference for anyone getting a new radio or
spare set of crystals. We believe that by using this list we can avoid
having any radio channel duplications here in our club. However, for
the instances where some of us might visit another club, or have
visitors at our site, it is probably a good idea to have an extra set
of crystals.
Club members be sure to notify Gary Watson if there
are any changes or additions to be made to this list.
A new technology came out a few years ago that will eliminate the need
for a list of frequencies. DSM is now available for most radios. With
DSM, your transmitter scans the area for available frequencies and
chooses an open channel for you.
Excerpt from website:
"What is DSM?
DSM is Digital Spectrum Modulation - a purely digital RF link between
transmitter and model that is based on Direct Sequencing Spread
Spectrum technology. It operates within the ultra-high 2.4GHz worldwide
ISM band, provides unequaled signal resolution, and is immune to the
most common forms of RF interference. It will even allow your model to
“talk” back to you. It requires no crystals and completely frees you
from ever having to monitor frequency usage again. Best of all, with
Spektrum’s DSM System you can literally plug this phenomenal technology
into existing transmitters like the JR R-1 and Airtronics M-8."
Check out the Spektrum Website for more
information.
|
23-Channel Conundrum*
by Chuck Winder
Readers of the CR 914 NEWS will know
about the potential of 2IM radio interference that is called 23-channel
syndrome. The puzzle has been: Why doesn’t it happen more often?:
1. A single group of Txs standing
together and having 23 channel separations will not cause 2IM
interference in their boats. This explains Hitec’s Tony Ohm’s
observation that it is not a problem in model car racing. In car
racing, drivers stand together.
2. However, if a skipper standing a
distance from the above group sails close to the group of Txs, he will
probably experience 2IM interference.
The reason there is no problem in #1 is
that the 2IM signal at 460 KHz is much weaker than the Tx primary
signal. But if in #2 the signal received at the boat is sufficiently
weakened by the distance of the Tx from the boat, the 460 KHz signal
generated by the grouped Txs can be large enough to cause lack of
control.
At some sailing venues (like at Shoreline),
skippers walk along the pond to be close to their boats. In this case,
if boats
are widely separated, the conditions
in #2 can occur and interference will be experienced. At the Cow Pond
Regatta (4/10/2004), there were three 23-channel
combinations for the 19 boats! No loss of boat control was reported. At
this regatta the skippers all stood the same distance from their boats.
Though it surprised me at the time, #1 above tells why there shouldn’t
have been interference.
Tentative Conclusions
- At a regatta where skippers stand
close together, there should not be 23-channel interference. Regatta
management can consider permitting 23-channel separations.
- If at any regatta the
skippers are restricted to remain within a small control area, then
23-channel interference should not be a problem.
(At a place such as Shoreline Lake, the
conditions for 23-channel interference can occur, but it is not likely
since skippers follow their boats from the shore and usually have their
transmitter in closer proximity than a transmitter that
could potentially cause interference).
* The above discussion is derived from information from Dave
Collings, D & M Electronics and appeared in The
CR914 News ,
Issue 41 pg. 10 |
| 2.4 GHz |
27 MHz |
75 MHz |
75 MHz |
75
MHz |
| CH |
Freq |
CH |
Freq |
CH |
Freq |
CH |
Freq |
CH |
Freq |
| All |
2.465 |
A1 |
26.995 |
61 |
75.410 |
71 |
75.610 |
81 |
75.810 |
Frequency
Assignments
for
Surface
Channels |
A2 |
27.045 |
62 |
75.430 |
72 |
75.630 |
82 |
75.830 |
| A3 |
27.095 |
63 |
75.450 |
73 |
75.650 |
83 |
75.850 |
| A4 |
27.145 |
64 |
75.470 |
74 |
75.670 |
84 |
75.870 |
| A5 |
27.195 |
65 |
75.490 |
75 |
75.690 |
85 |
75.890 |
| A6 |
27.255 |
66 |
75.510 |
76 |
75.710 |
86 |
75.910 |
27
MHz channels
are also identified
by color |
67 |
75.530 |
77 |
75.730 |
87 |
75.930 |
| 68 |
75.550 |
78 |
75.750 |
88 |
75.950 |
| 69 |
75.570 |
79 |
75.770 |
89 |
75.970 |
| 70 |
75.590 |
80 |
75.790 |
90 |
75.990 |
|
|
