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eHam Forums => VHF / UHF => Topic started by: KD8PGB on September 09, 2011, 04:21:31 AM



Title: 35 mile problem
Post by: KD8PGB on September 09, 2011, 04:21:31 AM

 I have a son studying for his Tech/General ticket and lives 35 miles away, flat ground (both of us at 650ft elevation with no major obstacles) we don't have a good repeater between us. So I am looking for suggestions for direct simplex operation. I currently have an 857d mobile, an 857d fixed station with a Jetstream JTB-1 mounted about 20ft up, a FT-950 with a G5RV mounted at 50ft. I would really like to find a solution that uses an HT on the other end but I know that is quite a stretch.

I am wondering if I used something like 2m SSB? or 2m AM? Could a handheld running 2m AM have greater range than 2m FM? What about using 6m or 1.25m? Could using SSB or AM produce reliable communication 24/7 ?



Title: RE: 35 mile problem
Post by: WB6BYU on September 09, 2011, 08:47:35 AM

 I have a son studying for his Tech/General ticket and lives 35 miles away, flat ground (both of us at 650ft elevation with no major obstacles) we don't have a good repeater between us. So I am looking for suggestions for direct simplex operation. I currently have an 857d mobile, an 857d fixed station with a Jetstream JTB-1 mounted about 20ft up, a FT-950 with a G5RV mounted at 50ft. I would really like to find a solution that uses an HT on the other end but I know that is quite a stretch.

I am wondering if I used something like 2m SSB? or 2m AM? Could a handheld running 2m AM have greater range than 2m FM? What about using 6m or 1.25m? Could using SSB or AM produce reliable communication 24/7 ?



35 miles isn't that difficult if you have good antennas at a reasonable height.  You probably can
manage on 2m FM with an HT at one end if it were feeding a yagi up 35 feet.

6m would probably be even better, again assuming good antennas.

SSB normally uses horizontally polarized antennas, and works much better with weak signals than
AM or FM.  It should be easy to cover that distance with SSB on any of the VHF bands, but you
may have difficulty doing it with an HT, just because very few HTs have SSB capability.


The most important factor will be antenna height.  Beyond that you'll just have to try it and
see what works.


Title: RE: 35 mile problem
Post by: WB2WIK on September 09, 2011, 10:03:30 AM
I'm not a fan of the Jetstream antenna but 2m FM at 35 miles over a fairly flat path should work fine for you if you simply raise your antenna higher above ground and use very low loss cable.

You should be able to make it work even with only a hand-held and "whip" antenna on the other end if you can get the antenna up about 120 feet above ground.  At 60 feet, it might work but you'd be right on the edge.  At 20 feet, it shouldn't work at all.

With a homebrew collinear here at home up about 65 feet above ground, I can work guys using hand helds 35 miles away on 2m FM as long as they're in a "clear shot" direction and not on the other side of an obstruction like a higher hill in the way.  Terrain makes a huge difference, and we have "a lot" of it around here.  If you're in a "flatter" area, it's easier.



Title: RE: 35 mile problem
Post by: KD8PGB on September 09, 2011, 10:50:40 AM

 Sadly about the maximum height I can get is about 50 feet, the max my son would be able to get is about 20ft. I have been looking for a 2m SSB HT but have yet to find one. I was hoping that using a different mode like AM or SSB might offer better propagation with my limitations on antenna height.


Title: RE: 35 mile problem
Post by: N1OFJ on September 09, 2011, 11:55:25 AM
this situation calls for 6 meters


Title: RE: 35 mile problem
Post by: AA4PB on September 09, 2011, 12:37:49 PM
If I were going to do this, and didn't want to spend money on stuff that didn't work, I would get a pair of 50 watt FM radios and a couple of 7 Element Yagis. Put them up as high as possible (50' on one end and 20' on the other). Assuming there isn't anything blocking the signal path you should be able to do okay over 35 miles.

SSB is good for weak signal work but I imagine you want a decent, quite signal. FM should be fine over a 35 mile path. I doubt that you'll find a SSB HT. I wouldn't use an HT anyway because the power will be limited to 5W and the receiver front ends often can't handle the other strong signals on the band that you are likely to encounter with a good antenna. An HT doesn't have much portability anyway when its tethered to a run of coax and a Yagi.

If you want to work other stations, mount the antennas vertically polarized. If you mainly want to work each other then you may find it easier to mount them horizontally polarized. Signal wise, it doesn't matter so long as you both use the same polarization.


Title: RE: 35 mile problem
Post by: AC5UP on September 09, 2011, 01:07:18 PM
I was hoping that using a different mode like AM or SSB might offer better propagation with my limitations on antenna height.

Although 20' is approaching a good working height, the other side at ~50' should be enough to make it reliable. AA4PB's suggestion about a pair of 7 el Yagi's is a good idea, if budget is an issue you can homebrew two Moxon's. Do a web search on " 2 Meter Moxon " and you'll see how easy they are to build.

