Base Station Antenna Question

[Cpch64]

Current Setup:

Wouxun KG 1000 Radio --->50' LMR 400 Coax-->Ed Fong UHF  +5 db Antenna (Approx 25'-30' above ground level attached to chimney)

I'm getting a 1.01 SWR reading and showing 51 watt output reading on SWR meter.  During evening & morning hours I can get an approximate range of 48 miles to a repeater located in New Orleans but during the day it is not possible.

Question:

If I were to purchase a CommScope DB404B or DB408B in your opinion would this increase my range in the RX&TX?  Going from a $50 antenna to a $500-$900 is a big jump.  Any advice would be appreciated.

Thanks,

 

 

[Sshannon]

1 hour ago, Cpch64 said:

Current Setup:

Wouxun KG 1000 Radio --->50' LMR 400 Coax-->Ed Fong UHF  +5 db Antenna (Approx 25'-30' above ground level attached to chimney)

I'm getting a 1.01 SWR reading and showing 51 watt output reading on SWR meter.  During evening & morning hours I can get an approximate range of 48 miles to a repeater located in New Orleans but during the day it is not possible.

Question:

If I were to purchase a CommScope DB404B or DB408B in your opinion would this increase my range in the RX&TX?  Going from a $50 antenna to a $500-$900 is a big jump.  Any advice would be appreciated.

Thanks,

 

 

I can’t answer your question, but what about something like this:

https://www.dxengineering.com/parts/cma-ca-712efc

 

 

[Cpch64]

I appreciate the information.  Looks like something i could try and if would not work out i would not cry as much :}.

TY

[Sshannon]

10 minutes ago, Cpch64 said:

I appreciate the information.  Looks like something i could try and if would not work out i would not cry as much :}.

TY

The reason I looked at Comet was because I followed a rabbit trail that started here. I read some posts here from some highly respected people like Marc Spaz that gave high marks to the Comet CX-333 tri-band antenna. 

So then I searched for a review of the antenna and found a comparison test of the Ed Fong antenna to the cx-333. 
The Comet did a couple dB better, which is significant.

Then the guy who did the tests contacted Ed Fong to get his comments. Mr. Fong spoke very highly of the Comet antenna and also of the Comet company and how accurately they advertise their products. 

 

[Cpch64]

Great info

TY

[JB007Rules]

I have a DB408 on my house, a 408 on my Rugged 575 TX antenna and a DB420 on my Crete 600 repeater tower and I can say 2 things for certain:

1) A DB408 will run CIRCLES around any amateur/consumer grade antenna.  END OF STORY, it's like comparing a Neon to a Lambo for speed.  Folded dipoles are far superior to any fiberglass stick.  This is the same reason all our public safety systems use them too.  Also why you see VHF dipoles facing all the same way to send RF up and down a long railroad track.

2) LMR400 is garbage compared to actual hard line and is a a *VERY* high loss line at these lengths.  at 50', not even including connectors you are losing at the minimum of 25% of your power.  At 100' of course it's 50%.  Yes, you read that correct.  The correct way to do it would be to put actual 1/2" hard line in.  Yes, it's *SLIGHTLY* more money and you have to know how to put it together but for $200 you can get a correct tool to do this termination.  I also own this tool and I have some spare line I wouldn't mind helping you over a video call.

 

If you're going to go big with a DB404 or 408 and use junky LMR400 that would be like getting a 1,000HP diesel truck and putting a transmission from a smart car in it.

 

Send me a PM if you want to chat on the phone.  I'm not a 100/100 when it comes to this stuff but I do have a bit of experience in putting in high profile repeaters and this is all we use here in the Midwest.  Even if you went with a DB404 you will be SHOCKED at what you can do with it but that LMR *HAS* to go if you're going to a big boy antenna!

 

Thanks!

[Sshannon]

1 hour ago, Cpch64 said:

Great info

TY

So here are some things to consider.  For many of us this is a hobby.  For others it's a livelihood or a quest for the technically perfect.

The Commscope DB404-B is probably a helluva antenna.  It's certainly built like a tank and it looks cool; folded dipoles do.  Also, according to the Commscope site it has a gain of 5.9 dBi.  That's certainly not bad.  JB007 is probably right in comparing it to a Lamborghini. Solid Signal has them for a little more than $426. 

https://www.commscope.com/product-type/antennas/base-station-antennas-equipment/base-station-antennas/itemdb404-b/

 

The Comet is not as unique looking.  It's not sold as an amateur radio antenna.  Comet does market it as a Commercial antenna.  Of course anyone can say nearly anything, but remember what Ed Fong said about his confidence in their published characteristics.  It has a gain of 9 dBi, which is 3.1dB better than the DB404-B.   

