5/8 over 5/8 mobile

[IronArcher]

So, long or short version, how does a 5/8 over 5/8 wave antenna “work”?

I’m looking at the Tram 1173/Browning BR-450 vs. Midland MXT 26.

The Tram/Browning has a separate coil, and you trim the top element to frequency needed.

The Midland has a just 1 piece antenna with a couple of loose “coil” winds in the middle.

How do those different systems compare?

The tram claims 5.5dB and the midland claims 6dB

Tram cost $20-25 Midland $40

I’m trying to find a reason to consider the Midland, but I am seriously doubting .5 more dB is worth $x2

 

What am I missing?

 

Thanks!

[mbrun]

Good Day IronArcher.

 

I will let those that no better than I to do the explanation.

 

Here is a link that provides a reasonably concise explanation.

 

https://www.electronics-notes.com/articles/antennas-propagation/vertical-antennas/five-eighths-wavelength-vertical.php

 

Now, as far a 1/2 dB goes that is absolutely insignificant. In real-world practical distance testing you will never, I say never, be able to tell the detect the difference, all else remaining equal.

 

BTW, I own and use the Midland. I have zero complaints about it. and I was fortunate I did not need to tune it. It was perfectly tuned from the factory. I would buy it again.

 

Hope that helps.

 

Michael

WRHS965

KE8PLM

 

 

 

 

 

 

So, long or short version, how does a 5/8 over 5/8 wave antenna “work”?

I’m looking at the Tram 1173/Browning BR-450 vs. Midland MXT 26.

The Tram/Browning has a separate coil, and you trim the top element to frequency needed.

The Midland has a just 1 piece antenna with a couple of loose “coil” winds in the middle.

How do those different systems compare?

The tram claims 5.5dB and the midland claims 6dB

Tram cost $20-25 Midland $40

I’m trying to find a reason to consider the Midland, but I am seriously doubting .5 more dB is worth $x2

 

What am I missing?

 

Thanks!

 

Sent from my iPad using Tapatalk

[gman1971]

The 5.5 dB claim is, simply put, not true. (also, if you don't see dBd or dBi its probably fake as well) That TRAM1173 (or MXT26) antenna probably has less gain than a simple 1/4 wave NMO, given the cheap coils used, and being only 2 elements, with insufficient phasing element separation between them (gain in collinear antennas is achieved by increasing the distance between the phased elements) not a chance in he11 it has 5.5 dBd... well, unless decibels dBs overseas are measured differently than in the rest of the world... that is.

 

For comparison, a real world 5.5dBd gain is what a 4-bay folded dipole has, which is a massive antenna, and coincidentally, it costs a lot of $$$$$...  too.

 

IMO, and in my experience, for a car install, a simple 6" inch NMO antenna cut to GMRS frequency will work absolutely great, as measured.

 

G.

[IronArcher]

The Tram (which is also the Browning BT-450) lists its gain as 5.5 dBd.

The midland claims 6dB

It would seem more likely that those should be the dBi numbers (4+2.1).

Again, my guess is that there isn’t a noticeable difference.

Reading the link above and some others, I am lead to believe it probably is closer to 4dBd gain.

Do you disagree with the link in the reply above yours that a 5/8 over 5/8 would have more gain than a 1/4 wave, with the penalty of being much taller?

[IronArcher]

Mbrun,

Thanks for the link! That helps.

I’m still not sure how that works with the Midland antenna.

I noticed some complained that their antenna was cut too short from Midland, though most got a proper replacement without issue.

I think I’m going to try the Tram as it cost much less, and my Tram 1/4 wave seems very good (at least on my meter), but if it isn’t all that, I’ll try the Midland seeing you have seen good results.

Did you notice any improvements over a 1/4 wave antenna?

[mbrun]

Mbrun,

Thanks for the link! That helps.

I’m still not sure how that works with the Midland antenna.

I noticed some complained that their antenna was cut too short from Midland, though most got a proper replacement without issue.

I think I’m going to try the Tram as it cost much less, and my Tram 1/4 wave seems very good (at least on my meter), but if it isn’t all that, I’ll try the Midland seeing you have seen good results.

Did you notice any improvements over a 1/4 wave antenna?

Honestly I did not try a 1/4 on my car. The 5/8 wave was first GMRS antenna on the vehicle. I use a 5w HT in the car. When not in the car the HT has a 1/2 wave Nagoya 771G on it. I have now been in a number of places (including outside my Home) where the HT and 771G may or may not open certain repeaters but result in no usable audio. When I switch to the 5/8 wave on the car I can carry on a conversation. So at least from that perspective I know for certain the midland is working better. But since I have not compared field strengths I cannot say for certain exactly what the difference is. Also, in my case I am on the fringe of all repeaters within range at home, the area around me is mostly flat and my elevation is above average terrain so I have opted for more gain on my mobile and base antenna. That may not material to others.