As for AM or SSB, the only advantage is is in weak signal work. I'm told that's why aviation still runs AM as it can be copied down to the noise floor and often a bit below. FM has a cliff effect in that weak signals deteriorate very rapidly then they drop below the receiver's threshold. You'll hear nothing using FM when SSB would give noisy copy from the same signal. There are no AM or SSB HT's as that doesn't work from a marketing standpoint... The attraction of a 2 Meter HT is a low cost entry point for repeater use and that's FM territory. An all-mode rig would be too pricey and (probably) clumsy to use. Also, high power and HT's don't mix as there's no better way to zero a battery pack than a rag chew at five watts or better.

BTW: You don't have a good repeater between you, but are there any repeaters you can hit from both places? In my part of the world a good repeater has a 75-80 mile working radius and could easily cover both locations. (?)



Title: RE: 35 mile problem
Post by: AA4PB on September 09, 2011, 01:33:17 PM
I expect that one of the reasons aviation still uses AM (other than the problems caused by a change-over) in lieu of FM is that AM doesn't have a "capature effect". If two aircraft transmit at the same time you can often hear both of them whereas with FM the stronger station wins. It captures the descriminator and blocks out the weaker station - not good from a safety standpoint. With AM the receiving station at least knows there was another station there, even if the transmission wasn't understood.



Title: RE: 35 mile problem
Post by: WB2WIK on September 09, 2011, 02:09:07 PM
There isn't really any advantage to AM over FM for this kind of application.  Bandwidth is similar, and that's what determines S/N more than anything else.  A very good ear on a static-free band can probably "hear" an AM signal that's a bit weaker than an FM one, but in the presence of static and noise sources, FM can often be (and usually is) better.

SSB has obvious advantages: Way less bandwidth produces more "power per Hz" than AM or FM and the use of narrower filters on the receiver can provide obvious S/N improvment.

There aren't any 2m SSB hand helds made today.  There were a couple many years ago, long discontinued.  Closest thing today is the Yaesu FT-817 which can run 5W PEP on 2m SSB (and also on 6m, and on the HF bands!) when powered by an external power source, or half that power using internal batteries.

The "50W and 7 element beam on each end" is a great suggestion and probably what I'd do also if I wanted 100% reliability, regardless of weather and everything else, over a 35 mi path on two meters.

For that distance, 2m is a very good frequency choice, I think.


Title: RE: 35 mile problem
Post by: KD8PGB on September 10, 2011, 12:33:34 AM

 Well it seems there is a consensus on 7 element Yagi's and 2m FM @ 50watts, so we will go that direction and see how that works. I'll post my findings here when we get it up and working.

Thanks for your input!
 


Title: RE: 35 mile problem
Post by: K1CJS on September 10, 2011, 06:59:23 AM
Yes, 50 watt radios at BOTH ends, but for that short a distance, you really don't need yagis.  The Jetstream antennas leave a lot to be desired, however.

I have a Hustler G7-144 antenna up about twenty feet, and I regularly talk to other 2 meter stations 40 to 50 miles away from my home.  Full quieting too.  Of course, your mileage may vary.  73.


Title: RE: 35 mile problem
Post by: WB6BYU on September 10, 2011, 07:35:01 AM
The 50 watts in itself isn't as important as "something more than an HT".  Yes, an HT will run
5 watts output, but if you need that much power regularly you'd be much better of with a
used mobile rig because the finals will last much longer and it won't burn your hand when it
heats up.  The larger mobile rig allows for better heat sinking, and you don't have to hold it.
And it will generally run higher power if needed - 10 or 25 watts at least.  That last increment
from 25 to 50 watts isn't nearly as important as the first one from an HT to a mobile rig.

There is no particular magic in a 7-element yagi, either.  More gain means a greater chance
of making the path with a given antenna height and power level.  Longer beams generally
mean higher gain.  Somewhere around an 8' to 10' boom length should give you 10dB over a
dipole - that's like an increase from 5 watts to 50 watts (as long as it is aimed in the right
direction.)  If you just want to experiment to see how much antenna gain you need, consider
building some of the WA5VJB "Cheap Yagis" as described here:

http://www.wa5vjb.com/yagi-pdf/cheapyagi.pdf

Once you see how much gain you need, you can look at more rugged antennas for a long-term
installation.


The truth is, we can't tell you exactly how much power, height, or antenna gain you will need
to cover the path, because it depends on a lot of other factors, primarily the terrain.  I've
been amazed at how much VHF signal strengths vary over "flat ground", because it usually
isn't as flat as one might think.  (Ask any bicyclist - they notice the ups and downs much
more than someone driving a car.)  So you have to decide whether it is more important for
you that the communications work the first time, or if it makes sense to try things incrementally
to find what works.  You might not need 50 watts, or 50' at both ends, or that much antenna
gain, or some combination thereof.  But unless there is some unusual circumstance that we
aren't aware of, that combination should be sufficient to give you reliable coverage.


Title: RE: 35 mile problem
Post by: AA4PB on September 10, 2011, 09:45:47 AM
Suppose you purchase a 5W HT and find out that doesn't cut it. So you purchase the Yagis and find out that works but the signals are rather weak and not "arm chair copy". So you purchase a 50W radio to finally get the link working with decent signals. Sure you can do it incrementally, trying to save a few bucks but my suggestion of 50W and 7 El Yagis is based on something that probably has a 99% chance of working from the get-go.

