The ZL1SIX Ocean Floater

For those of you that are fans of the low-powered "party balloon" floaters, such as the recent S-9 flight by VE3KCL, now comes a different kind of floater and one that really does float ... on the Pacific Ocean!





The "Ocean Floater" is the work of Bob, ZL1RS, who has been very active in tracking the other floaters from his excellent receiving site down-under. Like the balloons, Bob's beacon also utilizes the QRP Labs U3S hardware to transmit data in both WSPR and JT9 modes. The little beacon runs ~100mw on the 30m WSPR band and tracking this one will likely be a bit more challenging than following the high-flying balloons.

Bob's 'Ocean Floater courtesy: http://www.qsl.net/zl1rs/oceanfloater.html

Here is Bob's description as he posted to Yahoo Groups QRP Labs:

A small project inspired by Hans' Voyager ideas at
http://www.hanssummers.com/voyager.html ... the Floater is a 100mW
transmitter on the 30m band with a short base-loaded whip antenna
mounted on a buoy that will drift in the Pacific Ocean. It is sending a
standard WSPR transmission once and hour, followed by two JT9
transmissions giving its position, the temperature, and the battery voltage.

The project was deliberately kept very simple. A QRP-Labs U3S
transmitter and firmware made the electronics side easy. The U3S was
rebuilt on a board with a more open layout to allow experimentation and
the addition of a PICAXE controller to switch things on/off as required
to reduce overall battery consumption. Most of the "hard work" was in
the buoy body and antenna. More information about how this went
together can be found at http://www.qsl.net/zl1rs/oceanfloater.html

Today the Floater left on the yacht Windflower to be released into the
south-west Pacific Ocean in a few days time. This will ensure the
Floater is well clear of the coastal currents around ZL that would
otherwise have 'beached' it along the coast if it been launched from the
shore. Unlike balloon flights, things will happen very very slowly, so
updates to the webpage and tracking map will probably only be made on a
daily basis. WSPRnet spots will show the 4 character Maidenhead
locator position, and the JT9 decodes have a 6 character Maidenhead
resolution. Any JT9 decodes you receive will be appreciated via e-mail
to zl1rs@yahoo.com

73, Bob ZL1RS

The beacon will use the call "ZL1SIX" and will be launched shortly, near Minerva Reef. Watch Bob's website for tracking and updates and ... good luck Bob!

IC-7300 LF / MF Receive Performance

 

courtesy: Icom's youtube

Ever since the LF and MF bands have become a reality for European amateurs, Finbar, EIØCF in Ireland, has been actively involved on both bands, providing UK and continental hams a somewhat 'exotic' LF DX target.

Finbar recently had the opportunity to borrow and test-drive a spanking new Icom IC-7300. Like many of those interested in the LF / MF bands, he was particularly curious about its receiving performance in this part of the spectrum. His present mainstay LF receiver is the Icom R-75, which by any standard, is an excellent performer on the broadcast band and below.

Here are Finbar's anecdotal observations made with a borrowed IC-7300:

" ... my nearest radio amateur friend really surprised
me yesterday by telling me he had bought the new Icom 7300 SDR
transceiver. He offered me a quick loan to try it out. I drove the 9 km
straight away and getting home set it up side by side with my Icom R75.

3 hours later I returned it to it's owner having gained a valuable
chance to test it.

First off, he forgot to give me the instruction manual, but after a
short interval I had it sorted out, having seen the numerous videos, on line.

I disabled the MW attenuation and made sure not to have the Pre-amps
on, otherwise, within the medium wave band, it becomes very messy,
as one would expect.

Basically my R75 produced sharper, more sensitivity in the NDB band,
with some signals on the Icom 7300 being very weak to unreadable,
whereas the Icom R75 gave a much more solid signal, on those very weak
signals.

I did not test the rig on short wave, nor did I transmit or even key
it up, in any mode. I was much more interested in it's apparent receive
capabilities.

I will not be buying an Icom 7300, my Icom R75 is just fine and a
great receiver.

Don't get me wrong, the 7300 is a fine set, but as I see it, it
is the first of this new generation of non PC based SDR sets, and very welcome, at that. However the screen is just too small and crowded. Anyone used to a Perseus screen would be irritated by the sheer volume of screen and sub screen, all of which deserve a proper amount of space.

