As mentioned in my previous post, I'm planning on working on my repeater/link setup. I made it to the hardware/home improvement stores yesterday to pick up the rest of what I need for the caveties. Before I get started on all this, I'd like to see if I can coherently restate the goals of this project:
My apartment is not constructed in a way that I can reliably get a signal out in the directions I need/want them to go. The manamgement of the complex expressly forbids the use of external antennas in the apartment lease, and due to the contruction of the building, even getting a coax outside is next to impossible so a stealth antenna is also out of the question.
1. I would like to be able to use more than one of the local 2 meter repeaters. It would be nice if I could hit those in some of the surrounding counties as well.
2. In order to achive goal number 1, some sort of remotely controlled setup will be required. Some sort of a wireless link between my apartment and another more radio friendly structure. This link will have to handle an audio uplink/downlink with the VHF radio, and a method of changing channels as well as general system control.
3. Within my apartment, the control for this link must be portable and useable from any room.
These will be the base that I will work from. In furtherance of these goals, I have already purchased, bartered or built the following items:
(3) Motorola GM300 radios purchased from e-bay. 2 UHF, 1 VHF.
(1) Motorola R.I.C.K to be used as the repeater controller (bartered)
(4) Extra plugs for the rear of the Motorola radios (bartered)
(1) Motorola GM300 USB programming cable (built) used with Radio Doctor for Motorola Radius GM300 software. I'll try to provide a link later on.
(3) Mini-UHF male to BNC female to get the Motorola radio RF onto a more common connector (purchased from a local electronics supply store)
(2) BNC male to female T-connectors (purchased)
(2) BNC female bulkhead connectors (purchased)
(2) one gallon empty paint cans (purchased)
(1) 5/16 x 12 inch piece of brass tubing K&S brand (purchased from ACE hardware)
(2) 9/32 x 12 inch pieces of brass tubing K&S brand (purchased from ACE hardware)
(1) small tubing cutter (purchased)
(1) dummy load with rf voltage tap (built previously for a diagnostic project)
(1) inexpensive analog VOM (to be used to identify and set the correct notch for the caveties)
50 feet of RG58 coax (purchased for general project use)
(1) 20 foot by 1 inch wide tape measure (purchased for antenna building)
Miscellaneous lengths of PVC pipe for antenna building
Expected order of assembly for the project:
Build, calibrate, and test the notch caveties for blocking the UHF tansmit frequency on the receiver.
Clean, program, and test the Motorola tranceivers.
Examine the Motorola R.I.C.K., check the settings, and modify to use with the 3 radio configuration
Build (3) 1/2 wave dipole antennas. One for 2 meters, and two for 70 cm.
Convert a computer power supply to run the radios.
Wire up the radios and power supply.
Move everything to the remote location, assemble and test.
Timeline:
I'd like to have this done before the weather gets too cold to work outdoors. It's presently the 21st of September in Iowa, and normally this is still a warm time of year. But not so this year. At 10:30 AM, it's still less than 60 degrees outside. So I'm thinking this will need to be done before the end of October. That makes the timeline 6 weeks or less.
I'm really looking forward to doing this. I've wanted to do it for almost a year now. Why am I doing it this way as opposed to just buying something that would do all of this? For starters, I still have a limited budget. And some of the pieces I need to accomplish this are very expensive. I view this whole project as a great learning experience. Would I have had to build as opposed to buying the caveties? It's a toss up. For the two caveties I'm going to build, I've got about $30 invested. If I was going to build a full set of 6, that investement would go up to about $70. And you can buy some cheap Chinese made caveties tuned to your specific frequencies for less than $100. So in the long run, I'm not saving all that much by building my own. But the knowledge I gain by doing it myself is priceless. I've learned a lot just doing the research for this project.
For anyone that may read this in the future, as I perform each step, it will be documented with pictures and instructions.