Yes, LMR 400 has higher loss than hardline.  Nobody would dispute that.  Your antenna is probably at the end of a 50' cable, possibly 75'.  The loss for LMR400 is 2.7dB at 100 feet at 450 MHz.  Hardline has losses of 1.63 dB per 100 ft for the half inch diameter, 1.12 dB for 3/4 inch cable, so for a 50 foot cable the difference is 1.1 dB.  For longer distances it starts to add up, but if you're using only 50 feet you probably cannot tell the difference.  Plus, the LMR 400 is already paid for.

So, with a 50 foot drop, the combination of the $140 Comet antenna and LMR 400 cable that you already have still works out as 2 dB better than the Commscope antenna plus hardline.  It might not be quite as durable, but the Comet is rated for up to 112 mph winds.

It sounds like you're just trying to get a little bit more range from your base station.  None of us can make your decision for you.  A professional facility that must have 100% reliability would almost certainly go for the Commscope and hardline and I completely agree that would make sense.  But they would also probably use a Motorola radio and have a very complete ground system and lightning protection as well as a tower set in a block of concrete.  I guess the point I would make is simply that a person can spend a lot of money while only making incremental improvements that are not proportional to the cost.  Best is the enemy of good enough.

As far as the Comet antenna, other people have spoken highly of it on this forum as well: 

 

[Cpch64]

I can't thank you both enough for the information!!!

I went ahead and ordered the Comet GP-6NC GMRS/FRS Commercial Dual-Band VHF/UHF Base Vertical Antenna from DX and will give this a try 1st.  For $169 no biggie if it doesn't work out.  It is showing 9db gain and it will give me a bit more height also. https://www.dxengineering.com/parts/cma-gp-6nc

JB007Rules I may take you up on your offer either way and its much appreciated.  I want to test this antenna out first and then possibly donate it to my son or one of my friends that is getting into GMRS.  I just don't want to burn a grand on an DB408 this month since it could be my Christmas present within the next couple of months :}.

 

Many Thanks,

 

 

 

[Sshannon]

That seems like a very reasonable course of action.  Please be sure and let us know how you like it.

[Flameout]

I was using a Comet ca-712EFC and it was working quite well, other than hitting the 1 repeater I wanted to reach. I finally broke down and bought the CommScope DB404. Maybe I was expecting miracles but it performs worse than the Comet 712

I currently have both antennas mounted with about 24' of Andrew Helax ldf4-50a feeding the DB 404 and 50' of ABR Industries ABR400-UF (25400F) for the Comet. Both mounted at approximately the same height and about 20-25' between them. 

The DB404 will certainly outlast the Comet but if I had to do it again, I would have just bought a second Comet and saved myself $300

[wayoverthere]

9 hours ago, Flameout said:

I was using a Comet ca-712EFC and it was working quite well, other than hitting the 1 repeater I wanted to reach. I finally broke down and bought the CommScope DB404. Maybe I was expecting miracles but it performs worse than the Comet 712

I wonder if the difference between the antennas is in signal pattern.  I have a vague memory of a post mentioning the Commscope antennas mostly being designed for tower use, and with a tendency to focus the pattern downward somewhat.

Where my line of thinking is going: Combining the 0 degree downtilt, 27 degree beamwidth, and this illustration, has me thinking of the possibility that the DB404 is just putting the signal below those other stations you're aiming for...the coax/hardline lengths also makes me think they aren't up all that high.  A bit of searching didn't find me a spec for beam width or tilt for the Comet, but i'd expect it to little more balanced above and below horizontal compared to the Commscope.

Then again, I may be assuming too much and way off base.

