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Really Big Micro-Trak

V

VHS

Well Known Member
Well, I just sent out my prototype board for production to try a 30 Watt, single
channel Micro-Trak transmitter. The board is 4.7 X 2.4 inches and has a BNC RF
output. With a 17 volt supply, it could potentially produce 45 Watts of output
power!

Today I realized that the next larger sized amplifier module is in the same size
case, and it might even be possible to drop in the 60 Watt module ( 75 Watts at
17 VDC!) I can visualize APRS purists filling their molotov cockatails even as
we speak....

I have taken crazy-extravagant precautions to prevent the RF from swamping the
PIC, but there is ony one way to know for sure if its going to work. I should
have the boards back in a couple of days and will let you knwo how it works, and
put up photos (unless if fails massively, in which case, forget I even brought
it up!)

Allen
VHS
 
Power Corrupts

Absolute power corrupts absolutely.

My APRS outlook in Western Nebraska is suddenly much brighter.......

Here is your first request to beta test.
 
Last edited:
Mountaintop Digis

Ron,

I had better coverage in the mountains than I did over western NE. Granted I was not in the canyons, but getting the digis up high helps when you are flying over.

I think 60 watts would melt the jpole and the wingtip anyway.......
 
Pete,

Good point. We should test one of your antennas on the ground to see how it likes 25-30 Watts. It would not do to have it turn into a puff of metal and plastic plasma in flight.....

Allen
VHS
 
VHS said:
Pete,

Good point. We should test one of your antennas on the ground to see how it likes 25-30 Watts. It would not do to have it turn into a puff of metal and plastic plasma in flight.....

Allen
VHS
Click to expand...

This would no doubt be enough RF to send every electronic gadget in my panel into a state of total confusion.......... :eek:

Very happy with my MicroTrak-8000. :)
 
Lot of Power

Remember to double your range with power you need to square the power output. In other words if your transmitter's output is 10 watts you need to increase the power output to 100 watts to double the range. If the receiver you are transmitting to is over the horizon no increase in power is going to help you.
 
I would think that 30 watts at altitude would create more harm than good. Yes in areas where you dont have anything for 50 to 100 miles you would get a packet out, but think about when you are flying over a congested area.

If this system has a receiver then you might not ever get to transmit since it will be picking up everyone else.

If it is a transmit only, you will be stepping on a lot of other users, and keying up a lot of radios that dont need to hear the traffic.

It might be worth looking into a 6m aprs network.
 
APRS

SpicyChili said:
I would think that 30 watts at altitude would create more harm than good. Yes in areas where you dont have anything for 50 to 100 miles you would get a packet out, but think about when you are flying over a congested area.

If this system has a receiver then you might not ever get to transmit since it will be picking up everyone else.

If it is a transmit only, you will be stepping on a lot of other users, and keying up a lot of radios that dont need to hear the traffic.

It might be worth looking into a 6m aprs network.
Click to expand...

I agree. I have the AIO 10 watt with Ryan's J-Pole horizontal in the wingtip and I feel guilty with that.

I think that 300mw-2000mw with vertical polorization should be sufficient for most situations.

If you look at this track: http://aprs.fi/?call=n161rl&dt=1230508800&mt=m&z118timerange172800 with the 10W All In One with the J-Pole, you will see that it has fairly good coverage from the Austin,TX area to the NE Georgia area except in the Missippi/LA. area down low. I Stopped in Vicksberg for fuel and there's no tracking down low in that area.

According to Sam B. and looking at the digi-peaters in that part of the world, that is understandable. Kind of like the Nebraska area.

If there are no digi-peaters to be seen, no amount of power will help and no sense of drowning out others in the meantime
 
I would certainly not suggest operating a 30 or 60 Watt transmitter at full power while airborne except under one of a very few conditions. One being fully manual "IDENT" (pushbutton) control , operating at near ground level or very mountainous terrain ( or in the bottom of a Canyon), out at sea, or in distress. Fortunatly, the unit will have a two-positon switch selectable power output.

People tell me that there are still lots of places they can't hit digis. I have to disagree with the poster who talked about the over the horizon performance of VHF. Actually, the RF horizon exceeds the geometric horizon by about 15% ( for those of you taking the Extra class test take note: test question!) and even a little bit of extra power transmitted means more power at the receiving end, the inverse/Square law of Energy not withstanding. Would you turn down a couple of extra horsepower when flying in the mountains on the principal that you would need to quadruple your power to double your speed?

Allen
VHS
 
My mistake I should have mentioned the radio horizon as being different than the earth's horizon. Sometimes if there are hills in the way you can luck out and get a great deal more range over the radio horizon, its called knife edge refraction.
 
Big

VHS said:
I would certainly not suggest operating a 30 or 60 Watt transmitter at full power while airborne except under one of a very few conditions. One being fully manual "IDENT" (pushbutton) control , operating at near ground level or very mountainous terrain ( or in the bottom of a Canyon), out at sea, or in distress. Fortunatly, the unit will have a two-positon switch selectable power output.

People tell me that there are still lots of places they can't hit digis. I have to disagree with the poster who talked about the over the horizon performance of VHF. Actually, the RF horizon exceeds the geometric horizon by about 15% ( for those of you taking the Extra class test take note: test question!) and even a little bit of extra power transmitted means more power at the receiving end, the inverse/Square law of Energy not withstanding. Would you turn down a couple of extra horsepower when flying in the mountains on the principal that you would need to quadruple your power to double your speed?

Allen
VHS
Click to expand...

Allen:

I wasn't aware of the two position power switch. I think 300-2000mw with vertical polarisation at an altitude of 3-5 thousand feet is sufficient for 80-90% of the USA.

Given: In an emergency situation, I would want a 50KW transmitter!
 
MT-BFT update

I put together my first production MT-BFT transmitter yesterday, and it works great! About 35 Watts at 12 volts, increasing to about 45 Watts at 17 volts. I have to admit that I left the high/low power switch connection soff the baord though. Its easy enough to solder in a bypass for the power trimmer if someone wanted to add one.
list


I am waiting for parts, but these should be available next week. Also, I would like to apologize to those people who left me PM"s that I did not see before, I was not being rude, just incompetent. You can always contact me at [email protected] if you have any questions about our trackers.

Allen
VHS
AF60F
 
Dam! How do I post a photo thats on my PC but not on a website? Officially, "BFT" does not stand for anything......It was one of the names I floated to the Micro-Trak Yahoo group and it met with positive reviews.

Allen
VHS
 
Mike,

I don't think I can send an attachment as a PM, so I will need your actual E-mail address.

Thanks,

Allen
VHS
 
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