The demise of ACSSB in our area was the overall
range was limited to poor sensitivity relative to
a similarly situated uhf repeater.. Typical
sensitivity of the mobiles was .4-.5~.6uv or so
compared to sub .2uv on uhf and vhf fm mobiles
that were readily available.. Sound quality did not help ...
The noise floor is higher at 220 in many areas in
the cities... compared to uhf.... basically our
UHF systems killed 220 acssb once we could start
trunking efficiently with LTR... there was no
competition between the 2 as UHF engineered well was superior...
It was not possible to improve the sensitivity of
the front end due to the design of the hardware
and systems typically could hear farther than
they could talk... so mobiles lost the site
first... Typically most systems were SEA that
were actually getting loading... and those system
cost a lot more for 100w amps than the stock
20w.... SO most systems were deployed with 20w transmitters at the site..
talking to 20w mobiles.. the site had a preamp on
rx.... the combiners chewed up TX power ...
lowering outbound ERP... Downlink power was always less than uplink.....
In FM 100w PA's are no issue to add at will to a
20w repeater...... boosting the output of an
ACSSB transmitter required a complex amp with a
feedback loop controlling gain.... $$$$$ not a
$800.00 vocom or eq like on FM... We only owned
one and never deployed it... it double the cost of each repeater...
Performance was sub par for about any other radio
operation including 800 mhz....and probably 900....
Doug
KD8B
At 03:46 PM 11/11/2009, you wrote:
basically as the title states. i have never
heard of acssb outside of 220-222 mhz.
seems to me acssb was a good idea and was
curious as to why the ham community has not
picked up on it for mobile HF SSB use.
seems to me having the benefits of SSB without
the hassle of messing with a clarifier all the
time has it's advantages in a mobile environment.
also it seems running a AOR ARD9000 type device
over ACSSB would be a really great advantage.
i have zero experience with either of these
modes so i am not sure how this idea would turn out.
i know that the likely reason is NBFM and P25
for the demise of ACSSB, but as stated above
seems to me it would be at home in the HF spectrum.
I know i am going to get flamed for this, but i
think ACSSB would make a great replacement for
standard ssb in the 11 meter market.
it would also allow the use of CTCSS on HF using
a more efficient mode then FM. imagine haveing
ACSSB 10 meter repeaters instead of FM.
