Keyboard Shortcuts
Likes
- Repeater-Builder
- Messages
Search
Re: International crystal manufacturing
Chuck, I read your suggestion earlier.? In fact the Motorola Maxar does just that; a resistor sits next to the crystal case.
Some sites are off-grid (very low power consumption, like 50 mA on standby) so that's not an option for me. I have a State-side vendor for *just* the crystal so that's not an issue.? Idealistically, I was trying to find what ICM did for decodes. Thanks, folks, -- - Regards, Karl Shoemaker To contact me, please visit SRG's web site at? for the current email address. |
Re: Series-mode surge protection
Thanks for the links.? Well SurgeX is shy on diagrams or schematics to more fully explain?things though I guess protecting IP trade secrets might be the reason if not for the mentioning of this technique being patented.? If the patent exists, there's nothing to fear from publishing more detail than the ever so slightly?shallow verbal description. I recall some of the Polyphaser AC protectors used series methods as well. Perhaps it's time to buy one and dissect?it for the actual design.? Who knows... maybe it actually does what they say. John On Mon, Nov 21, 2022 at 10:26 AM <rsnyder@...> wrote: Here is a link to the SurgeX SX-1115-RT?datasheet: |
Re: Circularly-polarized antennas for two-way?
Matt,
I used a circularly polarized antenna on the WA6TDD repeater back in the 70's and early 80's. The antenna was a single bay antenna made specifically for the repeater by the JAMPRO antenna Company as a test for the 2-way world. It even has de-icers!? If you're familiar with the JAMPRO Penetrator antenna, this was the same antenna with the exception that it was center mounted; the mast was straight down below the white insulator at the feed point. This replaced a (linear) Phelps Dodge 4.8 dB gain Super-Duper Storm Master antenna.? The gain went from approximately +4.8 db to - 3 dB.? The ERP went from 100 watts to approximately 13 watts. Just to clarify, the repeater transmit was now circular and all of the users were linear; none of the users were circular.? The difference in coverage of transmit was amazing. For example: at the time I worked in a 33 story building with 6 levels of underground parking. With the linear antenna I was able to copy the repeater with its 100 watts ERP about 25 feet into the parking entrance and that was it. With the circular antenna on the repeater and a 19" spike on the top of my car I was able to copy the repeater solid down to the 2nd level and hear it spotty down to the 5th level.? At some places on the 5th level I could find spots that were almost full quieting.? People that listened to the repeater with radios like the old Patrolmen type receivers claimed that they no longer had to place their receivers near the window and fiddle with the antenna, they could now take the radio anywhere in their homes and hear the repeater with no problems. It was solid through areas like the Santa Ana Canyon and Sepulveda Pass. What was rather humorous and showed a lack of understanding by some users, who were upset that the repeater was no longer ""60 over S9," it was now only "20 over S9." The fact that it had better coverage and penetration was not the point! Now for the bad news.? It didn't hear very well.? It simply had too small an aperture. While stations could hear the repeater better than ever, and had been solid into the repeater with the 4.8 dB gain linear antenna, they? were now not so solid.? Handhelds that had no problems now had problems.? We eventually went back to the Phelps Dodge Linear antenna. What did we learn?? We learned that circular transmit to linear receive is a plus.? Yes, circular to circular is best, but not very practical. Think about putting a circularly polarized antenna on your car or handheld radio. If you have a circularly polarized antenna that truly commutates, it will be optimally coupled to a linear receive antenna even when the polarization of the signal as received is "spun" due to bounces and other propagation anomalies. It really works! You can read more about this at ? download and read the pdf file. Hopefully attached is a picture of the Antenna that JAMPRO build for the WA6TDD Repeater. Burt, K6OQK |
Re: International crystal manufacturing
AT&T had analog MSF5000 repeaters on the microwave sites that had a 4 wire circuit going back to the regional #4ESSMCI had a similar nationwide system with UHF repeaters but I don't know if or how it was tied into the switched network. Anyone from MCI on this list? Our company's warehouse is a former MCI microwave hub - I'd love to pick your brain about some of the equipment and facilities we inherited. I grew up in a telco family as well. Some of my earliest memories include visiting CO's in northeastern and central Pennsylvania with my dad. --- Jeff WN3A -- This email has been checked for viruses by Avast antivirus software. www.avast.com |
Re: Circularly-polarized antennas for two-way?
Will a voter switch fast/often enough to keep up with the flutter style fading?Good question. Simple answer: no, generally speaking, a regular SNR voter and two separate cross-polarized antennas won't be effective in combatting mobile flutter. The rate of mobile flutter is primarily a function of two things; the relative velocity of the stations (in the case of a repeater, only the mobile is moving), and the wavelength (the shorter the wavelength, the faster the flutter for a given velocity). A voting comparator designed to specifically deal with mobile multipath flutter could be designed, and back in the AMPS cellular days, such designs were effective, but the voting was not based on comparing relative SNR's in the audio domain like a typical two-way voter does. To others that have commented: at any instant of time, there is no guarantee that that, at any instant in time or space, multipath experienced at the receiver is being caused by cross-polarization. That is, don't assume that simply having two linear cross-polarized antennas, or even a single circular polarized antenna, is going to magically cure multipath. CP helps to address polarization skew caused by reflections, but the reflections are still there - there can, and will, still be destructive cancellation that can't be avoided regardless of whether the receiving antennas is linear or cpol. And of course, whenever a CP signal is reflected, its polarization sense is inverted, so a mobile CP antenna absolutely does not help deal with multipath if the repeater is also CP. The US is one of the countries that regularly uses CP on FM broadcast, and to a lesser extent on TV, but it's certainly not a worldwide standard. Many countries, including most of Eu, use linear polarization. There have been a lot of studies done on the subject of reception of Vpol vs Hpol vs Cpol vs slant-pol transmitted signals using linearly-polarized receiving antennas, often with conflicting results. Bottom line: CP can help in some situations, but it's not a magic cure. I'm not trying to dissuade anyone from experimentation, just have reasonable expectations on what you'll achieve. --- Jeff WN3A -- This email has been checked for viruses by Avast antivirus software. www.avast.com |
Re: Circularly-polarized antennas for two-way?
