Base loaded half sloper - part I.

Hello all Topbanders,

it's really long time ago when I posted the last article. I would like to send my appologize to all of You. I hope that I will be able to update this place more often...

In preview articles "Antennas inspiration"we talked about different antennas suitable for small pocket size lots. In fact I am still looking for some of that also as my fixed QTH is so small that I have no more than 10m x 15m garden available and just 6m high roof. No tower, no trees around.

Some time ago I found interesting article about shortened half sloper writen by Don, WD8DSB. There is what I found as the first on the internet about this type of the antenna:

Rugged 160 Meter sloper...

Our best selling antenna is our 160 meter, ruggedized version of our popular "half-sloper". We have been building these antennas for over 12 years. They work and work well.
It's features heavier, 14 awg insulated wire, a built-in SO239 connector and a solid cover over the coil. Ideal for 100-150 watt radios, this antenna solves the problems of working "top-band" and eliminates the need for a tuner. Trimmed to resonance at your favorite spot in the band this antenna offers omni-directional performance with minimum effort.

We start with a tightly wound 14 awg insulated wire coil.

This is the finished antenna, ready to be hung on your tower.
The radiator wire will be left several feet long to allow you to "prune" it to the length that tunes it to the exact spot in the band that you need. Once tuned near the center of the band at your location the antenna will cover the entire band without any retuning or tinkering. Note: this antenna can withstand quite a bit of power but we have NOT tested it above 150 watts. We don't build "high-power" antennas. We build antennas that give you that extra performance.

This antenna ships 75' in length and will be trimmed back to 68' or less on installation. It works best when attached to your tower at about the 45-50' level. This allows the wire to be angled down to the ground at a comfortable angle (somewhere near 45 degrees) and attached to a suitable support 8 or 9 feet off the ground ( to keep someone from touching it while you are transmitting) 45' or so away from your tower.

We have had one of these on our tower for 12 years with no problems.

We have made several improvements to the design over the years. The one shown here is a very early production model. (12 years in use...)

73 de Stan, KC5UYF

OK, it sounds good. What is important is that the installation need to have grounding point and some pipes or way to simulate the vertical part of the half sloper going to ground or better to the radials system.

The minimal height seems to be around 8-10m. Of course not for DXing but to come to TB in general. I am going to thinking about that...and need to find the original post from Don, WD8DSB.

73 - Petr, OK1RP
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Crappy Chinese cables in Your shack by Alan, N5NA

Watch Out for Crappy Chinese Cables!

At the beginning of the ARRL 10M Contest a couple of weeks ago I noticed several "squalling" noises across the band. I had heard these before but hadn't investigated. I thought it was probably from the Ethernet cabling in my house I decided to see if I could do something about it.

First I disconnected the coax from my rig, the noise disappeared. I reconnected the coax and turned off my router and wireless internet radio. The noise was still there. Next I disconnected the coax from the remote sensor for my SWR meter. The noise was still there. Hmmm, that's strange. I disconnected the coax from the antenna from the back of my amp. The noise was still there. Next I disconnected the jumper from my rig from the back of the amp. The noise was still there. At this point the only thing connected to my rig was a 6' coax jumper. I disconnected it and the noise disappeared!

That coax jumper was factory assembled with molded strain relief at the PL-259's. I replaced that cable with a homemade cable and the noise stayed gone.

I cut open the factory cable and found the coax had maybe 10% coverage, if you could call it coverage. It was junk. If I'm not mistaken I bought that cable from one of the large dealers at Hamcom. Below are a couple of pictures. It looks pretty until you cut it open.

A few months ago I was getting ready for the Texas QSO Party. I was testing a USB>Serial adapter that uses a separate USB cable. When I connected the adapter there was a noticeable noise increase in my Elecraft K3. Again, I tracked that noise down to the USB cable, which was a piece of junk from China. After replacing the USB cable with a Belden cable I didn't hear any noise from the adapter.

Moral of the story, beware of crappy cables from China!
73 - de Alan, N5NA.

