MrCoffee

Okay let's work this out. (Seriously) Point to me where to purchase an omi directional antenna with 12db? Thanks for the reply. MrCoffee

Hello, Has anyone installed an entire system on a tower? I have an outside utility box that I believe its big enough to fit two mobile radios, a duplexer (flat Pack) and a power supply and a fan. My thoughts are installing this near the top of a 50 foot tower and running 120 volts AC up the tower to the utility box to feed the power supply. Also a GFI and any other safety switches to prevent any hazard situations. Also maybe an internet connection to an AC outlet to cut the power off from another location in case of an emergency. I am sure there are other safety ideas and such. Now there will be heat issues in the Summer time and probably moisture issues too. In the winter, perhaps moisture as well. Also I am sure there will be some insect or even ants finding their way in as well. But is there anyone who has given this a try? I am looking for results, and of course issues! Since there will be signal loss in the flat pack, and of course in the coax if ran at long distance, this may be an alternative way to get a better signal over the air. Happy Thanksgiving to All! MrCoffee

Sorry I don't get a chance to get in here as often as I would like. Understood on a good duplexer and to have it correctly tuned. On your duplexer, roughly where are you located? Thank you for your reply.

This is a very good reply, well said. Only thing I would like to add. When making a purchase on a radio, be sure the output power will work on the band you plan to use. I found that the 706mrk2G will transmit on GMRS but the output power drops down to about 1.5 watts. WRQC527.... very well said.

I was told a long time ago that each connection takes about .05db from the circuit. It's been a while since I was told so, and my memory isn't the same back then! You can look it up. I personally would have soldered type connectors installed and then have it electrical taped, then some sort of coax seal over the tape and then taped again to protect the coax seal. The first layer of tape protects the connectors from getting the coax seal stuck to the connectors in case you need to separate them in the future. It is always best to have one complete run of coax instead of using a barrel connector. Speaking of which, an 'N' connector should be used for UHF and above. Really 100 mhz and above in my opinion but anyway....

Hello WRKC935, I'm sorry if in my reply sounded as I was maybe angry or disturb or... I guess I was just explaining who I am relating to your reply. Something like that anyway! Also I had worked on installing a new antenna for a friend all day yesterday and the heat from the sun worn me out! I did not take your reply in a harsh way, at least as far as I recall ! Just the same, I'm sorry if I did. Thank you for bringing this to my attention.

I try to be considerate, I don't like confrontation. That doesn't mean I will be quiet, but I will try to void any issues if possible, for the reason for this post. Life is to short, time flies by and later you are ask, where did it go? Thanks for chiming in.

Thank you, but I have had the cables and the connectors for a long time, its about time I start using them! My tower may be anywhere from 30 feet to 125 without counting the run to the house. More than likely though, I will probably place the tower height at 40 or 50 feet. I been around cells sights and other communications for a long time. However I need to learn the in and outs of GMRS. Connections, type of cables, how to seal the connectors, radius of the hardline, grounding, SWR, pointing Yagi antennas, tuning antennas...I have that covered. I just need to know the ins and outs basically. Meaning a good Repeater antenna, a good duplexer, and later down the road a good solid GMRS repeater instead of two mobiles connected for RX/TX. I can make all the connections, climb towers, install towers along with guy wires, and so on, as I have been learning all of this since I started in radio communications at the age of 10. I enjoy the installation experience more then anything! Thanks for the reply.

Yeah that is an issue isn't! One guy says he will tune it on my frequency. ($450.00). The other guy buy as is...(300.00)

Thank you Steve. I will be glad to post back when it happens! Everyone has been very helpful.

I never thought of that idea. I would first have to find who they are. I can't seem to access their repeater. Not sure what tone they may be using either. I have tried all of them! They may have some other coding/tones that I was not trying to use too. It seem that they may not be listed either, but I am not totally sure on that either. I am still searching. Thank you for that "Food for Thought"! In my opinion, that is a very wise thought.

Thank you for your reply and for your help on the antenna and the cabling. I have posted about what antenna to use so to speak or at least an idea of an antenna. I will look up the Laird Base Station antenna. I have several towers that I can employ for height purposes and maybe horizontal separation. However I think I want to keep it as simple as possible in the beginning. (KISS) So I probably will just use one antenna and a duplexer. As for cabling, I have some runs of LDF4, LDF5, and even some LDF7. Maybe even some LDF6, not sure how much though, but cabling I do happen to have. Thank you for your insight and as mentioned I will look up the Laird Base Station antenna.

Hello Steve, Perhaps? Just not at the moment. The group are mostly retired and doesn't have much or any experience using UHF frequencies. At the moment two are trying to communicate simplex. One using a HT only and the other did install a J-pole at maybe 20 feet. The one one with the HT is at lower elavation and the separation is a bit to far, well with only a HT. The group would rather talk simplex or on a private repeater with no one listening in except for the group. Two others can hit one of the repeaters that might be 30 to 45 minutes away. Maybe 30 minutes the way the crow flies. We are all generally close to one another. The one with the HT happens to the fartherest away. He does have a 20 or 30 foot tower that might help aid in getting signal across the way later on. I have purchased the Retevis RA87s and I am planning to installed them together for repeater usage. I figure they may be worth experimenting with as I have mentioned before due to their low price. I have my eye on a couple of DB Duplexers that may cost me $300.00 to $450.00 depending what one I might be able to buy. Anyway thats where I am coming from other then I also think it will be a good experience for me and hopefully for the others as well. Thank you Steve, I do appreciate your replies.

