Propnet 30m weekend

For once a non contest activity !

This weekend I participated to the propNet 30m weekend, a 30m propagation study. For more details on the propNet project, you may follow this link or this one

Here is a first summary of the weekend activity. More to follow...

Another vertical for 30, 40, 80 (and 160)

Following is a description of the multiband vertical antenna that I am using for several months.

Description in english

Une verticale pour 30,40 et 80m

Ca faisait quelques temps que ce blog n 'avait pas été mis à jour ! Désolé...
Voici, pour me rattaper une description de l'antenne verticale bande basse que j'utilise depuis quelques mois.
Article en Français

CN5W - Dar Bouazza Contest Group

The contest stories, pictures, stats and more are on
http://cn5w.blogspot.com/

The CN2WW 80m wire-beam

After testing the concept last year in the ARRL-DX from home (see http://f6irf.blogspot.com/2006/02/low-cost-2-elements-for-40m.html ) I designed a new antenna, especialy for the ARRL-DX from CN2WW. The terrasse dimensions, limiting us to 8m spacing, I used a director rather than the classical reflector. The drawing shows the 2 beams (40 and 80) using the same supports. Obviously with a such a reduced spacing (0.1 wl), the antenna cannot be designed for z=50 while giving satisfactory performances, but using a UNUN provides a perfect and broadband match, with very low losses (The steppIR uses the same type of broadband matching device). The multi-UNUN based on a W2FMI design and commercialized by CWSbytemark ( http://www.cwsbytemark.com/ ) offers an easy and flexible solution. A second unit allowed the 40 beam to be designed for max gain, with impedance around 36 ohms. The only difference is that the 40m UNUN was placed after a 1/2wl of cable, and not directly at the feed point ( the 40m dipole being on a fiber mast). The following graphs show the performances of the 80m aerial.


The bandwith was the main concern, but as shown by the graphs most of CW-contest band is usable with SWR below 2. Although I have full confidence in computer simulation, the results obtained with this aerial during the ARRL-DX really surprised me. see http://lists.contesting.com/archives//html/3830/2007-02/msg01551.html ). I believe that on top o f the 3.5dBd gain its main quality has been to protect us from the heavy EU-QRM.
View of the aerials installed at CN2WW, the fiber mast supports the 40m dipole and the 80m director while the tower supports the 40m reflector and the 80m dipole.
As information the dimensions provided by the computer model are the following one: For 8m spacing and a center angle of 120 degrees, the half-dipole is 21.18m and the half-director 20.6m. But of course the dimension may vary, fonction of the height, the angle, the environment, the wire used (i.e. plastic coated wire has a velocity factor in the order of 0.95), so it is strongly recommended to adjust the dipole alone first below the desired frequency (removing the director on the computer model gives 3.465 for jX=0) Then place the director and cut it until the desired frequency is obtained (3.532 for jX=0 ). I think that it is the best way to get the aerial working as expected.
Computer models (MMANA or NEC2) can be provided on request.

F6IRF 100,000 QSO's in 5years

Today I have uploaded the 100,000 QSO, since march 2002 to LOTW. Those include QSO's done with F6IRF, F6IRF/P, TM6A, IS0/F6IRF, FG/F6IRF, UT/F6IRF/P and CN2WW callsigns.
DM6DL is the 100,000, and wins a CN2WW Tshirt :-)

IC7000 review

The good the bad and the ugly !
Recently bought this TRX for travelling around for contests and to replace my 706 which did not have the adequate CW/RTTY filtering for contesting...
Weight= 2.3kgs, was also one of my motivations, taking into account the new limitations for hand-carried cabine luggage!

Tried this weekend in CQWW-160 and REF-test

THE GOOD
- Being familiar with the 706, it did not take long to get familiar with it... a few things have changed, but the user interface philosphy, remains moreless the same.
The display is really bright and contrasted and does not require that I put my glasses on...
For a CW-contester RX DSP-Filtering is really the strong point of this transceiver, together with the usual ICOM strong points (I am also owner of 756pro2). The "strong signal" resistance is not as good as my pro2, but sure better than the 706 (ie on 706 the preamp was unusable on 20m and the attenuator often required on 40)
A few have reported temperature problems... did not see this even during long sterile auto-CQ sequences with 3s RX-time. The temp indicator always remained in the blue zone (Had even tried 4 hours of the same regime at full CW-power on a dummy load B4 the contest - no problem...). Haven't tried yet in TTY... will see!