---

Inspired by Alan and his article I started to check all of my coaxial cables in the shack. Well because of tons of cables over here it's not the "one evening project" but some strange results are available even now...

I found that after changing some of the cables for high quality one I noticed the SWR changes on LF/HF bands and also I noticed some noise improvement. It not solved my noise issue completely of course but even just noticable changes in the noise level seems that cables was not good and put me in troubles with weak signal reception over here.

I am going to check all of my cables !

73 - Petr, OK1RP
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The 160M "No Excuses" Homebrew Vertical by John, K6MM

Hello,

some months ago I attended on the web seminar about the 160m antenna for limited space. Excellent presentation done by K6MM was named "No Excuses" homebrew vertical. I found this design very interesting so I am preparing some hardware and I will try to work on it in the summer time because my post stamp lot is quite similar to the John's one.

When I discussed about this antenna on few hamfests then I have got several emails about the antenna construction and I was asked for contact to John, K6MM etc.

So there I am posting the link to John, K6MM page where You can find all informations regarding his nice project.

I will be glad to get feedback over here about the performance in Your location.

73 - Petr, OK1RP
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Inverted L for restricted space...

Hello,

when I looked for more information about my antenna (base coil loaded half sloper) I found interesting antenna also for restricted space.

In fact the vertical part is helical vertical where 11.7m of insulated 2.5mmsq wire is wounded on the 5m of the fiber glass pole including the wire going to point A for feed line. The spacing for the winding is approx. 1.5cm.

The 2x 18.1m of the insulated wire used for radials on the ground is compromised solution for that installation. Definitely it's needed better grounding system and 16x 16m is recommended as minimum where 3dB loss is expected.

Well I did not tested it but for those who are space limited it can be inspiration for experiments.

Do not hesitate to share with us Your experiences with compromised antennas like this.

73 - Petr, OK1RP
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ZJ Beverages and how it works - part II.

Hello,

as I promised there I am posting the open discussion about the ZJ Beverages as I found it on the reflector.

TopBand: ZJ Beverage Box Comments and Update de W0AH
from [W0AH@aol.com] [Permanent Link][Original]
To: <topband@contesting.com>
Subject: TopBand: ZJ Beverage Box Comments and Update de W0AH
From: W0AH@aol.com (W0AH@aol.com)
Date: Wed, 5 Nov 1997 16:47:09 -0500 (EST)

On Oct. 22 I posted to the list that I was not happy about the performance of my NE beverage and also that my ZJ Beverage Box was not working and that I was going to try and fix it.

Several wrote and asked me to send them any information I received since
they also need ed to fix the ZJ beverage box. Therefore, this post.
First, I want to say that my ZJ beverage box worked fine when I first
installed it a couple of years ago. It brought my beverage signal up 2 or 3S-units as I recall. I had no intermod (I have no local commercial
stations). Using a coaxial hand switch between the transmitting antenna and the beverage (my transceiver had no separate receive antenna), I forgot to switch the antennas and ran power into the ZJ box.


I wrote ZJ, which a month later sent me a replacement device, gratis.
Now, over a year later, wanting too repair the ZJ box, I can not find the device he sent me. Thus my inquiry to the list recently.


My ZJ Box did not come with a schematic which is my main complaint.
Looking at the device, I thought it was a gasfet, but I have been informed by KM1H, W8JI, and K0CS that it is a MMIC. MMIC stands for Monolithic Microwave Integrated Circuit Amplifier. I have built several of the well regarded Down East Microwave kits (for 902, 1296, and 2304 MHz) which use MMICs. Both KM1H and W8JI wrote that the MMIC was a poor choice for a 1.8 MHz preamp. I agree that it is an odd choice, but my Avantek Semiconductor Data Book shows that the power gain and other MMIC specs are flat from about 0.1 to about 1 or 2 GHz, depending on the specific device. Also, the Avantek power gain versus frequency chart shows them being flat to DC! Therefore, the device should be suitable for 1.8 Mhz.

