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Calling all VHF specialists!
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Barry Rietz



Joined: 21 Jun 2006
Posts: 243
City/Region: Sierra Vista
State or Province: AZ
PostPosted: Sun Dec 30, 2018 7:20 pm    Post subject: VHF Radio Problem Reply with quote

David & Val,
I think you have already diagnosed the problem and don't realize it is in the antenna. 100% of the reflected power is going to be returned to the radio if a short occurs in any part of the feed-line. And as Bob has already stated, the radio's circuit has prevented damage to the final transistors by shutting down.

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Barry Rietz
N9DXC
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Sam Walker



Joined: 26 Mar 2004
Posts: 195
City/Region: Wherever the RV is today
State or Province: SD
PostPosted: Sun Dec 30, 2018 9:01 pm    Post subject: Reply with quote

One thing that I have not yet seen mentioned. When checking your antenna, you should check it 3 ways. The OP has checked one. That is make sure that the circuit is not closed (or is open) between the tip and collar of the PL 259 connector.

The next one is to check the tip of the connector with the antenna (or antenna inner connection at the mast) This circuit should be closed with very little resistance.

The third test is to check the grounded side of the antenna with the collar at the PL259 connector. Like the tip, it should also be closed (have good continuity) with very little resistance.

Upon further review, Barry did touch on it w/ the shorts. My explanation is how to find the shorts.

Abnormality in any of these 3 can cause many headaches.

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Sam on C's The Day or maybe Marinauty (Someday)
It does not matter how many moments that you take a breath, It is how many moments take your breath away.
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C-Val



Joined: 15 Sep 2012
Posts: 238
City/Region: White Rock
State or Province: BC
C-Dory Year: 1988
C-Dory Model: 22 Angler
Vessel Name: Seaduced
Photos: C-Val
PostPosted: Mon Dec 31, 2018 12:16 am    Post subject: Reply with quote

I met the ham radio club today.
They were very interested and helpful
They looked at my solder job and said it didnít look that bad
(Thanks for the illustrative pics Dr Bob!)

Tomorrow they are doing a field test on my antenna

Will let you know how it goes
David

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Writing a sea story with my C-Dory !
1982 22' Classic Popeye
1981 22' Classic Bad Boy Brutus
1988 22' Angler
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C-Val



Joined: 15 Sep 2012
Posts: 238
City/Region: White Rock
State or Province: BC
C-Dory Year: 1988
C-Dory Model: 22 Angler
Vessel Name: Seaduced
Photos: C-Val
PostPosted: Mon Dec 31, 2018 6:55 pm    Post subject: Reply with quote

Hi Everyone

The Ham radio club confirmed today what many of you already suspected - my brand new 5101 vhf shakespeare antenna is shorting out inside drawing too many amps and causing the voltage to crash. They confirmed my solder job was not the problem (yeah!) Both my old radio that came with the boat and my newer Standard Horizon 1700 transmit perfectly with virtually no voltage drop.

Now I have to apply for my Shakespeare warranty! (good luck to me)

What did get me by suprize is they also ask to test my "good" antenna which is a Shakespeare but higher quality (5225 xp) The swr reading was almost 4! (tech sheet says 1.5:1 but Ham club says 2 is acceptable)
They said it also has to go back for warranty!

Then they put a good quality antenna they had on and reception was a clear as a bell. My "good " one was working but not at the level is was advertised at.

Lessons learned for new year:
1 Everyone should know someone with a vhf swr meter
2 Don't trust new antennas. Check their output before you mount it.
3 Annual checks should be made on these antennas to make sure they are working at their designed level.(After all vhf is one of our primary life saving devices when out on the water) My "good" one was under transmitting for who knows how long and I did not know it. My radio checks were still readable.
4 Give a thumbs up to you local Ham radio clubs - they are there to help
5 Belong to the C Brat Boat club and never stop telling them how grateful you are for their wisdom and patience and we walk thru these issues together.

HAPPY NEW YEAR TO ALL !

David and Val
White Rock BC (with the still broken pier!)
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thataway



Joined: 02 Nov 2003
Posts: 16743
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
PostPosted: Mon Dec 31, 2018 7:20 pm    Post subject: Reply with quote

I am happy to learn that our issue was resolved--and that the local ham club helped. If I am buying a fiberglass antenna, I take my antenna analyzer with me to the store, and test an antenna, until I get a low SWR.

The below is comparable to the older model I have (mine uses a separate very accurate frequency counter)

MFJ makes a boat load of ham related gear. The average C Dory owner would not buy this type of meter, but the serious ham should have it.




There is a cheaper MFJ-208 for about $100 for VHF only. There is no frequency counter.

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Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL
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colbysmith



Joined: 02 Oct 2011
Posts: 2577
City/Region: Madison
State or Province: WI
C-Dory Year: 2007
C-Dory Model: 22 Cruiser
Vessel Name: Midnight Flyer
Photos: Midnight Flyer
PostPosted: Mon Dec 31, 2018 8:50 pm    Post subject: Reply with quote

There are many various SWR meters out there. I have an older Shakespeare ART-2 that works well. I just searched on Amazon, and a number of them are available for under $100. Not only great for checking when installing new radio's or antennas, but for checking them occasionally to insure everything is still working well.
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