The difference between 25W and 50W isn't all that much, but if you have to purchase new radios it isn't all that expensive to get a 50W, 2M only radio. You can always switch it to 25W or 5W (on most radios) if you find you don't need the power. If you've got a couple of 25W radios sitting on the shelf then certainly try that first.

The two of you may also find that you want to work some distant stations other than each other on 2M and the 50W radio and Yagi will help you to do that.


Title: RE: 35 mile problem
Post by: W8JX on September 10, 2011, 10:49:59 AM
Solution is pretty simple. At one in put a Hustler G6 or G7 at 40 to 50 feet. A other end use s small cheap Yagi st 20 feet and you will be able to chat no sweat on 2m FM. If you want to use a HT on one end, get a cheap new or used dual band radio that supports cross band repeat and you talk to it on 440 and it links to other station on 2m.

To merely use a HT on one end, the other end is going to have a very good antenna up around 100 feet or more. Basically a repeater antenna at home height wise. Also with would work better with 440 because you can get more gain on 440 even with a vertical and HT antennas are far more efficient on 440 as most are radiating dummy loads on 2 meters.


Title: RE: 35 mile problem
Post by: KD8PGB on September 11, 2011, 03:36:52 AM
Quote
Solution is pretty simple. At one in put a Hustler G6 or G7 at 40 to 50 feet. A other end use s small cheap Yagi st 20 feet and you will be able to chat no sweat on 2m FM

Why use an omni-directional vertical on the one end? Wouldn't Yagi's on both ends be better?


Title: RE: 35 mile problem
Post by: W8JX on September 11, 2011, 07:21:33 PM
Quote
Solution is pretty simple. At one in put a Hustler G6 or G7 at 40 to 50 feet. A other end use s small cheap Yagi st 20 feet and you will be able to chat no sweat on 2m FM

Why use an omni-directional vertical on the one end? Wouldn't Yagi's on both ends be better?

Yes you could use Yagis at both ends but the G6 or G7 at 50 feet would be the beacon to zero other station in on as it will always be aimed correctly so to speak and would let you work HT simplex at time when closer on high up somewhere else without having to aim beam again. I have a G7 that is 40 feet up at its base and feed with about 85 feet of RG 213. It has been up there for close to 20 years and has been trouble free and survived severe icing more than once and 80+mph winds on a few occasions. I was just trying to keep it simple and cheap and no need for rotor. Also with a long/tall vertical you can benefit for a larger capture area. As VHF/UHF waves travel thru space there can be holes in coverage and a bigger antenna spans these holes. These "holes" are easy to see/hear at times when you can move a few feet with HT or even a cell phone and see a improvement or total loss of signal. The higher the frequency the sharper and smaller the holes tend to be.


Title: RE: 35 mile problem
Post by: K9KJM on September 11, 2011, 10:14:25 PM
At only 35 miles there is no reason FM to a small hand held that is connected to a decent outdoor antenna with decent low loss coax should not work out, With no major obstruction between the stations on two meters.

Use good low loss coax like Times LMR400, Keep it as short as possible, Put your antennas up as high as you can get them, And yes, a good directional antenna at each end aimed at the other station Will help.

While SSB IS better, The very slight advantage is not worth the effort. Especially for such a short range link.


Title: RE: 35 mile problem
Post by: KD8PGB on September 12, 2011, 04:11:34 AM

 Thanks guys,  I will be working on this in the next week and will report my findings !


Title: RE: 35 mile problem
Post by: K1CJS on September 12, 2011, 04:45:21 AM
Why use an omni-directional vertical on the one end? Wouldn't Yagi's on both ends be better?

I said what I did because the range really isn't long enough to require yagi antennas at either end.  Also, many people would want a good, omnidirectional 2 meter antenna anyway, but may not have much use for a yagi.

Absolutely go for broke and get the yagi antennas--if you want to.  It just seems like overkill to some of us for the distance involved.

Also, the 50 watt reference I made was a little too narrow.  What I should have said is mobile rigs, not 50 watt radios.


Title: RE: 35 mile problem
Post by: KL2TC on September 12, 2011, 04:12:22 PM
I regularly (every night on our Geezer Net) speak with a friend up the road 38.9 miles away.  The catch is there is Lazy Mountain between the two of us and I can hit him regularly with my FT-2900 and a Larsen BSA 150C which they call a "radial whip".  It really works great!

73

Al


Title: RE: 35 mile problem
Post by: ONAIR on September 12, 2011, 11:25:42 PM
    You might have better luck on 10 meters SSB.  I believe there are 10 meter SSB handhelds available.


Title: RE: 35 mile problem
Post by: KD8PGB on September 13, 2011, 12:57:20 AM

 yes I was looking at the Super Radio SS-301, AM FM SSB 10M, I am wondering if that would work at 35 miles?

I  have an FT-950 and G5RV at home at 50ft inverted v, which could get out on 10m (please don't flame me on the G5RV, it works for me).

I am thinking my fixed station would require a more NVIS antenna to hit a 35 mile distance?


