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Posts posted by tweiss3
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If you look at the table, it's performance narrows and insertion loss increases as you approach 5MHz spacing. There is no way in hell that will have acceptable performance at 3MHz spacing.
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2 hours ago, WRDJ205 said:
Google is sending me to the same link as i found earlier ...
Repeater Duplexer 50W UHF 6 Cavity Duplexer SGQ-450D -
Be careful, that specification indicates a minimum spacing of 8-10MHz between RX and TX, but the US standard for UHF is 5MHz.
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Or hoarded by Crown Castle or another monopoly.
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2 hours ago, marcspaz said:
I wouldn't put a mobile duplexer in orbit. That would be a disaster waiting to happen.
I agree, but I don't see another way to remain within GMRS, unless you use two antennas and mount them like a dipole and only use 1/2W.
I have a trunked P25 P1 "site" in my living room where the CC is 0.05MHz below the VC, RX antennas are pointed up, and TX antennas are left and right away from each other. Works well, but it's only putting out 0.1W.
In theory, its a $7+M idea that would likely just become space junk before it is used.
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22 minutes ago, marcspaz said:
There are no restrictions on putting a GMRS satellite in orbit. We should start a crowd-funded account to make that happen.
While correct, I suspect the crowd-funding would be significantly short of the cost to get one up in near earth orbit. I wonder what space dust and the extreme temperatures would do to a "mobile" duplexer though.
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As others have said, ham UHF vs GMRS, you won't notice a difference with HTs. VHF high (2m) will get a bit further under normal conditions. VHF low (6m, 50MHz) gets to the point that an adequate antenna is the issue for HTs. It will act the same as 2m without atmospheric propagation helping, but when propagation is open, there are thousands of stories of talking across the USA on only 5w.
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I need to get back to studying for AE. Same as last years study course, life got busy and I'm behind again.
- FishinGary, AdmiralCochrane, WRXB215 and 1 other
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Heh. My wife doesn't necessarily participate, but finds them useful at times. She didn't really say anything after she saw my last purchase order other than "that's a lot of money" then walked away and didn't mention it again.
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As mentioned, testing of an HT antenna is nearly impossible to get completely accurate results. It should also be noted that sometimes a "better" antenna will cause the radio to perform worse due to RF saturation. That being said, for the APX, the Motorola antenna will work the best for that radio.
- WRUU653 and SteveShannon
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Other than shortcuts, the keyboard is only useful for DTMF tones, which could be used to control a repeater's features, such as changing the input tone, or disabling the repeater during a malfunction. It's not a huge selling point for many radios.
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Yea, I had 2 XPR3500 that had bad antenna sockets. Was fixed in about 20 minutes with the soldering station.
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It's in the rules.
Fixed station. A station at a fixed location that directly communicates with other fixed stations only.
Base station. A station at a fixed location that communicates directly with mobile stations and other base stations.
47 CFR 95.303
An example of a fixed station would be an RF link between 2 repeaters. They only talk with each other, at fixed locations.
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I'm a fan of distance contacts on 80m while doing 70 down the highway. I don't really ever have time to sit longer than 15 minutes.
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2 hours ago, Lscott said:
The inside booths are all sold out, or reserved. The notable thing is several of the big names are not going to be there. Alinco and Yeasu for two examples. Kenwood will be there but has a small foot print. So will Icom, and they look like they will have their usual huge display.
Both Alinco and Yaesu are listed as confirmed along with JVC Kenwood, Elecraft and Icom.
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From Bioenno
Long story, you can but you probably shouldn't.
- WRUU653, SteveShannon and Lscott
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4 isn't really that many if you have difficult terrain to overcome. Yes, it's an investment, but if it's useful to you, who cares. Now, having 4 tower leases, or even have someone willing to lease you tower space, that's the impressive part, considering crown castle won't even return a phone call.
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An external antenna would probably remedy your solution over an HT in the car. Doesn't matter if it's the same frequency, other electronics tend to not like transmitting anything near them. Computer screens, computer speakers, etc. all complain when even 2W of VHF, UHF or 6meters is transmitted within a few feet.
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3 minutes ago, WSHH887 said:
I guess my biggest surprise is that they are USB. You know "UNIVERSAL" Serial Bus". That crazy idea that port and IRQ selection would be a thing of the past.
Not when the radios themselves are 20+ years old, and were first programmed with a true serial port.
I can't remember if the TK-880 needed booted up in a programming mode or not. I guess check the manual to see? That may only be for firmware updates though.
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13 minutes ago, HHD1 said:
Do you have any suggestions for online retailers for these brands, other than Amazon? I'm not finding much of a selection there.
You won't find them new anymore. TK-3140 was a great Kenwood that has Part 95 certification. They used to be $70-110 used, I still have a handful of them, used the KNB-55 battery, which is also used on the NX-3000 radios.
These guys check the radios out before selling them, for $150 its fits your budget https://used-radios.com/kenwood-tk-3140-uhf-450-490mhz-250-ch-4w-portable-radio/?srsltid=AfmBOor3hXfzNg6frpl6zsTfAzixQGKZJjih1N4fJGGRJn8_YKKdad4w
SGQ-450D Duplexer - Tune-up and Review
in Equipment Reviews
Posted
I would also be weary of adjusting the power using the input voltage. That sounds dangerous for the long term survival of the circuits. That typically isn't the correct way to adjust a transmitter.