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[RFRY]

Below is a more direct, NEC4.2 comparison of the performance of the 3.5MHz OCF radiator that KH6AQ has posted here, for 1-ft and 16-ft base elevations AGL (other things equal).

The gain difference due to the elevation change for the conditions shown there is about 4 dB at zero degrees elevation.

NOTE: A calculation using only the NEC "far-field" values shows zero gains/fields in the horizontal plane at all distances from the radiator.

[WA5YOM]

RFRY....thanks for the comparison data...I appreciate your effort and feedback...
I will be experimenting soon...
Thanks,
Tim

[KH6AQ]

Tim WA6YOM, the MFJ-993BRT is ready to ship after receiving a part this week. The DC Block melted down on field day when it was left in line when an EFHW was plugged into the far end of the coax. It will ship via UPS today if that's okay with you.

[WA5YOM]

Excellent...looking forward to trying it out...
Thanks,
Tim

[KH6AQ]

The UPS system would not accept your QRZ address. Is that what I should use? I plan to ship through USPS instead for lower shipping cost.

[KH6AQ]

Tim, okay, the MFJ-993BRT is on its way to you by USPS priority mail ($28.75) with an expected delivery of 12/7. The post office could not use your QRZ address and so they changed it from AVE SW to ST.

The new Bias-T will be arriving from DX Engineering. It would be best to mail it all back after the holidays as our tiny yet understaffed post office has a long line (like hours) that get worse around Xmas. Use it as long as you like. USPS does not deliver to our house but UPS and FedEx do.

The Bias-T coax should be plugged into the ATU only, or a load that has no DC path to GND. That is how the original Bias-T melted down, being plugged into an EFHW transformer while powered from a car battery. This is standard Field Day operating practice.

[WA5YOM]

the tuner arrived today......waiting on the bias T........
I have installed the tuner,,,,at the base of the vertical, resting on a concrete block which puts it up about 6 inches from the ground.........installed a 8 ft ground rod which is connected to the gnd lug on the mft-993brt......
I have downloaded the manual on the tuner and bias t.......I will place the bias t in the shack close to the power supply....
 
the following is the configuration...

flex 6700 - pgxl amp - tgxl tuner- 8x2 4o3a antenna switch - bias t - mft-993brt - dxe mc20-1-1t 1:1 choke balun - greyline antenna.

I will take a picture of the outside installation....and post it here...

The PGXL will be powered down while using the greyline and remote tuner...also the tgxl is programmed to bypass mode when the greyline is selected....thus the tgxl will not attempt to tune the antenna.....

The Flex 6700 will be set to only run 10 watts while tuning...max power wqill be 100 watts while operating

I see that you sent a dc plug....and I see that the mfj- 993brt has a dc supply input......but I see no reference to it in the manual...

Did you do a factory reset as described in the manual?

I will let you know when the bias t arrives.......I am out of town this coming weekend.....

Let me know a payment method so I can reimburse you on the shipping......

Thanks a lot for you generous help..

Tim
wa5yom

[KH6AQ]

DX Engineering tracking shows the Bias-T is out for delivery today.

The DC is applied to the Bias-T and goes up the coax to the MFJ-993BRT. It takes an amp or so.

Ever since I saw these antennas I've wondered how the recommended tuners could tune them on 80 meters but apparently they do. I think of the antenna as a 25' vertical with a 3' vertical counterpoise. Anyway, I'm curious as to how you like the antenna. It should be quite good on 40-10 meters.

[WA5YOM]

I see this statement in the MFJ-993BRT manual.......
I guess I will have to research my antenna switch to see if there is a issue.....
"Note: The MFJ-993BRT is not designed to be placed AFTER remote antenna switches. Some antennas
and antenna switches have DC continuity between the center pin and shield which will short out the
power supply when switched to those positions."

The Bias T came in late this evening.....

[WA5YOM]

Yeah the separate 4117 bias T needs dc supply.....and the power supply is located in the shack.....and the 4117 bias T is also located in the shack...

And by design the 993brt has it's own bias t within it.....which is required....

The 993brt has a dc supply connection... and I see nothing in the manual that points out that connection...and that is my point of confusion....

[WA5YOM]

SO, everything appears to be working......I am directly connected to the antenna....awaiting to here from the manufacturer of my antenna switch to see if I connect through it......
The greyline works on 160.....but I am not getting a match at all.....did you ever try 160 with the tuner?

[WA5YOM]

Had to do a factory reset.....was not tuning all the time....upon opening up the enclosure I noticed the ground was loose....fixed it.......
Seems to be working better......will not tune 40 at all.....or anything above 3800 on 80 meters........
Tried 80 cw last night during cwt.....managed only two contacts......on a very busy band....
Connected to Remote Ham Radio.......never heard myself on 80....
Seems like it still doesn't radiate on 80.....
It tuned 40 before the factory reset.....so, not sure what is going on......

Something is not right with the antenna.....not sure what....I tried 10 meters....listened for my signal...nothing....tried a different antenna (yagi)....and heard the signal....granted the yagi is better....but with band open I should have heard the signal...

[KH6AQ]

I am sure that that tuner -- and I bought it over the MFJ-994BRT because it has a wider tuning range -- will not tune your antenna on 160 meters. For that the minimum antenna length is 90 ft. Even 80 meters is a real stretch with that odd antenna.

It should tune 80-10 meters if you run it as a vertical against ground with some GND radials. A dozen 20' radials is a good start.

The way I'd do it is to short the two halves of the vertical and leave the ladder line unconnected. Feed bottom of the vertical against GND radials. You then have a 28' vertical which should work quite well on 40-10 meters and make Qs on 80 meters. Radiation efficiency of 80 meters could be 20%, give or take.

[WA5YOM]

First of all the documentation on the Antenna is awful.....upon further review...I had to modify the installation... the tuner cannot be grounded.....nothing connected to the antenna can be grounded.....So, the balun I had installed at the antenna between the tuner output and the antenna had to be removed.....the antenna is now connected directly to the tuner as they require...positive (longest side of the antenna) on the wire connection insulator on the tuner, negative (shortest side of antenna) on the ground terminal of the tuner (which is not connected to earth ground, so now it floats as required), per the documentation the balun issupposed to be on the radio side of the tuner. because of the floatnig ground requirement..
Now.....it absolutely will not tune on 80 or 160 (when it tuned 80,,,,it didn't radiate anyway)....it does tune on 40 now.....
Greylines support is basically non existent.......there are parts missing that they know are missing and not even trying to supply.....

Here is a quote from the documentation...

"The ONLY satisfactory way to provide a true floating balanced output from an unbalanced tuner is to insulate it from the ground. Then to make it “float,” a 1:1 current choke must but placed in the coax directly ahead of the tuner. (This means to place it on the radio side of the tuner, for those of us who are blessed with laymen term knowledge levels)"

So, I will proceed and see what I can learn over the next few weeks......

Thanks for all your help and support.....

[WA5YOM]

One thing I have noticed.......The tuner dies not seem to like it when I change bands......I have to turn it off and on numerous times before it will tune again....did you have that problem?

The antenna appears to be radiating on 40...I ran a test (listening from RHR in the NE)...the signal from the greyline and my 40 meter bazooka were about the same......they were hearing about the same...the greyline noise level was lower.....

My main purpose was the low bands....and looks like that ain't happening.....

The reason I purchased (and it wasn't cheap) this antenna is, I will likely move soon.....and my bet is there will not be a tower in my future....so I was looking for a stealth antenna.....

Few neighborhoods are antenna friendly.....