Title: RE: 35 mile problem
Post by: AA4PB on September 13, 2011, 04:48:35 AM
NVIS doesn't work on 10M. Signals that hit the ionosphere at high angles generally punch right through rather than being refracted back to Earth. On 10M you'll need ground wave (low angle - on the horizon) to work 35 miles. You may have problems with the 35 miles at times when the band is open. I think 2M FM will be more reliable over that distance.



Title: RE: 35 mile problem
Post by: KF6DBZ on September 13, 2011, 06:59:21 AM
I have a Arrow J Pole 2 meter/440 antenna about 20 feet in the air and i use a icom 706 M2g radio. I am in the los angeles area and i can use the Catalina island repeater from my house with no problems. Catalina island is approx 26 miles away from me but it is over water. I however do have Palos Verdes which is approx 1000 feet high sitting right in between me and Catalina island. Like it was said before 50 watts and a good antenna should work fine.


Title: RE: 35 mile problem
Post by: ONAIR on September 13, 2011, 08:24:01 PM

 yes I was looking at the Super Radio SS-301, AM FM SSB 10M, I am wondering if that would work at 35 miles?

I  have an FT-950 and G5RV at home at 50ft inverted v, which could get out on 10m (please don't flame me on the G5RV, it works for me).

I am thinking my fixed station would require a more NVIS antenna to hit a 35 mile distance?
    On a quiet frequency you should be able to reach 35 miles on 10 meter SSB ground wave.  10 meter hams chat with locals that are 35+ miles away all the time.  Even CBers on 11 meters using SSB and 10 watts PEP, are able to do it.


Title: RE: 35 mile problem
Post by: KD8PGB on September 14, 2011, 04:09:53 AM
Quote
On a quiet frequency you should be able to reach 35 miles on 10 meter SSB ground wave.  10 meter hams chat with locals that are 35+ miles away all the time.  Even CBers on 11 meters using SSB and 10 watts PEP, are able to do it.

I was thinking that, however what would be a good a good base antenna configuration for ground wave propagation?


Title: RE: 35 mile problem
Post by: W8JX on September 14, 2011, 05:14:32 AM
A vertical ground plane antenna up 20 feet of more are base. But, when band opens up there will be QRM issues. 2m FM is really best viable solution here and quite doable.


Title: RE: 35 mile problem
Post by: KD8PGB on September 14, 2011, 07:56:13 AM
Quote
A vertical ground plane antenna up 20 feet of more are base. But, when band opens up there will be QRM issues. 2m FM is really best viable solution here and quite doable.

I only wanted to know for my own edification, I am leaning 2m, I am thinking an Arrow 146-4-BP 4 element beam with 100ft LMR400 and mounted roughly at 35ft as I can't go much higher than that.

My 857d puts out 50 watts which should be more than enough power, and we can try it against an HT at the other end, I'm sure he will be able to hear me, but I'm doubtful I will be able to hear the HT with a whip on it, most likely will have to figure out a roof mount antenna for him, or go to a mobile setup in his car.


Title: RE: 35 mile problem
Post by: W8JX on September 14, 2011, 12:04:55 PM
I am leaning 2m, I am thinking an Arrow 146-4-BP 4 element beam with 100ft LMR400 and mounted roughly at 35ft as I can't go much higher than that.

If I may suggest that if you are going to go through the trouble to put up a beam and the extra expense of LMR400 that you put up a bit for than a light duty low gain portable beam. It would offer no gain advantage over a good collinear vertical and likely have less effective gain because the vertical will be 12 to 15 feet higher than beam. If you stay with beam, use a bigger one.


Title: RE: 35 mile problem
Post by: KD8PGB on September 14, 2011, 02:59:18 PM
If I may suggest that if you are going to go through the trouble to put up a beam and the extra expense of LMR400 that you put up a bit for than a light duty low gain portable beam. It would offer no gain advantage over a good collinear vertical and likely have less effective gain because the vertical will be 12 to 15 feet higher than beam. If you stay with beam, use a bigger one.

 Well, I was looking at the gain less than I was looking at focusing direction, and trying to get away with a small beam due to where it has to be mounted. I am assuming a vertical orientation of the beam and really don't have the room to have an 8ft beam, so I was attempting to keep it small. Since it is necessary to mount the antenna about 90ft from the shack, I figured it was best to go with LMR400 to reduce loss on the coax...

 I am wide open to suggestions though!


Title: RE: 35 mile problem
Post by: K1CJS on September 14, 2011, 03:07:58 PM
Quote
A vertical ground plane antenna up 20 feet of more are base. But, when band opens up there will be QRM issues. 2m FM is really best viable solution here and quite doable.

I only wanted to know for my own edification, I am leaning 2m, I am thinking an Arrow 146-4-BP 4 element beam with 100ft LMR400 and mounted roughly at 35ft as I can't go much higher than that.

My 857d puts out 50 watts which should be more than enough power, and we can try it against an HT at the other end, I'm sure he will be able to hear me, but I'm doubtful I will be able to hear the HT with a whip on it, most likely will have to figure out a roof mount antenna for him, or go to a mobile setup in his car.

You seem set on doing it that way, so why are you asking?  The way you propose, the person with the HT may be able to hear you quite well, but you may not hear him that well at all.


