View Full Version : MCLAPP vertical 8-bay build, slight increase in pole height and dedicated DX'ing TV?

11-23-2016, 01:39 PM
I'm thinking about building an MCLAPP design vertical 8-bay with a reflector and going up another 10 feet with the antenna pole. This will "triple" my array (in that my present 4-bay is unreflected) and put the top of the antenna about 38 feet off the ground, as opposed to 24 feet now.

I'm also thinking about keeping the M4 to feed the house, put up the new antenna/pole right behind the living room TV and make it a dedicated DX'ing TV.

Anyways Jim Thomas encouraged me to research the CM4228. I'm not sure if I'm reading it right, but it looks like the M8 I propose to build mostly outperforms the "hot" CM4228 in gain. I know that's not all that makes a good antenna, and there's still things I don't understand, like "front to back ratio", "dB above noise floor" and how all of it affects antenna performance.

I'm hoping someone wouldn't mind to help me understand these things and maybe help check my research. I'd really like to get the best bang for my buck if I'm going to build another antenna. This time it will be precise with nothing left to chance. That's a lot of work and I'd like to maximize the reward.

Besides........Jim's new antenna is vacuuming up all the DX around here like Hoover cleans a rug! lolz

Thanks everyone

11-27-2016, 01:24 PM
Did I ask too broad of a question? lol

Gary Hickerson
11-27-2016, 03:07 PM
Your antenna, needs a "reflector". That will make it directional , also you will have front to back ratio. Without a reflector, your antenna, will pick up, in all directions. Jim's ant. has 12 elements, but it has a large reflector. Makes a big difference.
CM put in a lot of research, in developing their antennas. ALL of them, have reflectors ! Hard to improve on their designs...

Gary H.

11-27-2016, 05:21 PM
Yeah it does need a reflector, that's for sure. What is front to back ratio, and is there an ideal?

I'm sure CM probably does the finest research too, and everyone speaks well of the 4221, but according to MCLAPP's research his reflected M4 shows more gain overall than even a "hot" CM4221 with some mods. There's no doubt about how good Jim's antenna and mods are, it's a signal funnel!

There's also an antenna called a "FF4" (free-form 4-bay) and an "FF6". These show even more gain than the MCLAPP M4 but require the user to know the incoming angle of the signal and match the angle of the antenna to it when mounting it to the pole. I think this would make the FF series antenna less desirable for DXing. I would like to put up some research info but I don't want to step on anyone's toes or violate someone's copyright. I'm also not knocking the CM antennas.

Maybe it would be easier on all if I should just ask "what am I missing" (besides the technical knowledge I need to understand which way to go) and "does anyone here know anything about or have experience with MCLAPP design antennas?"

Thanks for the reply Gary!

Gary Hickerson
11-27-2016, 09:35 PM
I think k6sti in Calif., would be the person, to ask about F/B ratio, gain etc. He is able to model antennas and see whats going on. He has Posts in Antenna Forum and DX Equip. Forums.
I'm not famililar with the FF antennas.

Gary H.

11-27-2016, 10:19 PM
I'm not familiar with the FF either. Sounds like k6sti is a good person to ask, thanks for the tip Gary! I've been on forums where one can shout out to a member using @ before their screen name. Is there a way to do that here, or just contact through one of their posts/PM?

Just one more question for the TVDX folks......if you were asked for an antenna recommendation specifically for serious hard core TVDX purposes would it be the modified CM4221, and should I just take the blinders off and go that way?


Jim Thomas
11-27-2016, 11:29 PM
K6STI (Brian) hasn't been on the forums here for a couple months now. Not sure what's going on that he doesn't come back around.

I would go to Solid Signal and look at the top-of-the-line TV antennas they are selling, do some research on them and then maybe ask questions about specific models. The reason the 4221 and 4228 were so popular was because by virtue of design, they pulled hi VHF signals in, in addition to the UHF they were designed for. The reason for hi VHF reception was because of the screen reflector design. And that contributes to the F-to-B ratio. The NEW 4221's and 4228's were redesigned and CM quit using the screen on the new design. They now use a horizontal bar reflector background and it doesn't even affect hi VHF frequencies the same as the original design. That seriously changed the performance of high VHF reception, although the 4221 and 4228 were designed for UHF.