I appreciate the reply as I do from all, thank you. I sense a sign of hope!

Thank you for the reply. Being new to GMRS I just didn't want to rock the boat if its something thats not etiquette.

Okay here's the issue. I am wanting to place a repeater on a pair of frequencies. However, when searching for a Frequency to park on, there aren't any that aren't being occupied. So I have searched and I have been listening through the frequencies for the weakest repeater signals near me. So far I may have a place to park a repeater on a pair, as the repeater that has already perhaps been established but doesn't seem to be registered in no way that I can find is very weak on my receive. With that being said, my thoughts are maybe install an antenna at a given height that may in no way interfere with the said repeater. I am only looking to cover an area for some local folks within maybe a 10 miles or less radius. I even thought of using two antennas. Of course one for Rx at a higher height and the TX antenna at a much lower height which is practical for a repeater anyway and lowering the TX power as much as possible. (At Least this is what I have been learning anyway) I have posted about placing a repeater on the air and discussing antennas along with gain so to speak, but I just realized my situation that I am coming up against, in which is throwing a wrench in the equation. Any commits are appreciated either toward a solution using the same given frequency or even a reason to be against using the same frequency along with your opinion why. I only ask to be open to the idea that there aren't any unused frequency pairs available and having the idea of helping a small group of people in a small foot print. Thank you.

Vey interesting on the Dimond stacked antennas. I never heard that title or never heard from anyone ever experimenting with this idea. I may have seen this set on a Cable TV company's Tower with four yagis antennas in this configuration, but I never gave it a second thought. I find this set up very interesting indeed. I am aware if stacked above one another this will result in a forward gain compared to side by side where the gain is more left to right covering a broader distance instead of a forward distance. Of course in a H Frames configration the gain is both broader to the right and left as well as in the forward direction. Thank you for the link. I haven't looked at a Smith Chart or I should say a part of one in a while.

Oh okay I see how you came up with that now, since you spelled it out for me! Since the dipoles are in Parallel, you took the value of 72 and divided it by the four dipoles, I gotcha!

Just now seeing this... Thank you.

Thank you Steve, that helps clear things up.

Hello, I appreciate your comment, as I appreciate everyone who are chiming in. After what Steve Shannon had brought up about the cancellation, this stopped me in my tracks to rethink this idea. One thought that comes to mind is the 8 and especailly the 16 Folded Dipoles that is on the market. There has to be some over lap or cancellation involved with those antennas. As mentioned, especially the 16 element Folded Dipoles. Some more research is in order thats for sure. Perhaps I could shorting the Yagi down to only 2 elements and observe the results. It will not erase or change what has already been said, but at least it will allow me to experience the results that perhaps lead in a positive direction.(?) With that being said, I just had the thought of the second element only being mounted horizontal instead vertical. One thing I have learned in this RF hobby, the higher in frequency, the more critical things get with interesting results.

Eznec should surely show something. Yes agreed, a splitter would attenuate. And again as you mentioned with a fixed output doesn't help so to speak. I understand the impedance matching between the antennas. How come you mention 18 ohms? Are you saying 18 ohms due to all four or 18 per antenna? I was thinking somewhere around 75 to 80 ohms per antenna by themselves. As for the cancellation between the antennas, that would be quite true! I never gave that a thought, and I am glad you brought that up. I will have to rethink this idea and perhaps put it to rest. Thats an important factor to consider.

Well the Folded Dipoles coax are all connected together, not using splitters, I'm just saying. (?) However I would agree if using splitters or some sort of combiner would result in some attenuation. I don't want to over think this, but I don't want to think this can work, when actually it cannot or perhaps wouldn't be worth any possible gain when its all said and done. Again as I had mentioned, I am paying attention what is being said. I do appreciate any input as its good food for thought!

Hello, I believe the antennas on a cell towers per face so to speak are connected per radio down in the radio cabinet. Back in the day the cells ran three radios and then later added another cabinet with three more radios. The tree antennas per face had one transmit antenna in the middle and two receive antennas on either side. Perhaps I am misunderstanding what you are explaining, but I am paying attention, trying to anyway!

This idea may be far from actually working, but has anyone experimented with this idea? (Seriously) Think of the Folded Dipoles that are roughly a 1/4 wave separation between one another. (From top to bottom) Now instead of Folded Dipoles, install Four 3 element Yagis. Either installed them with a 1/4 wave separation as the Folded Dipoles or make up a special mount so that they will face North, South, East, and West but have them back to back so to speak. Meaning they would be all in the same plane (level with one another) but facing the said direction. I would like to think if 4 simple Dipoles can be tuned, why not 3 elements yogis instead of a single element. Sure, phasing cables would have to be calculated as such. The reason for only 3 elements per antenna, I am thinking the signal pattern may start to get tighter than one might want. I wouldn't actually called them in phased either but I hope someone is getting the idea. I would Just like to hear anyones thoughts on the idea. Just a little back ground, I used to run Four 15 elements Yagis in what I call True Phase arrangement. The frequency was between 144-148mhz. I hardly ever used an amplifier. One last thing I must add. This idea isn't for a single station, but the idea of using this type of antenna for Repeater use. All I ask here is to keep an open mind!!! Thank you.