boost signal 150 - 161 Mhz VHF

[balihi]

I work for a commercial towing company and we are having trouble with our marine radios. I have an antenna at about 60' but would like to boost its signal, especially on the receive end since most of the boats in trouble are going to have very low to the water antennas...can anyone reccomend an inline amp, or antenna setup that would help. im brand new to the forum and don't know anything else about VHF except that mine puts out 25 watts, the stations im interested in are between 150 and 162 mhz and VHF is line of site so antenna heigth is paramount. an amateur radio operator i met said that "if you could find the proper bandwith, a wire strung between two trees should blow your antenna outta the water"...make any sense?
thanks

 

[rfradioconsult]

First have your radio checked by a marine radio shop to ensure it is operating to specification. Check your antenna and feedline; you may see some benefit from upgrading your feedline to a less lossy line and perhaps the antenna can also be upgraded to a more efficent type with more gain than what you presently have.

Stay away from any sort of pre-amp, they can cause additional interference issues, for your application you want solid perrformance, not a makeshift patch.

Your "ham" friend was perhaps referring to HF-SSB and not VHF operation; at VHF frequencies height is everything.

 

[archduke]

With your tower height you have solved half of your problem...it's plenty high. Now do yourself a favor get out a bolt cutter, climb to the top of the tower cut off the shakespeare or digital antenna that you have on top as well as the so called premium rg8x white "marine grade" coax and give it to the other guy in town (red and yellow don't mix well...I know)...let him suffer with the poor performance.

#1 You need a professional antenna, one that will last more than a few seasons, and one that is rated in true electronic capabilities...for instance, a professional antenna like a Celwave/phelps "stationmaster" type rated at about 6db gain completely dominates any shakespeare or digital antenna "10db" antenna.

#2 Look on ebay for LD4 type 1/2" hardline heliax If you have a 60' run on the tower, try to find a hunk of cable that will go from the antenna to the radio without needing splice(s). the following is just an example:

Andrew 20ft 1/2" FSJ4 Heliax Coax Cable GR8 4 Ham Radio - eBay (item 290334142314 end time Aug-01-09 06:03:04 PDT)

Hopefully get a role with either N or UHF connectors already on each end, you can always fix any mismatches later with an adapter.

You are going to choke when you find out that the list price for a "stationmaster" is over $1000 or a 4 bay folded dipole like a decible products 6/9db antenna is in the same price range. Keep looking on ebay and craigslist they turn up once in awhile, ask your ham friend who recommended a piece of wire if he knows any hams that are running a 2meter repeater...they may know more about it than the "piece of wire" guy.
If you have to by a new antenna, try to get on to the Tessco radio parts site, they are in suburban Baltimore, they stock the antennas and sell them much less than list price but still in the $600+ area.

Look at it this way: If you yank a 25' grady off the beach tomorrow, you just earned at least $2500 so there you go.

PS a receive pre amplifier is a very bad idea, it will add problems not solve them. If you go with a Celwave or Decible Procucts grade antenna (Just like the CG rescue 21 system) you will find your biggest problem is you can't turn the squelch tight enough to get rid of the radio traffic from far distant areas.

 

[gewecke]

I agree with what the duke suggested! Only to add that a few days ago someone here on RR had a VHF Stationmaster for sale for $30!!! Many people don't like these antennas because they are long,at 24' and they do have some weight to them,but damn are they good. I've seen many that have been up for years with little or no wear at all. As mentioned stay away from preamps,because most of what you'll amplify will be noise from other electronics in the harbor or land based equipment. The celwave antennas are pricey but you won't suffer in the performance area.
Good luck!
N9ZAS.

 

[trainman111]

Here's a Celwave antenna for sale that's listed in the For Sale forum for $30. Sure seems like an awfully good deal!

http://forums.radioreference.com/radio-equipment-sale/152255-celwave-vhf-base-antenna-great-rr.html

 

[archduke]

Here's a Celwave antenna for sale that's listed in the For Sale forum for $30. Sure seems like an awfully good deal!

http://forums.radioreference.com/radio-equipment-sale/152255-celwave-vhf-base-antenna-great-rr.html

No doubt about it, this is a nice little antenna, good quality too... BUT not what is called for in this application. The "stationmaster" type of celwave is about 22' long, weighs about 30 -40 lbs, has 5-6dB of real gain and can't be shipped in a UPS tube, it ships by truck.

 

[prcguy]

My little Cellwave antennas are not the right thing for this application. The other posts are right on, the big 21ft long Stationmaster or 4-bay dipole array is it and don't forget the low loss feedline. If your comms are within a 180deg or less area the dipole array can be set for this and will have an additional 3dB gain.
prcguy

 

[SCPD]

Your antenna and feedline are the most crucial aspects of a radios system. I use only commscope or andrews heliax on VHF and up. I used to swear by the Decibel Products antennas, and still believe they are great. However, i have found that a Hustler G7 on vhf has been standing up to the performance i have gotten from the DB-224 antennas ive used in the past. I swapped out a 224 with a G7 on the same repeater and 1/2" heliax 2 years ago, and its still goin strong. Heck of a lot cheaper too. I have actually seen improved range on portables.

 

[RKG]

If you are operating a shore-based station on the Marine VHF channels, then you have a Limited Coast license, and the parameters for power etc. are stated on that license. I've heard of LC licenses for more than 25 watts but never seen one.

 

[ecps92]

Maybe even remoting the Radio to a Higher Site and Wireline/RF it back to the Dispatch Location

Height is the better option :wink:

If you are operating a shore-based station on the Marine VHF channels, then you have a Limited Coast license, and the parameters for power etc. are stated on that license. I've heard of LC licenses for more than 25 watts but never seen one.

 

[prcguy]

The G7 is down about 3dB in gain from a DB224 and the Hustler's don't do well in a marine environment. I had a G7 and several of the smaller UHF versions and the aluminum at the fiberglass coil junctions turns to white powder and the antenna falls apart in about 6 or 8 years at my location near the coast. I still have a 20+yr old DB224 up, its a little pitted from corrosion but fine otherwise.
prcguy

Your antenna and feedline are the most crucial aspects of a radios system. I use only commscope or andrews heliax on VHF and up. I used to swear by the Decibel Products antennas, and still believe they are great. However, i have found that a Hustler G7 on vhf has been standing up to the performance i have gotten from the DB-224 antennas ive used in the past. I swapped out a 224 with a G7 on the same repeater and 1/2" heliax 2 years ago, and its still goin strong. Heck of a lot cheaper too. I have actually seen improved range on portables.