The subsequent new SDR based transceivers by both Icom and other
set makers, will I expect, contain a larger screen, together with an
ability to feed the video screen into to a PC type monitor, yet
allowing the user to use an SDR type transceiver or receiver without being tied down to a PC.

I look forward to these more comprehensive sets coming on the market.
This is just the beginning of a new phase in receiver and transceiver
SDR technology, integrated in the sets without a lumbering PC having to be
run alongside. This will be a breath of fresh air. Bring it on."

Although I don't believe this is the first non-PC based SDR transceiver, it may be the first 'entry-level' radio of this type. These are one ham's observations made over a short period with one particular unit and your experiences may be much different.

Finbar would be very interested in comments on his observations as well as comments on your own experience with the IC-7300's receiver on the LF bands.

The R-75, although now discontinued, still remains one of the best performing LF receivers, dollar-for-dollar, if you're still looking.

Icom R-75

As well, from my own experience, I can vouch for the superb receive performance of the Icom 756 PRO III on the LF and MF bands.

courtesy: http://www.icomcanada.com

Bureau QSL Batch

The batch of bureau cards last week included several cards from Europe and were probably the last I'll get for my Cycle 24 10m fun, using the homebrew Tri-Tet-Ten.


As mentioned previously, this rig was the culmination of wondering, for many many years, if I could get a single 6L6 to work well enough on 10m CW, using a 40m crystal ... quadrupling to 10m ... and still have enough useful output to work Europe! As well, the note would have to be 'acceptable' as I realized that any crystal chirping would be multiplied four times, during the quadrupling process.

The evolution of my eventual transmitter, is described in more detail here, where you can also hear what the tone sounds like. Suffice to say, the results were much more than I had ever hoped for and during the peak years of this past cycle, many enjoyable hours were spent on 10m CW with my one tube tri-tet crystal oscillator.

I guess I could always move down to 20m CW but, for me, this just doesn't have the same appeal or sense of satisfaction as using it on 10m or what I like to call, "the other magic band". Who knows what Cycle 25 will bring to 10m? I may get another chance yet, if the solar prognosticators are all wrong!

QSL Bounty

The postwoman was very kind to me last week, leaving five QSL's in two days, as well as a package of cards from the QSL bureau. It rather evoked memories of anxiously watching for the Saturday morning postman (do you remember when they actually delivered mail to your door on Saturday's!) as an 11 year old SWL, hoping that there might be another QSL for my attic radio shack wall.

Four of the cards were for recent 2m EME contacts ...

 ... and one was for 160m, confirming a winter CW QSO with Haiti, bringing my 160m DXCC total to 158 confirmed.

I have always loved QSL's, and looking back, the whole concept of collecting these small treasures was one of the things that initially attracted me to the radio world, when reading a magazine article about shortwave listening and collecting QSL's. I'm not so sure I love the QSL bureau though, but that's a whole other topic ...

The Joys Of ERP

Amateurs and and U.S. experimental licence holders operating on the LF and MF bands, are limited in the amount of power they are legally able to run. Unlike the HF bands, where maximum power limits are expressed in either DC power input or PEP output, LF and MF operators are required to observe ERP or EIRP limitations. Canadians operating on 2200m are limited to 1W EIRP and to 5W EIRP on 630m.

Although this doesn't sound like much, mustering this amount of effective power can be quite a task on either band, especially on 2200m. This is due to the very poor efficiencies encountered when using antennas that are so small in size compared with what would be considered 'normal'. For example, a typical 1/4 wave vertical used on 40m is about 33' high and with a good radial system can achieve efficiencies in the 80% range, while the equivalent antenna for 2200m would be 550m or about 1800' high ... a little large for most suburban backyards!

The equivalent of a normal 2m 'rubber-ducky' antenna when built for 2200m would be over 600' tall, while one designed for 630m would be around 170' high! A 2" stub used on your 2m hand-held would be the same as a 56' vertical on 630m. Consequently, most LF / MF backyard antennas will realize efficiencies of less than 1% and likely, quite a bit less.

