March 24, 2012

Prior to my road trip to LCA 2012 Ballarat, I bought a new toy, namely a Yaesu VX8-DR handheld.

At that point it turned up only just before I was due to leave, so I wasn’t able to get the accessories I wanted. I cobbled together my own 12V charger lead by snipping the original power supply and soldering on a cigarette lighter socket, but otherwise I used the handheld in its out-of-the-box configuration.

Having gotten back, I have purchased the FGPS-2 GPS module, CT-136 GPS adaptor and the BU-1 Bluetooth module.

Transceiver performance

The set works quite well. The antenna is pretty deaf and useless on 6m, maybe I can get a better after-market tri-bander whip, but on 2m and 70cm it works reasonably well. I’ve heard APRS traffic over distances of 100km, and even been heard on APRS by a digipeater some 90km away.

Audio quality is good, both transmit and receive. Plug in a pair of stereo headphones, and the wideband FM receiver sounds excellent; in stereo to boot.

Probably my biggest nit, is you can’t simultaneously charge and externally power the set. To charge, you must either detach the battery and drop it into a separate charger cradle (an optional extra) or turn off the set.

GPS Performance

When I purchased the VX-8DR, it was a real toss up between it and the VX-8GR. The reason I went the VX-8DR was because it had 6m, and Bluetooth. Having gotten the GPS, I’ve run into the problem a lot have reported; the GPS module is deaf as a post.

The VX8-GR doesn’t improve on this either. However, the good news, is that because my module is external, I can (1) mount it in a better spot, or (2) replace it with a better compatible module.  For VX8-GR owners, this is the end of the road, they can do nothing but moan to Yaesu.  I at least have options.

The module is mounted vertically inside the FGPS-2 casing. Usually with GPS modules such as these, they embed a small patch antenna, whose radiation pattern is perpendicular to the plane of the antenna surface. Being vertical, this means when you hold the radio vertically (as you normally would), GPS reception is poor because the radiation pattern is directly in front of the radio.

The radio seems to perform a lot better, if the radio is held with the screen facing upwards towards the sky. It’ll even work inside my house if I do this. It seems this is a screw-up on par with the iPhone 4.  Another alternative is to replace the module, the FGPS-2 apparently uses 9600 baud serial with NMEA format strings.  However, it seems the parser in the VX-8 is rather crude.  I have a module that does NMEA at 4800 baud, so I’ll either need to coax it up to 9600, or use a microcontroller to buffer and convert rates, and perhaps do some tweaking of the sentence format to make up for the VX-8’s shortcomings.

My hunch; if I make an alternative bracket to the CT-136 adaptor, I can nail this, and another problem, the inability to plug in the GPS and a headset. I have the CT-M11 cable, and thus I plan to make a bracket to connect the FGPS-2 to the end of this cable; allowing me to also plug in a wired headset.

Bluetooth

I bought the Bluetooth as an insurance policy to give me another means of interfacing a headset. Then began the fun of getting it to work with my headsets. I have a couple; a Bullant earmuff-headset, a lightweight mono Digitech headset, and a “MyTalker” headset.

The first was one set I bought some years ago, back when the Bluez was far less stable than it is today, and also long before I was into Amateur Radio or possessed a Bluetooth-capable phone. I tried pairing using a USB Bluetooth dongle, but had little luck, so they got put on one side. Also despite advertising being able to stream music, it only supports HFP and HSP profiles, so you get to listen to your tunes in 8kHz 8-bit mono. They are sold at some hardware stores, such as Mitre 10 The Gap (where I bought my set).

The handheld did pair with this set, but I couldn’t get PTT to work, and the headset itself also had a few faults; namely it was always noisy, and the broadcast receiver stopped working, so I’ve taken them apart for now to see if I can fix these issues. I can key the radio up using the radio’s PTT, but then both internal and headset microphones go live.

The second set is sold by Jaycar, catalog number AA2080. This would be my preferred set to use with the radio as it can pair with two devices simultaneously. It supports the same profiles as the earmuffs, but it’s at least more lightweight.

The BU-1 takes one look at this set, and turns its nose up at it, with the VX-8 giving up and displaying “PAIRING ERROR”.

