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watch the power meter on the xiegu when I press the PTT button and holding the mic ...it modulates without saying anything...this only happens when the amplifier on the xiegu x125b is on....also when I select the built-in mic this problem doesn't occur even with the PA set to on ..only with the hand mic ..gain is set to 15 ..tried factory reset, swapping the mic cable the other way around ,trying a different cable nothing.. problem still occurs.
Update : i put a pair of headphones on and increased the monitor level to listen to the signal...all i hear is noise with some low level distorted audio in the background...and this issue also occurs when i select the built in mic and press the PTT.
In the beginning i thought it was a faulty hand mic but now that i se that the problem exists even built built in mic , i am starting to believe it is an amplifier issue...

I am quite new to this hobby... it is my first radio and? just got my ham radio license? a week ago... dummy load is on the way... when i receive it, I will update the status of the shack... if it is an RF issue as you say what can I do to fix this?

i have the same setujp. I use an EFHW antenna (wire in a tree!)). I had a serious common mode issue. I've put a choke (MFJ-915). It helps a lot, but I still have issues on 40 Meters. Have you tried various bands?? Just a thought, 73
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KD6YKI - Mike

I tied the transceiver at 80m and you were right.. everything is working smoothly.. probably an RF issue caused by the antenna (hamking hvt 400 ) ...I will wait for the dummy load to double check that ..and yes I know I must built a more efficient antenna

I also am running this combo. I made the mistake of hooking up the house interior ground to the x125b (has a nice ground post on the back). My longwire antennas share a fairly decent ground plane with three rods driven 8 ft into the ground plus radials. The resulting ground loop caused the amp to lose frequency control in auto mode. I also agree that you need a choke coming in off the long wire unun output. Destroyed a cheap amp by not paying attention to this. Anyway, ground loops and RF can do crazy things. Go back to basics (dummy load, as the commenter says) and proceed from there. The combo works well with patience. Good luck.?

I have found that the X6100 is very sensitive to common mode current. Adding the amp will make it worse. As mentioned earlier, using a choke helps, and if you have enough coax in the line, 6 or 7 turns in a 7" diameter held together with cable ties will help. I have an EFHW and a DX Commander classic 1/4 wave 8 band vertical. No issues using the DXC, but the EFHW has common mode current heading back into the amp without chokes. My amp would lose control of the 6100 and flash that message, the swr between radio and amp would rise, and the 6100 would transmit 0w. Chokes help, but do not eliminate it entirely. Make sure the tuner in the 6100 is off. I will turn the amp tx power off, and transmit on nfm through the amp and check swr, and push the tune button on the amp if needed. Go back to the proper mode on the radio, enable power on the amp and good to go. It's extra steps, but it tends to keep everything happier. You have to remember that the X6100 is a computer made into a radio. It's front end is not as robust as a G90. It is not nearly as forgiving as a dedicated radio.

On Fri, Dec 22, 2023 at 07:19 AM, Gale Smith wrote:
As mentioned earlier, using a choke helps, and if you have enough coax in the line, 6 or 7 turns in a 7" diameter held together with cable ties will help.
This RF choke that you are referring needs to be made where the antenna plug is situated at my balcony or near the transceiver's plug ? I run my antenna with a 10m rg213 and I Believe I can make 6-7 turns as a choke ... In advance I would like to THANK you all guys for trying to help me with the situation I am dealing with ...this community is very helpful and really trying to solve other people's problems..thx guys

It would work best near the transceiver in my opinion.

This is a good place to get a fairly priced choke core and they have some good info:

https://palomar-engineers.com/antenna-products/1-1-balun-kits

I have snap-on inline ferrite chokes, in various diameters.
Question for those with experience in these matters: do inline chokes work better than snap-on chokes? ?I do not know these things. ?I know the theory, but low on practical knowledge. ?(Just because a book says one thing does not mean it works that way in the real world.)

Hi Gale,

I build and use a lot of EFHW antennas…giving many to other members of my portable ops team. There are two general approaches to how the balun wind is connected to the coax. There’s either an external ground connection or not:

A. The so-239 or bnc connector has no external connector for a counterpoise (see B). This makes the coax shield the effective counterpoise. This will put part of the transmitted signal coming down the line to the radio.

IF a choke is placed at the balun connector, the antenna tuning suffers since the signal produces more standing waves. If the choke is placed at the transceiver end, the coax braid more effectively radiates part of the signal, making tuning a match easier.

B. If a connector to the ground side of the balun is placed outside the case, a small counterpoise can be attached which allows for a more effective match. I use 0.05 wl coins n the fundamental design frequency for a “pig tail” style counterpoise. Sometimes I add a 1:1 choke at the radio (or tuner) end of the coax but only rarely.

When I build EFHW antennas, I attach a Rig Expert Stick analyzer directly to the balun using a pl-259 to pl-259 adapter when I hang them up for final wire length adjustments. I use the Bluetooth connection to the Antscope 2 software to make the sweep without the contamination effects of the coax. This allows me to get the antenna length —- and the 0.05wl pig-tail counterpoise —- more precisely tuned to each band: the fundamental design frequency as well as the higher harmonic bands. Most of my EFHW antennas get hung up in the field and don’t require much ATU activity at all.

This is just how I’ve come up with doing it but others may have superior methods.

73,

Frank
K4FMH
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Frank M. Howell, PhD
Ridgeland, MS
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Hi John. It is my experience that an inline choke is more effective on feed line than the snap on type.

Hi Frank. For portable use, I tune my EFHW with the coax attached that will be used in the field. If I am going to use the 6100, I will add a choke at the radio, but with my G90, It doesn't seem to be bothered by common mode as much. Same with the uSDX. That said, I prefer to use vertical antennas overall.

Gale,

Sounds like you’ve got a good plan for your portable sites…

For others, it’s the practical part of what’s available at the site for expedient antenna deployment.

The stake in the ground works with a vertical and a counterpoise system. But…some parks are very particular at putting things into the ground. In these cases, I use a small (but heavy) patio umbrella stand I picked up for $30 at Academy Sports. It will take everything from the stake to a mast to a painters pole to deploy a vertical. I’ve not seen a park official banan umbrella stand, lol.

Trees are so abundant in my area that the EFHWs are very attractive, especially with the coax end attaching to the picnic table in many parks. But, alas, some parks claim that paracord over a limb, even temporarily, damages trees. So the patio umbrella stand with a mast for the farm end of the EFHW works in that case, too.

I’m glad you’ve got a good system that works for you. Some struggle with this so I hope my comments are useful for them.

73,

Frank
K4FMH
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Frank M. Howell, PhD
Ridgeland, MS
frankmhowell (at) hotmail.com
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What do you mean by “inline”? ?A magnet is a magnet. ?The snap-on can allow you make a loop if you want to block even lower frequencies. ?I’d be interested if people find using a torpid washer and wrapping it is better, but I doubt it would make a difference. ?I just ordered a bunch of snap-ons myself.?

I finally received my dummy load , made some tests and the transceiver is working normally ... seemed to be an RF issue.. problem SOLVED? with an RF choke that I built following the instructions that I found at hf kits.com... thank you all for all your opinions and help !!!