Sunday, January 25, 2009

NEW antennas for 432 Mhz EME

New antennas for 70cm EME.

After finishing to rebuild my 4x16 antennas for 2m EME,
Foto 1: 2m EME set- up. 4X16 elem antennas by I0JXX and LNA preamplifier.

I started to build the UHF set-up in my veranta at 3rd floor of my house. I am using the same type of antennas as in 2m, by I0JXX, The antennas are 4x25 elements Horizontal polarization only, for 432Mhz EME. Each antenna is 5.50m long (7,94 λ), with total gain of 22,46 dbd (without the coax and connectors losses).

Foto 2: The UHF antennas are under the table for the moment.

I lost a lot of time due to bad weather .... we had a lot of rain the last days.
Today I finished the 3 of the 4 antennas . Maybe next days I will complete the 4x25 system and start to try some qso’s on UHF via the moon .

Foto 3: The 3 from the 4 antennas under the dark sky and the rain.

My power is only 100w with the Rfconcepts transistor linear amplifier. This linear has also a preamplifier NOT so good as nf but good for first time to start. I am starting to build a new preamplifier with the ATF-33143, low noise Pseudomorphic HEMT , transistor,
Foto 4: The antennas from the ground.

I am using the ECOFLEX 15 coaxial from antennas to splitter. Each piece of coaxial is 3.90m long. I hope until next weekend to finish the set-up and to start the tests in UHF, EME .
More news to come soon and hope to see you on 70cm via EME.
73, Spiros SV8CS

Sunday, January 18, 2009

VINTAGES - Old memories

The January 2009 QST magazine waked up my memories!
In this issue of the QST, (page 39), I saw a very nice article by Jim Hanlon (W8KGI) with the title: Resurrecting a Command Set Transmitter.
This article made me to remember my radio activity when I was 20 Years Old. In the year 1968 I found in the Athens flee market this type of transmitter, the Command BC-458 (5.3 to 7 MHz). This kind of transmitters was first made for Army Air Forces (the BC series) and the T series for Navy. The BC-458 (5.3 to 7 MHz is equivalent to T-21 (for Navy series). The Command transmitter had a pair of 1625s tubes in the final stage. The 1625s are the same with the very popular 807s (with 12v filament) and very easy to modify the filament voltage.

In this photo my self in 1970 with the command at left (ex call SV1CS).

At the same issue of QST there is also another article in page 73 about Command RX by Phil Salas, AD5X.
My BC-458 was modified (hardly) to make it operate not only in CW in the ham band (40m) but also with voice modulation (Carrier control) like a pseudo SSB and AM of course in 40m. In the 2 octal sockets in the rear side I added 2 tubes to produce the voice modulation. For the CW operation on 40m I was keying the cathodes of the 1625s. In the front panel of my Command I added a Mic Jack Using a crystal AIWA microphone) and a modulation potentiometer. All my qso, in the years between 1969 and 1974 in 40m, were made with this transmitter and for receiver I used a normal domestic radio receiver.

Photo in 1973.
Also I made a small linear amplifier with the 811 tube. To demodulate the SSB (the very early years of ssb) I was using another receiver and with its tuning I was beating the 455KCs local oscillator to produce a carrier to the main radio receiver and so make a BIT to demodulate the SSB of ham radio signals.
In the photo (1974) the command with "modern" receiver and a 2m tube transverter . The 2m TX driven by an old mofified (28Mhz) CB radio.The 2m RX is close to command.

a) After years, during a sort trip to USA in 1990, I was surprised to see my early toy inside an aircraft cockpit in a visit I paid to Smithsonian Institute, Washington DC
b) I bought my command as surplus in the year 1968, for 200 Drachmas (0.65 Euro).

My self today (18 Jan 2009) in a "post modern photo" . The command in front of the YAESU FT2000- Kenwood TS2000- Yaesu FT847 etc.

If you have any vintage rig don't forget to take part in the CQ-CX -Classic Exchange (CX) contest held twice a year. January 25/26 and February 15/16. Please read more at :

See you in the CQ-CX contest - 73 de SV8CS

Friday, January 9, 2009

ZD8B- 2m EME qsl card - New One

Ascension Island qsl card for 2m EME qso

Thank you Ernie for the second New One on 2m after the 1st qso with you from KC4/W1MRQ.
73, de SV8CS

Thursday, January 8, 2009

9M6YBG - East Malaysia 2m - EME

Received the qsl card from GO (9M6YBG) for our 2m EME qso.

Thank you GO for the nice qso and New one on 2m.
73 NHY de SV8CS