On Jan 21, 2025, at 1:52?PM, steve isaacs via groups.io <isaacssteve@...> wrote:

? MFJ 1898 collapsible antenna is simply a new spin on an old product. There are several “similar in function” versions of this antenna, including one made by Wolf River coils, Buddipole, GRA (found on Amazon), and CHA. Of these, I believe the CHA recently introduced MCC antenna more closely resembles your antenna. I have attached a copy of their manual on how they tune the antenna which should help you turn your antenna. Until you can get the antenna “dialed in,” I recommend that you use a SWR meter. I have attached a manual of the MCC antenna from CHA.Let me know if you need additional help.

73

Steve Isaacs KO4IVH

On Jan 19, 2025, at 8:33?PM, CRY42 via groups.io <cy122042@...> wrote:

?Thank you, Don.

Had to smile, agree, a Dummy Load has a good SWR.

Am using the Xiegu6100 and have three radials attached.

Will keep tinkering.

Appreciate your time to reply.


73

Charles

On Jan 19, 2025, at 7:25?PM, Donald Hellen via groups.io <donhellen@...> wrote:

Charles . . .

On Sun, 19 Jan 2025 05:36:29 -0800, "CRY42 via groups.io"

<cy122042@...> wrote:

I purchased the 1898 collapsible antenna which came with no directions.

I looked on their website for directions and that product apparently doesn't

come with any directions. Most of their products did come with directions that

you could download from their website if they weren't in print form in the box

or package.

Do you have any tuning suggestions, I find it a bit touchy to tune.

Or have you worked out a Tuning Chart for the bands as to how to set the lower and upper sections

Perhaps someone else here who has one of those or has one of the similar

antennas sold under different names, but looking at what you bought, it looks

like you extend the telescoping part on top, then find a tap on the coil by

moving the silver metal part on the bottom out or in at the bottom, where you

get a low SWR reading on the low end of the band, then fine tune by shortening

the whip section. (I think I have that in the right direction, because shorter

means higher frequency.) It appears that there might be a coil inside and when

you move the bottom part down and away from the top, you are selecting a coil

tap. In essence, I think you are shorting out turns using the bottom silver

metal part by moving it into or partially out of the black coated section.

That's my best guess, so if I'm wrong, some of this may not apply.

You didn't say what radio you were working with, but if it has a built-in tuner,

you will probably have to use it if you change frequency in the same band. But

before using the tuner, I would bypass the tuner and get the SWR under 2:1, then

let the tuner do its thing. If you don't have a built-in tuner, you will

probably want one (or need one). I like an auto-tuner like the MFJ-993B but

their Versa Tuner II with the cross-needle SWR meter works well, too. It just

isn't automatic.

You will probably have to work out a tuning chart, but you are on the right

track. Since the antenna came with no directions, you will need a ground of some

sort, at least one wire up to or longer than a 1/4 wavelength on the lowest band

you will be operating on. So for 40M, somewhere around 33-35 feet or so. Ideally

(and this isn't an ideal antenna, of course), you would want several radials,

but this is an antenna for portable operation and we don't want to make this

difficult to set up, so one or two wires as a counterpoise for your ground,

connected to the ground of your tuner or radio, but it would be best to connect

it where the coax connects to the antenna.

You don't get anything to mount the antenna on, so you'll need something for

that. Maybe something like this:

https://mfjenterprises.com/products/mfj-342t?pr_prod_strat=jac&pr_rec_id=7c01d551c&pr_rec_pid=4393806332003&pr_ref_pid=6889855451235&pr_seq=uniform

Sorry, but when I shortened the link it didn't work. :-)

Then you would connect your counterpoise to the copper part of the ground mount

above. (I just ordered one of these ground mounts from MFJ. They apparently

still have some, along with some other goodies, some of which are factory

seconds.)

Here are three videos that might be of some help.

https://www.youtube.com/watch?v=Nl-smSwQBgE

https://www.youtube.com/watch?v=0RdyNZN343I

https://www.youtube.com/watch?v=nPXO-27M22Q

Maybe you can see how the presenters used their 1898. Keep in mind that a low

SWR does not mean your antenna is efficient. A dummy load is close to zero

efficiency yet it has a near perfect 1:1 SWR! Also, as ground losses mount (less

radials, dry, rocky ground, etc.), SWR may improve but efficiency can be very

low.

If you don't get what information you need here, try out our ham-antennas group

or the HamRadioHelp group.

https://ham-antennas.groups.io/g/main

(antennas, feedlines, anything related to antennas like tuners, etc.)

https://hamradiohelp.groups.io/g/main

(general purpose amateur radio discussion group)

Donald KX8K

----------------------------------------------------

Some ham radio groups you may be interested in:

/g/ICOM ??/g/Ham-Antennas

/g/HamRadioHelp ???/g/Baofeng

/g/CHIRP ?https://rf-amplifiers.groups.io/g/main

<cha-mcc-prv-sota.pdf>