GainMaster

**stang** · 04-04-2014, 11:27 PM

I bit the bullet and ordered the Gainmaster tonight should be here by next friday. Is the LMR-400 coax worth the extra cost? Only want to be buying once. It's about twice the price and I wont be running a lot of power as the gainmaster has a 500w limit. Someday down the road after I can build a tower I might be able to run more power through a different antenna. (beams) Although I will probably leave this antenna up and have them switchable.

Had to order the gainmaster through amazon H&Y is out of stock and DNJ radio's site didn't want to accept my card or paypal.

How high up should I go with this antenna. We are down in a bottom our TV and cell antennas are both roughly 40 ft off the ground. When I do this I would like to put the cell antenna on the same mast 10-20 ft below the cb antenna. Will this cause any problems? It's a small directional antenna less than a foot triangle. The mast will of course have guy wires. And yes I am planning to use top rail for mast I am to old and weak to be using iron pipe anymore. Ideally I am thinking a 60 ft mast with the cell ant. at 50 ft.. Luck me I don't have any neighbors to cause problems.

Thanks

**NY714** · 04-05-2014, 04:19 AM

As high as possible with antenna, and don't push 450-500 thru that antenna it won't handle it, friend of mine ran 500 watts and burnt out antenna in less than one week. Good for 300-400 watts. Definitely the LMR-400 will be the Best but don't get all the knock-off's, get the Times Microwave only LMR-400. The knock-off not nearly as good. MPD Digital is a company on web and Ebay that strickly sells only "Times Microwave" brand and it will work great.

**stang** · 04-05-2014, 07:34 AM

How long can coax be before you start having big loss issues?

Thanks

**wi544** · 04-05-2014, 08:23 AM

google wire gainmaster,, you can make one that will handle more power and be more efficient,, it uses rg-213 for the capacitor and rg-213 for the matching stub and a coax choke at the base just like the gainmaster. I made a few of them forless than $20 each and side by side with the original gainmaster work great could not tell the diff when on a coax switch,,, hang them in a tree or attach them to a fiberglass pole and mount like any antenna.

**stang** · 04-05-2014, 08:34 AM

Originally Posted by wi544

google wire gainmaster,, you can make one that will handle more power and be more efficient,, it uses rg-213 for the capacitor and rg-213 for the matching stub and a coax choke at the base just like the gainmaster. I made a few of them forless than $20 each and side by side with the original gainmaster work great could not tell the diff when on a coax switch,,, hang them in a tree or attach them to a fiberglass pole and mount like any antenna.

Wish you had told me that before I ordered the gainmaster. Thanks though. I will look it up and check it out.

Thanks

**222DBFL** · 04-05-2014, 08:24 AM

If you are going to use times microwave lmr400uf, the loss is very minimal to 100ft. Here are some specs from times microwave:
TIMES MICROWAVE SYSTEMS
Electrical Specifications
Performance Property Units US (metric)
Velocity of Propagation % 85
Dielectric Constant NA 1.38
Time Delay nS/ft (nS/m) 1.20 (3.92)
Impedance ohms 50
Mechanical Specifications
Performance Property Units US (metric)
Bend Radius: installation in. (mm) 1.00 (25.4)
Bend Radius: repeated in. (mm) 4.0 (101.6)
Bending Moment ft-lb (N-m) 0.5 (0.68)
Weight lb/ft (kg/m) 0.068 (0.10)
Flexible Low Loss Communications Coax

• Drop-in replacement for RG-8/9913 Air-Dielectric type Cable
• Jumper Assemblies in Wireless Communications Systems
• Short Antenna Feeder runs
• Any application (e.g. WLL, GPS, LMR, WLAN, WISP, WiMax,

**stang** · 04-05-2014, 08:37 AM

Originally Posted by 222DBFL

If you are going to use times microwave lmr400uf, the loss is very minimal to 100ft. Here are some specs from times microwave:
TIMES MICROWAVE SYSTEMS
Electrical Specifications
Performance Property Units US (metric)
Velocity of Propagation % 85
Dielectric Constant NA 1.38
Time Delay nS/ft (nS/m) 1.20 (3.92)
Impedance ohms 50
Mechanical Specifications
Performance Property Units US (metric)
Bend Radius: installation in. (mm) 1.00 (25.4)
Bend Radius: repeated in. (mm) 4.0 (101.6)
Bending Moment ft-lb (N-m) 0.5 (0.68)
Weight lb/ft (kg/m) 0.068 (0.10)
Flexible Low Loss Communications Coax

• Drop-in replacement for RG-8/9913 Air-Dielectric type Cable
• Jumper Assemblies in Wireless Communications Systems
• Short Antenna Feeder runs
• Any application (e.g. WLL, GPS, LMR, WLAN, WISP, WiMax,

Any others I should look at or is this about the best? Right now it seems to be a toss up between RG213 and LMR 400.

If I am reading you correctly I need to stay to 100 ft or less?

Thanks

**NY714** · 04-05-2014, 10:17 AM

Originally Posted by stang

Any others I should look at or is this about the best? Right now it seems to be a toss up between RG213 and LMR 400.

If I am reading you correctly I need to stay to 100 ft or less?

Thanks

Huge difference between the RG213 and Times Microwave LMR-400, can do the 100' run with the LMR-400 no problem but the RG-213 is going to have much bigger losses. RG-217 is more comparable to the LMR-400. I still say the Times Microwave LMR-400 and can go 150' if have to with minimal losses. check the spec's. Or go with the RG-217 Military Spec Coax which is as expensive if not more than the real Times Microwave LMR-400. Good Luck

**222DBFL** · 04-05-2014, 08:59 AM

No you don't have to stay 100ft or less. The loss on lmr400 is like 1db over 100ft I want to say, not enough that anyone including you will ever notice. And yes get the times microwave lmr400. Get the UF make (UF=ultra flex) as it is easier to work with. Run it once and be done. This same coax is still in use on most E911 systems in almost every cell site around. It is top notch quality coax and will last a very long time. It is made to handle the elements and weather alike. All of this is JMO, but if you want do some research and I promise you will find that this coax pops to the top of the list for any install. Mobile or base. Like I said, I use the lmr240 that's made by them for my mobile coax and the lmr400 for my jumpers. Overkill, maybe, but I have been told too many times that my mobile sounds like a rolling base station. Like I said before, don't skimp out on anything antenna system related, that goes for connectors, coax, and antenna. Amphenol makes good pl259 connectors that will go onto the lmr 400 nicely. If you want to step it up google Andrew and have a look at their connectors. But for the power you are running, pl259's should work fine. Like I said, get good ones, not the truck stop brand. Take your time making all connections and you will be a happy camper.