I value your comments and you might be right about the telescopic which
of this radio.
I agree about the directionality of an antenna and people have no idea
that its actually quite important.
For example too many people say "Use a TV aerial to receive DAB"? Well
no problem with that but due to the polarisation of our DAB+ system -
DAB+ is vertical whereas TV was circular - the end result will be a
reduction in the signal strength of the signal.
As for DAB systems? Well our system and yours are very similar, only
difference being that with ours we use AAC rather than MP2 as the U.K.
uses. I don't know about Canada for sure but I do believe they use the
same Digital Radio system as you and New Zealand uses the same as us.
If you buy a Digital Radio in the U.K. nowadays you'll most likely find
it marked DAB/DAB+ and all DAB=DAB+/DBM radios marketed in Europe, South
Africa and Australasia work on the DAB3 band, think that's around
170-230MHZ.
There are some variants to this of course, there's a DAB/DBM higher up
the spectrum, think its about 1.3GHZ, my Yamaha tuners are compatible
with this band and perhaps another list member could explain more given
he works for a communications company in Australia.
On 5/12/2016 9:20 AM, Gordon Smith wrote:
Heblo Everybody
I've just read through Dane's review of the DigiTech AR1946 multiband receiver.
I wanted to make some comments frimarily to him, but maybe others might find
them useful too. I hope from the outset that my comments will be taken in the
spirit of constructive feedback on an article which, refreshingly, was the work
of the original sender.
Firstly, Dane makes comment regarding the telescopic antena. He puts much emphasis upon the
"length" of the tubes, for want of a better description. Dane then goes on to state that the
antenna is "thick". Actually, Dane, I think you will probably find that these two elements can be
said to compensate for one another. Most likely, inside the tubes will but a spring-like coil of thin
single-core feeder. Usually, the telescopic design is used in high-end radios to house the actual antenna,
rather than functioning as the antena itself. Although sometimes it serves both purposes. In this case, in
all probability, the coil will be an "air coil", whose dimentions have been customised to suit a
multi-band antenna design. The problem with this kind of receiver is exactly that. In order to produce an
antenna which resonates in a multi-band environment, the user should normally experiness with the antenna,
adjusting both the polarity of the antenna and also extending and destending it to find the best performance
on the band in use at the time.
It is a common mistake that many people make to presume that pulling the antenna fully up and just
leaving it in a vertical orientation will work best for all bands. That is actually rarely the
case. Neither is the assumption that the antenna will produce inferior performance to a
"longer" or "larger" antenna correct. Non-Resonance of an antenna at a given
frequency usually manifests itself as noise and weak signal. It's actually amazing how much one can
improve an internal antenna's performance with a given signal and at a given frequency by adjusting
the antenna by use of the old-fashioned, but still very effective knuckle-jostt at the base of the
antenna. So, my suggesttion, for whatever it's worth to you, would be to experiment with specific
signals to try and obtain the best results. A receiver's sensitivity can often be dramatically
improved by the correct orientation of the antenna. In point of fact, that is a crucial element
with any RF device, whether a transmitter or a receiver.
The environment of these devices is usually another vital factor in its
performance. Sadly, those people who design devices like computers,
particularly those housed in cases which offer no screening from RF emmission,
can also play a huge part in a receiver's performance. I'm sure you'll have
encounteded this factor many times before now.
You and I, Dane, have discussed this topic many times privately. The
technologies used here in the UK are quite different to those used in
Australia, New Zealand, the US and Canada. I think that each system presents
it's own challenges and it's own plusses.
Although we over here use very different frequencies to those used where you are,
probably primarily for topographical reasons. I'm certainly not trying to suggest that
ours is superior, because there are undesputed advantages to each. In our case, the
technologies we use allow the broadcaster to play "nanny". This is necessary
because of licensing restrictions which every broadcaster must abide by.
We use a system known as "multiplexing". Each transponder on a multiplexer can
handle 6 signals. Thus, Although to the listener, when tuning a digital radio or TV
station, it appears that the radio or TV is changing frequency as with a traditional
annalogue transmission, what is actually happening is that the receiver simply changes
from one multiplexer or transponder to another. Thus, it is possible to compress a DAB
signal alongside other signals, and the receiver simply decompresses the signal and we
hear or to ee the results.
Your system is quite different, as you know. In point of fact, I don't profess
to fully understanding the technical methods your systems use, and that is why
I make no claims whatsoever as to which system wins the battle. I am very well
aware that geographical and topographical factors play a large part in
governing the most advantageous systems for use in that kind of environment. I
can certainly see many advantages to your system, not the least of which is the
capacity for far greater bandwidth of a signal, thus DAB+ becomes a reality.
But anyway, I may very well go and research this radio, as it may help me to
solve a longstanding problem here.
==============================
My Compliments And Kindest Regards
Gordon Smith
'Accessibility And Information Technology Support Specialist
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“Oh, I’m an activist and I’m OK / I sleep all night and I tweet all day.”