KM1H siad there had been a discussion of the ZJ Beverage Box which can
be found in the archives. So more information is available there. He also said that the ZJ Boxes had been shipped with "at least 4 different" MMICS including the MAR1, MAR3, and others. He stated that some of those devices needed different biasing. He also stated the ZJ Box was subject to overload and IMD. Carl said the "ultraminature 9:1 balun is just as bad." W8JI suggested replacing the MMIC with "a regular CATV transistor."


W4MPY wrote that his ZJ beverage box filled up with water and that he
has tried unsuccessfully to get help from ZJ.


Both W8JI and KM1H stated that a good beverage will not generally need
a preamplifier.

K0CS kindly sent me a MAR-3 device which had been supplied by ZJ as a
replacement device.

Looking at the various Avantek MMIC specs (I can not find my cross
reference to compare the Avantek MSA MMICs to the MAR MMICS) I see several MMICs with very similar specs (in some cases just different plastic packages-ie. cases). Almost all of them require 4.5 to 5.5 volts DC. I suspect the several different MMICs supplied in the ZJ boxes have identical specs at 1.8 MHz and that biasing is not an issue. For those who need to replace the MMIC, a MAR-1, MAR-3 or equivalent should work fine. MMICs are listed in several of my electronic catalogs for about a dollar each.


I hope the above is useful information and that some of you get your ZJ
beverage boxes back up and running. Unfortuately, mine still is not working after I replaced the MMIC. I suspect that the ultraminature balun, as KM1H described it, needs replacement. Not sure I want to proceed until I get a schematic. Does anyonwe have one? See also my next post on beverage transformers. Doug W0AH


TopBand: ZJ Beverage Box MAR3 MMIC Replacement?
from [km1h @ juno.com] [Permanent Link][Original]
To: <topband@contesting.com>
Subject: TopBand: ZJ Beverage Box MAR3 MMIC Replacement?
From: km1h@juno.com (km1h @ juno.com)
Date: Thu, 23 Oct 1997 18:58:41 EDT

On Thu, 23 Oct 1997 15:44:36 EDT W0AH <W0AH@aol.com> writes:
>Thanks K0CS for the info that the ZJ Beverage Box uses a MAR3 MMIC,
>which are quite inexpensive .

Wrong info Doug. Your ZJ "thing" has a MAR-1 in it according to ur
number. Owners have found at least 4 different MAR MMIC's so far. NOT interchangeable without changing bias resistor either.

As discussed here at length a month or so ago, the choice of device PLUS
the matching xfmr in the ZJ box makes it an all around poor choice for Beverages. Nice and cute toy but no good for real world use. Suggest you check the Archives for comments by users, W8JI, myself, etc.

73 Carl KM1H


I thought I had a MAR3 around here, but can't find it.
Can any of the following Avantek be substituted for the MAR3?
Avantek 0185, 0285, 0485, 0685?????
I'll post a message as to how this all turns out as others have contacted me concerning their non-working ZJ Beverage boxes.
I have the above. If no answer, I'll try to call WB5LUA, Mr. MMIC!
Doug W0AH

Well any other experiences with this system even negative are welcomed over there.

73 - Petr, OK1RP
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ZJ Beverages and how it works - part I.

Hello,

when I discussed some time ago about the Beverages and neccessary boxes I mentioned that one of my Beverage sets is W2ZJ system. After several emails received from some of You I decided to scan the user guide as it is not available on the internet.

I have not enough time to replying to each of You for questions about ZJ Beverage boxes...how it is designed and which parameters it has.

So there are all information I have and let's go to check it guys.

I am planing to install the ZJ boxes and test it as I heard a lot of negative reviews about it. On the other hands it's promissing the system with pre-amp on the Beverage side then sigs going to shack enough strong and filtered.

As I need the strong negotiation with neighbours to install the 164m of insulated wire on the 2m stands in country side I am not sure when I will be ready to test it.

Does anybody used ZJ Beverages and how it worked for You please?

73 - Petr, OK1RP
.../-.-

W2PM MiniDiamond RX loop by OK1RP - part I.

