Manager - NA4M
Manager Notes

Reviews For: Stockcorner JC-4 automatic antenna tuner 1KW

Category: Antenna Tuners/Matching Networks

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : Stockcorner JC-4 automatic antenna tuner 1KW
Reviews: 21MSRP: 499 Euros
Remote antenna tuner rated for 1KW pep. Two antennas. High
quality parts and high performance coupler.
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
K4JJW Rating: 2019-07-11
Totally satisfied Time Owned: 6 to 12 months.
You can purchase this tuner with confidence. I've been using auto-tuners for about 15 years and the JC-4 is very versatile and reliable. I use it on a 162' inverted L and it tunes all bands with ease and with a very low SWR. I'm in "hurricane alley" so I installed a simple weather shield above the JC-4. Casper's response time was excellent. Top quality components and construction.
PC3T Rating: 2019-06-08
Amazing ATU Time Owned: more than 12 months.
I've been using this ATU for 1,5 year inline with my 80m Inverted L. I can tune on 160m easily with around 20m long wire and a bunch of different sizes radials. Also the support from Casper is superb he never let me down when I raised some questions. I use the ATU also for all other bands that I do not have antenna like 60,30,17,12m bands and all tuned in 2-3sec. The price is a bit high but you get what your paid for, pour quality in all aspects.
MM1APS Rating: 2018-09-07
Simplifies things a lot! Time Owned: more than 12 months.
I use the JC4s for my holiday vertical - a 12m wire on a telescopic mast with eight radials on the beach - and for long-wires.
I intend to install the guts of the thing in a Peli-case with military connectors for ultimate weatherproofing - the 4-pin control socket and SO239 are quite short and not always easy to get the self-amalgamating tape round - otherwise it seems pretty much perfect, even allowing the use of doublets with balanced feeders.
W8IXX Rating: 2017-11-22
Initial evaluation of JC-4S remote tuner Time Owned: 0 to 3 months.
I was about to purchase a new JC-4S when I discovered a used unit on Ebay two weeks ago. I am lucky to have found it!

I use the JC-4S to tune two antennas: (1) a “Super Slinky” inverted-L for the 160 meter band and (2) a 12m (38') sloper for 40 – 10 meters. The inverted-L is connected to Channel A and the sloper to Channel B. For stealth the antennas are located in a wooded area about 200' from the shack, and the tuner is fed with a long run of RG-8X. The two antennas share a counterpoise consisting of nine wires placed in a somewhat random radial pattern. The tuner is placed at the connection point of counterpoise wires. The proximity of the antenna to property boundaries makes it impossible to have perfectly distributed radials.

The Super Slinky antenna for 160 meters allows operation on Top Band in a small footprint. (The antenna was a winner in the 2017 ARRL Antenna Design Contest.) NEC simulations show that the SS antenna is a good radiator on all HF bands, but its impedance varies widely from band to band. With the JC-4S it is possible to load up the Super Slinky on all bands from 160m through 10m and the sloper on 40m through 10m. The JC-4S drops the VSWR on the long coax line to under 1.3:1. This reduces losses due to high VSWR, which become significant on the higher HF bands. The low VSWR also allows use of a solid-state linear amplifier without excessive reflected power that would trip the amp's protection circuits. I can now run the amp at full power (500 W PEP on SSB) and 300 W on CW and digital modes on all bands.

Tuning and band changing with the JC-4S are very easy and fast using the provided little box. I tune using a 20 watt carrier signal. I plan to use my Kenwood's ATU button to tune the JC-4S once I get the connector that fits the Kenwood ATU control port. The only downside in my installation is the need for a long control cable. I use 200' of 8-conductor UTP cable purchased at Home Depot. To reduce ohmic loss I make four pairs of conductors. This has worked well. A good project would be to build a Zigbee-based remote control.

Quality of construction of the JC-4S is outstanding, and Stockcorner's user support is very good. Casper responds very quickly to email enquiries and is generous with his time. I can't imagine getting better support.

The JC-4S has vastly improved the performance of my station. The ability quickly to change bands, switch antennas (which allows the operator to choose the better antenna for a particular QSO), and run my amp at full power has resulted in improved operation on all HF bands and many more QSOs than before. I give the JC-4S my highest recommendation.