I also bought the MyTalker set from Jaycar, catalog number XC4894. This set is much like the earmuffs. It embeds its own microphone, but the unit itself provides a 3.5mm socket for you to plug in your own headphones, or use the supplied earphones (which are awful and uncomfortable, don’t use them). At the other end of the unit, is a lead terminated with a 3.5mm plug to plug into a music player. I’ve modded this set to be able to use an external microphone, switchable between a transceiver and the Bluetooth set, allowing a headset connected to a radio to also connect to a phone. I’m still working on this bit.

The VX-8 treats this set with much the same contempt as the mono headset before.

Today, I poppsed in and bought a more expensive set; this time I looked for A2DP functionality, Jaycar have one, catalog number AA2082. Like the AA2080 it can talk to two devices, unlike the AA2080 it supports AVRCP and A2DP. Also, not advertised, is it can function as an analogue headset; supplied in the box is a dual 3.5mm to mini-USB cable that can plug into the headset and allow you to use it with a non-Bluetooth capable device.

I plugged it into the bicycle’s battery to charge on the way home. When I got home, I read the instructions (which are in awful Chinglish). Basically, the English translation of the pairing instructions go like this:

1. Hold in the MFB button (the centre one on the right ear-cup) in for several seconds. You will hear the voice prompts “Hello”, followed by “Enter Pin Code 0000 on phone”.
2. When you hear the latter prompt, tell your device to start looking for the headset
3. When it finds a device called “AA2082”, select it, and enter 0000 as the pin code

So, the steps I followed:

1. Turn on the VX-8
2. Hold in the MENU key to bring up the Set menu, then select BLUETOOTH PCODE
3. Enter 0000 on the keypad.
4. Hold in the MFB button on the headset until you hear the “Enter Pin Code” prompt
5. Hit V/M on the VX-8
6. After a few brief moments, you should see “PAIRING COMPLETE”, press PTT to confirm.

Having got this working, I notice a few things:

• Stereo (A2DP) sounds a little weird, perfectly clear, but the compression is apparent. I’ll experiment with the laptop later to see if it’s the headset or the radio.
• Mono works well, pressing MFB toggles PTT on the VX-8. VOX doesn’t seem to work, but no great loss as I find VOX to be a disaster when outdoors.
• In mono mode, a buzzing is apparent on the received audio. This isn’t audible on transmitted audio, nor did I notice this on received audio when I tried using the headset with my mobile phone.
• Range seems to be quite restricted, possibly due to where the module is installed it doesn’t get the reception it perhaps needs. A2DP suffers more from this than HFP, with drop-outs being frequent. Again, I’ll need to do some experimentation with the laptop, and perhaps some experimentation with the radio without the battery installed to see if that helps performance.

I’m tossing up whether I get one of these motorcycle Bluetooth headsets.  I ride on the bicycle quite a lot, and at the moment I use headsets embedded in the helmet that are home-built from old computer headsets.  The longevity of the microphone seems to be the biggest problem  I also am on the look-out for an earmuff headset for things like the Imbill car rally, ideally one that can do A2DP.  The Bullant ones I know can’t do this.  I see some earmuffs in the $400+ price bracket that offer Bluetooth, but no idea if that includes A2DP, and frankly, I shudder at that price.

The motorcycle ones are designed to fit a wide range of helmets, and they look as if they’ll fit a set of cheap regular earmuffs quite well.  They typically sell for about $200, support A2DP, multiple devices, and intercom.  Add in $30 for a set of earmuffs, and it makes this a much more attractive option.

More experimentation will be needed I think, but this is looking promising.  I’ll probably post up more details as I come across them.

It’d be nice if Yaesu had been a bit more up-front on what the BU-1 supports: the AA2080 supports both HFP and HSP, yet the BU-1 won’t touch it, the Bullant set supports the same profiles yet the BU-1 works fine with it.  The reasoning for this is not clear, but it does seem that it’ll reliably talk to A2DP capable headsets, so maybe that is a starting point for others.

Likewise with the CT-136, I’ll see if I can fabricate a bracket using the CT-M11 cable, and see where that gets me.