FreeDV Mobile

[Mark Jessop]

Hi all,

Tomorrow, myself and 2 other hams are embarking upon a roadtrip from
Adelaide to Canberra, in Australia. On the way, we will have HF mobile
capability with a Codan NGT SRx + 9350 mobile whip.
Today, I made up an interface to connect my Signalink USB to the NGT.

What I'm hoping, is that we can find some people to work FreeDV with
while mobile. I'm not aware of anyone operating FreeDV mobile yet, so
this may be a first :-)

We will be on the road from approx 6:30AM-8:30PM CDT (+9.5), on both
Friday and Sunday. We should have internet access, so I should be on the
#freedv IRC channel on Freenode with the nickname 'Darkside', and I'll
also try and use the QSO finder (http://qso.k7ve.org/).

Does anyone have any idea when the band opens from Australia to the US?
Would be awesome to have a contact with someone at Dayton :-)

73s
Mark Jessop VK5QI

[Mark Jessop]

We've just successfuly had a FreeDV QSO while mobile, with VK5AKH and
VK2MEV, with David VK5DGR listening on the side. I recorded a shaky-cam
video, which I'll see if I can process a bit and upload once I'm back home.

For those in Australia, we're currently sitting on 7175 LSB, also shown
on the QSO finder (http://qso.k7ve.org/).

73s
Mark VK5QI/M/VK2

[Tony Langdon]

On 19/05/13 8:49 AM, Mark Jessop wrote:
> We've just successfuly had a FreeDV QSO while mobile, with VK5AKH and
> VK2MEV, with David VK5DGR listening on the side. I recorded a
> shaky-cam video, which I'll see if I can process a bit and upload once
> I'm back home.
>
> For those in Australia, we're currently sitting on 7175 LSB, also
> shown on the QSO finder (http://qso.k7ve.org/).

Cool, good work. :) I'm currently off air, due to a recent house move.
Have to work out where to to put the antennas.

--
73 de Tony VK3JED
http://vkradio.com

[Michael Carey]

Excellent,

Just woke up! (up 1/3 of the night with a sick child).

At home 7175 is smack on a HUGE S9 electronic buzz, give me the quiet
80's any day when it comes to HF!

Michael.
VK5ZEA

[VK2JI - Ed Durrant]

Well Done Mark!

Can you say whether copy was more difficult than analogue SSB mobile or better?  (I hope the latter).

Been out portable chasing Summits under the SOTA competition today, just a bit further down the band around 7.090 but didn't have my PC with me so wouldn't have been able to decode in any case.

73  Ed VK2JI.

[Mark Jessop]

Here's the video we took on the road:
http://www.youtube.com/watch?v=1-fgr-tkboQ&feature=youtu.be

I'd say the lack of extra background noise made FreeDV a bit better than normal SSB, as we already had a lot of background noise from being on the road!

The transmit audio equalization made a pretty big impact. Andy VK5AKH was using some DX-grade voice compression gear, which made his voice very punchy and readable, while Brenton, VK2MEV, had a quite bassy microphone, which didn't reproduce well on the laptop speakers (not in the video).

Cheers,
Mark VK5QI

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[Stuart Longland]

On 20/05/13 18:50, Mark Jessop wrote:
> Here's the video we took on the road:
> http://www.youtube.com/watch?v=1-fgr-tkboQ&feature=youtu.be
>
> I'd say the lack of extra background noise made FreeDV a bit better than
> normal SSB, as we already had a lot of background noise from being on
> the road!

That video is impressive. I see I'll have to get cracking with that
Raspberry Pi and interface to the FT-857D on the bicycle.
--
Stuart Longland (aka Redhatter, VK4MSL)

I haven't lost my mind...
...it's backed up on a tape somewhere.

[David Rowe]

I'm interested in bicycle HF as well. Was thinking of a quid pole or
fishing rod for a light weight mast. Maybe running FreeDV on an Android
phone with a SDR radio.

- David

[Tony Langdon]

On 24/05/13 9:15 AM, David Rowe wrote:
> I'm interested in bicycle HF as well. Was thinking of a quid pole or
> fishing rod for a light weight mast. Maybe running FreeDV on an Android
> phone with a SDR radio.

Antennas are a big issues. Whips have the issue of needing a suitable
ground/counterpoise, which is hard to obtain on a bike. A small
magnetic loop is an option that one amateur is using with success down
here on a custom built tricycle.

I'm currently capable of running VHF/UHF on my bike with a bicycle
mounted antenna, haven't made any plans for HF yet (first, I need a
suitable radio! :) ).

[Bruce Perens]

Magnetic loop bicycle... Did you read about the stored power in high-Q antennas? Thank goodness for the skin effect.

Sent from my Android phone with K-9 Mail. Please excuse my brevity.

[Stuart Longland]

I've done it with a couple of sections of brass tubing as the stinger,
and 100 turns of speakerwire onto a 36mm PVC pipe as an autotransformer
for tuning.

Some signal reports I've received (using SSB):

58 to Caragabal, NSW on 3.590MHz at 100W
59+20dB to Newcastle, NSW on 7.060MHz at 60W
59 to New Zealand on 20m at 100W
47 to Adelaide, SA on 21.185MHz at 100W

I've been heard as far away as the Cook Islands on 14.183MHz.

http://stuartl.longlandclan.yi.org/blog/2011/04/17/vk4mslbm-new-hf-antenna/

The photos there are quite dated. The green bag has a 40Ah LiFePO₄
battery pack which weighed 8kg. That plus the FT-897D was quite a load,
a little too much for that basket. I now run a FT-857D, a 10Ah LiFePO₄,
and the radio itself lives in a motorcycle topbox.

The station also moves between one of two bikes ... that one, and a 29"
mountain bike. The one pictured there is the one I'm on most
frequently, and I've had the longest (with some 10000 km on the odometer
by now after 3 years).

My biggest problem, particularly with lower bands, is RF feedback
getting into the microphone. This was the problem I had en route to
BARCFest this year, and why I ran at 60W that day calling in on the
Coral Coast net.

I think the RF feedback can be overcome by various means, such as
running the audio from the headset back via USB audio... I'll have to
give this some thought.

The biggest challenge will be user interface, as I can't be looking at a
screen -- it'll have to be something that can be tuned by ear ideally.

Regards,

[Tony Langdon]

On 24/05/13 11:32 AM, Stuart Longland wrote:
> I've done it with a couple of sections of brass tubing as the stinger,
> and 100 turns of speakerwire onto a 36mm PVC pipe as an autotransformer
> for tuning.
>
> Some signal reports I've received (using SSB):
>
> 58 to Caragabal, NSW on 3.590MHz at 100W
> 59+20dB to Newcastle, NSW on 7.060MHz at 60W
> 59 to New Zealand on 20m at 100W
> 47 to Adelaide, SA on 21.185MHz at 100W
>
> I've been heard as far away as the Cook Islands on 14.183MHz.
>
> http://stuartl.longlandclan.yi.org/blog/2011/04/17/vk4mslbm-new-hf-antenna/

Nice, looks good. :)