Solid Signal is a source for TV antennas as mentioned....

Also the other popular route to go is Antennas Direct, which is a St. Louis antenna manufacturer...

Very similar to the McLapp would be building "Big Bertha", the DB8 antenna....

11-29-2016, 01:43 AM
So after taking a look at Jim's links and adding some of my own "research" I've made a decision. I'll try not to be wordy with my reasons.

Ultimately for me I prefer to build something from nothing. I just like that stuff! If it isn't antennas it's special tools out of brass pipe or taking a free 1989 mobile home and turning it in to a place you couldn't buy for under 70 grand....and for half that!

In the final equation.....who cares what antenna has how much gain! For me it's all about the adventure.....and using something I built with my own two hands to do something I never thought I'd be able to do again....that is view TV signals from far away. I really thought DX'ing was gone when they switched everything to digital. In some ways it's like running across an enjoyable old friend.

For those reasons I will build the MCLAPP vertical 8-bay using his instructions and great care will be taken to follow them precisely and to the letter. It will also be cool to meet Jim Thomas and learn from his experience, as he offered to come out, meet me and help with the build!

So now that's settled. I can stop asking questions and just enjoy! Thanks for your replies and patience everyone.

07-17-2017, 01:06 AM
So I went and did it…the monster 8-bay “Megatenna” is built and deployed for testing! 20719Here are some highlights of the build:

As you can see from the pictures it’s a “mono-spine” design. Instead of bolting the insulators to a single long pole I stood eight pieces of square aluminum tubing up on the backbone, place the insulators on top of that and used one long carriage bolt to hold each of the stand-offs and insulators to the backbone. 20720

Each end of the aluminum stand-offs were hand filed to exactly square so they stand up perfectly vertical, thus helping to keep the insulators centered and perpendicular to the pole. The insulators are some kind of acrylic counter top material I had laying around.

The phase lines are 10ga copper. After straightening the wires all of the whisker attachment points, center feed point and location of the bends were precisely marked. After bending they were all final shaped together to ensure they are all identical. The ends of each phase line were cut perfectly square and they’re all identical length.

The whiskers are 8ga, or 1/8”dia copper wire all precisely cut to the exact same length, were bent around a ¼” fastener then further bent on a jig I made to shape them identically. A piece of wire was taped between each end of the whisker to keep them 5 ½” apart on the ends. The exact center was marked on the tape. 20718

Assembly was a PAIN with the “mono-spine” but its all together now.

I’ll be updating further later, but let me tell you…..last night I logged 4 stations 82 miles away with signal strengths as much as the local stations that transmit 11 miles away. This also happened the night before. Tonight I’ve logged 4 stations 165 miles away with a very respectable signal level.
All of this is with the antenna mounted 14” above the ground on a temporary pole!

Let me mention I am in a good DXing location here, 1420 feet above MSL so I know this helps…..but DANG!!!!!!!!!! IT’S NOT EVEN ON THE POLE YET!!!!!!!!!!!!!

07-18-2017, 07:35 PM
Thanks for the Update and Pictures of the finished Antenna. Looks great & professionally made. Keep us updated on what DX you receive on the Antenna.

07-31-2017, 07:50 PM
Sorry I haven't updated for so long, things been kinda busy around here with the new shop going up, and I wanted to test the antenna out over a couple weeks.

Before I start, let me say Jim Thomas has been a tremendous help to me with my DX'ing. Recently he ran an elevation report for me and found that with the exception of north-northeast to east-northeast....there's nothing in the way of my antenna. For reference I am near the town of Rogersville MO. The elevation here is about 1420 feet and is one of the higher up places within 10 miles. The best view for my antenna is basically from east to south to west. According to Jim, if a straight line were drawn out 10 miles at 240 degrees, an antenna at that location would have to be on a 281 foot tower to equal the height of my antenna here.