In order to reach the maximum radiated power levels allowed usually requires several hundreds of watts, especially on 2200m, where near kilowatt levels are needed. These small radiated power levels might seem discouraging but they don't account for radio's great equalizer ... propagation. More than anything else, RF loves to radiate, and at times, what can be achieved on these bands with such low effective radiated powers is stunning

It would seem that Industry Canada did us no favors when they stipulated LF / MF power levels to be measured in EIRP and not the, much easier to calculate, DC power input level ... or perhaps they did. I think that, unlike on HF, imposing EIRP rather than DC input power limits puts everyone on an even playing field. Amateurs with lots of real estate and room for a larger, more efficient LF antenna, will be required to run much less power to reach the allowable EIRP and 'stay legal', compared to someone with a small backyard in the suburbs ... the latter can legally generate the higher level of DC input power required to reach the EIRP limits since their smaller antenna is operating at less efficiency. However, determining EIRP is not as cut and dried as measuring input power.

With some fairly sophisticated (ie. expensive) field strength measuring equipment, not typically found in amateur radio operations, ERP / EIRP can be readily determined. This means that for most amateurs,  alternate methods must be used.

Neil, WØYSE in Vancouver, Washington, who runs an experimental 630m station under the call of WG2XSV, has produced an excellent treatise on calculating your station's EIRP level, providing a step-by-step procedure to follow.

In order to determine your ERP / EIRP, you must first determine your antenna's radiation resistance. Two methods of calculating the antenna's radiation resistance for both verticals and top-loaded verticals (inverted L's or T's) are demonstrated, using the physical size of the antenna in relation to the frequency of operation. Once this value is known, the antenna current is measured while transmitting. These two values allow the Total Radiated Power (TRP) to be calculated. The TRP is then multiplied by 3 to yield the EIRP or by 1.82 for ERP. Roughly speaking, 5W EIRP is the equivalent of 3W ERP. Thanks to Neil for this helpful resource.

An alternate method of roughly determining ERP / EIRP values is an interesting new online 'antenna simulator' at the 472kHz.org site. Using known physical sizes along with your ground quality description, the calculator will indicate what total power output is required to produce various levels of ERP and EIRP as well as expected antenna currents, at 472kHz. It's a good starting point if you are either planning a new antenna system or perhaps, repurposing an HF antenna such as an 80m inverted-L or an HF center-fed dipole for use on 630m.

Neil has also sent the following comments that will be of interest to those planning a sloping-wire tophat:

Hi Steve,

I just read ur article about the Joys of ERP and EIRP. I am always glad to see those blogs about the LF and MF bands. They help get people interested in the new bands.

Thanks for mentioning my treatise on Rr, ERP, and EIRP. On that page is a link to an Excel spreadsheet that I developed to make the calculations easy. You can see it here.

However, it assumes that the top wires are horizontal. If the top wires are slanting downward, as when they double as the upper part of guying lines, then we have to modify the data we enter in order to get closer to what a NEC antenna modeling program would tell us.

Here is what I learned recently from Jim, W5EST (in one of his recent articles on the 630m daily report on John Langridge's blog site). If the top hat wires slant downward, then we need to subtract 1/2 of the downward component of the hat from the vertical section of the antenna due to partial cancellation of the radiation of the vertical section. Similarly, since the wires slant, their horizontal reach is less, so we must add up all the horizontal components of the top wires and enter that as the top load data.

Here is an example from my own antenna system: My antenna is 40 feet tall. My three top loading wires drop 18 feet and they extend out from the vertical 17 feet. So my effective height (for this SS) is 40 - 1/2(18) = 31 feet. Then the horizontal number for my top load is 3 times 17 feet = 51 feet. I have attached a copy of the SS for you with this data entered into it.

Some of Jim's articles are being copied onto a developmental site here. Scroll down the left side to TRANSMIT ANTENNAS. There are 7 articles there by him and some others as well. Eventually (soon maybe ?) they will be moved over to "630m.net".

There are also a number of online calculators, such as found here, that will indicate your ERP / EIRP value when you plug in your antenna's 'gain' figure along with your TPO value. Some of the better antenna modelling programs can produce estimates of your antenna 'gain' at 630m and from there it is a simple matter of calculating what power is needed to reach the legal level.

I'm sure there will be a lot more information and discussion about this topic once the LF and MF bands are released in the U.S.A. but in the meantime, calculating your ERP / EIRP levels is not as hard as it might initially seem ... and is likely accurate enough for most agencies overseeing amateur radio activities.