[Mobile-Portable] Question about HF mobile

[K0DAN]

All the tips these guys have given you are correct (or at least not 
incorrect). Adding my $0.02, assuming your mobile & antenna are out in the 
open somewhere, I would trust the MFJ. Chances are, your antenna is fine. In 
addition:

a) Don't give up too easily. You're probably close to success and you will 
be rewarded by perserverance.
b) If you can borrow an external wattmeter/SWR, try it and see if it's close 
to what the built-in "meters" of the 706 are. Somethimes the 706 is right, 
sometimes not. As someone said, the RIG RF/SWR meters are OK, but prone to 
error especially if you have other unknown problems with your antenna 
system.
c) If you're in SSB mode and talking/whistling into the mic, and it shows 70 
watts, that could be full output and the best you can expect. PEP is 
(roughly) average power) so what you produce at the mic is roughly 1/2 the 
average power output. Someone suggested trying to key in RTTY or CW 
mode...this is a good idea...if all is working well, these modes will 
"appear" to have more output, but again, SSB will only show about 50 watts 
+/- on peaks, yet this is about 100W PEP output. Could be you have no 
problem at all.
d) The difference between 70 and 100 watts is not all that great anyway way 
less than one S-unit) and you should not fixate on that. Better to be sure 
the antenna is close to 50 ohm load (and I think you can trust your MFJ on 
this). And make sure you have nice BIG power cables from the battery to the 
rig. #12 wire is NOT enough; use #10 or even #8 if you are able, especially 
if the rig is remote mounted in the rear of the vehicle.
e) Avoid cheap/easy coax cable like RG58. It looks good on paper, but sucks. 
Ditto RG8X. Use RG213/RG214 or something like that. It will survive the 
environment better, has less loss, and will not leak your precious RF out of 
the cable, nor leak RFI into the cable.
f) Take the extra effort/time/expense to have a GOOD ground (to vehicle 
frame) at battery, rig, and antenna. If you have an ohmmeter an can measure 
between these points, the resistance should be near zero ohms; at least 
should be well onder ONE ohm.

There's more, well documented on this site, but it looks like you've been 
going down the right roads and getting good advice. Be patient, check out 
the tips one by one, and have fun. Hope you report back that things are OK.

Good luck es 73

Dan
K0DAN

----- Original Message ----- 
From: "Brian K. Gaskamp" <ka5bkg at sbcglobal.net>
To: "Mobile-Portable Reflector" <mobile-portable at mailman.qth.net>
Sent: Wednesday, July 18, 2007 5:14 PM
Subject: Re: [Mobile-Portable] Question about HF mobile


> Ok all I have another question abt my HF mobile setup.
>
> I'm about to run out of ideas.
>
> I put a MFJ-269 analyzer on my 40m Hustler antenna the other day, the 
> analyzer shows 1.1:1 at 7277, flat SWR but yet I go to transmit and might 
> be getting 70 watts PEP out.
>
> If I had known HF was this tricky, never would have even attempted to try.
>
> I'm open to suggestions, cause its got me baffled.
>
> If I don't get it going with lower SWR, there will soon be a 706MKII up 
> for sale and I'll give up on my idea of HF mobile.
>
> 73,
> Brian
> ----- Original Message ----- 
> From: "Brian K. Gaskamp" <ka5bkg at sbcglobal.net>
> To: <Mobile-portable at mailman.qth.net>
> Sent: Tuesday, July 10, 2007 6:29 PM
> Subject: [Mobile-Portable] Question about HF mobile
>
>
>> Hello all, I'm new to the list here and also new to HF mobile and I'm 
>> having a problem that has me stumped.
>>
>> I'm running a Icom 706MKII with a Hustler 40m ant on my truck.
>>
>> I can be in front of my house and I get full output on 40m and everything 
>> works great...
>>
>> I check into a 40m traffic net during my lunch break and my power out is 
>> abt 50 watts, and swr is 2.3-1...
>>
>> I just stumped and what could be happening and need some advice, 
>> suggestions, on what I'm doing wrong...
>>
>> Or better yet, what happens to my HF mobile from the time I leave my 
>> house and why it acts like it does once I get to work.
>>
>> 73,
>> Brian
>>
>> ----
>> Your Moderator: Dick Flanagan K7VC, mobile-portable-owner at mailman.qth.net
>>
>
>
> ----
> Your Moderator: Dick Flanagan K7VC, mobile-portable-owner at mailman.qth.net
>