HA5X Rating: 2017-08-21
First impressions Time Owned: 0 to 3 months.
This is going to be about my - very positive - first impressions. I hoped to write a more thorough review after some more experimentation, but unfortunately I have not had as much time to play with it as I had hoped. I might write a follow up later.

As at home I only have a 3x1 m balcony as an antenna farm (and I promised my XYL half of it will not have any antenna of that "huge" plot) I have to resort to temporary, low footprint antennas. That usually means a vertical fishing rod with one inadequate radial, or another fishing rod holding a radial horizontally over the neighbour's garden. Of course nothing can stay, I have to remove all after the weekend contest...

Given these limitations, I have had to make severe concessions and found that in my case non-resonant antennas are the easiest to use: push out some wire along the fishing rod, tune it to impedance with some tuner and enjoy. No time to fine tune something resonant just for the few minutes there antenna is there for... But, such antennas are very lossy and I sometimes compensate for this loss by using 300W, that makes me sound just a bit weaker than a 100W station with some proper antenna :)

After having used indoor desktop tuners and a 9:1 UNUN for a decade anda half, I finally decided to try a remote tuner for two main reasons. First to reduce the loss of my coax and also to make tuning a bit more comfortable than having to do it manually. While browsing reviews for some commercial tuners, I accidentally ran into this very JC-4s review page on eham. Nobody gave this tuner less than 5. Woww, interesting. While most available remote tuners are 100W only, this one can easily handle more. Woww. So I navigated to the stockcorner website and read the available info there. I sent an email to Casper, and he responded literally within minutes. Woww. All questions answered. I paid using PayPal and the box arrived to the other corner of Europe within 4 working days. Woww.

The tuner seems well built from the outside (I have not opened the box yet.) It is a bit bigger than I had expected (but actually it is still smaller than another tuner I was looking at), so it might not be travelling in my suitcase, but I will buy the smaller JC-3s for travel, but who knows :) As an eager boy I just wanted to try it ASAP. Unfortunately there is no control cable in the box, you have to prepare some wire yourself to hook it up. UTP is explicitly not recommended for this purpose, but as I happened to have quite a few meters of UTP on a drum it was obvious that I cut a 15m or so long piece and soldered up 2x4 wires to the supplied plug on one end and the control box on the other. Honestly, a few minutes after my first experiments I decided to add some connector between the control box and the control wire, as if you want to use it like me (not connect it once and leave it there) having the control box soldered to the whole length of the cable will make it quite difficult to lead the wire in the room, it is way easier just to lead the cable itself an then connect the tiny control box once the cable end has reached the radio desk. Not having some connector on the back of the control box is actually the only one negative point of design I have found so far. But anyone - even I - can DIY something in a few minutes, so not a big deal.

Anyway, I placed the tuner under the fishing rod, pushed out some 7 meters of wire with some random coil, and an absolutely random length of wire on a 5m fishing rod as counterpoise and powered up the thing. There you have to be very careful: you either have to run the tuner from the power supply of the radio itself, or connect the ground of the radio with that of the other power supply, otherwise it will not work. Although it is clearly stated in the manual, I just forgot about it first and was scratching my head for a few minutes thinking the tuner did not work. But it actually does, it was the operator who was lame :)

Tuning goes very fast indeed, within seconds the "antenna" matched on all bands from 160m to 10m. I heard a few stations on 80 and 40m, and whomever I heard also replied when I called them. The tuner memorizes tuning at different points within a band, so it is very convenient, however, you have to re-tune it after changing the band. But as it takes only a few seconds to tune, it should not be a problem.

I had some RF feedback problems inside the shack at first, but by adding a common mode choke at the tuner-end of the coax it is fine now, even with 300W. Whatever wire I just connect up, the tuner will match it just fine. The only band where I have had some difficulty was 10m, I think some of my wires are a bit too long electrically for that band. Fortunately, the JC-4s has two antenna ports, so you can use a longer wire for the low bands and a shorter one for the higher frequencies. At the moment what I use the two antenna connectors is actually changing between a horizontal and a vertical fishing rod :) Polarisation does make some difference at times.

