Hi Rob.
>>> Sorry if this is slightly off topic? I am new to the list
>>> but have been a linux fan and ham for a long time. I have
>>> seen several emails on the list about plans for TNC's /
>>> packet modems, etc.
>>> Does anyone know of any plans for data only radios (xcvrs)?
>> Depends what you mean by "data only radios"...
>> If you mean "radios that can't be used for anything other
>> than data" then there's no such thing - any radio can be
>> converted to work with data, and likewise can be converted
>> to work with voice as well.
> Aren't you being a bit pedantic Riley. But then again,
> from listening to you via VHF repeaters in the UK, that
> wouldn't be you otherwise! ;-)
If you're referring to the fact that I tend to think in a logical
manner, somewhat like Mr Spock from the original Star Trek
series, then I plead "Guilty as charged". I've always been that
way, and I doubt that will ever change. My experience has shown
that it can be both a blessing and a curse as well, and I would
imagine the same is true of less logical thought patterns.
> The guy means data radios. IE: Transceivers that have been
> designed specifically for the transmission of digital data.
Having recently been stung by assuming that with a ham friend who
was SERIOUSLY asking about radios that were physically incapable
of receiving any other mode than data, I am NOT willing to make
that same assumption any more.
> As radio amateurs we have a hands on ability to butcher
> wireless equipment to do virtually anything we want,
> providing the basic design will allow us.
We also have the ability to make inane comments due to the fact
that our expertise in (for example) designing TNC's is matched by
our LACK of expertise in some other area of the hobby. I've most
certainly done so in the past, and I'm sure you have as well.
>From experience, when one is diagnosing a problem somebody else
is having, and is doing so remotely, one HAS to be prepared to
discover that the two parties concerned have been talking at
cross-purposes due to the fact that one of you knows considerably
less about some relevant issue than the other, and is thus making
assumptions that just aren't valid.
> Take a design that uses no voice demod chip, ie: MC3356
> instead of a MC3357 (or is it the other way around). One
> has af out, the other has raw data out. The pinouts are
> similar, but not the same. Yes you could mod a rig based
> around the data chip to do voice, easy on TX, lots of work,
> if not really worth it, for the RX.
> In Europe Motorola used to market a box called the
> MC-Micro. A synthesized rig that came in two basic variants
> - voice and data. The data version could pass up to
> 16Kbit/sec with 12.5KHz filters fitted. It was/is a very
> good basis for a 9K6 RUH compatible transceiver. A few of
> them have filtered out of the commecial world into hands of
> radio hams, but not many. (I keep looking!).
Fair enough. I've never personally used any of those, so can't
declare myself to be more than an interested listener at this
stage.
>> If you mean "radios that can be used for packet radio at
>> 300 or 1200 Baud" then just about any radio can be used for
>> that without modification.
> That's not data, that's damn near semaphore man!
Agreed, but that doesn't stop people asking for it. Even people
who should know better since their Internet connections work much
faster - I was recently asked for one by a ham friend with direct
T1 connection to the Internet !!!
On the other hand, I was recently asked by one ham why he should
be unable to connect his 100base2 ethernet to his radio and
transmit that on top band. Maybe he can do that on 70cm or 23cm
but I can't see it working on top band at all, even if doing so
was permitted.
I don't even listen to top band myself, so I've no idea what's
permitted and what isn't there, but I have a feeling that any
form of 100 Mbps data transfer would require a bandwidth wider
than top band is...
>> If you mean "radios that can be used for packet radio at
>> 9600 Baud or above", then yes, most existing radios require
>> some modifications to be made before they can be used for
>> this purpose. However, there is a radio on the market that
>> is (or at least was) specifically designed for use with
>> 9600 Baud packet on the 70cm band, and it was made by one
>> of the major manufacturers of ham radio trannies. I don't
>> have the details to hand though.
> And 9600baud is old-hat too.
True, but it's also the point at which standard off the shelf
radios need to be tweaked to get it to work. That's why I said
"or above" there, not because of any bias towards such speeds.
> I think that David wants plans for the type of radio that
> can be used for 38K4 and up.
I have to admit having a personal interest in one that can work
in the 10 Mbps range, something along the lines of the WaveLAN
cards one hears about, but with much larger distances between
stations. However, I have little experience to offer with such
products.
> Your basic amateur, indeed commercial spec land mobile
> voice radio needs a lot of IF work if you are going beyond
> 50KHz bandwidths.
With modern radios, they need a lot of IF tweaking to go beyond
30kHz bandwidth, never mind 50kHz.
> There are many designs available, for 70, 23, and 13cm.
I know.
> If you find the homepage of the Slovenian national radio
> society, you will find links to their data experts. They
> have designs for complete systems that handle 1.222MBit/sec
> on 13cm, as well as designs for 70 & 23cm.
I'm looking at it as we speak - thanks for the pointer...
http://www.hamradio.sl/hamradio
...for those interested. The IARU website has links to all
national societies that it knows to be online, and that is
one of them.
> Then there's the Derbyshire IP Group's web page that
> details 70 & 23cm data transceivers suitable for up to
> 128Kbit transmission.
> Check out BayCom's homepage for more designs. Their latest
> parallel port based modem works at up to 600Kbit/sec.
> If you look closely, you will find many designs from all
> over the world.
> Try these : http://lois.kud-fp.si/hamradio
> and http://www.dutch.nl/bdj/index.htm
> There. That's better.
Note that I never said that such didn't exist.
Best wishes from Riley GM7GOD / KB8PPG.
---
* God Made 7 Greedy Old Devils
* Kilroy Bought 8 Personal Pregnancy Guides
