RADIO HABANA CUBA
DXERS UNLIMITED
WEEKEND EDITION
SATURDAY, AUGUST 11, 2001
By Arnie Coro CO2KKSend your comments, questions and ideas to: arnie@radiohc.org
Hi, amigos radio-aficionados around the world! Your radio receiver is tuned to Radio Havana Cuba, the name of the show is Dxers Unlimited, and for the next seventeen and a half minutes you will be able to pick up the latest High Frequency bands propagation update and forecast, tips about new and rare DX stations that will be operating on the amateur bands, our technical topics section reviewing yet another ultra-simple amateur radio rig that uses just one integrated circuit and one transistor to provide 5 watts output, and we will answer questions sent in by Dxers Unlimited's listeners in our popular YOU HAVE QUESTIONS and Arnie answers them...
That's a panoramic view of our menu for today, and if you notice noisy and difficult short wave reception, blame it on a high speed solar wind gust that is hitting the Earth's magnetosphere since a few hours ago.
I am Arnie Coro, radio amateur CO2KK, your friend here in Havana and host of this twice-weekly show, entirely, absolutely devoted to our wonderful hobby... yours and mine... RADIO!
Margarita Delgado long-time RHC veteran audio engineer is at the controls of Studio 7's mixer board, and YES, she is looking at the stopwatch, too... Stay right on this same frequency, I'll be back in just a few seconds...
Short wave reception Saturday, Sunday and possibly Monday too, is not going to be very good, due to a disturbance caused by a high-speed solar wind gust that came from a solar coronal hole... The 60, 49 and 41 tropical and international broadcast bands are going to be noisy, and the same holds for the 80, 40 and 30 meters amateur bands... Solar activity is now going down again, after the number of sunspots during this solar rotation reached a peak about one week ago.
Amigos, amateur radio need not be an expensive hobby at all... of course, you can dry up your bank account buying a sophisticated ready-made ham station, but as I have said here many times, then you are losing about three-quarters of the enjoyment. Sure, and I do recommend it, it's nice to have a factory-built simple, no-frills, amateur band transceiver; a second handset in good shape is more than enough, but what's really enjoyable is to homebrew your radios, my friends...
And each and every day I come across very clever circuits designed by radio amateurs that are simple to build and yet pretty effective... The most recent example is a one integrated circuit and one output power transistor rig that has a very low parts count, and provides between 3 and 5 watts of clean output power on the 160, 80, 40, 30 and if you use a faster integrated circuit, the rig will also work on the ever popular DX band, 20 meters!!!
This little transmitter uses a quartz crystal to control the frequency of operation, and is powered from a single 12 to 14 volts DC power source, which feeds the output transistor, and through a simple 5 volt zener diode regulator, it feeds the single SN7400N integrated circuit that is the rig's crystal controlled oscillator. So, the little, simple, rig is just an IC crystal oscillator feeding an NPN output transistor. The output transistor's tuned circuit is a very simple LC or inductance, capacitance tank circuit, and the antenna is coupled via a link coil wound to match the feedline's impedance, three to four turns will usually do it!
Amazing as this may sound to you, the 5 watt QRP or low power amateur rig uses only 2 resistors, 2 electrolytic capacitors, a disk ceramic capacitor, a variable capacitor and a trimmer capacitor, the homebrew coil and, of course, the two active devices, that is the integrated circuit and the output transistor... My parts count shows just eleven components in the original circuit, but later I added three more parts, an emitter resistor for protection of the output transistor, and two 0.1 microfarads disk ceramic decoupling capacitors.
The rig has so far allowed me to work stations at distances of more than two thousand miles when propagation conditions were good... Using a portable SONY ICF7600 receiver that has a built-in BFO, the little 5 watt low component count transmitter completes a portable station that is hard to beat for simplicity!!! I am still writing the text of an article about the 5 watt low parts count rig soon to be posted at our Dxers Unlimited website, but in the meantime, if you want just to take a look at the circuit diagram, just drop me an e-mail to arnie@radiohc.org, and I'll send you the small .GIF file with the circuit diagram...
And also, if you want to start looking for the integrated circuit, it is a type SN7400N, a very popular device by all standards... again, my version of the 5 watt low parts count uses just a 7400 IC andan RF power output transistor...plus 9 or 11 other electronic components. You can build yours in a couple of hours for a fun weekend project, or you can spend more time assembling the rig into a nice little cabinet, including an antenna switch and enough space for a rechargeable nickel cadmium or metal hydride battery.
NOW, you see my point at the beginning of the show, amigos! Amateur radio need not be an expensive hobby, and this is a good example... just a portable receiver with a BFO for picking up CW and SSB, the eleven or 13 components transmitter, a 12 volt rechargeable battery, an antenna and YOU ARE ON THE AIR!!!!
Again, it you want to browse at the circuit diagram, send me an e-mail to arnie@radiohc.org, and I will send you a small .GIF file with the simple transmitter circuit diagram.... If you are not connected to the INTERNET, just send me an AIR MAIL postcard and Irma Veitia, of our correspondence department english section, will send the diagram to you, and maybe by the time your AIRMAIL postcard reaches Havana, the text file with the full description of the rig will be ready and she will then include it, too...
Yes amigos, this is the weekend edition of your favorite, listener-oriented, radio hobby program, Dxers Unlimited, which now continues with tips about new and rare, hard-to-find DX stations.... ready to copy.... you can also tape the show and then transcribe from the recording...