THE BAD
- Do not like the RIT/XIT on the coaxial pot... even more unusable than the 706 RIT (why not the main dial when selecting RIT like in the Yaesu FT857D. It Would be far more convenient !). Of course it is possible to use the split, but there is always a risk to move the TX freq, especialy when using auto-CQ from your contest software.
- A pity that the local-monitoring (CW-sidetone and SSB-monitor) is not available from the fixed-level audio output on the ACC connector (if you record your pile-up through this line, you won't have your own signal !)
- The RF-power output is a bit "limited": From 95W on 160 down to 80W on 10m and 75W on 6m (but will check this again with a professional wattmeter). Not a problem when using a modern tetrode PA or an SSPA, but a bit just for entering LP-category (especialy in those contests for which LP is 150w

THE UGLY
- The long spotted "audio white noise" is really annoying with a normal headphone without pots. It becomes acceptable with audio-pot around 11h, so will make an external attenuator / low-pass filter for the next contest, but it is a pity that Icom did not fix this pbm, despite all user-complaints (maybe for the PRO version!?). Maybe another solution is to use a vintage low sensitivty/limited bandwidth headphone.

SUGGESTIONS FOR THE PRO VERSION
- Improvement of the a/m BAD and UGLY features
- Why not make the second SO-239 connector (dedicated to VHF/UHF) usable for a second HF antenna and/or a RX antenna (it sure would be appreciated by 160m freaks !). It could be done from the main setup menu (disabling VHF/UHF, if required)
Of course this is a CW-contester/DXpeditionner point of view which may not be relevant if your main use is as mobile-rig... Despite the few a/m problems it is definitely a good choice for a small TRX, so I give it 4/5.

Regards and 73's

Patrick
F6IRF/CN2WW

F6IRF in CQ ham-radio (JA)

Thanks to Hisami 7L4IOU for sending me the October 2006 issue of the Japanese magazine CQ-ham radio.

F6IRF/P: A bit of traffic from South Britanny

Stew Perry Topband Challenge
Call: F6IRF/P
Operator(s): F6IRF
Station: F6IRF/P
Class: Single Op LP
QTH: IN87
Operating Time (hrs): 8
Total: QSOs = 112
Total Score = 1,416
IC756pro2 -100W
inverted-L on 2x 12m fiber masts

One of the 12m mast used to support the 160m inverted-L

Part-time effort, just to enjoy the low-noise level of my secondary QRA on a band which is usualy forbidden for me due to the HT-line hi-noise level at my main location. Quite a few DX stations heard, but none logged...
Une participation en diletante, juste pour apprécier le calme radio-electrique du QRA secondaire, sur une bande qui m'est habituelement "interdite" en raison,du fort bruit de fond généré par la ligne 380kV qui jouxte le QRA principal. Pas mal de stations DX entendues, mais aucune contactée...Les condx ne semblaient pas terribles, aucune station W/VE dans le log, alorsque j'en ai assez facilement contacté qqs unes pendant la semaine...Stn: IC756 et antenne L-inverse sur 2 mats en fibre de 12m. (pas de radians...juste le grillage entourant le QRA en guise de contrepoids...)QTH: Arzon, dpt-56 (au bout de la presqu'ile de Rhuys, entre golfe et ocean...)

Above, the mast, also supporting a 30m dipole, and here the R7 antenna

I have been active all week, mostly on 160, 30 and 17m both in CW and digital modes...
CN2DX on 160m, recorded fm F6IRF/P (CW and SSB)

Phasing / Unphasing 2 yagis - Solution and benefits

Having 2 yagis at home for SO2R-contesting, I quickly realized that it was sometimes very useful to use the 2 antennas on the same band. For example, during summer, the 20m band is still open to Asia, simultaneously with North-America. Having one antenna in each direction, just switching from one to the other, was the obvious first step. Then logicaly, the idea came to feed them both... I first used a "UnUn" to match the antennas fed in parallel, but this solution although working fine was lacking flexibilty. I then decided to buy a "stackmatch" allowing to use one or the other, or the 2... Using this device, I quickly realized, that the phase relashionship between the 2 antennas was essential, and that the antennas being not identical and not in the same plane I had to be able to play on the phase relationship between the antennas. I then looked for some commercial solution or description, but could not find any(*); I then decided to quickly build something, and try it...


