RadioBanter - View Single Post - Recomend dual band VHF / UHF antenna for two radios

Channel Jumper · March 14th 15, 02:24 AM

"Tom W3TDH" wrote in message
...[i]

As I already said I am not totally conversant with D-STAR. I was under the impression that the persons participating in any given QSO could hear each other over the access point they were using. I had pictured it as somewhat akin to the remote receivers on our club's analog FM repeater in that the other users on the QSO would hear the conversation over the repeaters output. Our D-STAR repeater is located in Germantown and I do not actually know what it's effective range is. We operate six different sites with four repeaters, four remote receivers with radio links back to the analog two meter repeater, and two APRS digipeaters. In addition to those sites we will have several members hosting D-STAR hot spots in order to fill in the edges of our service area that are outside the effective receive range of portable radios. Those using mobile or base station radio will, hopefully, be able to raise the repeater without resorting to one of the hot spots We can make changes to the location of the various elements of our repeater system including the location of the D-STAR repeater itself if that is needed to allow all users to hear the conversation.

On the harmonic de-sensing issue I can purchase a DCI low pass filter that cuts off at 160MHz if that becomes a problem. It would be inserted between the two meter radio and the filter/diplexer so that the harmonic would not reach the diplexer at all. Part of this question affects operations well beyond my home location. The county ARES unit is gearing up to support hospital emergency communications in our area. Our first client hospital purchased an Icom IC-7100 transceiver for the hospital station. If that remains the only transmitter at the hospital's EOC then the use of directly connected multi band antennas will work fine. But if the hospital discovers that it needs more than one mode or frequency to be used at the same time then our team will have to devise a Diplexing setup in order to keep the two radios from clobbering each other. I could see them needing both local tactical voice and medium range digital at the same time in a real disaster situation.

In the Mid Atlantic region the most common natural disaster with region wide effects are severe ice storms. Since I moved to three land in 1980 we have had three such storms that have wiped out communications infrastructure over wide portions of our region. It usually takes at least a week to get all of the wires and fibers back up in the air. Were about fifteen years out from our last bad one so we're about due. The hospitals have learned that continuing to operate when it is very difficult to talk to anyone that is not on campus is more than challenging. That's why I think they are going to want more than one communications pathway available to them and nothing carries long documents as quickly and accurately as digital.

Thanks again for taking the time to help on this.

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Tom Horne W3TDH[/quote]

Tom,
The ICOM IC 7100 is a lousy choice for a all in one rig for what you are trying to do and I don't think that it is going to be sufficient for your needs. You need to have separate rigs for your UHF / VHF and your HF so one can be sending messages digitally while the other one is being used on FM phone to communicate with your Indians in the field.

You need to talk to the hospital and impress upon them that everything other then dealing with the other local hams, on a local basis is probably going to take place digitally on the HF, either 40 or 80 meters.

Find someone to put on a presentation for your group about NBEMS / FLDIGI
The Sunday morning net would be a good place for your group to start.
I'm sure that Dave KB3FXI would be more then happy to help, as time permits.
What you are going to find is that everything is going to run either through your section manager and The Phone Traffic Net, or ARES, or Races, or FLDIGI.

I'm not sure where you are located at, most of what I concern myself with is with the third region, but also participating on the State Wide - once a month net - RACES, Central and Western Region nets, along with the Saturday morning ARES nets and the late Sunday morning NBEMS nets.

What your group is going to find will be two fold.
First off - D-Star Sucks!
Second - with the advent of the new Yaesu System Fusion repeaters, that does a lot more then what D-Star does, the D-Star system is going to become defunct, while the System Fusion is going to be the Ex Post Facto once a emergency happens and the people in charge see's how good the System Fusion works and more people buys a radio.

The only thing D-Star had going for it was the fact that they gave repeaters and radios away and they gave the ARRL heaps of money to promote D-Star.
The ARRL pimps and panders for anyone or anything that puts more money into their coffers.