[JB007Rules]

Well I will say this. I have an extremely tall house. In addition to having a tall house when you go all the way up to the peak where the pitch is which is where the antenna is mounted it's another 10 ft gained. The base of my db408 is at about 37 ft with the tip extending up to about 47 ft. I am in a fairly new subdivision as well where there are not many trees but I could tell you right now that I could see out for miles. I could see out far further from the roof of my house then the neighbor's house because of how tall it is so height is might. I'm almost wondering if the comet antenna was performing better to the gentleman that had it at 20 to 25 ft tall because you're not getting above the tree line or your neighbor's houses. I'm not an RF expert by any means but in my circumstance where I'm at here in Illinois a compscope (Andrews is who invented it) with folded dipole antennas run circles around pretty much all of the fiberglass ones I've used. That's not the only antenna I have on the roof of my house. I also have a very cheap $60 fiberglass stick (Tram BR-6140) just to get a connection back to my main repeater which is only 10 miles away so for that logic there as a link radio, I wasn't going to spend a ton of money on another high-end antenna when I only needed it to go 10 miles. Certainly everybody's circumstances are different and I don't blame you for not wanting to spend $1,000 on this antenna at this point. I only paid about $750 for mine far before inflation and this country went down the drain. Hell, I was paying $1193 for DB420's before bidenflation and they are $1475 now so I get it, trust me.

 

My furthest contact was down in Louisville Kentucky about a month ago and I got into the KARS repeater... that's about 300 miles or so from me and i did it on 5W so to me, it's worth it.

 

Ohh and I'm at about 100' run for both antennas.  I am using LMR400 for the baby link antenna and using 5W. I measured the power on the roof and it was at 2.3W so IMO LMR is junk period. I will concede though that it does have its place on this Earth and that it is far easier to work with. Obviously I'm doing what I need to do with only 2.3 watts all day so no need to spend money on the better line there either. And in my opinion at 100 ft LMR is just absolutely abysmal. It's literally over 50% loss at 100'

 

I built all of my infrastructure for emergency use so if anything were to happen I have communications. So for me it would be a matter of life and death even though I hope that that is not the case ever for me or my children but I'm ready and when me, my wife, or one of my children hits the button to talk it's going to freaking work.  Buy once cry once.

 

I appreciate the other replies too BTW. Internet forums can sometimes be silly with people saying stupid things but I think every single person that's replied to this thread so far has been absolutely great in offering opinions and comments!! Kudos to you all!  Randy from Notarubicon would be proud of you all 

[KAF6045]

45 minutes ago, JB007Rules said:

Well I will say this. I have an extremely tall house. In addition to having a tall house when you go all the way up to the peak where the pitch is which is where the antenna is mounted it's another 10 ft gained. The base of my db408 is at about 37 ft with the tip extending up to about 47 ft.

Lucky you... Zoning limits at my location are a MAX of 35 feet (which was basically equivalent to the power lines, before the city moved the power lines underground and removed the poles) -- EXCEPT for licensed AMATEURs who are permitted 75 foot (of course, in my lot, even a 35 foot would risk falling into a neighbor's yard -- lot is only around 80 feet wide; I'd have to install dead center to have any leeway.

 

[Sshannon]

So today I accompanied the young man who maintains our amateur radio repeater. Our repeater is at about 9700 feet MSL, which is about 4,000 above where I live. Our repeater has an amazing coverage on 2 meter, reaching nearly a hundred miles in some directions, despite being situated in a mountain range. Our repeater uses a collinear array of four folded dipoles. Because they are a phased array the coverage pattern can be electronically modified wider coverage or to tilt the pattern by adjusting the phasing harness, but of course wider coverage comes at the cost of lower gain; which is why the Comet has higher gain. Here is a picture of the tower with our antenna being the highest 4x folded dipole array and a picture of the view towards Butte from the lookout. 

[Cpch64]

Man I'm envious of that view!

Again I cant thank everyone enough for the information and will report back in a few days since it shows the antenna arriving tomorrow. Sshannon I also appreciate the link to DX.  I ordered that antenna late Friday and with free shipping it will be here Monday.  They don't mess around.

TY

[Sshannon]

Unfortunately, our repeater guy hasn’t been given a key to the new gate lock. So, we had to walk up the last 1,300 feet (vertical feet, many more than that horizontally through numerous switchbacks over lose shale).  Here’s what it looks like from where we parked looking up at the tower.  The smudge on top of that rocky bump is it.  I won’t need to take a stress test.

[tcp2525]

On 10/7/2022 at 5:37 PM, JB007Rules said:

I have a DB408 on my house, a 408 on my Rugged 575 TX antenna and a DB420 on my Crete 600 repeater tower and I can say 2 things for certain:

1) A DB408 will run CIRCLES around any amateur/consumer grade antenna.  END OF STORY, it's like comparing a Neon to a Lambo for speed.  Folded dipoles are far superior to any fiberglass stick.  This is the same reason all our public safety systems use them too.  Also why you see VHF dipoles facing all the same way to send RF up and down a long railroad track.