 

Michael

WRHS965

KE8PLM

 

 

Sent from my iPad using Tapatalk

[gman1971]

Well, I am not trying to be combative here, contrary to people's belief. I certainly don't know every bit of antenna theory ever discovered, but claims can be easily verified with a calibrated RSSI meter, and I've never seen a 5.5 dBd improvement on any antenna I've owned to date... that claim just doesn't seem possible given the overall antenna length/number of elements and separation.

 

The gain number claimed by those collinears can only achieved through more elements, and certainly a lot more separation between them, at least that is what collinear antenna gain theory states. I have a Hustler G6 UHF, a vertical, which also claims ~6 dBd, and that antenna is huge compared to that little TRAM... based on RSSI measurements from the XPR5550e meter, the Hustler G6 is closer to a 4 dBd antenna at best, as measured. So, based on several mobile antennas I've measured, the gain difference of 5/8 over 5/8 couldn't be precisely determined (due to fluctuation on the RSSI being larger than any observed gain) vs. a simple 1/4 wave 6" inch NMO. So, based on my measurements, I think the improvement you see in those two element collinear 5/8 antennas is likely due to a better pattern towards horizon.

 

G.

 

The Tram (which is also the Browning BT-450) lists its gain as 5.5 dBd.
The midland claims 6dB
It would seem more likely that those should be the dBi numbers (4+2.1).
Again, my guess is that there isn’t a noticeable difference.
Reading the link above and some others, I am lead to believe it probably is closer to 4dBd gain.
Do you disagree with the link in the reply above yours that a 5/8 over 5/8 would have more gain than a 1/4 wave, with the penalty of being much taller?

[IronArcher]

Gman1971,

I didn’t take you post/s to be combative. I hope you aren’t taking mine as combative either

[gman1971]

You weren't, I am just making sure another "give it up" kind of situation develops.

 

Yes, it could be gain what makes the better pattern, but a more favorable pattern can also happen if the lobe(s) where gain is present extend in more suitable direction, without much overall gain increase. The best example is a Yagi pointed to the sky, vs the same Yagi pointed towards the horizon, in both cases the antenna has the same gain, but the direction of the gain is not the same. Antenna construction, ground plane, etc... all those affect pattern quite a bit... 

 

The point I am trying to make is that all the effort and money should, IMO, be concentrated at the base setup, b/c with a good base setup it reduces the need to use higher gain antennas on mobiles... that is why ham VHF repeaters have tens of miles range using just portables, b/c the setup is very good, be it due to good component selection, a great location placement, or both.

 

G.

[RickW]

I have mentioned it before, but it still surprised me when my wife and I did some testing a few years ago. I have a GP-9 on a 40 ft tower at our ridge farm which is 1240 ASL and I drove my vehicle way down to the nearby Sidie Hollow, which is less than 900 ASL. These are deeply notched valleys (called coulees) in the Driftless Area of Wisconsin. Distance back to the farm was around 3 miles. With a cheap dual band 2 mtr/440 ham antenna retuned for GMRS, we could barely communicate. Switching to the tiny Midland mag mount 6 inch quarter wave, the signals became quite readable and one bar on the Midland MXT400's which we had on each end, running low power. Switching to the Midland mag mount with the "3 db" gain Midland 5/8 wave antenna increased it to another bar. Switching to the "6 db" gain Midland 5/8 over 5/8 wave increased it to another bar. I think we compared power levels from the lowest power setting to medium and that helped as well. I really did not expect to see that much of a difference. Especially when you consider that the gain antennas tend to put more signal closer to the horizon. It may be that the RF was bouncing around the hills and sort of filling in from different directions. I have no way of measuring the difference in db's for each bar. It would be helpful to have a ballpark number.

[gman1971]

Hello, fellow Wisconsinite... can you reach the Madison 700 repeater from where you live?

 

Well, from 5W to 50 W is a 10 dB increase, that is a big difference; but from 25W to 50W is only a 3 dB increase. 

 

A 40 foot tower and only a 3 mile range from a 5W portable is a bit on the short range. What antenna are you using at the base? It sounds like the same problem I had, b/c more gain = thinner lobes, when altitude drops you go into a null... and while adding more power will help one direction, I suspect you have also a problem of unequal TX and RX ranges...  if that is the case chances are you have a problem with radiation pattern rather than antenna gain.