Hello,

as I am still looking for the receiving antenna which will allow me to improve the receiving performance on my pocket size QTH (250msq) I was very happy to get construction details and description of receiving loop with name MiniDiamond from Pete, W2PM. I have to say that Pete is real gentleman and he provided a lot of effort to help me with RX antennas. Pete helped me to understand how to build the very small loops effectively for 160m band.

So after some time I decided to start with building the MiniDiamond loop and as Pete said I am making it as large as possible. All will be posted here step by step according to the progress of building. You will see used hardware, construction, mounting process, measurement and testing of the final product as same as the on-air results. If the antenna will not work then You will be able to check where I made the fault and learn from it to avoid Your own issues.

Today I will show You few pictures from bulding the main cross support.

I decided to use bamboo as the main cross support because all the other materials seemed to me worse. Fiber glass poles are too breakable, plastic poles used quite often as potatoes support on the garden are too heavy and short as same as wooden poles. On the picture You can see the used tickness. The only problem was in the local store with finding few bamboo poles enough straight, hi.

As the mounting support I used universal plate from the local store. You can see a lot of holes in the plate...great as I did not need to make any hole just decide for right one with the screws.

The cross support is already done waiting for mounting the last wooden part which will be screwed on the rotor unit. I hope that it will fit to the old rotor used for light UHF antennas...

Finally You can see the box arrived by snail mail with non-inductive resistor and 900/50ohms transformer units all in nice water resistant plastic houses.

If You are interesting in this RX Loop kit then be noted that they are available for loops, Beverages and also Ewe antennas in different versions like BNC, F connectors etc.

That is all for now and see You soon with some progress with building the loop.

73 - Petr, OK1RP
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MW stick vs. Half Sloper antenna receiving test by Petr, OK1RP - part I.

Hello,

when I spoke to several DXers about the Mini Whip stick all of them said "uhh, Petr if You are interesting in serious operation on TB then forget it and focus on good RX loops or so".

I do not like to evaluate or reprobate anything (specially antennas) without testing it first and mainly You never know which antenna and when will help you to hear weak signals on the TB so...I have this stick now and there is comparison with TX antenna > based coil loaded 11m high half sloper (see preview article about it)...

10/11/2010
22:45 160m W1MK S6/sloper S5/MW (better s/n on MW)
22:53 160m N3IR S3/sloper S2/MW (better s/n on MW)
23:20 160m VE1ZZ S5/sloper S4/MW (the same readability)
23:20 160m 9K2YM S6/sloper S5/MW (the same readability)
23:30 160m W8FJ S5/sloper S5/MW (better s/n on MW)
23:33 160m K1VW S4/sloper S4/MW (better s/n on MW)
23:35 160m TK5IH S6/sloper S5/MW (similar readability)

My personal feeling > in most cases the signal levels from MW were lower but quieter. The s/n ratio was definitely better on MW although the differences was not big sometime. Only in one case (TK5IH) I though that reception is better on Half Sloper because of stronger signal. 

The Mini Whip stick was mounted inside of the house in the attic just 50 cm bellow the ridge of the roof. Feed-line about 10m of the 50 Ohms cable down to the radio-room. Half Sloper is mounted about 5m far from the MW using the pipes into the total height of 11m where the base coil and sloped wire is mounted. Feed-line is 27m of cable going down to radio-room. No radials yet just copper strap going along the pipes down to ground where it's connected to grounding point.
The distance between both antennas is no more then 5m.

Used radio Elecraft K3 where Notch 900 Hz masking used, AGC off, AF gain at 11 o'clock, RF gain at 12:30 o'clock, DSP BW 150 Hz (200 Hz IF Inrad).

Of course there is no doubt that this stick is not comparable to full size Beverages or full size RX loops like Delta, K9AY or even Hi-Z phased verticals array but be noted that we are looking for "makeshift" solution compare to noisy TX antennas !

Interesting results...isn't it? What do You think about it?

More information You can find here: PA0RDT or here G3GRO

73 - Petr, OK1RP
.../-.-