Title: RE: 35 mile problem
Post by: W8JX on September 14, 2011, 06:08:56 PM
If I may suggest that if you are going to go through the trouble to put up a beam and the extra expense of LMR400 that you put up a bit for than a light duty low gain portable beam. It would offer no gain advantage over a good collinear vertical and likely have less effective gain because the vertical will be 12 to 15 feet higher than beam. If you stay with beam, use a bigger one.

 Well, I was looking at the gain less than I was looking at focusing direction, and trying to get away with a small beam due to where it has to be mounted. I am assuming a vertical orientation of the beam and really don't have the room to have an 8ft beam, so I was attempting to keep it small. Since it is necessary to mount the antenna about 90ft from the shack, I figured it was best to go with LMR400 to reduce loss on the coax...

 I am wide open to suggestions though!


Directivity and Gain go hand in hand. A beam with say 7dbi is actually inferior to say a Hustler G7 vertical that has 7dbd of gain (or 8.7dbi they sometimes use dbi ratings because they look higher). Just because it is directional, it does not mean it is better than a good vertical. If horizontal space is limited against a longer boom on a beam and more element than 4, I would go vertical with a G7 and get it as high as you can and you will not be disappointed. Many have used them as a repeater antenna.


Title: RE: 35 mile problem
Post by: KD8PGB on September 15, 2011, 02:57:05 AM


You seem set on doing it that way, so why are you asking?  The way you propose, the person with the HT may be able to hear you quite well, but you may not hear him that well at all.

I'm actually not set on anything yet, I am trying to get opinions on the best way to do it. I was  under the apparently false impression that a directional yagi would be more sensitive in the specific direction (than an vertical) and therefore be able to pickup the HT.

I have a Jetstream JTB3 vertical (4.5db gain), its currently only about 12ft off the ground, now I'm wondering if I could get it up high if it would not suffice? I can probably get it up about 35 or 40 feet.  Or should I be focused on something with considerably more gain like a Hustler G7?


Title: RE: 35 mile problem
Post by: AA4PB on September 15, 2011, 04:25:29 AM
A good Yagi will have more gain, and therefore receive a stronger signal, in the direction it is pointing than an omni-directional vertical. No one can guarentee that it will be enough difference to receive an HT with a "rubber duck" antenna. It will increase your odds however. There are just too many variables to make any guarentees.

The directional antenna will also lower noise and interferrence received from directions other than where it is pointing. This may or may not make any difference depending on your particular situation.


Title: RE: 35 mile problem
Post by: KD8PGB on September 15, 2011, 04:41:36 AM

 But is gain simply gain regardless of vertical or yagi? I'm getting confused!

 Would a Hustler G7 at 8db gain be better than an Arrow yagi at 4db gain? I would think so, but is the directional isolation more important?

Would my "inexpensive" JTB3 vertical at 4.5db gain @ 40ft be worse than a 4db yagi at the same height?


Title: RE: 35 mile problem
Post by: AA4PB on September 15, 2011, 08:13:56 AM
Well, basically gain is gain whether vertical or a Yagi BUT you have to be careful about the reference and measurement conditions. Gain can be measure against a dipole (dBd) or against isotropic (dBi). The dBi reference results in about a 2dB increase in the number. A vertical may be referenced against a 1/4 wave whip as well. If the references are not the same then the absolute amount of signal received by the two antennas will not be the same.

An omnidirectional vertical gets its gain by narrowing the focus vertically and (hopefully) placing it down near the horizon. A yagi gets its gain by narrowing the focus horizontally to concentrate the signal in one direction.

One of the benefits of a directional antenna of course is that it minimizes noise and interferrence from other directions while an omnidirectional vertical receives equally from every direction.



Title: RE: 35 mile problem
Post by: KD8PGB on September 15, 2011, 08:29:58 AM
Well, basically gain is gain whether vertical or a Yagi BUT you have to be careful about the reference and measurement conditions. Gain can be measure against a dipole (dBd) or against isotropic (dBi). The dBi reference results in about a 2dB increase in the number. A vertical may be referenced against a 1/4 wave whip as well. If the references are not the same then the absolute amount of signal received by the two antennas will not be the same.

An omnidirectional vertical gets its gain by narrowing the focus vertically and (hopefully) placing it down near the horizon. A yagi gets its gain by narrowing the focus horizontally to concentrate the signal in one direction.

One of the benefits of a directional antenna of course is that it minimizes noise and interferrence from other directions while an omnidirectional vertical receives equally from every direction.



So for the noise reduction alone that would lead me to believe the yagi is a better choice for receiving a weak station at known location. Would that be true?

So on a yagi, essentially the higher the gain, the more focused the antenna is? In effect the lobe should be more narrow? Would this also lead to further noise reduction? Higher gain = narrow lobe and less noise? 





Title: RE: 35 mile problem
Post by: W8JX on September 15, 2011, 03:04:03 PM
Well, basically gain is gain whether vertical or a Yagi BUT you have to be careful about the reference and measurement conditions. Gain can be measure against a dipole (dBd) or against isotropic (dBi). The dBi reference results in about a 2dB increase in the number. A vertical may be referenced against a 1/4 wave whip as well. If the references are not the same then the absolute amount of signal received by the two antennas will not be the same.