2) LMR400 is garbage compared to actual hard line and is a a *VERY* high loss line at these lengths.  at 50', not even including connectors you are losing at the minimum of 25% of your power.  At 100' of course it's 50%.  Yes, you read that correct.  The correct way to do it would be to put actual 1/2" hard line in.  Yes, it's *SLIGHTLY* more money and you have to know how to put it together but for $200 you can get a correct tool to do this termination.  I also own this tool and I have some spare line I wouldn't mind helping you over a video call.

 

If you're going to go big with a DB404 or 408 and use junky LMR400 that would be like getting a 1,000HP diesel truck and putting a transmission from a smart car in it.

 

Send me a PM if you want to chat on the phone.  I'm not a 100/100 when it comes to this stuff but I do have a bit of experience in putting in high profile repeaters and this is all we use here in the Midwest.  Even if you went with a DB404 you will be SHOCKED at what you can do with it but that LMR *HAS* to go if you're going to a big boy antenna!

 

Thanks!

I'm partial to the ASP705K, which has good gain and really holds up well. I like the fiberglass radome as it protects the antenna from the elements unlike the folded dipoles on the 404/408. Both antennas are good, just how much money do you want to spend.

[Cpch64]

Reporting Back:

Thumbs up on the "Comet GP-6NC GMRS/FRS Commercial Dual-Band VHF/UHF Base Vertical Antennas GP-6NC"!!

It bridged the gap on the TX side and better RX.  I'm now able to talk with both repeaters 45-58 miles away during daytime hours in which i could not do before. 

Many thanks for all the information!!

[Sshannon]

4 minutes ago, Cpch64 said:

Reporting Back:

Thumbs up on the "Comet GP-6NC GMRS/FRS Commercial Dual-Band VHF/UHF Base Vertical Antennas GP-6NC"!!

It bridged the gap on the TX side and better RX.  I'm now able to talk with both repeaters 45-58 miles away during daytime hours in which i could not do before. 

Many thanks for all the information!!

That’s great news!

 Thanks for the update. 
Steve 

[flashover52]

Curious if anyone has tried a GMRS tuned yagi, such as the one Tram Browning sells?

[Sshannon]

4 hours ago, flashover52 said:

Curious if anyone has tried a GMRS tuned yagi, such as the one Tram Browning sells?

I haven’t used one for GMRS but I have used Yagi antennas for finding radio trackers. If you only want to reach in one direction, such as to a repeater, a Yagi is a good way to enhance gain, but it will be nearly deaf in other directions, so it might not be a good choice to talk to your friends on simplex.

How would you picture yourself using it?

[kidphc]

Also if you don't want to work with hardline for 100 foot runs LMR600 can work well. Hardline is still less lossy.

Have you tried adding an extension to your mast mount? This could help with far receive. Having a good antenna helps, but uHF really likes height. Even with that said, its a matter of luck sometimes. Sounds like you were experiencing some light ducting in the early morning, that wasn't there at night.

[BearFamily]

UHF frequencies work better during the evening/night/morning because of the sun ionizing the atmosphere. 

[KAF6045]

14 hours ago, BearFamily said:

UHF frequencies work better during the evening/night/morning because of the sun ionizing the atmosphere. 

Not really -- VHF & UHF (and microwaves) are used for satellite control BECAUSE the wavelengths PASS THROUGH the ionosphere with minimal effect. 6m skip is somewhat rare except at solar peak, and 6m is considered in the "VHF 'octave'" (30-300MHz, HF is 3-30MHz, UHF 300-3000MHz).

HF frequencies, OTOH, are affected by ionization, and are why many AM broadcast stations have to reduce power or change antenna directionality at sunset/sunrise -- to avoid having nighttime propagation affecting other stations on the same frequency (and the few clear-channel stations that are allowed full power at night now cover multiple states rather than just a few counties).

 

If you are seeing a difference it is more likely due to industrial and business activity generating increased background RF noise which swamps out low powered GMRS signals. Though I will concede I encountered something that I think was a tropospheric ducting event a few months back. https://en.wikipedia.org/wiki/Tropospheric_propagation

[WRUS537]

1 hour ago, KAF6045 said:

AM broadcast stations have to reduce power or change antenna directionality at sunset/sunrise

I never knew this, learned something, thank you