- AMSAT-BB - mailman.amsat.org

Dual band cavity filter?
by Robert Bruninga 22 Jul '20

22 Jul '20

Many of us use dual band radios but when operating on mountains or hills we need a front end cavity filter. The DCI dual band helical filter is ideal but I just learned it is $530! I'm starting to visualize a cavity filter made out of a piece of aluminum drain pipe. With a capacitive screw at the top for tuning VHF and a smaller one about 1/3rd the way up for UHF. My theory is that the lower UHF capacitance will be at a UHF high-Z point and will tune the UHF nicely and the one at the top will tune the VHF nicely. Of course with very much interaction. Unfortunately for our annual Golden Packet Event, the 3rd harmonic of our APRS VHF operating frequency is at 432 and our use of APRS UHF talking freq at 445.925 is quite away away. Maybe if such a single cavity design could work, we could use the event's UHF voice coordination frequency closer to the 3rd harmonic to make the filter easier or possible to tune dual band (Though we night then also Desense voice with every packet). I want it to buildable from Home Depot and common tools. Wont be as good as the $530 DCI filter, but maybe close enough for our event. It wont be robust and it wont be quality, but might work for us AND amsat dual band operators in the field. my big assumption is that a 1/4 wave cavity filter will also work on its 3rd harmonic? We only need to knock down QRM to prevent desense. Anyone have cheaper than $530 solutions? Bob

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"Walking and chewing gun at the same time"
by Michael Tondee 22 Jul '20

22 Jul '20

So now the line is that an HEO or a GEO, besides being expensive to launch, will be difficult and expensive for the average ham to acquire the equipment for so we should just forget about it? Is that what I'm reading? The hams I once knew, never backed down from a technical challenge. By all accounts it wasn't exactly "easy" to build an AO-40 station but a whole bunch of hams managed to get it done. There was a time when generating and receiving an SSTV signal was an enormously involved process but somehow the early innovators in the field got it done. Now it's one of the more simple and inexpensive things to do. Hams have always overcome technical challenges. It's what we do, or we used to do it anyway. Correct me if I'm wrong but AMSAT used to be able to walk and chew gum at the same time. We had AO-40 and a myriad of other sats with varying degrees of challenge to working them. I don't think anyone is saying that we should just abandon the so called "easy sat" concept. Far from it. If that's what you enjoy, then more power to you but there is a large number of people out here that want something more than that. We enjoy the challenge. It's what drew us to this side of the hobby in the first place. Why can't we do both? We used to do that back when I was an enthusiastic member of this organization and I think it can be done again. I wouldn't still be here on this list hoping and praying for a change in it's direction and a return to it's former glory and status if I didn't. 73, Michael W4HIJ

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"Walking and chewing gun at the same time"
by Joe Leikhim 22 Jul '20

22 Jul '20

YUP, WHAT HE SAID RIGHT THERE BELOW: "So now the line is that an HEO or a GEO, besides being expensive to launch, will be difficult and expensive for the average ham to acquire the equipment for so we should just forget about it? Is that what I'm reading? The hams I once knew, never backed down from a technical challenge. By all accounts it wasn't exactly "easy" to build an AO-40 station but a whole bunch of hams managed to get it done. There was a time when generating and receiving an SSTV signal was an enormously involved process but somehow the early innovators in the field got it done. Now it's one of the more simple and inexpensive things to do. Hams have always overcome technical challenges. It's what we do, or we used to do it anyway. Correct me if I'm wrong but AMSAT used to be able to walk and chew gum at the same time. We had AO-40 and a myriad of other sats with varying degrees of challenge to working them. I don't think anyone is saying that we should just abandon the so called "easy sat" concept. Far from it. If that's what you enjoy, then more power to you but there is a large number of people out here that want something more than that. We enjoy the challenge. It's what drew us to this side of the hobby in the first place. Why can't we do both? We used to do that back when I was an enthusiastic member of this organization and I think it can be done again. I wouldn't still be here on this list hoping and praying for a change in it's direction and a return to it's former glory and status if I didn't. 73, Michael W4HIJ" -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida JLeikhim(a)Leikhim.com 407-982-0446 WWW.LEIKHIM.COM

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Is This AMSAT's Future?
by Joe Leikhim 22 Jul '20

