A99 VS. I MAX CHOICE AT IMPROPER HIGHT

[Needle Bender]

TOA is something I've been finding is interesting with regard to local contacts here in town. For local rag chew I find a higher vertical omni angle like 25°-30° seems to help on 10m & 11m for 5-20 mile contacts, then the lower (5°-10°) angle seems to come into play. That's why I'm going to try out a .64 since it seems to like 22°- 28°, depending on installation elevation. mine will be at 54' at the radials.

 

[wavrider]

I'm not talking about any bands at all. I mentioned wavelengths, not bands. The same applies no matter what the frequency is. The height just changes with the frequency sa the wavelength gets longer/shorter.

But that is an effect of propogation which is variable and to which we have no control over, rather than anything to do with antenna height. We're discussing things we have a direct control over and antenna height is one thing we have direct control over.

Bands are designated by wavelength?????

10 meters, 11 meters, 12 meters?? Is this not the length of the wavelength.

Perhaps i mis understood the statement you may have meant wavelengths above ground level? My apologies.

https://www.arrl.org/files/file/antplnr.pdf

Good read explains pretty much all you will need to know to understand how TOA and AOA VS height of antenna

http://www.dx-antennas.com/Height versus take off angle.htm

national bureau of standards test results

http://nvlpubs.nist.gov/nistpubs/jres/65D/jresv65Dn2p167_A1b.pdf

Beam antenna height vs AOA
http://radio.n0gw.net/radio12.pdf

I do know my 75 meter 1/4 wl 40 meter 1/2 wl ground mounted vertical would 9 times out of 10 be stronger on TX and RX than my dipole into EU.

Local up to 1k miles the dipole was better

 

[222DBFL]

I have found that by going from 18ft to even just 27ft made an improvement on both rx and tx, 1-2 s-units of gain on both rx and tx to my locals 30-50 miles away. I would imagine at 36ft to feedpoint I would see another jump, be it maybe another s-unit locally. Dx I picked up about 1/2-1 s-unit of rx, tx was a bit better as well. And I started to get away from more noise the higher I went. Right now I'm fighting a bad electrical or RF short nearby causing me to get an S7+ constant trash noise in my RX on AM, and on SSB it's 3-5 S-units. When it rains hard here it happens every time until it dries out. Not sure what it is, but I know where it's at. 3 doors down at the neighbors house. Enough to make me not turn radio on! Sucks!! And it seems with the A99 I pick the noise up twice as much than with my sirio tornado. Used to be just about 1 s-unit of crap on SSB when it happened before. Boy I hate this A99 POS. antenna. I know my tornado wasn't the best antenna made or anything special, but it did work well the way I had it setup! I will have another one soon! Very soon!! the antenna served me well and it was totally my fault the one I did have got broken. With that said I will be beefing up some areas of my next tornado. Thinking ss hose clamps. Cut slits and install 2 at each section then weather proof with some self amalgamating tape. Should make for a bit sturdier antenna. Maybe add something inside the 2nd and 3rd sections to help minimize the bending. Will have to see when I get the new one. At any rate some great info here!! Thx for all the relies and info from all that have contributed!!! Much appreciated even by someone that didn't make the post!! A lot of good and valid points and info for sure. 73 and God Bless.

 

[Needle Bender]

I have found that by going from 18ft to even just 27ft made an improvement on both rx and tx, 1-2 s-units of gain on both rx and tx to my locals 30-50 miles away. I would imagine at 36ft to feedpoint I would see another jump, be it maybe another s-unit locally. Dx I picked up about 1/2-1 s-unit of rx, tx was a bit better as well. And I started to get away from more noise the higher I went. Right now I'm fighting a bad electrical or RF short nearby causing me to get an S7+ constant trash noise in my RX on AM, and on SSB it's 3-5 S-units. When it rains hard here it happens every time until it dries out. Not sure what it is, but I know where it's at. 3 doors down at the neighbors house. Enough to make me not turn radio on! Sucks!! And it seems with the A99 I pick the noise up twice as much than with my sirio tornado. Used to be just about 1 s-unit of crap on SSB when it happened before. Boy I hate this A99 POS. antenna. I know my tornado wasn't the best antenna made or anything special, but it did work well the way I had it setup! I will have another one soon! Very soon!! the antenna served me well and it was totally my fault the one I did have got broken. With that said I will be beefing up some areas of my next tornado. Thinking ss hose clamps. Cut slits and install 2 at each section then weather proof with some self amalgamating tape. Should make for a bit sturdier antenna. Maybe add something inside the 2nd and 3rd sections to help minimize the bending. Will have to see when I get the new one. At any rate some great info here!! Thx for all the relies and info from all that have contributed!!! Much appreciated even by someone that didn't make the post!! A lot of good and valid points and info for sure. 73 and God Bless.