(click on diagram to enlarge it)The F6IRF antenna monoband phasing device: It just requires 3x2RT switches. Phase delays are obtained using 3 lenghts of coax cables 1/8wl (45degrees) 1/4(90degrees) and 1/2 (180degrees). Combining the 3 allows 0 to 315 degrees variation by 45 degrees steps. The device is inserted in one of the antenna line, after the stackmatch. I have used 5D-FB foam coax cable, and high-current switches (losses and impedance mismatch are neglectable and it was tested at 1KW without problem...)



The phasing device in service, during the 2006 CQWWDX-contest from CN2WW (SOSB20m).
From Morroco, it is a big advantage to keep one antenna toward EU, while playing with the second one, to get mults in exotic directions, or to boost the EU rate, with the second one toward states...

Potential applications and benefits

First example: The 2 antennas at 12m are in the same plane pointing at the same desired direction and spaced horizontaly by 0.8wl (my home setup to JA). As shown by the following examples, varying the phase allow some direction adjustment, which is quite useful as the horizontal pattern is quite narrow (even with the simple 2elements used for the simulation - just imagine with 2x 5 elements).

Click on images to enlarge them. Here, the 2 antennas are at 12m agl, in the same plane, perpendicular to the desired direction, spaced by 0.8wl and fed in phase (I.E. identical antennas with equal lengths of coax cable). In red is the pattern of 1 antenna, in black the pattern of the stack. The gain of the stack is 3dB compaired to a single antenna, but the pattern becomes quite narrow.


Left: the antennas are fed with 90degrees relationship (in red the pattern of a single antenna as reference). Right: The antennas are fed with 180 degrees relationship, the pattern becomes bidirectionnal, with a nul in the main direction (in blue the pattern of the antennas in phase, in red a single antenna). By varying the phase, it is therefore pssoible to adjust the pattern to any value between +/-30degrees compaired to the perpendicular axis of the antennas.

Second example: the 2 antennas are not in the same plane, and one antenna is turned by 45 degrees...


right: The pattern of each antenna fed separatly. To be noted, the backlobe of each antenna is distorted by the presence of the other one.


Left: one antenna phased out by 45degrees, the result (in black) is almost a virtual antenna pointing between the 2. Center: the phase relation is 225degrees, the bidirectionnal pattern is almost restored. Right: the phase relation is now 315 degrees, the bidirectionnal feature remains but with a substantial advantage for one of the antenna.

Third example: Here the 2 antennas are pointing at 90 degrees directions; you may think that the phase relation is less important in this case... it is, but still, it is not completly useless to play on the phase...


center: the 2 antennas are fed in phase, the expected bidirectionnal pattern is here, but with some distorsion (in red the pattern of a single antenna)The 3dB loss is normal taking into account that each antenna is fed with half of the power. Right: In black the 2 antennas are fed with 180 degrees phase relationship (in red, the antennas in phase, in blue a single antenna as reference).

Fourth example: Like in example 2, the 2 antennas are looking at 45 degrees directions, but it is the second antenna that has been turned (as shown in picture below).


Left: the patern of each antenna fed separatly. Right: the patterns obtained when phasing the 2 antennas with 0, 90, 180 and 270 degrees phase relationship.


Comments : This system was built-up for 20m band, however, it is also usable on 15 and 10 (with 90 degrees step on 10 and something in between on 15). It is also usable on 40 but then the phase limit is 315/2=157.5 degrees. Of course it is possible to add lines and switches if you are interested by multiband capability, but the spacing of the antennas will have to be somehow "compromised", especialy if you are looking for "extra gain"(as shown in example 1). All simulations have been done using MMANA203 by JE3HHT and can be verified using NEC2 engine for MMANA by UA3AVR (allows MMANA antenna files to be converted to NEC2 files).

Does it work ?: The answer is yes ! just moving one switch maybe sufficient to get a station out of the noise and QRM, and this has been verified in several contests....
(*) To be accurate Array-solutions commercializes a "180degrees-unphaser" which allows high angle radiation for verticaly stacked yagis.


Above my home setup used in 2005 in more than 30 contests (a 2elts steppIR and an OB6-3M). Here the setup used at CN2WW for the CQWW-CW 2006 (SOSB20 - 3 elts SteppIR and 3elts spiderbeam) .

The maa and nec files are available here
http://mangafight.free.fr/2x2elts%20maa%20and%20nec.zip

Une version Française est disponible ici en pdf
http://mangafight.free.fr/Phaser.pdf