 

G.

 

I have mentioned it before, but it still surprised me when my wife and I did some testing a few years ago. I have a GP-9 on a 40 ft tower at our ridge farm which is 1240 ASL and I drove my vehicle way down to the nearby Sidie Hollow, which is less than 900 ASL. These are deeply notched valleys (called coulees) in the Driftless Area of Wisconsin. Distance back to the farm was around 3 miles. With a cheap dual band 2 mtr/440 ham antenna retuned for GMRS, we could barely communicate. Switching to the tiny Midland mag mount 6 inch quarter wave, the signals became quite readable and one bar on the Midland MXT400's which we had on each end, running low power. Switching to the Midland mag mount with the "3 db" gain Midland 5/8 wave antenna increased it to another bar. Switching to the "6 db" gain Midland 5/8 over 5/8 wave increased it to another bar. I think we compared power levels from the lowest power setting to medium and that helped as well. I really did not expect to see that much of a difference. Especially when you consider that the gain antennas tend to put more signal closer to the horizon. It may be that the RF was bouncing around the hills and sort of filling in from different directions. I have no way of measuring the difference in db's for each bar. It would be helpful to have a ballpark number.

[IronArcher]

So are we all from Wisconsin here?

[gman1971]

Yep, from Madison WI here.

 

The saving grace is that the darn Candelabra tower, the Superdoppler and the other 1200 foot RF firebreathing angry towers aren't <5 miles of your house... so that probably helps quite a bit in your situation. With a setup like yours I had a few years back I couldn't get more than 2 miles simplex, and that was using 50W mobiles to home base... I think there are other members here with the same kind of problem. Its not the power, its the garbage receiver.

 

BTW, which repeater you speak off? yours? or is it someone else's repeater? 

 

G.

[IronArcher]

Someone else’s repeater.

Hopefully, I get my new mobile wired up Sunday.

It’s not a top end radio, but it has to have better rx than my POS HT

[gman1971]

Lets hope so.

 

G.

[haneysa]

I have and use the factory midland 1/4w magmount (that comes with the lower power MXTs), Laird NMO mount 1/4w, TRAM 1181 NMO, and a DPD Productions (looks like a Browning/Midland) 5/8 over 5/8 NMO. I live in NE Washington, where we have mountains and forests. Field-test results lead me to believe that the mono-band antennas perform better than the Tram 1181. I get better range with the taller (as in the 5/8 over 5/8w) antennas. This may not be a function of gain, but of height AGL. The 1/4w NMO certainly is less visible and less likely to strike over head obstacles than the taller antennas...and you can get them for $10 on the internet.

[IronArcher]

So a quick update for anyone who finds this in a search.

I currently have 2 1/4 wave antennas, the Tram/ Browning 450 5/8 over 5/8 wave, and the above mentioned Tram 1181 dual band(I just got my Tech and General ham lic).

Results:

1/4 wave antennas. Very good on tx, not so great on rx. I would score it 9/6 (tx/rx on a 10 point must system)

Tram dual band. NOTE, I do need to trim this antenna, SWR is a little high on 467MHz so this score may change.

Tx is fair, but disappointing (again, timing may help) rx is a bit better than the 1/4 wave antennas.

Rating is a 7/7

Tram/Browning 5/8^5/8. So far, this one is the Mac daddy for GMRS use. Like the 1/4 wave antennas, it is very well tuned. Tx is a bit better than the 1/4 wave antennas. Not a HUGE improvement, but a touch better. Rx is amazing. The repeater we use is noticeably stronger and cleaner. 10/10 score.

I have made an NMO mount for my Jeep, and even one for my house.

The house has used 1 of the 1/4 wave antennas and the Tram 5/8^5/8. Same results.

I believe the rx is strongly tied to the amount of metal there to pick up a signal.

Hopefully the 1181 improves a bit with tuning, as the base has my 5/8 antenna.

The 1/4 waves are frustrating in that I do get great tx with them, but I can’t rx as well as rx with them.

The 1181 is more balanced, but needs tuning (I hope) to get all of its potential.

I’m really hoping that does the trick as for a dual band antenna, has some very broad dips in the SWR trace. The 2m band is virtually flat on the floor over a 6MHz sweep! The 70cm sweep is a bit wavier, with a nice extra dip in the GMRS range... not awesome, but the whole 70cm band is 1.5:1 or better, and 2m is 1.1:1 or better... though the frequencies are a touch low.

Will post any updates that are worthy of reporting.

That said, if you are looking for a GMRS antenna I would suggest the Tram/Browning 5/8^5/8.