Welcome to Tropical band

To most people the phrase "tropical bands" bring a pretty clear picture to mind - a bunch of shirtless guys playing calypso music. But to experienced shortwave DXers those two little words express the most challenging and enjoyable part of the radio hobby. The phrase kindles memories of a DXer's best catches and favorite QSLs, of exotic stations, music and of early morning listening sessions. (Don Moore)
I like the "Tropical band" name for new 60m allocation. (OK1RP)

Effective from 1st Jan 2017 please paper QSL via OM-bureau only.

Monday, January 9, 2012

W2PM Mini Diamond RX loop by OK1RP - part I.


as I am still looking for the receiving antenna which will allow me to improve the receiving performance on my pocket size QTH (250msq) I was very happy to get construction details and description of receiving loop with name Mini Diamond from Pete, W2PM. I have to say that Pete is real gentleman and he provided a lot of effort to help me with RX antennas. Pete helped me to understand how to build the very small loops effectively for 160m-60m band.

So after some time I decided to start with building the Mini Diamond loop and as Pete said I am making it as large as possible. All will be posted here step by step according to the progress of building. You will see used hardware, construction, mounting process, measurement and testing of the final product as same as the on-air results. If the antenna will not work then You will be able to check where I made the fault and learn from it to avoid Your own issues.

Today I will show You few pictures from building the main cross support.

bamboo tickness

I decided to use bamboo as the main cross support because all the other materials seemed to me worse. Fiber glass poles are too brittle, plastic poles used quite often as potatoes support on the garden are too heavy and short as same as wooden poles. On the picture You can see the used ticknes. The only problem was in the local store with finding few bamboo poles enough straight, hi.

Cross mounting support

As the mounting support I used universal plate from the local store. You can see a lot of holes in the plate...great as I did not need to make any hole just decide for right one with the screws.

loop cross

The cross support is already done waiting for mounting the last wooden part which will be screwed on the rotor unit. I hope that it will fit to the old rotor used for light UHF antennas...

transformed for loop 1

Finally You can see the box arrived by snail mail with non-inductive resistor and 900/50ohms transformer units all in nice water resistant plastic houses.

transformed for loop 2

If You are interesting in this RX Loop kit then be noted that they are available for loops, Beverages and also Ewe antennas in different versions like BNC, F connectors etc.

That is all for now and see You soon with some progress with building the loop.

73 - Petr, OK1RP

Sunday, January 8, 2012

60m band in CT - all licenses renewed for 6 months!

Hi all,

great news for all of us arrived from Jose, CT1EEB:

Good morning,
Just to let you know that Anacom is renewing all 60 meter band licenses for 6 months.
I have actually asked a one year renewal but the license is good until th3 30th of June 2012.
Same conditions as before:

5288,5 kHz
5371,5 kHz
5403,5 kHz

Modes: A1A and J3E

No power limit so we assume its the power authorized in our regular Ham licenses, for me is 1500 Watt, but really I never go over 100 Watt in 5 MHz.

A report as to be submitted to Anacom and the Army in the end of each period.
About activity, I'm not sure how many States I have for WAS but surely not all of them, I still find it difficult to work the 6 and 7 call area States. I give a try with Hawaii but no luck and never was able to contact that KL7 station that has been active.
For DXCC I have 46 DXCC entities at the moment, almost reaching the magic number of 50 and become one of the 50 plus club member, Hi!
73 Jose CT1EEB
The first station ever licensed for 60m in Portugal.

I am sending big congrats for all our friends in Portugal and also for great results on 60m band to Jose, CT1EEB!

Enjoy the 60m...

73 - Petr, OK1RP

Wednesday, January 4, 2012

Sunset-watchers on 5MHz - II. by Peter, G3PLX

Hi all,

there I am posting another interesting comment from Peter, G3PLX about the GL phenomenon. The original article I posted already here on the blog:



I have not done any study of greyline propagation so I cannot say much about it, but I am sure that there is nothing 'magic' about the exact local sunset time, since the path is not at ground-level but high in the sky. In the case of long distance paths, there will be a big effect of the D-layer absorption, and the D-layer is much lower than the F-layer so the D-layer sunset will be only about half an hour later than at the ground and not an hour or more as it is at the F-layer height.

But, as I said in my posting, that's not the whole story and there is no sudden 'best time' at sunset, even at D-layer sunset. The D-layer absorption is getting lower and lower, starting well before the sun sets and it doesn't reach the minimum absorption until some time after sunset, so it's not clear how the 'best greyline time' will relate to the exact sunset time. If your experience is that there is a peak in the signals, then that must mean that there is another effect which is making the signals weaker AFTER darkness comes, and the peak that you experience is the overlap between (or the gap between..) the two effects. For the higher bands it may be that this second effect is the F-layer MUF dropping through the band, but I don't think this
can be true for 160m dx, so I cannot guess the answer.

But for sure there is no good reason to set your clock too accurately!
Start listening well before sunset and keep listening until much later!