An omnidirectional vertical gets its gain by narrowing the focus vertically and (hopefully) placing it down near the horizon. A yagi gets its gain by narrowing the focus horizontally to concentrate the signal in one direction.

One of the benefits of a directional antenna of course is that it minimizes noise and interferrence from other directions while an omnidirectional vertical receives equally from every direction.



So for the noise reduction alone that would lead me to believe the yagi is a better choice for receiving a weak station at known location. Would that be true?

So on a yagi, essentially the higher the gain, the more focused the antenna is? In effect the lobe should be more narrow? Would this also lead to further noise reduction? Higher gain = narrow lobe and less noise? 


Noise/static is not a issue on 2m FM.  Gain is gain and a 7dbd gain G7 will easily out perform a 4 element yagi on 2 meters for several reasons. One is larger capture area. Two, it will have a very low and focused angle of radiation. Three, if you put up a yagi at say 30 feet it is at 30 feet but a G7 at 30 ft at base will exceed 45 feet at tip.  Also hustler is rated 7 dbd not dbi like a lot a lot of fiberglass verticals. I have had on up for close to 20 years and have had no issues with it at all and still same feed line too.


Title: RE: 35 mile problem
Post by: K1CJS on September 16, 2011, 12:33:14 PM
I'm actually not set on anything yet, I am trying to get opinions on the best way to do it. I was  under the apparently false impression that a directional yagi would be more sensitive in the specific direction (than an vertical) and therefore be able to pickup the HT.

I have a Jetstream JTB3 vertical (4.5db gain), its currently only about 12ft off the ground, now I'm wondering if I could get it up high if it would not suffice? I can probably get it up about 35 or 40 feet.  Or should I be focused on something with considerably more gain like a Hustler G7?

Jetstream antennas aren't as good as some of the other antennas that are available.  They're what a lot of people refer to as 'Pacific Rim knockoffs.'  In other words, a copy of a proven design antenna that was made somewhere else--and may not be made as good as the original was made.  It may work fine for you, then again, another comparable antenna may work better.

Generally speaking, the higher you can get the antenna, the more range you may have while using it, but as others have said, there are a lot of factors that figure into it.  Now, if you were to put antennas on higher supports at BOTH ends, you improve chances that you will get a signal through.  A yagi will tend to ignore--that is, reject signals from the sides and will tend to maximize signal transmission/reception in one direction.  It's similar to how putting a passive megaphone to your mouth--or your ear--may help you to hear or talk to someone a little farther away.  It doesn't improve the signal, it just concentrates it--that is where the gain factor comes in.

An omnidirectional antenna with more gain would tend to concentrate the signals from all direction, but to a greater factor.  Now, if all you want to use the two meter stations at either end is to communicate with each other and with nobody else, you may well be better off with the yagi.  BUT--if you want to have general use stations to talk to anyone, anywhere, you would be better off with good, high gain omnidirectional antennas such as your Jetstream--or a Hustler G6/G7.  Such an antenna setup at both ends would let either of you talk to the other station--and with anyone else you may want to.

 


Title: RE: 35 mile problem
Post by: KD8PGB on September 16, 2011, 01:36:02 PM
Ok,
Today I did a test, I have a nice repeater near my house with an antenna at 180ft,  I went to my son's house with both my mobile and my HT, set them both on the repeater.  I keyed my mobile and made a call to the repeater. The repeater tripped open, and my handheld heard it, no problem, however my audio did not come through, only the repeater opening with no audio. So this leads me to believe that the mobile is sending a strong enough signal (CTCSS) to open the repeater, but the audio is not strong enough to be heard at the repeater.

So my next test was to key the HT against the repeater, and to my surprise the repeater opened! My little 5w HT with a 19" rubber duck opened the repeater from 40 miles away! But again the audio did not come through, which I really didn't expect the HT to have audio go through but it really surprised me that it opened the repeater at all.

So what this is telling me, is that FM 2m across this distance / terrain is not going to be effective unless I put a very high antenna up on both ends, apparently higher than what is possible at my house or my sons house.

I know, why not use the repeater and a higher antenna at my sons house? Because we don't want to tie up the repeater with our jabber and we don't want to rely on the repeater in the event of a power failure.

So now I am wondering if 10m is not a better option?


Title: RE: 35 mile problem
Post by: W8JX on September 16, 2011, 03:15:23 PM
Test was not very effective or relevant. I cannot say for sure why audio did not come thru but it was repeater doing it not you. If it was CTCSS it would not even key without it. I you put up a G7 at least 30 feet at base and son use a external antenna you will be able to talk. 35 miles is not hard to do at all on 2m.


Title: RE: 35 mile problem
Post by: K1CJS on September 17, 2011, 11:34:06 AM
OK Dan.  Now, you have to know a few things about that repeater to see how meaningful that teat was.  First, what kind of antenna is it using?  There is a difference between a Stationmaster (a very good, high gain antenna) and a Ringo Ranger (a plain antenna with no gain).  How high is that antenna mounted?  Does that repeater use a preamplifier before the receiver?  Is the repeater a quality commercial model, or is it a cobbled together home made version?  (I'm not saying there is anything wrong with that, some homemade repeaters are good.)  And there is more to consider too, such as weather and atmospheric conditions.