22 Jul '20

Why not? QO-100 is a success. The antennas for up link and downlink for such a station are easily made or procured. The LNB a simple decades old modification. The stations would be friendly to HOA and apartment dwellers alike. I dont see the objection. "These new projects - seems like they are “marketed” towards a very small segment os satellite operators. Is there truly a worthwhile “return on investment" when a ground station might have to include … “ … radio system is a 10 GHz downlink that will support 1 Mbps. You'll need a 10 GHz antenna that can be steered to track a LEO satellite and probably a low-noise block downconverter (LNB) feeding an SDR. I think similar receivers are used for QO-100, so a Google search may yield some designs that are currently working, although QO-100 is nearly stationary … “ Feels like a very few hams will partake … Exciting, indeed. But surely not geared to the masses … Clint Bradford K6LCS" -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida JLeikhim(a)Leikhim.com 407-982-0446 WWW.LEIKHIM.COM

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Upgrade of equipment
by Russ Kinner 22 Jul '20

22 Jul '20

When I first got my license, 2 meters was the highest freq. typically used, 440 was an experimenters band and anything above that was AT&T Microwave links for phone and network video. It took a few years but now you can buy 1.2 GHz gear from several sources. The experimenters area becomes common to all in a few years. I At my radio beginning, there were no PCs, mobile radios were crystal controlled mostly, and you bought a keypad to generate telephone tone pairs to use a repeater auto-patch and wired it in yourself. Things change to meet the demand and it won't take long to have microwave gear and antennas easily available. Just takes a demand that a HEO or better satellite in orbit generates. It's one of the reasons AO-92 has L/v mode. I welcome the change. Rusty, WA8ZID

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LVB Tracker vs. Yeasu GS-232B
by Robert MacHale 22 Jul '20

22 Jul '20

What is the status of the LVB Tracker - I notice it was once promoted by AmSat, but is currently out of stock. The Yeasu GS-232B feels a little over priced at $589. What is the current recommendation for connecting the Yeasu G-5500 to tracking software? [1] For reference, AmSat: https://www.amsat.org/product/lvb-tracker-complete/ [2] For reference, HRO: https://www.hamradio.com/detail.cfm?pid=H0-002778 73 Robert MacHale . KE6BLR Ham Radio License . http://www.aprsat.com/predict . http://www.spaceCommunicator.club . Supporting Boy Scout Merit Badges in Radio, Robotics, and Space Exploration Silly Joke: What did the little mountain say to the bigger mountain? Hi Cliff! He who dares not offend cannot be honest. -- Thomas Paine

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Is This AMSAT's Future?
by Clint Bradford 22 Jul '20

22 Jul '20

These new projects - seems like they are “marketed” towards a very small segment os satellite operators. Is there truly a worthwhile “return on investment" when a ground station might have to include … “ … radio system is a 10 GHz downlink that will support 1 Mbps. You'll need a 10 GHz antenna that can be steered to track a LEO satellite and probably a low-noise block downconverter (LNB) feeding an SDR. I think similar receivers are used for QO-100, so a Google search may yield some designs that are currently working, although QO-100 is nearly stationary … “ Feels like a very few hams will partake … Exciting, indeed. But surely not geared to the masses … Clint Bradford K6LCS

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Re: [amsat-bb] Is This AMSAT's Future?
by Clint Bradford 22 Jul '20

22 Jul '20

>> This could very well be. Tech changes over time. IMHO, Hams need to change over time to keep the hobby viable. That required station is quite a jump from enjoying LEOs - and getting involved in satellite communications for well under $200, though. Clint Bradford K6LCS - Still having clubs approach me for info on “Getting Started … “ (g)

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Open Source Thruster (was: Elections HEO QO-100' Linear NB + Digital WB)
by Daniel Schultz 22 Jul '20

22 Jul '20

I've been going to Electric Propulsion conferences for over a decade now, and I always had a sneaking suspicion that I could build one of those things in my garage, but then common sense takes over when I remind myself how long it would take me to accomplish that. It looks like he is way ahead of me in getting a vacuum system up and running. One thing the twitter feed does not mention, where is Applied Ion located? An open source electric thruster is a very key element in returning AMSAT to HEO. Is there anything we can do to help him along? Dan Schultz N8FGV ------ Original Message ------ >As it happens, Applied Ion is reporting partial success with a thruster >design today: https://twitter.com/Applied_Ion >His cost per thruster is much closer to Zach's $100. Two thrusters of a >previous design of his are scheduled to fly on the AMSAT-EA Genesis >satellites, NET September. These are Open Source designs.

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Re: [amsat-bb] My Ballot arrived - now what?
by Clint Bradford 21 Jul '20

21 Jul '20

They’ll never do it. Clint Bradford K6LCS > On Jul 21, 2020, at 7:36 PM, amsat-bb-request(a)amsat.org wrote: > > I challenge each candidate to address the issue and detail a plan to > deal with it.

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