6m radio project (again)
ka2zev at yahoo.com
Mon Oct 29 13:40:58 CDT 2007
The answers to your note below....
It's a beast because of the transmitter.
110 watts is nothing to sneeze at.
The control head is about 5 wide, two high, and about three deep.
The radio is about 14 inches tip to tail, about 9 inches wide, and three inches tall.
Will try and take some photos with a ruler for a size reference.
It's about 10 pounds, mostly heat sink for the drawer unit.
As for the data conversion, that is a project for Frank and company.
Ive never had to do anything like that, and wouldn't know where to start.
This is just the drawer unit, but the photos are good.
Note this is a B radio, 35 to 45MHz approx..
This is the package I purchased 10 units of.
During the Taco's meeting we unpacked the first box.
Seems these were part of a bus fleet, so some of the control head cables are only about 5 feet long!
Some of these are going to end up under car seats because of control cable limits.
I don't have a lot of extras on this part.
I'm used to 3 and 4M cables for trunk mounting.
Also some of the power cables are a little short.
Will have to fix some of that.
I make a few mods to the units to get them working on 6m.
First one is to reprogram the TVI filter.
In it's stock form, at the top end of the band it kills about 80% of the transmit power.
So I take apart the filter house, and one by one remove the three coils, removing one turn each and soldering them back in.
I check SINAD each time to be sure it's doing what I want.
Remember these are intended for 40 to 50MHz.
So above 52MHz, the filter starts to work.
Then I re tune the RX for best performance.
Right now that works out to about .3uV for 12db SINAD.
I also shoot for power flatness from 50 to 54.
I also have to reset the internal VCO's to work at this higher frequency.
This weekend I have my high school's 30Th reunion, so the soonest I can get a few free would be the weekend of the tenth.
Frank has offered his shop as a rally point for any installation party that can be organized.
I should have two or three 70-375 C units available for install by that date, as well as the units AMRAD holds. There are three or four of those in the collection.
So if you want one, get an antenna.
I like the Larson NMO base load, but most anything that tunes will work.
Check the power ratings!
Smoke is not our friend.
Keep it safe
"Tom Azlin, N4ZPT" <n4zpt at cox.net> wrote:
I am interested also. Sorry I missed the meeting on Saturday but was
down at the marathon finish line getting stuff set up there. I have a
ton of actions including a balloon launch in early December so your
timing is fine.
When you say it is a beast, how big and heavy? I would have it at home
as I have a 100 watt 6m rig in my car now (200 watt HF) that will go
with me for deployments. I have not looked as to modifying it for 9600
Would use it for FM voice, but also want to experiment with packet
perhaps at 9600 baud or 4800 baud depending on what would work.
73, Tom n4zpt.
"You are, what you do, when it counts"
"Gravity, the quickest way down"
Mayor John Almafi
"You ever drop an egg, and on the floor you see it break?
You go and get a mop so you can clean up your mistake.
But did you ever stop to ponder why we know it's true?
If you drop a broken egg you will not get an egg that's new?"
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