Peter, G3PLX

It will be very helpful to get some comments from another DXers regarding the SS/SR effect on the propagation specially on the LF and mainly over here on 60m band.
Do not hesitate to pot Your comment below or let me know by email I can post it on the blog to share with all of us.

73 - Petr, OK1RP

Tuesday, January 3, 2012

Winter edition of THE 5 MHz NEWSLETTER by Paul, G4MWO now on-line


The 2nd - Winter - Edition of The 5 MHz Newsletter has just been published and includes news and features about 5 MHz, including a chart of the current 5 MHz allocations worldwide.

You can freely access this latest edition of the 5 MHz Newsletter from Google Documents at

Although originating in the UK, the 5 MHz Newsletter invites world-wide interest, both in readers and contributors. Understandably all that we ask is when contributing items of news concerning new 5 MHz permissions or allocations, that the contributor can provide a means of official verification of such. Its size of course is dependent on news and other relevant contributions from 5 MHz operators and listeners around the world.

For those without Internet access wishing to have a paper copy of the 5 MHz Newsletter, a Self-Addressed Envelope (SAE) of sufficient size to take folded A4 sheets, together with adequate postage (or IRCs in the case of outside of the UK) will bring a copy of the latest edition. Requests should be addressed to the Editor, G4MWO, who is QTHR in the UK Callbook and on QRZ.com

Many Thanks and take care,

Paul, G4MWO

Sunday, January 1, 2012

KH6 - DXCC #27 on 60m

Hi all,

yes it is not joke! I worked Merv, K9FD/KH6 from his famous QTH on Malokai, Hawaii Isl. on 60m band...

I do not know if it is some distance record or not but definitely I will never forgot the morning when I worked him on the Tropical band. Excellent xmas gift for me although it was on 28Dec morning.

When I heard Merv from Malokai on LF bands I did not believed that it will be possible to work him also on 60m. I know that my Inverted dipole works well with apex 10m but I used just 100W legal limit and most issue on my side was reception of course.

So I decided to prepare a bit for the trial. The rotary Mini Diamond receiving loop, Mini Whip stick, Inverted V dipole w/apex 10m and 60m long BOG has been prepared for reception on the antenna switch connected to 5MHz band pass filter and connected to W7IUV high IMD preamplifier. The reception chain was then connected into the KD9SV front-end saver then directly to external RX input of the K3/Elecraft tcvr.

When I checked the VOACAP the prediction was really not optimistic.

The time for the QSO seemed to be the best around 06:00Z when Merv heard some EU on 60m band already which corresponded to VOACAP prediction.

The Solar info indicated the numbers which from my experiences does not help to us on 60m band so much so I though it will be just trial and we will have to wait for better days... unfortunately my permission was valid for last 3 days!

After some discussion with friends operating also on 60m we agreed that the major issue will be the rece
ption on my side but also the TX side must be as best as possible so I decided to check antenna for TX properly. I verified if balun connection is ok, connectors are tightened and if antennas is properly tuned in the band. Unfortunately the nite before we had short windstorm in our area and pipes supporting my Inverted V antenna bowed a bit. I had no chance to repair it so I had to be confident that all will work well in the morning.

Last check of the propagation and Ionosphere without comment...

I turned ON the radio about 10mins before the sked and I realized the band is not as noisy as it sounded nite before. Well I started to call for Merv on the 5260kHz but after few mins I realized on this frequency some carrier. It can make the reception issue for Merv so I decided to tune up a bit and started again on 5260.5kHz. For the first few mins I did not heard any sigs on 5403.5 so I did not believed that we can make the QSO. I tried to call K9FD/KH6 again and tried to switch between all of my RX antennas arranged. The Mini Diamond rotary RX loop was the best at this moment. Interesting was that the best reception and signal arriving from 360/0 deg direction.

In the noise I catch my call... Is it really Merv on the frequency? Unfortunately I did not catch any report so I tried to give a call again. I send the report for Merv and asked for report for me. In the next few mins I was amazed... I copied the report but I was not sure with the numbers. Gosh, I had to ask Merv again to be sure. Again I tried to concentrate for reception. Yes, the report is 559 definitely...559 for me from Malokai, Hawaii Isl.

The amazing QSO has been finished. I classified the signal from Merv S3 only on 5403.5 in my QTH with QSB but heard him for sure including my signal report 559 for my signal on 5260.5 frequency.

Yes, yes, yes... it is done. The distance over 12.000km on 60m band crossed over using just 100W output on my side. Also Merv used just
the Zepp antenna with an open feed line and the tuner. The same polarization of the antennas maybe helped too although the signal reflection is changing the polarization for sure.

K3 setting: dSP t3-1 / IF NAR3 / NTCH 900Hz / AGC OFF / PRE ON / Ant beamed to 360/0 deg. / FL3 / 2.3kHz used.

Thank You Merv, K9FD/KH6 for amazing morning on 28Dec11 and for giving me the new one #27 from very hard Oceania direction. Great operator, nice guy and excellent friend is Merv.

73 - Petr, OK1RP