I am 100% certain this explains at least some of the reason I'm seeing the performance I am from this antenna. Some other reasons: The coax I'm using to test this antenna is 40' long and a straight shot from the transformer to the tuner box, no junctions. On the other hand there's no pre-amp and the antenna was anywhere from 14 inches to 10 feet or so off the ground measured to the bottom screen reflector.

I deployed the antenna from 5pm to as late as 3am nearly every day. During these times, when I point it towards Kansas City, at least one Kansas City station decodes. It's usually KCTV or KPXE first, but as the sun starts to set, eventually the stations I can get all show up. The signal usually swings wildly from super strong to super weak but as the night wears on things stabilize and the KC channels become watchable a good part of the time. With or without enhancement indicated on APRS, Kansas City seems to show up regularly.

It's the same way for stations in Joplin, northwest Arkansas and Little Rock, with or without enhancement. if I point it their way at least one of that market's stations will decode with a swinging signal that eventually stabilizes around and after sunset. With Joplin (269deg@90mi) it's usually 43/12 KODE....and that's with KYTV 44/3 close (55deg@11mi) and kicking out a 1Mw signal. Northwest Arkansas is 50/51 KNWA (235deg@66mi) and Little Rock is usually KATV 22/7 (169deg@165mi) with KOZK 23/21 (55deg@12mi) adjacent. The signal from Little Rock swings more wildly and is less watchable than KC until later in the evening.

When I point the antenna towards Memphis, Jonesboro AR Tulsa and St. Louis I see evidence their signals are there, but they're usually way too weak to decode without some kind of enhancement present. I like to call this "in the background".

The first night I put it out on my front porch I got full decodes from 4 Dallas TX market stations @380mi and decoded the big four stations in Oklahoma City @265mi with tropo present. What's remarkable about that is only half the antenna could see over the roof to get them. This antenna has garnered me about 12 new logs in the past two weeks.

The signal levels are anywhere from two to fifteen times better than the Hobotenna and the stock Winegard PR8800 I got from Jim. The PR8800 would not gather enough signal to decode K26GS in Harrison Arkansas (178deg@66mi, 11.2Kw, 2edge, predicted NM 1.7 and power -89.2dBm), averaging a signal strength of 5 to 8 on the Digital Stream box. It always decodes with the Megatenna at an average ss of 36-39, after sunset raising to the mid 40's.

I see no reason not to put the Megatenna in to service. Now that my 19'2" tall shop is done it will make for a great place to put a pole. The bottom of the antenna is planned to be 10 feet over the metal galvalume ribbed roof (unless anyone can see a reason to go up more) placing the top of the upper receiving assembly at about 37 feet.

For now I'm done with testing. I don't want to take a chance damaging it....since it only took 3 months to complete. It would take a heck of a good DX forecast for me to put it back out, until it goes on the pole. Once it's in real-time service I'll start officially logging and reporting DX with it. Will keep everyone posted as time permits!

08-18-2017, 08:45 PM
Last night and this morning we had a DX event strong enough to warrant deploying the Megatenna. About 8:30PM I put it out on the front porch settling on a southwest point.


If you noticed, only slightly more than half of the MT is over the roof line, and the new shop (at 19’8” tall) is just left of most of the MT’s beam width. These are the logs from this direction.