So, here we go with a list of some nice amateur DX stations that have announced recently that they will be active on the different amateur bands:
8R - Look for Esmond, 8R1AK to be active during the International Lighthouse & Lightship Weekend from Georgetown Lighthouse in Guyana(to be assigned GUY-001). QSL via CBA. [TNX VA3RJ]Well amigos, I hope that you have enjoyed listening to this list of nice DX stations that are now active or are going to be activated in the near future. For those of you who are not yet the happy owners of an amateur radio station license, you can monitor the amateur bands with your receivers and try to pick up the Dx stations, and if you do hear them, send a signal report and QSL request to the DX station, because most amateur radio opertors do QSL back to Short Wave Listeners for one very solid and good reason... Practically all of us, today's amateur radio enthusiasts, started as SHORT WAVE LISTENERS, and we all want more SWL's to become ham radio operators...A5 - Robert, S53R reports he will be going back to Pakistan on 16 Augustand after a few days he will move to Bhutan, where he plans to be active (mostly on CW) in his free time as either A52RK or A52KR.This should happen just after 20 August for about 7 days, when he will return to AP. QSL via S53R.
BY - Terry, BD7NQ and other operators from the Chinese province of Guangdong will operate as BI7D from Do-Ao Island (NO-REF, claimed for AS-131) between 7 UTC on 17 August and 2 UTC on the 19th. They will operate (CW, SSB, RTTY, PSK31, Satellite) on 80m-70cm with three HF stations and one VHF/UHF station. QSL via BD7NI (P.O.Box306, Guangzhou, 510030, China). [TNX BD7NQ]
C6 - Al, K3TKJ plans to operate (requested call C6TKJ) from Andros Island (NA-001), Bahamas between 13 August and 27 September. [TNXThe Daily DX]
C9 - Reinhard, DL6DQW (C91RF) will be active (SSB and CW) from Quirimba Island (AF-061), Mozambique on 19-23 September. QSL via home call (Reinhard Fendler, Waldteichstrasse 34, 01468 Boxdorf, Germany). [TNX DE0MST]
EI - A group of operators from the Wicklow Wireless Society will activate the Lighthouse at the Old Head of Kinsale (IRE-055) during the International Lighthouse & Lightship Weekend. QSL via EI9HQ.[TNX EI9HQ]
F - Francis, F6HKS and Jean-Claude, F6HDH will participate in the International Lighthouse & Lightship Weekend (18-19 August) from the lighthouse (WLH 0271, ARLHS FRA-007) on Cordouan Island (EU-159, DIFM AT-032). They will be active as homecall/p on 20-40metres SSB and CW. QSl via home calls. [TNX OPDX Bulletin]
KH3 - Dan, KH6UW will lead a group of four operators including Mike/AL7KC, Bob/W7TSQ and Tom/K7ZZ to Johnston Atoll (OC-023) on 11-18 September. The group will be using K3J on 10-160 metres, WARC bands included, SSB and CW. Two and possibly three stations will be used and European contacts will be emphasized when band openings permit. QSL via AH6HN. [TNX KH6UW and K7ZZ]
KL - Bruce, KD6WW confirms his activity from the Shumagin Islands (NA-087) [425DXN 517]. Look for him to operate as KL6/KD6WW from Popof Island on 18-20 August. QSL to KD6WW either direct or through the bureau (bureau card requests welcome at kd6ww@inreach.com).
NOW, don't forget that those very rare spots DX expeditions do ask for international reply coupons and self-addressed envelopes to be included with your QSL request, so don't forget to find out the exact QSL pathway to each DX station, and then do exactly as they request in order to receive your QSL card... I have a nice collection of SWL QSL cards obtained following this standard practice, and in some of them, the DX expedition operators have included some nice comments about how much they appreciated SWL reports!!!
Now amigos here is YOU HAVE QUESTIONS and Arnie answers them... this one from a listener in the state of Virginia, USA: Amigo, you are right!!! Regulating the filament voltage of vacuum tubes will prolong their life a lot... something essential when you are dealing with antique sets using rare and very hard to find tubes, Another good idea is to include a step start system during power-up... I use here a 100 ohm sandbar resistor that is shorted out after about 30 seconds, enough time to reduce the power-up surge current to an insignificant value.
And now here is, as always at the end of the show, Arnie Coro's Dxers Unlimited's HF plus 6 meters propagation update and forecast: Geomagnetic disturbance likely to be in progress by the time you are listening to this program; the A index, the geomagnetic disturbance indicator at high latitudes may reach storm levels, and the lower frequency bands will be noisy... There are good chances of 6 meter band openings that usually show a high degree of correlation with the geomagnetic field disturbances. Solar flux was 160 units on Saturday and was moving down, the effective sunspot number Saturday was 115 and the number of sunspots very near 120...
Best band for amateur radio DXing will be 15 meters, closely followed by 17 meters... Short wave listeners will have nice reception during daylight hours on 13 and 16 meters...
See you at the mid week edition of Dxers Unlimited amigos, and don't forget to send me your signal reports and comments to arnie@radiohc.org via e-mail or to Arnie Coro Radio Havana Cuba, Havana, Cuba via AIR MAIL, a postcard report will be fine!!!
Arnie Coro CO2KK
Havana, Cuba
August 11, 2001Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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