Altus Metrum altimeters tested at Airfest

[keithp]

Bdale and I tested a pile of stuff at Airfest last weekend.

I wrote up a report on my blog:

• https://keithp.com/blogs/Airfest-altimeter-testing/

In brief:

TeleMega looks great! We're working to have this for sale by the end of October:

• https://altusmetrum.org/TeleMega/

TeleMetrum version 2 is working, but GPS reception isn't what we want. Bdale has a pile of new RF testing gear which should help sort this out:

• https://altusmetrum.org/TeleMetrum/

TeleMini v2 needs more firmware work, but the basic hardware is running well:

• https://altusmetrum.org/TeleMini/

EasyMini v1 saw a bunch more flights and we're going to hand-assemble a small batch in the next few weeks to see how many people want them:

• https://altusmetrum.org/EasyMini/

TeleGPS has the same GPS reception issues as TeleMetrum, and the firmware isn't quite finished:

• https://altusmetrum.org/TeleGPS/

 

[troj]

It was great fun out at the Away RSO on Sunday, with the entire Altus Metrum gang! Really cool to see AJ and Mike both get their Level 3, too!

-Kevin

 

[CarVac]

Exciting work!

That TeleGPS is incredibly small, the new TeleMini looks easier to use thanks to the USB interface, and the EasyMini looks splendid.

And the MegaMetrum looks to be the new all-in-one solution: truly safe staging in one reasonably sized package.

 

[BEC]

Neat stuff, Keith. Maybe that tiny GPS device will be ready by the time the Estes F15-0s and their PSII booster come out. I'm itchin' to fly a two-stage F to F model and may well need the GPS to find it, even at the Pasco sod farm....

 

[jpummil]

Bdale and I tested a pile of stuff at Airfest last weekend.

I wrote up a report on my blog:

• https://keithp.com/blogs/Airfest-altimeter-testing/

In brief:

TeleMega looks great! We're working to have this for sale by the end of October:

• https://altusmetrum.org/TeleMega/

TeleMetrum version 2 is working, but GPS reception isn't what we want. Bdale has a pile of new RF testing gear which should help sort this out:

• https://altusmetrum.org/TeleMetrum/

TeleMini v2 needs more firmware work, but the basic hardware is running well:

• https://altusmetrum.org/TeleMini/

EasyMini v1 saw a bunch more flights and we're going to hand-assemble a small batch in the next few weeks to see how many people want them:

• https://altusmetrum.org/EasyMini/

TeleGPS has the same GPS reception issues as TeleMetrum, and the firmware isn't quite finished:

• https://altusmetrum.org/TeleGPS/

So much cool stuff....I definitely have an application for the EasyMini (29mm min diameter stuff).

As I progress, I'd like to look into the more advanced stuff ;-)

Wish I'd met you guys at AIRFest...despite being there two days, it seems like I missed as many people as I met.

 

[keithp]

That TeleGPS is incredibly small

Well, one of the theories about the poor GPS RF performance is that the board is too small, so it may get a bit wider if that's what we need to make the GPS reception solid...

The new TeleMini looks easier to use thanks to the USB interface, and the EasyMini looks splendid. And the TeleMega looks to be the new all-in-one solution: truly safe staging in one reasonably sized package.

Thanks! We got a bunch of feedback about the original TeleMini, which was definitely optimized for size more than functionality. Adding a beeper, USB connection and real screw terminals for battery and switch should make it a whole lot easier to use.

 

[keithp]

Wish I'd met you guys at AIRFest...despite being there two days, it seems like I missed as many people as I met.

Even though it seemed quieter than last year, it was still a big launch with lots of people.

 

[maxvelocity]

Consider one EasyMini sold...

 

[llickteig1]

Even though it seemed quieter than last year, it was still a big launch with lots of people.

... This ...

BTW, while at AIRFest, look for Bdale, Keith, and others in the Altus Metrum entourage at the D & M Concessions booth ... mmm ... corn ...

--Lance.

 

[Viperfixr]

Even more cool altimeters making my decisions harder all the time! For the TeleMetrum & TeleMini, will the price points be similar to the existing versions?

 

[keithp]

For the TeleMetrum & TeleMini, will the price points be similar to the existing versions?

Yup, that's the plan.

 

[CarVac]

Yup, that's the plan.

How about the EasyMini?

 

[keithp]

How about the EasyMini?

We need to get a firm quote for assembling the boards before we can set the price. We're working to get that information for all of the new products as quickly as possible.

 

[UhClem]

Well, one of the theories about the poor GPS RF performance is that the board is too small, so it may get a bit wider if that's what we need to make the GPS reception solid...

It appears that the antenna used has specifications which assume that it is mounted on a 50mmX50mm ground plane.(Although the vendor is happy to provide custom parts for different sizes of ground planes. If you pay them extra of course.) Since that isn't present, then it isn't going to do well. Detuning of the antenna and poor VSWR are to be expected.

The mounting holes are very close so the mounting hardware will also impact reception. There could be other problems with the PCB but the pcb file in the git repository is wildly different from the product photo so I can't comment.

 

[cerving]

Have you tried one of the helical antennas such as this one by Sarantel? They're active, and they don't require a ground plane. More expensive, of course...

 

[keithp]

Have you tried one of the helical antennas such as this one by Sarantel? They're active, and they don't require a ground plane. More expensive, of course...

The helical ones are both expensive, and also very fragile. We've used amplified patches from Taoglas on past products with good results, but we've had to hand epoxy those onto the boards, which is a huge pain. The goal is to get good reception with a passive patch - inexpensive, and robust. TeleMega shows that it's possible, given the right board geometry.

 

[keithp]

the pcb file in the git repository is wildly different from the product photo so I can't comment.

The current prototype was built from the 'minimal' branch. And, yes, we're well aware of the requirements from the patch manufacturer. Bdale just replaced his vna, so we should be able to analyze the boards and figure out how to make them work.

 

[zortness]

Good stuff!

What about adding a u.FL connector for an external active antenna? It would seem like an uphill battle trying to enlarge the ground plane on a layout that small.

 

[keithp]

What about adding a u.FL connector for an external active antenna?

TeleMetrum v1 shipped with active antennas, and they work great -- almost as good as the uBlox Max 7 on TeleMega. However, we were never happy with how they mounted, and they're quite a bit more expensive than the passive ones.