SteveShannon

He didn’t initially bring broadcast TV up; you did. All he did was reply to your comment from Saturday:

There’s a guy named Steve who sells them to people all fixed up for GMRS. Of course for GMRS use they must be limited to 50 watts.

Nope, no stars between us and Voyager. Voyager is 15 billion miles away. The nearest star (other than our sun) is 23 Trillion miles away.

But why not just setup a repeater on one of the other pairs? Nothing is gained by intentionally running interference (and yes I appreciate that you said you wouldn’t.)

That’s correct. For UHF it’s several percent further than the visual horizon.

I'm sorry. In the context you intended it was not snarky. I must have been overly sensitive that day.

Although Diamond doesn’t specifically say no ground plane, they do declare that the antenna will work nearly anywhere on a vehicle:

Not the radio battery but perhaps a small battery or super cap installed on the pc board whose only purpose is to support the chip that stores settings. But I agree; the failure you’re talking about would destroy your confidence in Wouxun.

I’m the worst at thread-creep, but this sounds more like the battery or capacitor than a chip failure. In a computer it would be like the battery for the real time clock.

High Frequency (HF) amateur bands have the greatest range, but propagation can vary. Yesterday I was easily able to talk to a ham many hundreds of miles away (Butte, MT to Chelan, WA), but at the same time I could not hear a ham who was thirty miles away in Anaconda, MT because our signals were passing over each other’s heads. GMRS has no range advantage over amateur UHF. Neither does amateur UHF have a range advantage over GMRS. Their ranges are practically identical. But, there are many times more amateur repeaters than there are GMRS repeaters and unlike GMRS the amateur repeaters may be linked together in networks. On Saturday I used my 70 cm handheld and talked to a repeater 30-40 miles away which was linked to a worldwide net at the time.

If a means of emergency communications is truly important, other members of the community should be willing to help pay to do it right.

I agree with @WRKC935; you shouldn’t feel that way. Hopefully my answer didn’t contribute to you feeling that way. I hope you ask more questions and I hope someday you enjoy helping others here. There will always be those people who attempt to make themselves feel better by attempting to make someone else feel worse. @Socalgmrs is one of those people. He especially relishes trolling newcomers. You did nothing wrong! One of the features of the forum software is the ability to place other users on an ignore list. SocalGMRS is on my ignore list because I enjoy not seeing his trolling.

No, I don't believe there are any part 97 rules which prohibit ham radio stations from transmitting on frequencies other than the ham bands. There is no certification of ham transmitters (except linear amplifiers). There are rules within some of the services which prohibit certifying transmitters for those services if they can be used on ham bands, and there are rules which prohibit using transmitters which are not certified for the service, but there are no specific rules in Part 97 that say a radio may not be tuned out of band.

Ahh, so it was. I apologize.

That’s not correct. A GMRS radio could be certified for multiple services. The last sentence (italics) could be interpreted to prohibit transmission in VFO mode. Here’s the rule: No GMRS transmitter will be certified for use in the GMRS if it is equipped with a frequency capability not listed in § 95.1763, unless such transmitter is also certified for use in another radio service for which the frequency is authorized and for which certification is also required. No GMRS transmitter will be certified for use in the GMRS if it is equipped with the capabilities to operate in services that do not require equipment certification, such as the Amateur Radio Service. All frequency determining circuitry (including crystals) and programming controls in each GMRS transmitter must be internal to the transmitter and must not be accessible from the exterior of the transmitter operating panel or from the exterior of the transmitter enclosure.

I thought perhaps LEARN was an acronym for Lawrence Emergency Amateur Radio Network. He might be from Lawrence County.

The FCC doesn’t collect a physical station address for either amateur or GMRS. They’ve stated that a PO Box is fine.

Welcome to the forums. Only people in the Denver area are likely to be able to talk to you because of the distance limitations of GMRS. Your best bet would be to look at the map here to see what repeaters exist in your area and look at the clubs to see which ones are in your area.

You’re just a young guy! Before Tandy Radio Shack there was Allied Radio Shack and before Allied Radio Shack there was Allied Radio and Radio Shack, two separate companies. Allied Radio was a well respected competitor of Lafayette. Not everything sold by Radio Shack has been poor quality. They even sold some reasonable quality coax but they also sold some crappy coax as well. Personally I prefer to stay away from inexpensive coax. I would rather use quad shielded RG6 for UHF, even at 75 ohms, than some of the lossy 50 ohm cable.