Will a voter switch fast/often enough to keep up with the flutter style fading? Eric WB6TIX On Mon, Nov 21, 2022, 09:00 RFI-EMI-GUY <rhyolite@...> wrote: Actually, My suggestion is for the second antenna to he a horizontal loop avoiding the hassle and loss related to a CP antenna. |
Re: MIII Programming Software
The last version of the Mastr IIe/III program, which I believe is V17, is what is needed, and it is not tied to a PC. It looks DOS based, but it runs fine in XP at least.
toggle quoted message
Show quoted text
ProGrammer is what is tied to a PC, and I never used it for MIII's. I don't even remember seeing the option for that to be supported. On 11/21/2022 11:38 AM, J Donovan via groups.io wrote:
For the newer stations (stripes) you will need the newer win based software package that is tied to you computer. I don't know if Harris still supports these stations as we bought everytning we needed in 2012. It required an online verification or an activation key for each computer (seat)? by email. |
Re: MIII Programming Software
Having said that and using both packages from my experience on stations we purchased in 2012That has been my experience as well, at least for analog stations. You may need the Windows software to program a P25 station which has a DSP card needed for P25; I don't have any P25 stations so that's just an educated guess... --- Jeff WN3A -- This email has been checked for viruses by Avast antivirus software. www.avast.com |
Re: MIII Programming Software
For the newer stations (stripes) you will need the newer win based software package that is tied to you computer. I don't know if Harris still supports these stations as we bought everytning we needed in 2012. It required an online verification or an activation key for each computer (seat)? by email.
Having said that and using both packages from my experience on stations we purchased in 2012 you can program the newer stations with the older DOS based software (PIA), but using the newer software on the older non striped version will brick them. |
Re: Circularly-polarized antennas for two-way?
Actually, My suggestion is for the second antenna to he a horizontal loop avoiding the hassle and loss related to a CP antenna.
toggle quoted message
Show quoted text
On Sun, Nov 20, 2022 at 09:39 PM, Matt Wagner wrote:
? -- The Real RFI-EMI-GUY |
Re: Series-mode surge protection
Here is a link to the SurgeX SX-1115-RT?datasheet:
According to the datasheet:
This web page describes the theory of operation: "...a reactor with two opposing air core inductors to slow surge current down to a trickle. Any residual energy leaving the inductors is eliminated by a clamping board. It removes all surge energy, allows zero let-through voltage to reach connected equipment, the ground or building wiring, and produces no common-mode disturbances. Its zero let-through technology stops all surge energy, up to 6,000 volts, without producing harmful ground contamination." |
Re: International crystal manufacturing
Nobody ever said they were a full service shop like International was. They sell good stable crystals that you should be able to pop into a channel element and go. ?I have two low band crystals in a Micor base and am not having any problems. ? You are not back to square one, you have a good resource for crystals l, now you just have to do the assembly work yourself. I am sure you will get better results and less frustration than products from Bomar despite paying out the rear end for international shipping by DHL. ? As for the international calling issue, VOIP providers can do whatever they want because they are largely unregulated and don¡¯t have to follow the dialing plan mandated by the state PUC. They try to follow the NANP but due to their revenue constraints they are not going to use a real carrier to get around the world. They stick with other SIPP providers and, as a result, you get what you pay for. ? As for the ¡°dial a code to make a long distance call on a party line to get the billing right¡± that code was called a ¡°circle digit¡±. ?I have never seen it used in practice but see the references in the software for line assignment. ?Only have seen single digit circle digits, never two digit circle digits because party lines never went beyond eight parties so one digit was enough. Otherwise the call went ONI for Operator Number Identification.? Kevin KA0JQO? |
Re: Two UHF repeaters sharing the same antenna.
I did lol? we're going to try to go back up to the side again over the Thanksgiving holidays hopefully we can get this thing back up online and working. Frequency on the ham band is 444.050 plus offset And the commercial band is 462.275 plus offset. I have two other old station Masters down in the shop. One of these I'm going to use to replace the broken one up on the tower. On Mon, Nov 21, 2022, 8:11 AM Jim W7RY via <jimw7ry=[email protected]> wrote:
|
Re: Two UHF repeaters sharing the same antenna.
Jim W7RY
¿ªÔÆÌåÓýI'm sure you knew what I meant... 500 KHz between TX frequencies (not MHz).Jim W7RY On 11/21/2022 7:33 AM, Keith Ford
wrote:
--
Thanks and 73, Jim W7RY |
Re: Two UHF repeaters sharing the same antenna.
Thanks Jim for the reply yeah I have to Motorola Micor and a Motorola quantar they have the same setup as you're talking about but one of them is a six cavitity T1500 and the other a six cavity which should supply even more isolation between the two. On Wed, Nov 16, 2022, 11:30 AM Jim W7RY via <jimw7ry=[email protected]> wrote:
|