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HF9V issue - hoping to find a quick fix


Steve W6IFN
 

My HF9V was working peachy keen just a week ago.  Today I ran my analyzer across it in preparation of doing the Canada Day contest that starts in a few hours, and I suddenly have problems...

- 6, 10, 12, and 15 meters are all fine.  No issue at all.
- 17, 20, 30, and 40 are suddenly having issues:
     17 meters: (always poor SWR) resonance point has shifted up past the top end of the band.
     20 meters: SWR has increased to where it's now right around 2:1 across the whole band
     30 meters: SWR has increased slightly and the resonance point is now below the bottom end of the band.
     40 meters: resonance point has dropped lower in the band than where I had it.  Top of the band is now around 3:1

I haven't looked at 80 meters as I was getting ready to retune it to the phone segment anyway.

I'm looking all around the antenna and can't see anything obviously wrong or different.  I've double checked that all 36 radials are still attached.  Any ideas what I could check?

I normally like to try to figure out issues like this on my own, but I was really hoping to do that contest in 3 hours  :-(    Thanks a bunch!

Steve W6IFN


 

Steve,
I would look at the 30 Meter assy.  If might have slipped down and that is affecting the low bands.  Aslo double check the 1/4 coax at the base of the antenna, it might have gone Hi-Z for some reason.  Water in the coupler of bad crimp on the ring connector on the antenna.
Al
WB9UVJ


Steve W6IFN
 

The 30 meter assembly seems as solid as ever.

I'm suspecting that 1/4 coax at this point - I've found some nicks in the outer jacket that weren't there last time I looked.  I bet I have water in there  :-(

I will order a replacement from DXE immediately - this time I'm going to use the "liquid electrical tape" stuff to seal it instead of trying to do it the conventional way.

I'll just have to keep an eye on my SWR and do the best I can in the contest.

Thank you, Al!

Steve W6IFN


Dave N3IL
 

The 75-ohm matching cable at base is for 20m only. If you suspect it is bad - remove it and install a 50 ohm jumper coax in its place.


Barry <boat.anchor@...>
 

On Tue, Jun 30, 2020 at 02:42 PM, Steve W6IFN wrote:
The 30 meter assembly seems as solid as ever.

I'm suspecting that 1/4 coax at this point - I've found some nicks in the outer jacket that weren't there last time I looked.  I bet I have water in there  :-(

I will order a replacement from DXE immediately - this time I'm going to use the "liquid electrical tape" stuff to seal it instead of trying to do it the conventional way.

I'll just have to keep an eye on my SWR and do the best I can in the contest.

Thank you, Al!

Steve W6IFN
Steve
In an emergency and keeping power down to 100W you can use good TV coax 
as a short term fix. I did this for 2yrs till I found right coax at swap meet.
GLde
Barry


Peter VA3PET
 

Hi Barry,

I had something similar occur with my hf9v but found the issue to be a high resistance joint  between the 80m and 40m coils. If your connections look tight then check across electrical connections with an ohm meter.


Good luck

Pete.

va3pet/va3hr


From: Butternut@groups.io <Butternut@groups.io> on behalf of Barry via groups.io <boat.anchor@...>
Sent: Tuesday, June 30, 2020 6:40:02 PM
To: Butternut@groups.io <Butternut@groups.io>
Subject: Re: [butternut] HF9V issue - hoping to find a quick fix
 
On Tue, Jun 30, 2020 at 02:42 PM, Steve W6IFN wrote:
The 30 meter assembly seems as solid as ever.

I'm suspecting that 1/4 coax at this point - I've found some nicks in the outer jacket that weren't there last time I looked.  I bet I have water in there  :-(

I will order a replacement from DXE immediately - this time I'm going to use the "liquid electrical tape" stuff to seal it instead of trying to do it the conventional way.

I'll just have to keep an eye on my SWR and do the best I can in the contest.

Thank you, Al!

Steve W6IFN
Steve
In an emergency and keeping power down to 100W you can use good TV coax 
as a short term fix. I did this for 2yrs till I found right coax at swap meet.
GLde
Barry


 

Steve,
You can easily make your own 1/4 wave match with a piece of 75 ohm coax.  At least it will give you a better idea of where to look.
Al


Will Grocott, M0LGW
 

Steve
My 17m tuning moved until I put a pipe clip either side of the bracket. I have my HF9V guyed and I have found that when the gales arrive and the mid section bends the collar for the coil moves up and down the main section. Although you need the copper grease, it tends to help move the coil clamps enough to adjust the tuning. Placing a pipe clip either side stops the movement an will help the antenna hold its tune. 


What is you wx like? I have also found my tuning will move if we get heavy rain or long dry spells. It doesn’t move much but you can see it on the analyser.


Thanks
Will, M7APJ