73
Steve
KDØWSW
Sunday, September 21, 2014
Friday, September 19, 2014
Summer's almost over
Greetings all,
Well, my son, the one I picked up from North Carolina in my last post, actually followed through on his desire to become a licensed ham operator. Took and passed his test the first part of August. Took his test on a Sunday, and his call sign was in the FCC database by Thursday morning. Very fast. His call sign is KEØBLE. He's been having fun since then.
I managed to do some bartering with a "local" business radio repair company and picked up a Motorola R.I.C.K. Supposedly it came out of a local fire truck that used it as a cross-band repeater. It's not exactly what I was looking for, but after having a long look at the manual, I think I can get it to do what I want. Which is to receive using one UHF radio and key the VHF radio. Then to receive from the VHF radio and transmit on a different frequency using a second UHF radio.
Originally I was going to go for a local repeater with a link to the VHF site. There was only a marginal reason to have a full repeater. The goal with this congolmeration is that I can still key the VHF radio if it's receiving. Why would I do that? Since it's primary use will be to link with a VHF repeater, there's a certain period of time after a transmission ends where the repeater's transmitter is active but there's no actual conversation taking place. It's permissible to key up and continue the conversation at that time. I'd like to be able to do that.
One of the things that concerns me with this setup is that I don't have any sort of duplexer assembly that one normally uses with a repeater. I never intended to have the radios share antennas. But the close proximity of the transmitter and receiver could still cause problems. I think I can get away with some sort of bandpass/bandreject filtering on the receiver. To that end, I found a set of instructions for making a diy UHF duplexer out of 3 LB coffee cans. After doing a lot of research on the internet, I'm going to try using gallon paint cans instead. I picked up the connectors I'm going to need at the local electronics parts store. I'll pick up the empty paint cans and the other pieces and parts I'm going to need at either a local home improvement store or a local hardware store. Then I'll try my hand at building some notch filters.
I'm going to document this entire build process with pictures, so hopefully I'll have something to post soon.
Until then ...
73
Steve
KDØWSW
Well, my son, the one I picked up from North Carolina in my last post, actually followed through on his desire to become a licensed ham operator. Took and passed his test the first part of August. Took his test on a Sunday, and his call sign was in the FCC database by Thursday morning. Very fast. His call sign is KEØBLE. He's been having fun since then.
I managed to do some bartering with a "local" business radio repair company and picked up a Motorola R.I.C.K. Supposedly it came out of a local fire truck that used it as a cross-band repeater. It's not exactly what I was looking for, but after having a long look at the manual, I think I can get it to do what I want. Which is to receive using one UHF radio and key the VHF radio. Then to receive from the VHF radio and transmit on a different frequency using a second UHF radio.
Originally I was going to go for a local repeater with a link to the VHF site. There was only a marginal reason to have a full repeater. The goal with this congolmeration is that I can still key the VHF radio if it's receiving. Why would I do that? Since it's primary use will be to link with a VHF repeater, there's a certain period of time after a transmission ends where the repeater's transmitter is active but there's no actual conversation taking place. It's permissible to key up and continue the conversation at that time. I'd like to be able to do that.
One of the things that concerns me with this setup is that I don't have any sort of duplexer assembly that one normally uses with a repeater. I never intended to have the radios share antennas. But the close proximity of the transmitter and receiver could still cause problems. I think I can get away with some sort of bandpass/bandreject filtering on the receiver. To that end, I found a set of instructions for making a diy UHF duplexer out of 3 LB coffee cans. After doing a lot of research on the internet, I'm going to try using gallon paint cans instead. I picked up the connectors I'm going to need at the local electronics parts store. I'll pick up the empty paint cans and the other pieces and parts I'm going to need at either a local home improvement store or a local hardware store. Then I'll try my hand at building some notch filters.
I'm going to document this entire build process with pictures, so hopefully I'll have something to post soon.
Until then ...
73
Steve
KDØWSW
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