Manager


Manager - NA4M
Manager Notes

Reviews For: Bilal Isotron

Category: Antennas: HF: Verticals; Wire; Loop

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : Bilal Isotron
Reviews: 82MSRP: 59.95 to 179.95
Description:
HF Antennas for SMALL Spaces
Product is in production
More Info: http://www.k1cra.com
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
15824
KB1GUF Rating: 2002-03-20
So far, so good! Time Owned: 0 to 3 months.
First, I'll definitely agree with the previous reviews that state "Read the instructions!".

I bought this antenna in order to get onto 80 meter PSK-31. I have a 1/4 acre suburban lot so there is no room for a full size 80m dipole. The rig I intended to use is a PSK80 Warbler from the NJQRP. It puts out about 2 watts, so antenna efficiency was a concern. Since the Warbler is rockbound at 3581 KHz with 1 KHz bandwidth, I was not concerned about the Isotron's narrow operating bandwidth.

Construction of the Isotron was straightforward mechanical assembly. Tuning it was the trick (read the instructions!). The instructions repeatedly stated that the Isotron must be mounted on a metal mast. For starters I U-bolted the antenna to a 5 ft metal lamp pole that stood in my downstairs den. I took care to ground the antenna to the pole by extending the supplied groundstrap and using a sheet-metal screw into the pole next to the lower U-bolt. Then I grounded the bottom of the lamp pole (with another sheet-metal screw) to an electrical outlet ground. I followed the tuning directions (read the instructions!) and got the SWR down below 2:1 with 2 watts. With the antenna in my den, I could receive PSK31 signals as far out as the Midwest (my QTH is near Boston). However, my signal did not propagate so far (what did you expect from an 80m antenna in my den?).

Well, the den was not intended to be the final installation location. Next, I took the whole antenna assembly (lamp post and all) and U-bolted it to the railing of my wooden deck. The deck is about 10 ft off the ground. The antenna was bolted on the railing about 1 ft from the corner of the house and near a metal downspout (which I'm sure does nasty things to the radiation field pattern). The antenna was still grounded to the pole. The pole now got grounded to an outdoor electrical outlet. I did not perform any additional tuning adjustments. SWR was still below 2:1 (about 1.7:1). Now I could be heard! With 2 watts, I easily worked some New England stations and was able to be heard as far as Dayton OH (about 650 miles west). Not too bad for 2W into a "bird feeder" size 80m antenna on my deck!

I haven't had much airtime (yet) on this, but I hope to work as far south as Florida (we'll see).

All in all, this is an amazing piece of applied E-mag theory on the part of Ralph Bilal. If you are in a tight spot and want to get onto 80m, I recommend the Isotron.
WA9BXE Rating: 2002-03-19
Good Compromise Antenna for 40 mtrs. Time Owned: 0 to 3 months.
I'll start by saying,"Read the instructions!" Follow them like they are Gospel and you'll be suprised and a whole lot less frustrated (this has been stated by others).

Environment
I reside in a second floor apartment, about 12 feet above ground level, in a brick and wood-sided building. There is a wrought iron railing, outside of my front door. Approximately 20 feet to the west, is the side of an ajoining 3 story brick building. Approximately 6 feet to the north are the stairs and railing to the thrid floor. The southern exposue is un obstructed.

I neglected to mentioned that all walkways (ground, second and third floors) and stairs are concrete. I would imagine they are all reinforced.

What Didn't Work
I first tried tuning the antenna, in my my dining room, with the mast grounded to the water heater feedline, but could not get the antenna to resonate anywhere within 40 meters.

I moved to the living room (no ground this time) and I was able to get the SWR below 3:1 around 7.06Mhz. Move 100Khz up the band and the SWR went off the chart.

I finally moved the antenna to the railing outside of the front door, on a 4 foot aluminum mast from Home Depot. I, for the most part, ignored the instructions and grounded the mast at the base, to the railing. I couldn't get the antenna to resonate anywhere in the band.

What Did Work
I got the antenna to tune almost flat across 40 by doing the following:

1) No ground (it runs contrary to all that I know but, what-the heck at this point....)
2) NEW RG-8U feedline and connectors
3) Attached the mast to the railing with stainless steel u-bolts that are only finger tight (I need to put the antenna up or it may become a bird feeder somewhere else in the neighborhood).