K6SBA Rating: 2017-07-14
The Best!! Time Owned: 3 to 6 months.
If you are looking for a 1-KW rated remote autotuner, you must seriously consider the JC-4. Once you remove the top cover and look at the fabrication of the unit, you will be sold. The construction puts to shame any other tuner sold to the amateur market.

I am using the tuner with a 43-ft vertical, a modest radial field (25 radials of different lengths) and 125 of LMR-400 coax. Tuning is flawless from 160- to 10-meters.

I can't say enough about the quality of the unit. It is packaged in a NEMA-style raintight enclosure. I opted to install the tuner inside another large enclosure just to provide added protection to the exterior connections.

At the current (fluctuating) Euro exchange rate, the cost in US dollars is about $680 + international shipping. I feel this represents one of the best investments I have made in amateur radio.

73 de K6SBA
David in Santa Barbara, CA
DJ1DK Rating: 2017-05-09
Fantastic Antenna Tuner Time Owned: more than 12 months.
This automatic (remote control) antenna tuner is manufactured in very small series by Casper (PA7DX). His website and webshop may be visited on stockcorner nl.
I use this antenna tuner since more than 1 year with my "Lazy Yankee" antenna (which is a horizontally mounted endfed antenna having the shape of the letter "Y", with a coil at the bifurcation - as described by DO4IH). I have made some design changes as I do not use a transformer to feed the antenna and my wires have some other length.
In my case the antenna is fed directly through the JC-4S antenna tuner at the feeding point, so the transmission line losses are reduced to a minimum. And the tuner does a very good job. Thanks Casper, for this great antenna tuner at a very reasonable price!
HB9RYZ Rating: 2016-11-26
Great HF-Tuner Time Owned: 3 to 6 months.
This is the best tuner I ever used for 1kW. I’m using an Inverted-V with only two short legs of 6.5m each and an 10m ladder line (wireman) from the tuner to the antenna. I can easy tune 10-80m with such a small Inverted-V antenna. I installed an 1:1 current balun (1771ts) from Balun Designs between the ladder line and the tuner output. From the tuner on the top of my roof to the shack is an 28m long RG-213 Ecoflex Plus coax which is connected to my Expert 1K-FA amplifier and then to my transceiver IC-7700. I have absolutely no HF in my shack with the configuration. just after the Digital Wattmeter LP-100A shows me the exact SWR and power.
You can see a lot of pictures on my website
Thank you Casper for such an excellent 1Kw remote tune and your great support.
73’ Wolfgang
HB9DLF Rating: 2016-08-06
FANTASTIC Time Owned: 0 to 3 months.
First I tried several other products which were partially cheaper.
Finally my choice was the JC-4S from the Dutch company Stock Corner .
The manufacturer offers 3 models

200 Watt
1000 Watt
4000 Watt

All this models for a amazing price. The 1KW IC 4S is available for Euro 535 .— That is really a very good price

The 12 V DC power and control unit is connected by a 4-wire cable and works perfect.
The first tuning procedure is done under 4 seconds. After that it takes usually less then 1 second to get the SWR nearly 1

I have never noticed any tuning steps during operation

The processing of the tuner is excellent! Generous dimensioning of the components give pleasure!

The description is available in english and also in German with great details and practice example

The manufacturer's support is EXCELLENT !! Within 24 hours I`ve got an answer to all my questions. Even to my phone. Great

Anyone looking for a reliable tuner is very well served with the tuner. You get also a big reserve for QRO operating.

I can recommend the tuner without any restrictions

vy 73 de
K8NDS Rating: 2016-05-28
Fantastic Tuner Time Owned: 3 to 6 months.
I am using this tuner with an off center fed doublet and 600 ohm ladder line. The doublet is 128 feet long cut for 80 meters. The tuner is mounted remote at the ladder line.
This antenna tunes better than 1.15/1 on all bands (80 to 10) including 160 meters. The tuning rate is extremely fast, after tuning a few times the tune time is less then 4 seconds. On most bands it is about 1 second. It is the best tuner that I have owned up to date. Purchase this tuner with complete confidence.