Hey 222DBFL, Would you do me a favor? I'd like to know if the Tornado is ground-shunted. If so, it will exhibit a direct short across the bottom coax connector.
If you have a Volt-ohm meter, could you take a resistance reading across the coax connector and let me know if it's near zero ohms or open (infinite)?
Thanks & 73

 

[222DBFL]

It's DC transformer grounded. I know its not true DC grounded thus my reasoning for adding the solid #2awg from base of antenna down mast to ground. But I will check when I get a chance as I happen to have the base section laying aroibd somewhere. Give me a day and I'll posts my findings NB.

 

[222DBFL]

Okay NB, here is what I have found. I took the coil off of the antenna at the base but added a piece of wire for now just to test the grounding. So in place of coil is the red wire pictured. Here are my readings. With meter set to ohms I get an open when going from center pin to ground. When I go from center pin to coil i get continuity. When I go center pin to ground, no continuity. I then only get ground at the radial hub and below. And the outer part of SO239. Hope this helps. Here are the photos as follows.
1. Center pin to ground.
2. Center pin to coil.
3 & 4. Outer part of SO239 to ground.
The reading that shows zeros is the only closed reading I got. which was center pin to coil. Again hope all this helps.

 

[222DBFL]

Let me know if you would like anymore readings. Be glad to post whatever I can.

 

[Needle Bender]

Okay NB, here is what I have found. I took the coil off of the antenna at the base but added a piece of wire for now just to test the grounding. So in place of coil is the red wire pictured. Here are my readings. With meter set to ohms I get an open when going from center pin to ground. When I go from center pin to coil i get continuity. When I go center pin to ground, no continuity. I then only get ground at the radial hub and below. And the outer part of SO239. Hope this helps. Here are the photos as follows.
1. Center pin to ground.
2. Center pin to coil.
3 & 4. Outer part of SO239 to ground.
The reading that shows zeros is the only closed reading I got. which was center pin to coil. Again hope all this helps.

Hmmm, bummer. Thank you for the effort and proving it is NOT a DC grounded radiator. I actually find it odd that Sirio didn't design the Tornado to be similar to the 827 with a DC grounded coil/radiator.
I can attest to the fact it's a good performer though, outperforming a new Imax2000 when installed at a friend's home, same mast & coax. We all saw almost a full S-unit stronger signal than his usual signal on the Imax.

Nice antenna for the money, but I'm going to encourage my radio friends to steer clear of antennas not DC grounded.

Thank you again 222DBFL! You went to a lot of effort and it's appreciated.

 

[222DBFL]

Not all all. There is a thread on another forum MD, that shows a guy making his DC grounded. I just add a solid ground from base of antenna to ground. Don't know if it helps but it makes me feel better knowing I have solid copper from base of antenna to ground. For the money it's not a bad antenna, and can be made DC grounded. I will most likely be getting another here soon as the A99 just don't cut the mustard!!!

 

[222DBFL]

Real Estate is my biggest issue. Houses aren't very far apart side to side, and front to back is not very far either! Makes for funny looks by the neigbors. As long as they don't get into my business or I don't bother them, all is good.

 

[Stellasstillarat]

I actually believed the poor job i did on replacing the pl259 that was removed when i cut the extra 30' of LMR 400 was the cause of the swr and problems that didn't exist before I replaced shortened the coax and attempted replacing the pl259.
I sent my LMR 400 to my tec along with some equipment that need attention, and the poor job I did on the pl259 was absolutely the cause of my I'll's. My tec did the job like it shouldve been done in the first place. Somrone who lacks the knowable or skills should leave it to the people like yourself who know what their doing. I will create a new post and let everyone know how everything's working. I really want to thank everyone who's helped me throughout the eight months I've been on the air. My station would nevrr be working as well as it is without all your help.