NOTES: I am located 5 miles south of Rogersville MO
* denotes a new log

KXNW 34/34 Eureka Springs AR
KNWA 50/51 Rogers AR
KHOG 15/29 Fayetteville AR
KODE 43/12 Joplin MO
KFJX 13/14 Joplin MO
KSNF 46/16 Joplin MO
KOAM 7/7 Pittsburg KS
KEMV 13/6 Mountain View AR
KAFT 9/13 Fort Smith AR
KFSM 18/5 Fort Smith AR
KJRH 8/2 Tulsa OK
KOTV 45/6 Tulsa OK
KOED 11/11 Tulsa OK
KMYT 42/42 Tulsa OK
KKYK 30/16 Little Rock AR
KTHV 12/11 Little Rock AR
KLRT 30/16 Little Rock AR
KATV 22/7 Little Rock AR
KVTN 24/25 Little Rock AR
KARK 32/4 Little Rock AR
KTVE 27/10 El Dorado AR
KFOR 27/4 * Oklahoma City OK
KOCO 7/5 Oklahoma City OK
KWTV 39/9* Oklahoma City OK
KTBO 15/14* Oklahoma City OK
KOCB 33/34 Oklahoma City OK
KUOK 36/29* Oklahoma City OK
KAUT 40/43 Oklahoma City OK
KOCY 48/29* Oklahoma City OK
KTUZ 29/30* Shawnee OK
KTEN 26/10 Ada OK
KSWO 11/7* Lawton OK
KJTL 15/18 Wichita Falls TX
KAUZ 22/6* Wichita Falls TX

The antenna direction is noted in degrees for the remaining captures, these were mainly received this morning. This is the view of the MT to the south southwest:


K26GS 26/26&12 Harrison AR 168
KAIT 8/8 Jonesboro AR 151
KTEJ 20/19 Jonesboro AR
KJNB 42/42* Jonesboro AR
KVTJ 48/48 Jonesboro AR
WSIL 34/3 Harrisburg IL 080
WATN 25/24 Memphis TN 130
WPXX 51/50 Memphis TN
WBUY 41/40 Holly Springs MS
KETS 7/2 Little Rock AR 168
KLRA 20/49 Little Rock AR
KASN 39/38 Little Rock AR
KTVV 18/18* Hot Springs AR 168
WMAO 25/23 Greenwood MS 158

All sub-channels included there were 158 total out of market channels logged for this event.

Here’s some screen shots!


This was my best night ever, so when DX conditions are sufficient there will be future MT deployments and reports that will follow!

08-20-2017, 04:31 PM
On the 18th about 23:00 I was seeing pilot signals on multiple channels so I decided to deploy the Megatenna again. It’s a good thing I did, because I got a few new logs, including K07XL-D in Harrison AR with an ERP of 114 watts on a 183’ tower some 62 miles away! Thanks to Jim Thomas for this ID….I actually thought it was K26GS trying out a new transmitter for the re-pack!

I re-deployed the antenna about 20:30 that evening and again got several new logs from the north northwest. Both events combined there were 10 new logs and 115 total out of market channels

* denotes a new log

KQTV 7/2* St. Joseph MO first full decode
WDAF 34/4 Kansas City MO
KCTV 24/5 Kansas City MO
KSDK 35/5 St. Louis MO
KEMV 13/6 Mountain View AR
KMOS 15/6 Sedalia MO
WOWT 22/6 Omaha NE
KOAM 7/7 Pittsburg KS
KETV 20/7 Omaha NE
KLKN 8/8* Lincoln NE
KMBC 29/9 Kansas City MO
KODE 43/12 Joplin MO
KAFT 9/13 Fort Smith AR
WHDF 14/15* Huntsville AL
KXVO 38/15* Omaha NE
KDSM 16/17 Des Moines IA
KCPT 18/19 Kansas City MO
KTEJ 20/19 Jonesboro AR
KAJF 16/21* Kansas City MO
KNLC 14/24 St. Louis MO
WATN 25/24 Memphis TN
K07XL-D 7/26+12* Mountain Home AR
K26GS 26/26+12 Harrison AR
WAAY 32/31* Huntsville AL
KBIN 33/32* Council Bluffs IA
KHIN 35/36* Red Oak IA
K38HE 38/38 West Plains MO
KMCI 41/38 Kansas City MO
KSHB 42/41 Kansas City MO
KPTM 43/42* Omaha NE
KVTJ 20/19 Jonesboro AR
KPXE 30/50 Kansas City MO
KNWA 50/51 Rogers AR
KSMO 47/62 Kansas City MO

Here's some screen shots!