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Lscott

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Everything posted by Lscott

  1. I hope it doesn't mutate in another cell phone store. At the end the local Microcenter computer store had more electronics parts for robot builders in one section than Radio Shack had in the whole store.
  2. Then turned in to "cell phone shack." Then went bankrupt. I did hear they might be coming back in a few areas. I also remember going to Lafayette and Olson Electronics as a kid. They're gone too. Heath Kit is kaput. Lots of kids, and adults, got their first exposure to electronics building their stuff.
  3. Use to be able to go to Radio Shack, Best Buy etc and they had rolls hanging on the display pegs in the TV accessories area. I think If one wanted to build a Slim-Jim I would try the 450 ohm ladder line. That's what the N9TAX ones use.
  4. The RigExpert antenna analyzers are nice. The main attraction I have for them is the scan function. As a Ham you don't operate on just one fixed frequency. It's important to know what your antenna tuning looks like of the range you are going to use. I built one of the cheap 300 ohm TV twin line J-Pole antennas just for fun to see how well they work. These are the type recommended to have newbies build because they are simple to make and usually work well enough for an HT indoors or out on a field trip. The SWR is also reasonable. You ABSOLUTELY need the RF choke at the base of the antenna. I just used about 10 to 15 turns, single layer, of RG-58 rolled up on a 1 inch wood dowel pin. Good luck trying to find 300 ohm TV twin lead now days. Oh well. http://hamuniverse.com/2meter300ohmslimjim.html Antenna Scan Results (2M Roll Up Twin Lead).pdf
  5. I used the Rigexpert AA-1000 to make my measurements. The antennas are a bit sensitive to the environment where you make the measurements so I’m not a bit surprised by slightly different results. Also the antennas are all hand built and tuned. That can result in differences too. I haven’t heard good comments about the Surecom meter. Most are about the same as yours, inaccurate results. But people like them and they keep selling.
  6. I did a test on the N9TAX antenna a while ago. It’s similar to a simple Slim-Jim. The SWR isn’t outrageous on the GMRS frequencies. There are two versions. One tuned for MURS/GMRS. The other for 2M/70cm. N9TAX-MURS-GMRS-VHF Scan.pdf N9TAX-MURS-GMRS-UHF Scan.pdf N9TAX-2M-70CM-VHF Scan.pdf N9TAX-2M-70CM-UHF Scan.pdf
  7. Is it the ProTalk version?
  8. That’s nothing to worry about. You can use the antenna full time with that SWR ON GMRS. Most radios don’t start having issues until the SWR is 2:1 or higher.
  9. That would be a nice feature to have on a radio. Maybe not at the end of every transmission. There is a feature on one of my digital radios to do it. But it has to be manually initiated through one of the menu selections every time I want to send it. Not very convenient.
  10. Also consider the environment a typical HT is used in. hand-held, mobile with external antenna, hanging on a belt, stuck in a utility vest pocket. All those will really screw up the SWR. I was looking at the spec's for some of the hybrid RF power blocks used in many HT's and some mobile radios a while back. The HT one's I've seen they're rated to work up to a max SWR of 20:1!! Basically no antenna. It sort has to be that way due to the highly unpredictable environment HT's have to work in without failure. See example file attached. Look at the first page at the bottom. M67799MA.pdf
  11. A 50 ohm dummy load will give you a perfect 1:1 match, but nothing radiates from it.
  12. This is why some people keep a couple antennas in their vehicle. They use a low gain, 1/4 wave, in very hilly or mountainous area or a high gain antenna in nearly flat areas.
  13. This is getting a bit off topic and into the weeds a bit. But the rule specifically mentions equipment certification. Anything after the cutoff date will not get certified if it has any kind of voice obscuring features. However it’s silent about equipment that was certified before that date and no mention the feature must not be used in that case. So, it’s very possible voice scrambling in OK, BUT only on radios certified before Dec 27, 2017. So, my favorite Kenwood radio, TK-3170, I use for GMRS, which by the way is certified Part 95 in 2004, has analog voice scrambling so it could be legal to use that feature. Interesting thought.
