Diamond Quad Band and Auto Tuner

[KB1UGX]

So i got a Diamond Quad band to use as a base antenna for the house. I made a mount for it andhave it on a UHF Barrel

The antenna has several slide out sections for tuning
I just got an LDG Auto Tuner.

How do you adjust the sections of antenna length wise if you are not doing it with a manual tuner?


Thanks

 

[Moleculo]

Is this the antenna that you got?

Diamond® Antenna ~ CP-725H Quad Band Trap Vertical Antenna

 

[KB1UGX]

http://www.eham.net/reviews/detail/4946

No its this one

 

[Moleculo]

I assume that you're just planning on using the auto tuner for 6 & 10 meters? That antenna requires a ground plane, so if you're using it on your house, you're going to have to come up with something. The manual also says this in all caps:

"MATCHING NETWORK IS COMPENSATED FOR TRUNK LIP MOUNTING
AND IS NOT RECOMMENDED FOR CENTER ROOF MOUNTING."

Check out the manual here which gives detailed tuning instructions with diagrams:

http://www.rfparts.com/diamond/pdfdocs/CR8900.pdf

 

[KB1UGX]

Here is what i did so far

It tunes fine on 10 meters but the tuner wont get it below 2.5 on 6 meters

Im a complete rookie with this and its my first rig.

Could you please offer some suggestions to help. Its very hard living in the city. All i have to use is my fire escape which is why i did the mobile in the first place.

Here are some pics.
Any help at all would make my day

[/IMG]

 

[Moleculo]

is that fire escape rail powder coated or painted? The first thing to do is to make sure there is conductivity between the aluminum bracket and the rail, which means that you may need to scrape some paint/powder coating off. When you say that it "tunes fine on 10 meter" is that using the auto tuner? If so, what is the lowest SWR on 10 meters without the tuner?

 

[KB1UGX]

i know it wont work with the paint lol

I used paint stripper and then a wire brush in a power drill and took care of all that. The dug out my ohm meter and tested for continuity from oppisite ends of the area i clean just to make sure everything was gone

I dont have an HF swr meter besides the one on the tuner
It tunes fine on 10 meters 1.1 ish the tuner does well

On 6 though it was 2.5 previously

I just ran a few extra ground wires down to a second ground location and got the 6 meter swr down to 1.3 now
So now im thrilled its all working and i made my first 6 meter contact today aswell!

Now just waiting to work 10 a bit if they band ever opens
Thank you so much for your help!

 

[Moleculo]

Good deal. I was going to suggest that the problem was probably as simple as not good enough ground plane...so adding some extra wires did the trick. Are you using the 10 meter band on SSB or FM only?

 

[TonyV225]

9 out of 10 times its a ground issue glad you are getting it figured out

 

[KB1UGX]

Thanks guys

Im only useing SSB because im only a tech and cant use fm

Im studying for my general though
I have yet to make a 10 meter contact.

Hope to soon
Tomorrow on filed day i hope to have some luck

My radio gives me 2 modes
Which should i be on?
USB
or LSB
There is no plane SSB?
Thanks for all the help!
I cant tell you how much i appreciate it

 

[packrat]

USB.

 

[Beetle]

Thanks guys

Im only useing SSB because im only a tech and cant use fm

Im studying for my general though
I have yet to make a 10 meter contact.

Hope to soon
Tomorrow on filed day i hope to have some luck

My radio gives me 2 modes
Which should i be on?
USB
or LSB
There is no plane SSB?
Thanks for all the help!
I cant tell you how much i appreciate it

USB and LSB are both SSB modes. The "U" and the "L" define which of them you're using at the time.

An AM signal has two sidebands - "U"pper and "L"ower. If you're eliminating the carrier plus the lower sideband, you're transmitting whatever's left: the USB.

(Not to be confused with "Universal Serial Bus") ;-)x