What You Should Never Do
I dropped the tuning rod from the second floor. It fell about 12ft. to the concrete sidewalk below, and BROKE off one of the threaded ends.

I ordered replacement from Bilal (I did not have the nerve to ask them to replace it but I did gladly pay and got the replacement promptly - of course they did laugh at my gaff).

The is not a fragile antenna but you should handle it with care. In other words, don't drop it!

Satisfaction
I have stayed in the phone portion of the band with good results. It seems a bit noisy but does not seem any worst that my random wire antenna.

I seem to have a lobe that allows me to work north, NE, SE and East coast states. I get consistenly decent signal reports using a IC 706MK2G running barefoot.

I have not worked any western states other than Texas and Oklahoma. I really haven't tried either.

I have not heard any DX but I have learned that if I can hear them, I can usually work them.

This antenna is not going to perform like a directional array or fullwave dipole. But it will get you on and heard.

Overall, I am very pleased with the antenna and its performance.
K5FNG Rating: 2002-03-18
It's small, but not just for limited space installations. Time Owned: 0 to 3 months.
Having recently become interested in QRP, I’ve spent quite some time researching and experimenting with various radios and antennas. Finding a performance transceiver was simple. Ten Tec was the brand of choice. Antennas on the other hand were a challenge. Being an avid HF’er, I already had multiple antennas to choose from. 2 – G5RV’s set up in both an inverted Vee and Sloper configuration, and a 40 meter horizontal loop, all of which are at about 40 feet high pulled up in some pine trees..

I decided to purchase the Isotron 20 (http://www.rayfield.net/isotron) and play around with it. It is inexpensive and the reviews were good, although there were not many 20 Meter reviews on the product to choose from. I assembled it in the shack (a second story bedroom in my home) and start playing around with the SWR adjustment. Needless to say, there are many factors that come into play when making the antenna resonant. My goal was to chimney mount the antenna atop a 15 foot aluminum mast, putting it a total of 40 feet up in the air. It didn’t take long to figure out that adjusting the antenna for resonance in the shack, then moving it to the back yard atop the mast, then mounting it in the air on the chimney all affected the SWR negatively. The instructions that come with the antenna tend to make you believe that once you adjust the antenna for resonance it will stay that way in any installation. Definitely not true.

After about an hour of trial and error on top of the house, I finally got the SWR FLAT in the middle of the 20 Meter band. At the band edges it sits at 1.4:1. Adding a ground wire to that mast as the directions state simply does not work. It caused the resonance to go way out of adjustment. Also, my chimney mount consisted of a couple metal straps that are placed around the brick chimney and tightened. Purchased it at Radio Shack. The mount itself had a negative effect on the resonance of the antenna since it and my mast were both metal. Nothing some good duct tape didn’t take care of though. I used it to insulate the mast from the chimney mount and BAM, the SWR flattened out perfectly. I have since gone back and mounted a good piece of PVC pipe to the chimney mount, and dropped my aluminum mast into it. Now for the big test stacking it up against my other 3 antennas.

I have to say, I am very impressed with it. In most cases, the Isotron 20 out performs both of my G5RV’s. I would say 60% of the time (6 out of 10 contacts) the Iso20 is my antenna of preference. It is no noisier than my G5RV’s, but is noisier than my loop. Loops after all are known for their noise rejection. On air reports indicate in some cases 1 to 3 s-units improvement over the G5RVs. Of course, the other 40% of the time, the Iso20 does not perform as well, but even using it in those situations does not disallow me from making contact with what ever station I want. I have successfully worked European, African, Australian, and many other DX stations running 3 watts using the Iso20. Running 100 watts, I get many DX stations on the first call. State side and local contacts are unchallenged. I am not restricted on the type of antenna I can put up. I have the room to install a full size 80 Meter loop if I wanted. Although advertised as an antenna for "small spaces" the Iso20 is not a restricted space antenna only. Actually in my opinion it is quite the opposite. The higher you get it, the better it works. I can not really give you a good evaluation of how the antenna would have performed at 10 or 15 feet high. I didn’t use it at those heights. But I can tell you that at 40 feet it exceeded every expectation I had. I have since removed both of my G5RV’s and use the Iso20 for all of my 20 meter activity. It just flat works.