  14. https://3fs.net.au/tropospheric-propagation/
  15. Sargent Schultz, I see nothing.
  16. Manufactured by Gollum Radios I'm guessing.
  17. I'm not a conspiracy believer, but either the government has a secret "kill switch" or an understanding with the cell phone companies to turn off the service when asked/ordered to do so. If nothing else the FCC has the authority to license and control transmitters, which of course includes cell phone towers, and force the shut down. People forget that Ham radio was shut down during WWI and WWII by the FCC. It took a lot of lobbying to allow Ham radio to resume in a fashion like it was doing before the war. Not likely today, but that could change. https://bw.billl.net/wp-content/uploads/2019/11/Radio-History-03-Amateur-Radio-Before-and-During-WWII-By-Dan-Davis-W8LUX.pdf Then there is the question what happens to the Part 95 services? Is it also possible they too might be ordered to cease operations?
  18. Just think about what if the government wanted to pull the plug on purpose?
  19. Could also be some mixing products in the radio's front end. Take a frequency on 931.6MHz (public safety frequency) and mix it with 469MHz (business frequency) you get the difference of 462.6MHz right in the GMRS range. It could also be just the radio. My Kenwood dual band TH-G71A shows a full scale signal on channel 7. Take the antenna off, nothing. Then I tried several other radios on the same frequency. They show nothing there. So apparently it something weird with just the one radio.
  20. What kind of radio is being used? If it's a cheap Chinese radio they're not known for good receivers. Note that channel 3 is the Interstitial frequency, 462.6125, between the main channel 17, 462.6000, and main channel 18, 462.6250. For GMRS the channel bandwidth is 25KHz so there is considerable overlap on channel 3 with the adjacent channels 17 and 18. If the radio doesn't have extremely good selectivity you're likely to experience significant bleed over on 17 and 18 from a strong signal on channel 3. Also a strong signal on either channel 17 or 18 will bleed over on channel 3. FRS-GMRS Channels Layout.pdf
  21. Here is one idea used on an expensive Motorola XPR7550 radio. Allows the use of an external antenna by using a stud type adapter to BNC. The ground is made externally using a strip of sticky back copper foil tape over the back side of the case to the chassis for the ground connection to the adapter. Something like this could be use on the cheap radio. https://youtu.be/O3KEazVQ-RA?si=UV8kiC5HQjQ3gqMG
  22. At that price you can afford to destroy one or two and not feel too bad.
  23. If I have a choice I typical go for the 400MHz to 470MHz range since most of my usage is Ham so that covers the full band. It's also usable on GMRS, but as I mentioned before they're not certified for Part 95, but typically for Part 90 of course. When looking for used commercial grade radios there are several things I'll do before dropping my money on one. 1. Look up the manufacture's brochure to see what features the radio has, namely number of channels, display type, frequency ranges etc. You might decide at this point it doesn't look so appealing. 2. Look up the FCC ID's, usually on the manufactures brochures. Check to see what the certifications are for the radio, tested power levels, modulation types and frequency ranges. You need the FCC ID to verify what you're trying to buy or bid on. I frequently find sellers who get the model name wrong or frequency range wrong in the ad description. The FCC ID doesn't lie. 3. Check and see if the programming software is obtainable. This is a big one. Sometimes it almost impossible to find. If I can't get the software the idea is dead right there. It doesn't matter how good the radio is. Commercial radios are basically useless without the programming software, you REALLY need it. 4. Most commercial radios are firmware up-gradable. Chances are the one you're interested in will need a firmware update to make it compatible with the recent radio programming software release. 5. Are important accessories like battery packs, chargers, programming cables, microphones, power cables etc. easy and cheaply available? There are some nice used radios out there but battery packs are almost unobtainable as an example. 6. Then I go looking for the documentation for the radio. Important things like user manuals, service manuals, any programming tips etc. 7. Then it comes down to just how much you want to spend. Some sellers price the radios like they are gold plated. The worse offenders are sellers of digital radios with P25 being at the top of the list. In general it seems that the VHF gear sells for a premium compared to the UHF stuff.
  24. The miss match caused by the clips on the leads may eventually damage your radio. I would very seriously look for a good quality adapter for your radio. Unless it’s totally proprietary to the manufacturer you should find one. In the case of this cheap radio you could use it as is, or disassemble it and install the pigtail directly on the circuit board. I’ve seen this done in the past with FRS radios. There are some YouTube videos on the topic.
  25. It’s not a concern. You have to specifically enable it in a radio AND have to put in the particular code to do it. Leave the code out and “turn the feature off” NOBODY will have the ability to stun or kill your radio. That’s the case for every Kenwood radio I’ve programmed.
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