[Collins] {Collins} 30L-1 / 20.5 ' Cable

[Bill Hammond]

Hi Carl,
Don Jackson, W5QN did a excellent job of addressing that question in “Signal”  4Q 2013, page 28, in “30L-1 Instability-Cause & Cure". I would read that article to get the back story he was able to glean in his research.  In addition he adds some insight in stability issues with the amplifier.  Don asked for additional information from the readers concerning the cable length mystery.  Perhaps Don has an update he can share? 

I asked your same question a few years back on this reflector and the most common answer I got was to ignore the 20.5’ cable note.  I choose to use a 20.5’ length of cable.  For better or worse that is my choice and it all works great.  Losses in RG-58U in the HF range are not great and for the most part can be ignored for 20.5’  length in most low power environments.

73,
Bill-AK5X
Dallas, Texas
AC12-12683



> On Nov 10, 2014, at 12:51 PM, carl domanico <domanico88 at icloud.com> wrote:
> 
> Hello again group…once again I get to draw on the vast knowledge of all the Amateurs who participate in this listing. OK here is my question….this pertains to the 20.5 Feet of RG-59U coax that Collins calls for between the exciter and the amplifier ! Now on my first 30L-1 some 20 years ago i did exactly just that and it worked out fine…..on the one I now have i use about 5 feet of the same coax and it seems to work out fine….I would imagine one advantage to the shorter coax is the fact that I get somewhat more RF to the input of the amp…however, i am sure that is not necessary..there is enough RF from the exciter to handle that even with some of the loss in the 20.5’ length…lets face it the amp only requires 70 watts at most to function properly….So my question to all you electronic wizards out there….is... Do you think the Distortion levels would be lower useing the 20.5’ of RG-59U or does it make any difference ?? Right now I have a 5’ section of coax…but I am wondering if i should replace it with the 20.5’ of coax which I have here  ???
> Bill if your around..I would also appreciate some of your Professional advice on this matter !
> 
> Thanks People
> Carl
> WB2PVY
> 
> P.S. If I am not mistaken…i think Collins changed their views on the length of coax between the exciter and amplifier…but that is a here say….I heard that through the grapevines !
> 
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