It isn't as simple as "I can key the repeater with my 5 watt HT."  There are a lot of other factors involved, and most of them have to do with details--just as your setting up the antennas and the rigs at your house and your sons house does.


Title: RE: 35 mile problem
Post by: KD8PGB on September 18, 2011, 02:29:21 AM
Test was not very effective or relevant. I cannot say for sure why audio did not come thru but it was repeater doing it not you. If it was CTCSS it would not even key without it. I you put up a G7 at least 30 feet at base and son use a external antenna you will be able to talk. 35 miles is not hard to do at all on 2m.

 On the contrary, there is some relevance to the test in that I was able to open the repeater with CTCSS,  but could not hear my audio returning from the repeater, I tried this several times with both the mobile and the HT and the repeater opened every time. What this showed me is that I can hit 180ft omni-directional antenna, next I need to test to a somewhat lower antenna as I cannot put mine up 180ft regardless.

I am getting two conflicting opinions here on the forum, both make sense, and I want the best possible solution before I spend my cash. I understand you have had great results with the G7, I'm just trying to quantify if it is the best solution for my application.


Title: RE: 35 mile problem
Post by: KD8PGB on September 18, 2011, 02:32:43 AM
OK Dan.  Now, you have to know a few things about that repeater to see how meaningful that teat was.  First, what kind of antenna is it using?  There is a difference between a Stationmaster (a very good, high gain antenna) and a Ringo Ranger (a plain antenna with no gain).  How high is that antenna mounted?  Does that repeater use a preamplifier before the receiver?  Is the repeater a quality commercial model, or is it a cobbled together home made version?  (I'm not saying there is anything wrong with that, some homemade repeaters are good.)  And there is more to consider too, such as weather and atmospheric conditions.

It isn't as simple as "I can key the repeater with my 5 watt HT."  There are a lot of other factors involved, and most of them have to do with details--just as your setting up the antennas and the rigs at your house and your sons house does.

I am not sure what the club is running for a repeater or antenna, I will have to get on and ask one of the members about it ,  I'm sure its a good unit, not some cobbled together system, they are one of the biggest clubs in the state. But the antenna is at 180ft up, which is a massive help, at that height I am sure line of sight is nearly unobstructed from my sons house.



Title: RE: 35 mile problem
Post by: AA4PB on September 18, 2011, 05:16:41 AM
There is something wrong somewhere if you can reliably key the repeater but can't get your audio through it.


Title: RE: 35 mile problem
Post by: KD8PGB on September 18, 2011, 05:21:16 AM
There is something wrong somewhere if you can reliably key the repeater but can't get your audio through it.

I would agree, there may have been something going on with the repeater, I am going back over there today to try it again....


Title: RE: 35 mile problem
Post by: AA4PB on September 18, 2011, 06:18:14 AM
Were you transmitting on one radio and listening for the audio on the other with them located close to each other? If so, it may be that your transmit audio is getting into the repeater but the strong signal from your transmitter is blocking the other receiver. When you release the PTT your transmit signal stops and both receivers pick up the squelch tail from the repeater.

Try taking the HT down the street to get it physically away from the mobile and have your son listen on one while you transmit on the other.


Title: RE: 35 mile problem
Post by: KD8PGB on September 18, 2011, 06:23:04 AM
Quote
Were you transmitting on one radio and listening for the audio on the other with them located close to each other? If so, it may be that your transmit audio is getting into the repeater but the strong signal from your transmitter is blocking the other receiver. When you release the PTT your transmit signal stops and both receivers pick up the squelch tail from the repeater.

 I kind of wondered if that might be the issue, both radios were picking up the squelch tail, but neither received the audio that was being broadcast.

I will try doing it with some separation between the radios today and see what I get.


Title: RE: 35 mile problem
Post by: AA4PB on September 18, 2011, 07:21:23 AM
Just a few comments on the antenna issue. The G7 vertical that W8JX proposed is quite a different vertical than a 1/4 wave or some of those that claim more gain than they can actually provide. I would agree that over a normal 35 mile path the G7 mounted in the clear should work okay.

If you are considering an HT on one end with an attached whip antenna then vertical polarization on the other end is a MUST in order to avoid a huge cross polarization loss. Yagis can be mounted vertically polarized but this often generates mechanical mounting difficulties. You want to avoid a metal (conductive) support mast running between the elements. That means either a non-conductive mast or some sort of offset mounting. You'll probably find the G7 easier to mount.

Of course if you use the repeater near you then probably both of you can get by without going to extremes on antennas. You'll probably find that the HT on the far end will be sensitive to location. You may find, for example, that it hits the repeater okay from the deck outside but doesn't work so well from inside the house and certainly not from the basement. Unless it is an exceptional repeater and/or house location you probably won't be able to walk around the house with the HT. You may be able to find a "sweet spot" inside where it will work okay.