KK2QQ Rating: 2002-02-03
A mousey antenna that gets out Time Owned: more than 12 months.
Ok, I've had the 40/80 Isotron combo for about 10 years. I used to live in an apartment in NYC, so this antenna was pretty much the only way for me to get on these bands.

Now I live in Seattle and have more space, but cringe at having to put up lots of wire or something enormous. So I took the 40/80 combo out of storage (after 4 years), popped it on the top of a 20ft push-up mast mounted in the back of my garden shed and "hid" the whole assembly under the arching branches of a tall weeping willow tree.

Well, I didn't think I'd reach much, but at least I'd be back on the bands. Then, just last night I checked into the Triple H Net on 40m. To my surprise, I was able to contact the coast of North Carolina with a decent report.

How about that! 100 Watts into an 40m antenna that is no bigger than 24"H x 6"W and get out to the Southern East Coast from way north on the West Coast.

80m also gives great outtage on the local nets.

I still am impressed. This is still $160 bucks very well spent.

VA2DV Rating: 2002-01-31
Incredible ! Time Owned: 0 to 3 months.
First,i must say is my second try with this antenna (80m version).a few years ago,i have tested it and the performance was very disapointing.Sold it for almost nothing.Recently,
i have move into a very restricted place for antenna.I was left with only the balcony for my
aerials with no access to the roof...So my choices where very limited.10-15-20 was easy to
overcome with a loop from MFJ but 80m was another history ! I have decided to give the Isotron another try.
Glad i did it !
This time , the antenna was easy to tune and the
results are just fantastic.Low noise and good copy.I have made an extensive signal comparaisons
with a lot of stations in a 50-500 kms range and
they cannot see the difference between my station signal and any 100w-dipole equiped station.
My isotron is mounted on a short 4' mast into a
3 foot tv tripod on my balcony at 20' off the ground.With the help of my rig internal tuner,i can covers around 150 KHz of the band.
In conclusion,in my case,the performance
is very close to a "real antenna" and i am very
satisfied.Comments from other hams are :
"i cannot beleive this thing is so small ! "
" not the weirdy antenna in QST ad ? "
" Where do you found this thing ? "
VE6XX Rating: 2001-08-19
A tuned circuit that radiates.....WELL! Time Owned: more than 12 months.
Greetings All: I have had my Isotrons up for several years(80/40 combo, single feedline), & they have done yeoman duty. Essentially, I wanted a test antenna for my shop(I repair quite a few radios) so I always wanted to try an Isotron. I live about 50 miles south of Calgary Alberta, Canada, & I assembled the 80 metre antenna in my basement shop. I hooked it up to an Icom 735 I had on my bench, & heard two stations on Vancouver Island(400 miles) talking. This with the antenna lying on the basement floor! I had a tuner in line, so I tuned, & gave them a call. The one station answered & said " You aren't very strong OM, about an S4 to S5"!. I told him what I was running, & he asked....No, he DEMANDED that I apprise him how the antenna worked when it was up in the air. I have the pair of Isotrons mounted on a slip-up mast, about 20ft off the ground. They allow me to work anyone I can hear! No, I don't have any significant dx
on 80 or 40 with these antennas, but I have worked JA's on both bands on phone, running 100 watts. I do not break pileups, or receive tremendous reports. Contacts in the Americas usually are 5x5 to 5x8, . Stations in the western Canada & USA quite often give me 5x9+ reports. The antennas are quiet compared to my dipole & NVIS antenna for these bands. I fed the coax down the inside of the metal slip-up mast, which has a 10ft commercial copper plated ground rod attached to it, but still needed a ferrite bead balun on the feedline to keep RF out of the shack. An observation, not a complaint. The tuning on 80 is fiddley, but what you would expect...no worse than a mobile "bugcatcher" to tune. Once tuned(not a biggy, but you MUST follow the !@#$%$ directions) I have found that weather has only a very small effect on tuning. Mine have been up several years & are still tuned where they were on installation. Ralph at Bilal, is easy to deal with & very helpful, as well as knowledgeable. These antennas will not let you take 1st place in an 80/40 metre contest(without a LOT of luck!) but they will allow respectable operation on their respective bands. My hat is off to Ralph, these antennas fill a real need for some people, & my neighbors(who don't care what antenna I erect....they have dogs that bark, & I don't complain!!!)
think the Isotrons are birdfeeders!!! If you are looking for an attic antenna or a "low visual impact" antenna, you won't be disappointed with the Isotron! Well Done Ralph!
KC4CLD Rating: 2001-08-18
Good for restricted spaces Time Owned: 0 to 3 months.
I have one Inverted L for 160 meters and went for the Isotron just to have a second antenna ( a noise antenna) for use with the MFJ-1206 Noise Canceling unit and playing some tests with this noise unit.

