There are chips/devices that can accept USB and spit out NMEA-looking data as TTL, but you would have to handbuild USB drivers for any and all of the USB GPS receivers. The Maritime standard may be old school ( Heck, APRS uses Bell 202, and besides smoke signals, it does not get much more "old School" than that!) but it is at least a standard that is commonplace and generally well understood. If anyone out there knows of a universal GPS-to-UART converter, I would love to see it!

73,

Allen AF6OF

You may want to consider a GlobalSat BR-355. I have used them on TT3 for many years.

It is a SiRFStar (III or IV depending on how old it is) and supports a wide range of NMEA sentences and can be configured. It will remember the config.

Do a web search and you will likely find new ones.

regards

rich

N0RAP

73,

Allen AF6OF

I dug up the spec sheet for the Garmin GPS 16 LSV ( https://static.garmin.com/pumac/GPS_16x_tech_specs.pdf ) and it looks compatible. You will need to do some connector surgery. I see these are retailing in the 120 to 140 dollar range ( I have not checked EBay) and if you don't find a significantly better deal, you might want to consider the Byonics GPS 5 @ $65.00, which is warranted to work and is plug and play with the TT3+ units. It is a shame that RS-232 serial is quickly disappearing from all the Garmin products! I loved their GPS (60?) that was cheap and output NMEA, and accepted and plotted Waypoints from the TT4 and other devices.

73,

Allen AF6OF

73,

Allen AF6OF

One new product is our MTT4B-Mini. This is a TT4-based transceiver with nominally two watts of output power Max. It measures about 1 X 2 inches, and weighs .44 ounces. It is a populated PCB, not a kit. It was designed for use as a superlight fill-in digipeater, a simple telemetry transmitter, CUBESAT transceiver, drone, solar digi, etc.? ( Unlike the TT3, you don't need to have a GPS connected to it to have it send telemetry) Of course the unit has the mini-connector on the board for our OEM-style GPS, either the high or low altitude version. Unlike our bigger transceivers, this unit does not have an RS-232 converter on the board. Our friend, Bob Bruninga found that the clock noise of a MAX-232 chip is a problem when used in a CUBESAT, so we left it out. ( In space, Microprocessors can hear you scream!) It speaks TTL. You can connect to it for PC operations, programming, sending WX reports, etc. with a cheap .99 eBay USB-to-TTL cable, or to your UART if you are so inclined. Byon has non-counterfeit cables in stock.? Anyone who has worked with the TT4 will have a short learning curve with this transceiver. Happily, there is no need for experimental audio settings with the integrated transceivers, the defaults that live in them? just work. These units are already in service by a Beta Tester, but if you know of anyone who plans a HAB flight in the near future, and has the excess lift capacity, I would love to send a MTT4B-Mini, antenna, and GPS module so we can test it above the world ( As a cross-frequency digipeater and tracker) It is not up on the Byonics website yet since we don't have a manual, but the product actually exists ( Not vaporware!) and we have some in stock. These will retail for $199.00 The unit has a number of I/O's that can be used for telemetry or control pins. I like the idea of the low power transceiver operating with a "split" in the frequency. My idea ( Which may prove wacky) is to send "pings" from a transmitter carried by a payload recovery crew on its input frequency, and listen for the digipeated packet on another frequency. HAB payloads seem to have a real affinity for landing in godless territory without digipeater coverage, heavy forest canopy, military shooting ranges, snow banks, swamps, and oceans. Being able to ping it, or activate a noise maker by sending an APRS command, should be helpful for finding the Payloads when the internal GPS is hor's de combat.?

We have an older product that I suspect not a lot of Hams know about. This is a DTMF Remote controllable switching module. Our teams of consultants met for several days and decided the unit should be called the "DTMF Remote" I( I wish I had a degree in marketing!) It is also a bare-board product designed for easy implementation with your projects. What does it do? Good question. The device, nominally 1X 2 inches is a transceiver that can receive VHF FM between 135 and 170 mHz, and using the TouchTone controls on your radio, you can control up to seven outputs. These logic-level outputs can be programmed via a PC connection to operate as logic High or Low. You can control each of the outputs, setting any of the outputs as momentary or latched. We designed the board so that it was plug and play with eBay 8 channel relay cards, for handling more power. These also come in single and 4 relays boards.?

The neat thing about the DTMF Remote is that after you send it a command, it pauses a second or so to make sure you are not sending another command, and then (optionally)? transmits a set of beeps to indicate which channels have been commanded, followed my station ID in Morse. This gives you complete proof that your command has been handled. Of course, only Hams can use the transmitting feature of the DTMF Remote, and only in the Amateur 2 Meter band, so the TX range is hard-limited in firmware. The unit can be set to encode and decode CTCSS and DCS tones so you can operate through a repeater, and have increased security. It can operate on split channels. There is a 5 place numerical password to lock and unlock the device if you wish. Combined with CTCSS, DCS, and wide frequency choice options, the unit provides a pretty good level of security The transceiver has a selectable, low power, "sleep" mode to save power in battery operation. You wake it up by sending the first tone command a tad longer.?Originally, the DTMF Remote was intended for a secure, one-shot, commanded operation with confirmed operation. No, not for bombs or anything evil, but for simple implementation of parachute cutdown commands in HAB payloads. It has been used in a lot of ways, like using DTMF controlled operations in HAB payloads, remote control of digipeaters and repeaters, wireless rocket launching, and remote cabin controls.?