Title: RE: 35 mile problem
Post by: W8JX on September 18, 2011, 10:25:16 AM
On the contrary, there is some relevance to the test in that I was able to open the repeater with CTCSS,  but could not hear my audio returning from the repeater, I tried this several times with both the mobile and the HT and the repeater opened every time.

Point I was making is that if both a mobile and a much weaker HT open repeater and neither has audio, especially mobile, it is not because of signal strength.


I am getting two conflicting opinions here on the forum, both make sense, and I want the best possible solution before I spend my cash. I understand you have had great results with the G7, I'm just trying to quantify if it is the best solution for my application.

Please understand that height is everything in this scenario. You will be able to 15 feet higher at its peak with a big vertical verse a small beam and this helps a lot especially 50 feet. 


Title: RE: 35 mile problem
Post by: WB6BYU on September 21, 2011, 09:18:03 PM
Quote from: W8JX

...A beam with say 7dbi is actually inferior to say a Hustler G7 vertical that has 7dbd of gain...



Except that, contrary to the manufacturer's claims, the G7 CANNOT have 7dBd gain.  It isn't long enough.

To get 6dBd on 2m requires and antenna somewhere around 20' long.  The G7 is only 15' long, and
7dBi (or about 5dBd) is more likely for an antenna of that length.

(The length sets the maximum possible gain for an omni vertical, but it doesn't guarantee that a specific
design achieves that gain.)

It's a pretty mediocre 3-element yagi design that only has 7dBi of gain.  Even a 24" boom can give 8dBi,
and W4RNL's 6-element OWA is a very well-behaved yagi with over 10dBi with a boom length around
4 1/2 feet.  Two of those (or any such design, for that matter), stacked on either side of the mast, avoids
any pattern distortion and gives even more gain in a very short space.



But, if there is a repeater that you can hit from both stations, that simplifies matters greatly.  Just put up
a simple antenna at each end and talk to each other through it.


Title: RE: 35 mile problem
Post by: KI4SDY on September 22, 2011, 08:35:09 AM
I am sure that you have a good relationship with your son, but he might get pretty bored just talking to one person all of the time. Why not have both of you point 2 meter beams at that hard to hit repeater so you can fully enjoy the local community of ham radio operators.  ;)


Title: RE: 35 mile problem
Post by: W8JX on September 22, 2011, 11:46:26 AM
Well with good verticals high up no need to point them to work simplex or repeaters.


Title: RE: 35 mile problem
Post by: K1CJS on September 22, 2011, 12:40:41 PM
Well with good verticals high up no need to point them to work simplex or repeaters.

Or any other station on simplex within range of either station!


Title: RE: 35 mile problem
Post by: KI4SDY on September 22, 2011, 05:27:53 PM
Apparently, you fellows did not read the inquirers original posts regarding the son's and Father's antenna height restrictions and the far away repeater.  ::)


Title: RE: 35 mile problem
Post by: W8JX on September 22, 2011, 06:03:02 PM
Apparently, you fellows did not read the inquirers original posts regarding the son's and Father's antenna height restrictions and the far away repeater.  ::)

Yes I did. I have lived with a G7 at 40 ft at its base for nearly 20 years and I know what it will do. I live north of Dayton and I can easily bring up repeaters in Middletown and northern Cincinnati to south and up as far as Lima to north. Normally I can not get Columbus because ground rises about 250 feet  30 miles east of here and then Columbus is about 350 feet below that. Unless there is a big ridge between them it will work if you get one end as high as possible and other end at least 20 feet at base.


Title: RE: 35 mile problem
Post by: KI4SDY on September 22, 2011, 06:13:10 PM
My post regarded making contact through the distant repeater, not with just each other, to add variety of contacts. The poster says that is not working for them at this point. Maybe you should read his original post again and then mine.  :-\


Title: RE: 35 mile problem
Post by: W8JX on September 22, 2011, 06:23:19 PM
My post regarded making contact through the distant repeater, not with just each other, to add variety of contacts. The poster says that is not working for them at this point. Maybe you should read his original post again and then mine.  :-\

I did long ago. There was a issue with repeater because they could bring it up with a HT or base but no audio going thru. If HT brings it up and base (with a much stronger signal does too) but no audio it points to repeater. I used to do a LOT of 2m FM. (and 440 too) Used to run a full sized collinear on 2m mobile at times too (5/8 over 1/4wave) and know what you can do with band and mode.


Title: RE: 35 mile problem
Post by: KI4SDY on September 22, 2011, 07:37:28 PM
How would using a weaker antenna than a beam solve their repeater issue?  ???


Title: RE: 35 mile problem
Post by: W8JX on September 22, 2011, 08:48:22 PM
How would using a weaker antenna than a beam solve their repeater issue?  ???

Height and capture area is everything with VHF/UHF.  A 15 foot plus verticals offers gain, capture area and 15 feet more peak height that a beam on same mast. Now if they could get up beams at 50 feet and more and more than 3 elements I would go for beam.


Title: RE: 35 mile problem
Post by: KI4SDY on September 22, 2011, 09:06:12 PM
I should have read their last posts. I didn't realize they were trying to use the radios right next to each other.  :-X