Six meters mobile does work ...

... when propagation helps!

That's the case of yesterday 27/5/2008 with a super ES opening when I could work HA3UU (JN96), 9A3GI (JN95), HA807PL (JN97), YT1VP (JN94) between 1630 and 1700UTC.

I could also hear SV and I7 stations. All those I could hear were working DL and G as well: there were several ES clouds.

This morning I greeted IW1FZV and IZ1ERV in a local QSO, since the band was closed.

The mobile shack - inside.

The mobile shack - outside

PS: all these mobile contacts were done in SSB with 5W.

Operating QRP mobile on 6m

The 2008 sporadic-E Spring season has started, so did I with home>office and office>home 6m QRP mobile activities.

The first attempt was on Friday, May 23 between 1500 and 1545 UTC, on the way back home throughout the banlieue of Torino.

The setup consists of:

• FT817, 5W, SSB
  
• homebrew earphone-microphone adapter
• modified CB antenna to 6m

On 6m a 1m long antenna has a minimal loss compared to a full 1/4lambda vertical. A urban environment does not help, though! The adapter includes up/down tuning buttons, as in the original 817 microphone, and a switch to use an external voice keyer for automatic CQ.

I checked the DX cluster before getting in the car, and there were no spots to/from my area, but the band was open indeed: always try a scan through the (beacon) band before giving up!

A few observations.

• Even last year I had noticed that calling CQ when QRP mobile is not a successful way to achieve some contacts. Search&pounce has proven to be more effective with my setup when the band is open and stations are calling CQ.

• VOX operation is cool, but noise in the car can turn into pain (open windows, horn, ...): better add a flip PTT switch, so your hands are free except when you have to change TX/RX. Moreover I suffer from some kind of VOX apnea...
  

• Paper logging the contact is awfully dangerous especially in the city traffic if you are both the driver and the operator. I do prefer to record the audio with an MP3 player/recorder and then fill in the log, but this requires the audio to be broadcasted in the cabin, so VOX disabled.
  

This June/July 2008 look for me on 6m between 545z and 630z and after 1530z!

Magmount base, cable attenuation

Once I've seen the lossy look of the RG58 coax cable, I did a quick loss measurement with the MFJ-259:

MHz	dB
10	0.6
50	0.8
145	1.4

Given a cable length of 5 meters (I think), this is not the best performing RG58 ever.

Magmount base, one more fix

New problem on the new magmount base: the PL-259 connector.

Moving the coax cable right at the plug sent SWR from 1:1 to infinite. This is a sign either of a short or a broken connection.

Heated the soldering iron and found out two things:

1. it was a short caused by erroneous (criminal?) coax preparation
   
2. the crimp-on section for the coax braid was loose and I could pull the coax out with no effort

I re-peeled the coax and replaced the PL-259. Now it works.

Morale: if you care about your finals, check the plug assembling quality on your new magmount base!

Now I wonder how bulky the pseudo RG58 coax is! Will do some measurements soon.

The SW30+ is here!

23/04 to 02/05: 9 days including a weekend, a national holiday and a stop by the customs. That is how long it took the small packet to come.

I had to pay extra 13 EURO as import duties and postal service theftcosts.

The PCB is really compact. I could fit 4 SW RTXes into the one I had chosen, or all accessories: battery, antenna, key, log.

Building will begin shortly.

First mod will be a better polarity reversal protection, in place of the 1N4001 D13 diode. I will instead use a fuse and a surge-suppressor diode.

Additions to my SW30+

This is a brainstorming reminder, so that I won't forget to add useful modules to my SW30+, when it arrives.

• improved polarity reversal protection (bypass D13)
  
• keyer, using SKC and an additional 78L05
• integrated LED frequency counter (with on/off switch)
  
• integrated LED SWR bridge
  
• integrated antenna tuner (z-match or L-network?)
• output power pot
• vernier reduction tuning pot
  
• trail-friendly box

So, on the front/top panel there will be:

• tuning pot
• RF gain control
• keyer button
• SWR LED
• counter's LED and switch
• power switch

And on the back panel:

• antenna BNC connector
  
• power plug

Location TBD:

• key, probably on the LHS
  
• headphones, probably on the RHS

I keep on dreaming...

Small Wonder Labs SW-30+ - shipped!

According to the "shipping status" page, it started its journey on 23rd April, 2008.

Keeping my fingers crossed...

A (great?) weightsaver for SOTA excursions

I am test driving an SGH-i780 smartphone that weights about 120 grams. It has:

• mobile phone
• internet surfing abilities
  
• embedded GPS
• photocamera 2Mpx
  
• videocamera 320x240
  

The operating system allows running all sorts of applications, including HAM related ones.

In 120g you have at least two devices you would probably carry along: the photocamera (say 150g for ultracompact year 2008 models) and the GPS receiver (that's 100g for my Geko201). You might or might not want to film your activation, that accounts for 400g or more. A light mobile phone is around 90g. Some crazy SOTAers have carried laptops with them, that is at least 1kg... Let's try a comparative table:

Tool	Weight (g)	Weight gain (g)	Cost (EURO)	Saving (EURO)
Mobile phone	90	Assuming i780	30	Assuming i780
GPS	90	with second	130	Costs 400 EURO
Camera	150	battery is 160g.	100
Videocamera	400		160
TOTAL w/o laptop	730	570	420	20
Laptop	1000		300
TOTAL	1730	1570	720	320

As of mid April 2008, this smartphone seems to be both a weight and a cost saver for technologically sick SOTA activators.

Drawbacks found so far:

• it has a non-standard connector for audio in/out, so it cannot be easily used for digital modes with PocketDigi
• the battery does not last very long, and Samsung sells the device with a second battery
  

Let's see how it performs next Sunday if WX allows for an excursion.