I agree with most of what you have to say and we both agree his load is reactive. But unless the load is a 50 ohm resister I would expect to see a slightly higher swr with a reduced bandwidth due to the return loss of the 30 ft of cable at 11 meters.
But come on, inexperienced operator ,a99 mounted 15 ft of the ground ,objects in it's near field , no choke ( at last report), swr tested at end of cable. Then raised another 5 ft, 30ft of cable removed. And driven with 1kw pep.
What could possibly change !!!

 

[DJboutit]

Imax is a much better antenna I have made a contact to 853 Australia on 40USB from Houston that is like 9k miles and another day I made 11 contacts all barefoot. Only thing I have done to my radio is turned up AM power to 7w

 

[RadioDaze]

The IMAX2000 is advertised as DC grounded and there is a short between the + pin and the mounting plate.

I recently bought an "MAX2000" and will be putting it through it's paces soon. Mainly because it is very quick and simple to put together when I want to get on air quick being a mobile station (and considering winter time cold setup). And also just for comparison and interest value really vs the Gain Master.

It seems to VSWR ok, No RF back in the shack issues as yet. And that is without any choke in the feed line. My mobile base station seemed happy enough with 200W pep up it. I found this old review online of the GPK....it appears to fractionally lower the TOA (very slightly)

http://www.copperelectronics.com/discus4/messages/7750/20506.html?1023340740

I would have thought the "A99 exposed" review would have made people opt for the IMAX2000 by default ?

My first impression is the MAX2000 seems like a nice bit of kit. I cannot comment on how it compares to the Gain Master as yet, though in most set ups people seem to say the Gain Master has better RX, less static pick up and a little more poke as long as you get it very high.

I can only get my verticals to 24ft high maximum being a mobile static base station so wondered if the IMAX2000 could be beat out the GM at this relatively low height.

 

[Stellasstillarat]

I agree. I don't know why anyone would concider the a99 over an I max. Thr only reason I purchesed mine was, it was bought by a friend of mine who did me a favor and went to a local cb shop while I was out of town.
I told him to get an I max 2000, but the shop only had the a99, so he bought it.

• I had purchased everything I need except the.antenna and was ready to get on the air.
• When I got home I called the shop to swap the antenna for an I max. Unfortunately the shop needed a week to get it and I just couldn't wait.
• Now that I have the 2000. I know what a better antenna it is. Atleast that's my exsperiance. Stronger recived signal, and quieter. As for the gain difference, an s-unit is huge. I would have to up my output to 2400 watt in order to gain an s-unit.
• For $100 you can't beat it. I did àdd an MFj 915 rf choke to it. I'm not sure if the choke stopped the stray rf as I didn't have one on the a99 and didn't put the I max up without it. So I don't know if the stray rf would've ceased if I would've put up the I max without it., but either wsy, no stray rf any more. If i have to ever change out the antenna I'd definitely go with an aluminum omni directional but for now I'm happy.

  The IMAX2000 is advertised as DC grounded and there is a short between the + pin and the mounting plate.

I recently bought an "MAX2000" and will be putting it through it's paces soon. Mainly because it is very quick and simple to put together when I want to get on air quick being a mobile station (and considering winter time cold setup). And also just for comparison and interest value really vs the Gain Master.

It seems to VSWR ok, No RF back in the shack issues as yet. And that is without any choke in the feed line. My mobile base station seemed happy enough with 200W pep up it. I found this old review online of the GPK....it appears to fractionally lower the TOA (very slightly)

http://www.copperelectronics.com/discus4/messages/7750/20506.html?1023340740

I would have thought the "A99 exposed" review would have made people opt for the IMAX2000 by default ?

My first impression is the MAX2000 seems like a nice bit of kit. I cannot comment on how it compares to the Gain Master as yet, though in most set ups people seem to say the Gain Master has better RX, less static pick up and a little more poke as long as you get it very high.

I can only get my verticals to 24ft high maximum being a mobile static base station so wondered if the IMAX2000 could be beat out the GM at this relatively low height.

 

[KD2GOE]

i had the A99 and iMax 2k on the same mast talking to the same people each one had 2 years on the mast...
the guys i talked to ranged from 2 to 20 miles away and the Imax2k blows them out i have talked to them on 10, CB and 15 meters there is a great deal more single both ways..
as for skip having them setup the same way was not possible.. but the Imax 2k did outperform the A99