I don’t recall ever saying that you are using the wrong coax. I pointed out that RG8x has a foam dielectric and RG58 has a solid dielectric and that’s why RG58 is frequently used for mobile installations. RG400 also has a solid dielectric and a tiny outside diameter. It’s expensive though. A person could build a Frankenstein cable using RG400 where needed and something with less attenuation elsewhere to make up the necessary length, but the splice points reduce reliability and potentially add losses. Also, nothing I’ve said has been demeaning or critical of you or in any way personal. I’ve tried to stick to factual information, demonstrating how I did any calculations.

Antennas typically consist of reactive elements and radiating elements. The reactive elements are used to match the impedance of the radio and feedline which is usually 50 ohms. The radiating element is one or more metal wires or rods that convert the signal into RF. It’s usually the most visible part of the antenna.

RG58 is used because the dielectric is solid and doesn’t deform like foam dielectrics, but you’re right that it’s even lossier than RG8x. Choosing cables for a mobile installation is a juggling act. The only cables that will withstand being pinched in a door are thin and stiff because of solid dielectric materials. But they’re also very lossy. So you minimize the length as much as possible and accept that they aren’t ideal.

I picked 10:1 as an example to demonstrate how SWR readings can be completely misleading when made through lossy cable, not as any assumption of the SWR of your antenna. Th right tests are important, but tests can be very misleading. If you want to know the SWR of your antenna, measure it at the antenna feed point, not at the radio. If you want to see how well your cable works, SWR of antenna and cable combination isn’t really an ideal test. Test the cable with a dummy load at the end. Test the SWR of the antenna separately. And put a power meter next to the antenna and then next to the radio and compare the results to see how much power is lost.

Those SWR numbers are not accurate. Keep in mind that SWR is calculated by the following formula: SWR = (Forward Power + Reflected Power) / (Forward Power - Reflected Power) But that requires an accurate measurement of the percentage of the reflected power compared to the original power output. At GMRS frequencies RG-8x converts 44% of the RF output to useless heat before it ever reaches the antenna. So of the maximum of 50 watts transmitted by a GMRS radio only 27 watts reaches the antenna. That’s the Forward Power. Then, if the impedance of the antenna isn’t perfect, some amount of the power is reflected back towards the radio. That’s the Reflected Power. By the time it reaches the radio 44% of the reflected power has been converted to heat. So, let’s say you have an SWR meter right at the radio and let’s also assume that the antenna truly has an SWR of 10.0:2 at 462 MHz. An SWR of 10.0:1 means 67% of the forward power is reflected. That’s a pretty abysmal SWR for any antenna. So for a 50 watt transmitter 33 watts reflects off the feed point of the antenna and back towards the radio. But now let’s introduce attenuation. 50 watts doesn’t really reach the antenna. We’re using RG-8x so only 27 watts reaches the antenna. Two-thirds reflects back towards the radio, so only 9 watts of power is radiated instantly. 18 watts is the reflected power at the feed point but of course 44% of that becomes heat due to attenuation. 56% of 18 watts, or 10.1 watts makes it back to the SWR meter. So the SWR meter sees all 50 watts forward power and only 10.1 watts reflected power. It’s calculation says that is a perceived SWR of about 2.6:1. The point is that lossy coax results incorrect SWR measurements, whether done by a nanoVNA, an expensive bench model Vector Network Analyzer, or the priciest antenna analyzer out there and seeing a lower SWR becomes meaningless.

That does make a difference, but what is the actual difference? How much of the difference is due to the antenna? Are the cables exactly the same length? Have you tested the insertion loss for each cable at each tested frequency? Remember, attenuation in an antenna makes SWR appear better. I believe these are the tabular results and I’ve arranged them by frequency It appears the older cable actually results in lower SWR for the 2 meter and 70 cm bands when connected to an antenna designed for those frequencies according to the value in the upper left of the screen. It would be interesting to see a single wideband sweep of just the cables into a dummy load to eliminate the effects of the antenna. Frequency Old Cable SWR -> New Cable SWR 462.000-470.000. SWR 1.900:1 -> 1.495:1 441.000-450.000. SWR 1.464:1 -> 1.498:1 151.800-154.600. SWR 1.888:1 -> 1.408:1 144.500-146.400. SWR 1.151:1 -> 1.395:1