There are various sources of "Mods" around for most rigs including Packet BBSs, local packet groups and the more enthusiastic radio dealers. Mike Mansfield G6AWD has recently compiled a large number of these "Mods" in his book High Speed Radio Transceiver Connections available from Siskin Electronics. (or you can contact mike direct) Ex-PMR equipment can present a problem as much of the Pye/Philips equipment is "Phase" rather than "Frequency" modulated but do not fear as placing a varactor diode across the crystal will give true FM, an example is included in Mike's book using the Pye Olympic.
WHAT SYSTEM?
If satellite use is to be considered an essential feature to look for is NOT G3RUH compatible but whether the TNC/card whatever actually USES the G3RUH modem system. Some TNCs indirectly claim G3RUH compatibility but do not actually use the G3RUH circuitry. Whilst this would not be a major problem for 5/9 each stations when one gets out into the real world of Doppler, central heating thermostats cutting in and generally weak signals the G3RUH method comes into it's own for both OSCAR and terrestrial operations.
UPDATING EXISTING 1200 BAUD EQUIPMENT.
Gosh folks, you actually have a fairly wide choice at last. If you already own a 1200 baud TNC you may not need to rush and buy a new TNC, instead why not considering adding a G3RUH type modem to it. Units such as the PacComm Tiny 2, TNC-200, TNC-220, TNC-320, Handi-Packet, MFJ-1270/74/78, AEA PK80, PK88, G0BSX-2, G3KFN and MaxPak DL-2 all sprout a modem disconnect of varying standards which can be mated to a 9600 add-on card. Owners of older models such as the TNC-200, MFJ1270 and PK-80 will find that updating the CPU ands SIO to 6 or 10MHz clock speeds will greatly improve throughput. The Kantronics KPC-2, KPC-3, KPC-4 and KAM/KAM PLUS will NOT support 9600 owing to hardware constraints. Although the PK-232/MBX will on the face of it support 9600 experience has shown that the end result is usually disappointing as the PK-232 firmware is already fully subscribed to performing other functions and is a definite non-starter for Full Duplex 9600 satellite/dedicated link applications. The Thor RLC-100 PC card also has four modem disconnect headers for use with external modems and add-on cards such as those mentioned below.
1) The bare PCB (Eurocard size) and parts list direct from James Miller G3RUH at GBP18 including UK and Europe postage , GBP19 for the rest of the world. EPROM's GBP6.00. James cannot process credit cards, however cheques and Postal Orders in pounds sterling (NOT Foreign currency) are acceptable.
2) A built and tested version of the above is available from James Miller.
PLEASE CHECK WITH JAMES FOR HIS CURRENT PRICES AS I WILL NOT BE UPDATING THE INFORMATION IN THIS PAGE !!
de G1GYC Martin
3) The PacComm NB-9600. Similar to the original G3RUH card (uses RUH modem technology) but slightly smaller and will actually sit INSIDE a Tiny 2 and many other TNCs. Although this is a more expensive option than item 2 above you could save a few pounds on another box and cabling.
9600 SPECIFIC TNCs.
Once again you now have a choice. For PC owners the decision as to whether to use a slot card or separate TNC is probably only a question you yourself can answer (I.E. if you run a node or BBS and are running out of COM Ports a slot card can save some grief but please but there is trade off when sharing interrupts for such applications).
1) The Symek TNC2 H - a no nonsense plug in and go 9600 TNC using G3RUH technology also implementing DF9IC recovery techniques. The unit has had very favourable reports from Amsat users and is also used by a number of UK nodes and BBSs. The TNC2H is a TNC 2 clone and so will support EPROM's such as TAPR, Netrom/TheNet, WA8DED etc. This is a dedicated 9600 unit and will not support 1200 baud but may reduced to 4800 or increased to 19,200 etc. by changing a handful of components.
2) PacComm SPIRIT - a relative newcomer to the 9600 scene the Spirit does not vary much from the TNC2H above but does have a slightly more substantial cabinet and promised accessory list. Once again the Spirit DOES use G3RUH circuitry and is a TNC-2 compatible. A special 38,400 baud backbone model is also available for dedicated high speed links.
3) The Kantronics KPC-9612 - similar to the original KPC-4 dual port the 9612 offers one 1200 baud and 9600 baud port with a Gateway facility between ports using the built-in KA-Node. As far as we know the KPC-9612 does not use G3RUH technology but seems to work after a fashion. It is a definite no no for satellite and important links although across town it should be OK for offering a local cross-port gateway etc. The PMS and node can be accessed from either port.
4) AEA's PK-96 is a development of the PK-88 with a built in 9600 facility. The unit will support 1200 or 9600 simply by typing one command. For someone just starting out the PK-96 probably does offer a good degree of future proofing although once again we should stress it does NOT use G3RUH technology so may not be ideal for satellite operators.
PC SLOT CARDS:
The BayCom Modular USCC 4 card is a 16 bit standard ISA Bus card which allows individual piggy-back modules to be plugged into each of the 4 ports. Both 1200 and 9600 modules are available and may be changed at will. The card can use IRQ's 3,4,5,7 or 10-15 with one of 8 jumper selectable I/O addresses. This card has proved popular to both Node/BBS Sysops and end users alike and may be used with various software packages such as the BPQ code, most flavours of NOS/TCP/IP, the original BayCom software and TPK etc. The card is available built and tested from Siskin or alternatively the bare PCB with EPROM's and pre-programmed GALs is available from the North West Packet Group.
BayCom PAR-96 - not strictly a PC slot card as this unit uses a PC parallel printer port rather than a precious COM port. This unit is available built and tested from Siskin or alternatively in kit form from the North West Packet Group.
9600 BAUD READY RADIOS:
Siskins are now stocking the TEKK 9600 2 watt UHF '9600 ready' transceivers. These are a crystal controlled true FM radio that really are 'plug in and play' for 9600 baud.
Addresses:
James Miller G3RUH, 3 Bennys Way, Coton, Cambridge. CB3 7PS. Tel:
01954 210388. fax 01954 211256.
Email: james@jrmiller.demon.co.uk.
Siskin Electronics, Unit 1a, Hampton Lane, Blackfield, Southampton. Tel: 01703 243400 SO45 1WE. Fax 01703 243500. EMAIL: info@siskin.co.uk OR orders@siskin.co.uk
North West Packet User group (19:00 - 210:00 only) c/o: Phil Jones tel no.: 0151 334 2452.
FOOTNOTE:
We've heard and read a lot about some GMSK high speed modem devices of late: "the answer to all our prayers". We've done a little bit of work on these chips and the bottom line for some amateur radio applications (notably amateur satellite operation) is not positive. Yes, they do work, but not under some of the less than ideal conditions experienced in the amateur radio world.
We are not saying don't experiment with these devices, they can work very well, just bear in mind they are designed for an ideal world like a digital telephone line or line of sight micro-wave link, not your average 70cm multi-user 25khz radio channel.
Questions and information: info@siskin.co.uk
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