Are there any more affordable options for Tianji?

BG5EQA

已经短波FT891半个多月了（采用MA01），现在主要遇到2个问题
1、usb连接电脑发射，原来是超过5w，JTDX就提示找不到设备。现在加了磁环能设置14w，发射时候PO有点不稳定0-14波动。如果单纯安卓音频线FT8CN连接就不会。
2、明明测好驻波近1.2。然后馈线接到FT891上采用FM模式测试驻波远高于2，发射不了。主要还是偶发，每次更换完线圈重新拿天分去测。毕竟我现在也FT8通联了十几个。

想想还是入手个天调，以后可能会新增其他天线，现在频繁更换线圈，测驻波有点麻烦，而且垂直和鱼竿两种模式驻波不一样，加个天调应该能稍微改善一下。谢谢大家提供参考建议。

Liridice

Could I ask you a few questions? How far away is your antenna from the transmitter? Is it a magnetic loop that's been added to the feed line? Does the magnetic loop refer to a plastic case with clips attached to the feed line, or does the feed line wrap around a ring of ferrite material? Based on your description, it seems like we should first address the problem of poor ground conditions causing common-mode current in the feed line.
If you need automatic antenna tuning, the mAT-30 is worth considering. Many HAM radio operators have complained that the construction quality and performance of LDG antennas are far inferior to those of HAM, but the mAT-30 offers a good balance between price and performance, allowing it to work seamlessly with FT-891, just like the FC-40.

BG5EQA

Liridice The magnetic ring is connected to the data cable that connects to the computer. The antenna is one meter away from the computer, with a wall and window separating them. If I don't use the data cable to connect to the computer, but instead use a single audio cable to connect to my phone, this problem won't occur. Grounding frequencies above 14MHz are typically below 1.2 meters when vertically mounted. They tend to be higher when using a fishing rod style antenna.

BG2EFX

听劝买LDG~
如果你用MA-01 别指望ATU能帮你消停换线圈

BG5EQA

BG2EFX What LDG model are you looking for? They seem to be quite expensive. I might try the FC50 instead. It's a hassle to change the coils, and switching between frequencies like 14.074 MHz and 14.270 MHz could potentially increase the standing wave ratio. Well, I definitely plan to upgrade the antenna in the future. But honestly, after working with shortwave radio, I've learned quite a bit.

BG2EFX

BG5EQA
FC belongs to Bai Ge.
Both the Z-11 Pro II and the AT-100 Pro II are suitable.

Liridice

BG5EQA
I've encountered most of the issues you described. The combination of a data cable and an inductor doesn't seem to offer much benefit. If you can't improve the antenna's position temporarily, adding a choke or a 1:1 unun at the GP power point can prevent the feed line from participating in transmission, reducing common-mode current entering the room along the feed line. This should also noticeably improve the issues you're experiencing with signal drop and standing wave variations. The biggest problem is that the antenna is too close to the transmitter; if it resonates, it could damage the equipment.
Using the original FC tuner is definitely not an option, as it won't work if the resonance exceeds 3. If you want to use the tuner to bring the MA-01 to full frequency range, just forget about it.

BI1XNN

BG2EFX
I was wondering why I could only find AT 100M PRO on Taobao, but not AT 100 PRO II. Are they the same product, or is there no distributor for AT 100 PRO II in China?

BG5JKZ

I'm also a 891, a DIY GP with 8 ground wires. I use an extension dock to connect one USB cable and a Type-C to audio adapter, plus I made my own inductor using an FT240-43 magnetic ring. The 100W FT8 doesn't have any problems at all, and you should also make a good ground connection. Initially, I would lose the USB connection as well, but after adding the inductor, I no longer have this problem. Furthermore, the "skywave" technique is essentially deceiving the transmitter, so I prefer to use a traditional antenna tuner myself.

BG5EQA

BG5JKZ So, I'm going to buy a grounding ring to try. Can I use the 16-pole cable you mentioned for the ground? I have 5 meters of cable that I've divided into 8 groups. However, it wasn't very effective. Should I use 3.5 meters instead, or two pieces of 16-pole cable? I don't understand why they said that if you make your own ground wire using 0.5mm and these cables, there is a difference.

BG5JKZ

BG5EQA Yes, I am using a 16-position patch panel, with 4 positions per group, 8 ground wires, and a 5.6-meter pull cable. The frequency range from 10 meters to 20 meters can all be adjusted to have a standing wave below 1.1.

bh1cqz

A full-size GP or full-size vertical antenna, when tuned using a tuner, doesn't require a separate tuner unless your environment prevents you from bringing the standing wave down (e.g., fishing on a balcony or in a poor ground condition).

BG5EQA

bh1cqz It's the fishing rod, it's too long and dangerous. The wind on the fourth floor of the office is also quite strong, sometimes the wind blows and I can see the line moving in the air. The wind is even stronger at my home on the 13th floor, so there's always a constant whistling sound. That's why I chose the ma01. Right now, I'm just learning how to use it for casting, trying to avoid making mistakes early on.

bh1cqz

BG5EQA If possible, try to install a directional antenna or directly use a 750 MHz antenna. If that's not feasible, use the MA-01 or a small sausage antenna. These are functional, but their performance is limited.
When deployed in the field, the choice of GP, Positive V, End-to-End, and DP depends on what works best for your specific needs. The primary focus should be on maximizing efficiency.

xyzyx

One issue that the original poster encountered; we might even be able to coordinate efforts.😂
https://forum.hamcq.cn/d/7684/31

BG2EFX

BI1XNN The local representative for HAM is located domestically.

BI9ALM

Gimbal solution

BG5EQA

bh1cqz

BG5EQA That's pretty good! What's the furthest place SSB can communicate with?

BG5EQA

bh1cqz 5W, to Brazil using FT8. While I bought an antenna, SSB hasn't started yet, but I found that it was too close and affected the mouse, keyboard, and computer at 10W. The safest option is 5W for communication. Currently, setting up the antenna takes about 30 seconds. However, I need to adjust the ground connection each time. There may be some settings that need to be modified for SSB and FT8.

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