MACO VQ3

[BJ radionut]

Now if I could stop wasting watts in reflect

Your not "wasting" ANY watts!
Even at a 2.0:1 VSWR power transfer to antenna is 90+%

SWR POWER LOSS TABLE (firestik.com)

As shown in the table @ 2.0:1 ratio... a 400 watt transmitter will still radiate 356 watts...DUH...
NOBODY will ever know that on the receive end!!!!

Same as trying to get every last watt out by getting the SWR below 1.5:1 (OMG that's totally unacceptable!!!)
Nobody but the guy fixated on his watt meter will loose a contact running "only" 500 watts vs. 800 watts!
The receiving station will never know the difference

 

[lonestarbandit]

I didn't say it makes a difference on a contacts recieve. My primary concern is the reflect and what effect it might have on the HG2879s. I should have been more clear.
I am well aware that I'd need a 8 pill to show any improvement on the other end.

 

[lonestarbandit]

Well. Frustration still reigns supreme.
Have IMAX on other side of house hooked up.
1.3 SWR WITH amp. No problem.
A Daiwa 2 way switch is inline.
Barefoot on VQ3 nearly flat.
WITH amp SWR across the band 3.
Maddening. Long conversation and photo exchange with Tom of Maco and everything seems correct. Gamma match is correctly assembled and installed. Antenna is correctly assembled to spec. Difficult to blame amplifier or radio tune as its inline in the circuit before the switch and on the IMAX theres no issue. Yes I have switched coax runs on both antenna to eliminate that variable and have tried without switch inline to same readings.

 

[magnuman]

Where did you place your meter when tuning the V Quad? Hopefully right at the antenna. Possibly the additional coax jumpe is causing the SWR to rise. Vary the jumper length and see if the SWR changes much.

 

[lonestarbandit]

So I have 2 meters in line. The meters location isnt the issue I dont think.
As mentioned previously I have both antennas to a 2 way switch then into the "system". One antenna on same system works fine with power on. One doesnt.
Swapped coax runs between antennas and problem stayed with the Maco. Therefore the coax runs aren't responsible for the problem.
Likewise the "system" works fine on both antennas at low power.
Only the Maco reacts extemely badly to application of power.
Even tried various amps to same result so the amp isnt the fault.
Properly confused with this antenna.
Also chokes and low pass filters have no impact on the condition
At this point I'm going to completely tear the station down and reassemble.
Nothing to lose.

 

[lonestarbandit]

I have to come hat in hand and eat the proverbial crow @magnuman and @NightThumper as I dont know which of your solutions worked or combo of both ... Out of sheer desperation I installed a THIRD meter after the switch and with some of nighthumpers jumpers and the meter AFTER the switch shows a dead flat match on the VQ3 the ones before the switch show 1.5 ish no idea why nor do I care as the one dedicated to the VQ3 after the switch shows flat. Changed a few more jumpers nothing else changed but why in Gods name a THIRD meter brought down the SWR from 3 to flat I have no idea. Pardon the rambling but extremely tired I've had that antenna lowered and raised at least 70 times .... Trying for weeks.... And somehow its now perfect...
Short of rerouting coax through walls etc I will just leave the 3rd meter where it is.
Hallelujah!!! Now the Chinesium rotor will snap to punish me for my success

 

[The20poundhammer]

Out of curiosity have you hooked an antenna analyzer straight to the beam to see what it says without anything else in the way?

 

[dave457]

I'd be suspect of that grey coax

 

[lonestarbandit]

Out of curiosity have you hooked an antenna analyzer straight to the beam to see what it says without anything else in the way?

No, I haven't got one and its 20 feet in the air now.

 

[lonestarbandit]

I'd be suspect of that grey coax

I did remove some of it. To be fair after a month of suffering I was suspecting everything. About 3 jumpers worth were the grey new RG8X but bought commercially didnt solder them myself. They rang out ok but replaced some anyway. At this point all looks great and I'm not gonna sabotage that by any more fiddling been fighting this for almost a month.
Now I just need some skip to test her out.

 

[magnuman]

Sounds lovely, but what counts is the SWR that the amp is seeing. That is the important one to go for. Keep fiddling the coax length till it comes down. Sounds like you have tuned the V quad and the coax instead of just the V quad.
There is only one way out of it from here. Put the swr meter at the antenna and re tune. Best way is stand the antenna on the ground in the clear on the reflector with the beam facing the sky. Dont stand too close to the beam when checking the swr. You can have any length of coax running back to the radio but the SWR meter must be an inch or two from the beam. Another option is to work out the velocity factor of your coax and put the meter exactly an electrical half wave from the antenna.
From here on everytime you change something your SWR will change.
Just because a meter 6ft down the coax is showing a low swr does not mean the amp or radio is seeing the same low SWR. You need to retune your quad properly.

 

[magnuman]

If you were to put a 50 ohm dummy load on the end of your coax that fits into the antenna you will probably see a low swr anywhere on your coax.
Your results tell us that you have not tuned your antenna to 50 ohms or anywhere close so it will not be working as well as it should.
Thus a retune is required.
Not much skip about yet so now is the time to do it!
That is why the SWR on your IMax does not change much when you add the amp or additional coax. It is factory tuned to 50 ohms.

 

[lonestarbandit]

Before I take anything back down..
WITH a low pass filter inline and as it sits the SWR in the radio sees nothing. After amp to the meters and switch sees less than 1.5 across band and after the switch to the VQ3 is not even readable a tiny flicker. These readings are with full power applied.
You think it's worth pulling this heavy monster down again? This isnt an 8 pound quad but about 30 pounds w VQ3 and rotor at the top of 20 foot pushup pole.
When it starts to go its like hanging on to a rodeo bull.

 

[lonestarbandit]

So took it down checked at the antenna w a 4th SWR gauge but can't hit that one with power got it to a 1.1 barefoot. Got it back up it thinks its 1.3 to 1.5 SWR with power on so assume still its something with jumpers fooling the main line SWR. Put it back up.
Spent enough time taking this thing up and down one of these times the stress will snap this rotor. Guess still something to sort in thr shack system.

 

[dave457]

Get some good quality jumpers and ditch those grey looking ones