After many tests I discovered that the Isotron IS NOT too ground dependent as the manual said. I got lots of noises and when I use a proper ( good) ground, all the noise went away making reception acceptable and useable.

Now...THIS IS NOT A DUMMY LOAD like many comments I read in some places. I was able to contact KK4TR in Florida 332 miles from my place in Miami using the Isotron 160C and running only 100 watts IN SUMMER TIME, and this hapened in August 17 around 10.30 PM EST with noise over +15 in the bad at that time.

Jose, KK4TR ( located in North Florida) was able to copy me close to the noise level ( very high noise in summer time here in Florida) with the antenna mounted in a mast over the roof ( less that 20 feets high) and this is telling me that the Isotron is NOT a Dummy Load.

The people I can copy in a normal way with the inverted L are down 2 or 3 S units ( sometimes 5) in the Isotron but noise is lower with the Isotron and works fine. I was also copying the cuban novicians in 1.916( CL6BEE, CM6RSR and CL6CEE working in AM and running 8 watts ( CM6RSR) and 15 watts ( CL6BBE) . All these stations came fine ( 3 S units down compared with the inverted L)

I'm not saying that the Isotron will perform or OUTPERFORM and normal 160 meters antenna ( Inverted L or normal dipole) but usually is good for stateside contacts and good for any ham with a small backyard or house.

I can get 50 Khs usable bandwidth without antenna tuner, but again, in my situation I need to connect a very good ground to the antenna in order to work.

I will test my amplifier ( Ameritron 811H) transmitting with the antenna to see if the Isotron can handle the power but this is not going to be a problem since many postings here used amplifiers without any problems.

WA1GJF Rating: 2001-01-23
Effective small antenna Time Owned: more than 12 months.
I bought this antenna on the advice of a friend, and was very skeptical. It appeared too small and too exotic in design to be effective, a coil of wire on a fiberglass shaft, and 2 square sheets of metal at the ends.After extensive tuning attempts, and then resorting to reading the directions, the SWR did come down to an acceptable level. Performance was above expectations. Signal reports were on par with the dipole, as was receive strength. As I said, it is too small and weird to work. Good thing I'm wrong! Take the time to tune it properly and enjoy!
KD9FT Rating: 2000-10-17
I just can't believe it!!! Time Owned: 0 to 3 months.
I bought the 40M version of this antenna out of necessity. Antenna restrictions prohibit any kind of 40M antenna in sight. I hoped that this antenna would just get me on the air but its done more than I expected. I have no imperical evidence but I suspect an out in the clear wire antenna would perform better at 50 to 60 ft.... but I can't build that antenna here. So, the Isotron is in the attic (about 30 ft above ground) it radiates, I can hear a lot of stations and I can talk to them. It may not be the best antenna but I'm sure its the best antenna in my environment. Glad I'm on 40M
N6RDE Rating: 2000-05-03
Isotron 80 M Time Owned: 3 to 6 months.
I currently run a Kachina 505 DSP formerly using a Cuscraft R7000 ( a big mistake that deserves a separate review) and now using a GAP Eagle, a much better choice, however in bother of the verticals I lacked an 80 M antenna. I chose the isotron because of it's size just 3' tall and it's unusual shape and profile. It has worked great. It is a different concept that the typical antenna but is no typical antenna. It works well but has a narrow bandwith, as do most antennas which are at this frequency and with the reduced physical size. However it tunes no problem across 75/80 I usa a MFJ 949 E versa tuner.

Since I changed from the R7000 which had 30 M to the Eagle which does not I am strongly considering a 30 M Isotron which can be mounted on the same mast back-to-back with the "same feedline". I work a lot of HF Digital modes and 30 M has it's place. A great antenna....