JohnE
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Posts posted by JohnE
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at the very least there should be an isolator on both transmitters for IM , mixing and protecting the PA's from a bad antenna.
Did this in the 80's w/2 remote base's 700kC's apart. Much easier w/frqs that close. I think the total loss was 3dB overall.
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its called ducting and yes it can and does happen under the right conditions. mostly weather related.
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have a look at the PCTEL (old antenna specialist) ASP7795 Mosaic antenna 3dBd
https://d3dqzy9ky05fbv.cloudfront.net/wp-content/uploads/2020/06/ASP-Mosaic-Series.pdf
been using them for yrs, mostly 5dB version but the 3 is short enough to clear most garages on top of an SUV or mini van.
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I've seen and measured their duplexers. losses pretty much on the money .
typical real world loss I have measured was 40 in 28-32 out so that would be around 1dB loss or a little more.
just an FYIJE
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I always referenced between two mountain tops in a vacuum and then it was a maybe.
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WOW 400 bucks ouch.
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https://rfguys.com/products/kenwood-kmc-14-replacement-kmc-27c-6-pin-mic-tk-730-new
this is what you are looking for KMC 27C mic
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the 8400 is more than adequate for GMRS use. I can't begin to tell you how many I have out there in commercial service that see pretty much 100% tx time at least during daylight hrs.
have there been failures, yes there have but that is true of any radio that sees continuous use. I have had a string of MTR failures in the past 2 months. had 4 supplies, 3 PA's go south and 2 that just software fails w/no recovery.
nothing is fool proof.
JE
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On 8/27/2021 at 3:04 PM, Guest Bob said:
I just got a VXR 7000 and want to make sure I hook the external duplexer up correctly.
The VXR was programed for GMRS and I do have a license. Programing is 467.5500-467.7250.
Thank you
that programing will not work
462.xxxx/467.xxxx is how it should be programed.
concur w/Radioguy7268 also
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I will post this again as it is universal to all RF
dB loss power loss in %
0.5 10 100W in 90W out
1.0 20
1.5 30
2.0 37
2.5 44
3.0 50
3.5 56
4.0 60flat packs tune for Notch/Notch ----\___/----\___/----and should never be tuned W/power
typical loss for the ones I use are 1.5 or less most ~1.
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https://www.amazon.com/Nashua-Multi-Purpose-Length-Width-Aluminum/dp/B002EX855S
also available at home depot
use it all the time to make ground planes in fiberglass vehicles.
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the "pulse" can be turned off on some controllers.
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LTR falls w/in the rules as far as sub audible tone goes, its no different than tone/DCS as it is under 300 cycles.
now doing multiple machines linked together as a system is another story.
W/8 channels so close in frequency each machine would have to have its own filters and antennas if it were done at a single site.
you would have to have some really heavy use to warrant that kind of set up.
QuoteMy understanding of LTR is that there isn't a control channel, the control data is a burst included in the voice channel, and you stay on the frequency you are on, unless the data burst indicates a change
in LTR there is a home rptr # ,area bit, and the encode/decode data. all the steering is done by the controller.
did this yrs ago when I had some trolls playing w/my machine a little too much. I made it switchable form conventional to LTR over the air.
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I have found radio mobile to be pretty accurate once you dial it in correctly.
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I would run a propagation map to see what it will take to achieve that and if it can be before pushing any higher
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Yes, absolutely change the cable. 400 is not capable of handling a strike. If it were 1/2" or 7/8" hard line I would say give it a go.
ground the pipe and get yourself a poly phaser to at least give you some protection.
just my thoughts
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a little light reading
https://www.blm.gov/sites/blm.gov/files/Lands_ROW_Motorola_R56_2005_manual.pdf
note: this is from 05 , there have been updates
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you can turn them up but be aware that a lot of the used radios can be a little "soft" after yrs of service already.
the pins on the brick sometimes need to be "touched up" w/an iron as they get heat fatigued.
just an FYI
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if it is set as a cap + it "pulses" and there won't be any data there.
Kenwood Bluetooth Microphone for TK8180, TK8360, etc.
in Technical Discussion
Posted
Otto as mentioned makes pretty good stuff. Used them for many yrs in PS and commercial LM.