A great QSO in 15m with LU!

The past sunday I was amazed by a very fun QSO with Juan LU4VL in North Patagonia, Argentina. I was running about 2.5W with the 817 using a multiband up-and-outer antenna tuned with Elecraft T-1.
LU4VL report my signal 55, he was 59 on my side.

This morning I've received an e-QSL from a Brazilian SWL confirming the QSO. In his location I was 56.

Coaxial stub half-wave end-fed antenna for 10m band

I'm a true fan of end-fed antennas, and I've built one for 10 meters band.
The antenna itself is 5 meters long, and matching is obtained using lambda/4 coaxial stub. The matching method is the same used in J-Pole antennas: a lambda/4 * VF (velocity factor) transmission line shorted at the end.

I've used RG58 cable for matching line and 1mm PVC-covered copper wire.
The sketch below shows the building detalis:


The left side of coax is shorted; the right side is connected (only central conductor) to half wave wire (braid is not connected). At feeding point I've used a BNC T adapter to connect all together.

I use the antenna mounted vertical on a fishing pole and attached directly on the rear connector of my FT-817 (no cpunterpoise, no choke, no balun, no antenna tuner on 10m). SWR is acceptable (1.5 - 1.8 between 28.400 and 28.600).

Today in the morning I've got some nice QSOs. The most remarkable is Japan (Yeah!!!!)JA1NVF with 5W SSB! Not bad anyway, eh?

This antenna, tuned with my Elecraft T-1, is useful also on 12 and 15m. Build one for your preferred band, is an "instant" antenna, very cheap and simple to build. Of course, if you've a few meters of twinlead for build matching line, the performance may be better (modify lenghts....).

07-08-2014 UPDATE: Using this antenna I've many QSO with DX locations (Brazil, Argentina, Japan), and I won the 2013 CVA DX Award, see here.

SEM 52-S military handheld

Months ago, I've bought a german military handheld: a SEM 52-S. Specifications: see http://www.kpjung.de/e_sem52s.htm
Is an FM handheld with frequency coverage that includes 6 meters, 1 watt circa power out, very big and weighty, but so cool! 6 fixed channels programmable with internal contraves.




The radio is a SEM 52-S/FZ/46 and is not born as an handheld: is user on tanks with a mount, see http://www.greenradio.de/e_sem52sfz.htm, but is useable as handheld using a SEM 52-S battery pack (delivered with the transceiver).
I've also the antenna, a long (93 cm!!!) SEM 52A antenna, with fits perfectly in SEM 52S

• First Job: rebuid battery pack

The battery pack comes with a broken, unusable NiCd battery pack. The box is also very dirty and in bad conditions. I build a new battery pack using two docks for 4 AAA battery, and fit in 8x900 mAh NiMH AAA. The result is shown below:

• Second Job: arrange an alternative antenna

I have an original antenna, but is very long (93cm) and I want a smaller one for short-range contacts. I choose to modify a commercial item. I buoght an old 43 MHz whip antenna: 43 MHz is almost a dead band, and dealers are happy to sell one for a very discounted price. The antenna is a CTE model HP-FLEX/B.


The antenna is 54 cm long. Using the FT-817 as a tunig tool, I cut the antenna until a dip in SWR happens (I stop at 1.5:1). The antenna is now 36cm tall (from bottom of BNC connector to top of the whip. See the shorted antenna mounted on SEM 52-S


Next job: building a speaker-microphone (to do)

Yaesu SSB Filter XF-119SN for FT-817

I've bought an SSB filter for my FT-817. The filter is NO cheap at all, but I've found an used item for half price. Installing the filter is simple: open upper cover of FT-817, locate the two connectors on the low right side of the board and mount the filter.


The filter is enabled/disabled via main menu.
The results are very good: great improvement in RX, the selectivity is really much better. Suggestion for FT-817 owners that use mainly SSB: buy one, also on full price!

Simple window loop antenna

I've no way to set any antenna on the top of my building. This is the reason because I'm often in /P. But also at home I've some QSO using strange antennas. This is one of them: a window loop!

I've a window 158x140 cm pointing to east, with no other buildings in the way. A wire installed in the window perimeter is circa 1 wave lenght in 6 meters.


Anyway, the loop is not resonant on 6 meters: is not a perfect 1 lambda, the wire is too near to radiator etc., so I use this loop as an untuned loop, connecting a tuner in the low right corner of the window, as shown above:



Results: amazing! Hungary and Ukraine in 6m! I use this antenna also on 10, 12 with good results. On 15 meters the results are acceptable, but I've got very few QSO in 20 and 17 meters.

Next step: trasforming the untuned loop in a short magnetic loop for the 20 and 17 meters.

PL support for camera tripod

I've built a simple support for using HF and VHF mobile antenas with a camera tripod.

The base is made of plywood. The support for BNC connector and ground connection is a small steel "L" piece, wich may be found predrilled (fits also BNC!) in any hardware store.


The two wing nuts are for radials. Detail view:

12V 6800 mAh LiPo Battery

I've bought on e-bay a LIPO battery, 6800 mAh, from a Hong-Kong seller for few euros (a bit less than 35). After about three weeks, the battery arrives. Specifications:

• Weight 230g
• Measures: 56x106x18 mm
• Input (for charge) 12.6VDC
• Output: 12V 6800 mAh

The battery comes with a charger and have a little on-off switch and red led.


I've used often with FT-817 in /P, and also as a emergency supply source for handhelds. Great item!