Comet HA-750Bl Mobile Antenna Review

Thanks to JE0DKR



The other day, when I visited a local OM house, I mentioned that I was planning a solo trip to Michinoku Mobile during the summer vacation, saying, “If you go anyway, you should get out of 18MHz or HB. I’ve been looking for an HB mobile ANT that can QRV while driving.

At first, I thought it would be nice to have an HM6 that can produce a lot with one car, but I gave up knowing that I couldn’t do QSY without getting out of the car one by one. I thought I would be a mono bander if I got off the car anyway. When I was thinking, “I think it’s definitely MD for performance, but I can’t afford to have all the coils …”, COMET’s HA750BL was recommended. It was painful that 10MHz, which is indispensable for mobile CW, is out of the standard, but the total length is 2.4m, which is about twice as long as it is an improved version of HA750B. In the worst case, I compromised because I thought it would be possible to put it on my Kranishi MTU.

<Characteristics of each band SWR>

On the way home, park the car in the middle of the rice field in the neighborhood, assemble the elements, connect to the 857 without adjustment, and check the SWR of each band. 7, 14 to 50MHz on the spec is about 1.2 with RIG’s SWR meter. It was like sending to a dummy load. (Maybe in a sense.) I tried 10MHz, which I was worried about, with no use, and it was about 1.7. “Maybe you can use 10MHz? I called the Miyakojima City Mobile Bureau in Okinawa Prefecture, and there was a one-time response. The opponent’s S wasn’t swinging, but if it wasn’t piled with the same PWR, it would be possible to get it. (10MHz is out of the manufacturer’s standard, so please take your own risk.)

<Communication result (7MHzCW)>

HB seemed to have poor CONDX and could not QSO with anyone, but I tried to issue CQ with 7MHz CW. It was about 30 minutes in the evening, but I was able to communicate with 10 stations. I wasn’t called anymore, so when I issued a CQ while driving on my way home, I was called by the Mito station. (However, when I got home, the hatchback base was moving without being able to withstand the wind. Hi)

After returning, I plotted the QTH of the communication station on a map and imagined the path of ionospheric reflection.



-Performance is good for mobile ANT. (It’s only
7MHz . Some people have a maximum of + 20dB.)・ QSY is easy anyway.
・ SWR 1.5 or less (excluding 10MHz) from 7MHz to 50MHz ・ No
need to worry about wraparound. (It seems that grounding is unnecessary, but the base is grounded.)
・ Is 50MHz a bonus? (It was about S3-5 different
from SG9700 .)・ Not suitable for hatchback base (base height 1.5mH + L = 2.4m = 3.9m, so it is too long and dangerous while driving. )

* Please note that this is a subjective impression after a short operation of about 30 minutes.


In the end, the original idea of ​​HB ANT, which allows QRV while driving, was missed, but I am very happy to be able to come out easily. In the future, I would like to try it in each band and accumulate results.

VE3IPS: It appears this antenna is 50 ohm dummy load with a 5:1 matching lossy balun like the CH-250B base antenna. This antenna can be replicated with a similar length of wire and a 4:1 balun with a tuner.
It transmits on 7, 14 and 56 Mhz as per the SWR chart. It is a compromise antenna but with proper band conditions and say 20-50 watts of power, you will make contacts.
 HA750BL Review This is a review of
Comet’s Broadband antenna HA-750BL.
Weekend ham, so the review was a little late.
By the way, there are many reviews for this antenna, so I think many of you already know the general idea. I installed it on the balcony, so I will report on the situation.
There is no adjustment for SWR and there is no problem at all.
7MHz … It was within 1.5 in any band. It was about 14MHz … 1.3. 21MHz ・ ・ ・ 1.1-1.3.
Sensitivity is definitely reduced.
I used to use a monoband V dipole, so I feel sorry for the comparison, but the S meter doesn’t really swing. The S meter does not shake, or even if I try to respond to a station that shakes faintly, it is not picked up. However, for stations where the S meter swings firmly, it will take about 55 to 57. In short, it depends on the condition.
QSO is possible.
Communication was established at 7MHz, 21MHz, and 24MHz. In particular, I had no plans to purchase an antenna for 24MHz, so it was a nice first communication. The feature of this antenna is that you can immediately QSY to other bands. It’s fun to press the band button on the rig and turn the dial. It will be interesting when the high band opens.
After all the antenna must fly. Therefore, it will not be the main antenna of a fixed station. Even if it can be received, the transmission ability is not good enough. Probably because it doesn’t resonate. I think it would be interesting if it was a mobile station.

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