On a linked system, the activity means the activity of that particular repeater being transmitted on.

A recent article on this topic, “Understanding regulations when designing a wireless product in the . . . → Read More: Understand the Unlicensed Services]]> We share several of our UHF bands with unlicensed services, and from time to time, you’ll encounter those signals on the bands. Another reason to be familiar with them is that there are companies that have their eyes on them.

A recent article on this topic, “Understanding regulations when designing a wireless product in the unlicensed frequency bands,” notes:

The wireless unlicensed frequency bands—especially the industrial, scientific, medical (ISM) bands—are the most appropriate for many new applications and products. They are part of the frequency spectrum that can be used without a license. However, products developed in these bands still are required to be compliant with rules defined by the country’s regulatory bodies before being deployed in the field. This article focuses on the technical design requirements and mandates for the US region.

Could be interesting reading.

On March 25, a group from AMSAT-DL bounced radio signals off the surface of Venus, marking the first time Amateur Radio operators have bounced radio signals off another planet. According to AMSAT-DL President Peter Guelzow, DB2OS, the Earth-Venus-Earth (EVE) transmission is another step in preparing for a mission to Mars. . . . → Read More: German AMSAT First To Bounce Signals Off Venus]]> From the April 3, 2009 ARRL Letter:

On March 25, a group from AMSAT-DL bounced radio signals off the surface of Venus, marking the first time Amateur Radio operators have bounced radio signals off another planet. According to AMSAT-DL President Peter Guelzow, DB2OS, the Earth-Venus-Earth (EVE) transmission is another step in preparing for a mission to Mars.

According to an AMSAT-DL press release, the team’s transmitter was generating about 6 kW CW on 2.4 GHz. Guelzow said that signals were sent from a ground control station at the IUZ Sternwarte observatory in Bochum: “After traveling almost 100 million kilometers and a round trip delay of about 5 minutes, they were clearly received as echoes from the surface of Venus. This was the first German success to receive echoes of other planets. In addition, this is the farthest distance crossed by radio amateurs, over 100 times further than echoes from the moon (EME reflections).”

The EVE experiment was repeated on March 26 for several hours with “good echoes” from Venus, Guelzow said. “Morse code was used to transmit the well-known ‘HI’ signature known from the AMSAT OSCAR satellites.”

For receiving the EVE reflections, Guelzow said that the team used a fast Fourier transform (FFT) analysis with an integration time of 5 minutes. “After integrating for 2 minutes only, the reflected signals were clearly visible in the display,” he said. “Despite the bad weather, signals from Venus could be detected from 1038 UTC on until the planet reached the local horizon.”

Guelzow explained that with the EVE reflections, the high power amplifier “has therefore passed this crucial test as a final key component for the planned P5-A Mars mission. By receiving generated echoes from Venus, the ground and command station for the Mars probe has been cleared for operational use and the AMSAT-DL team is now gearing up for building the P5-A space probe. AMSAT-DL wants to show that low-budget interplanetary exploration is possible with its approach.”

Development, design and construction of this first German Mars mission have been achieved by AMSAT-DL and its partner organizations, Guelzow explained. “Already a third of the total project costs were performed. More work shall follow during the mission. AMSAT-DL would like to demonstrate that their approaches to low-cost space missions are feasible.”  

Information provided by AMSAT-DL. Pictures of the equipment used can be found on the AMSAT DL website.

yesterday’s Space Station contact from the Ann Arbor Hands-On Museum was a success. Despite the low orbit . . . → Read More: Space Station QSO a Success]]> Thanks to Ig, N0EFT, and his crew:

• Tim, WA8VTD, back up radio operator;
• Steve, KB9UPS, ARISS mentor and antenna and az/el rotor operator;
• Olivia, KC8VGH, who handled the microphone and kids; and
• Candy. KD8IPC, who made the initial contact and helped with the kids;

yesterday’s Space Station contact from the Ann Arbor Hands-On Museum was a success. Despite the low orbit (21 degrees), the contact lasted nearly nine minutes and they were able to ask 14 questions.

I hope to post video later, but in the meantime, here are a couple of news stories:

• Ann Arbor Chronicle: To Infinity and Beyond: Ann Arbor talks to an astronaut on the International Space Station. This article is the better of the two. It includes a paragraph or two on our station at the museum.
• Kids at Ann Arbor Hands-On Museum talk by radio with astronaut on International Space Station. This story has a little more technical detail on the QSO, but fails to mention our museum station.

I got to thinking about how we might use it. The first thing to cross my mind was digital TV. Other . . . → Read More: 900 MHz??]]> Someone recently offered to give our club a 900 MHz repeater. 900 MHz?? Who uses that band Well, apparently, there is a lot of activity up there, and maybe the least of it amateur activity.

I got to thinking about how we might use it. The first thing to cross my mind was digital TV. Other kinds of digital apps, such as some kind of instant messaging, might also be interesting.

Here are some resources:

• Exploring 900 MHz by KB9MWR. Some good basic information on the band and equipment you can use there.
• AR902MHz Yahoo Groups Mailing List. This list has more than 1,400 subscribers and is relatively active.
• San Diego 900 MHz ARC. General info on 900 MHz as well as specific info on what’s going on around San Diego.
• GEMoto.Com. This is a networking group made up of mostly New England hams interested in converting and using GE and Motorola commercial radios. According to Ben, N1WBV, there’s a fair amount of 900 MHz activity around Boston because their use of 440 MHz is fairly restricted.

Will a CB SWR meter work on a 2 meter ham radio??

Mark, K5LXP, replied:

Yes and no.

I use a CB SWR meter to check 2M antennas all the time. There is a trick to it however.

If all you want to to is check SWR on your 2M antenna, you . . . → Read More: No VHF SWR Meter? No Problem.]]> On the HamRadioHelpGroup mailing list, a ham asked:

Will a CB SWR meter work on a 2 meter ham radio??

Mark, K5LXP, replied:

Yes and no.

I use a CB SWR meter to check 2M antennas all the time. There is a trick to it however.

If all you want to to is check SWR on your 2M antenna, you don’t necessarily have to buy a dedicated VHF/UHF SWR meter. What I keep in my toolbag for that is a cheapie $5 hamfest special CB SWR meter. They really don’t work well on 2M but there’s a trick you can do that will net a reasonably accurate SWR reading on 2M with one of these meters. What you do is connect up the meter as usual, key the rig with the switch in the forward power position, set the adjustment for full scale. Now, without touching anything, swap the coax connections so that the rig is connected to the “ANT” side of the meter, and the antenna is connected to the “XCVR” side. The reading you see on the meter will be very close to your real SWR. The closer to 1:1 your SWR is, the more accurate it will be. It would be more convenient to have a real SWR meter or antenna analyzer if you do a lot of testing, but for a quick antenna check after a mobile install or whatever, the $5 CB meters work OK.

When I asked his permission to use this, Mark said, “I don’t get the credit, I picked it up from some OF years ago.” (E-mail me if you don’t know what an OF is.) Well, Mark, you might not get the credit for thinking this up, but you certainly get the credit for passing it on. Thanks!