Far north propagation

Mon Dec 5 06:58:11 EST 1994

Comments on far north propagation for 160-40 and not being heard by
the lower 48 forces me to continue this thread. Mostly because I'm
an expert in this field as owner and operator of KL7RA for the last
23 years. (100 miles from the arctic circle and directly under the
aurora zone)

Jay WX0B writes "Hearing the lower 48 means that you should be able
to at least get through". Not true Jay. During the CQWW PHONE I
called your station for over a hour on 75 meters and never was
heard. I spent that hour bleating my heart out mostly for something
to do because 40 thru 10 were dead. When I say dead I mean "no
signals heard" period. Here is why:

Far north stations have all the usual bad stuff like high
absorption, skewed paths and aurora that you may experience at
times but we see it almost daily and at its full effect. We also
have sporadic-E that comes over in patches that will cut our low
angle radiation off and limit our first bounce to 500 miles or less
not allowing us to get the reverse path back to the lower 48. We
have no electrical storms or city QRN and few locals allowing for
a very quite receiver noise floor. Because of this we can hear
"loud" signals (s-2 or 3) but they can not hear us because most
lower 48 stations have at least some noise on 160 or 80.

During the 160 meter contest I talked to Jay VY1JA and a few ve8's
off and on as we struggled with the band. I put in about 10 hours
and worked (hold on to your hats) 20 people. I couldn't work any
west coast stations until their rain showers stopped. But it was
fun. I heard Europe and the east coast at times but didn't try
calling them to often. Jay and I would take turns calling then go
find somebody else who couldn't hear us either to blast.

"maybe with some improvements with antennas"
Well could be. I dont know. This is what I have:
KL7RA   Icom 781 + homebrew 1500 watt amps
160- inverted vee @ 190 feet
     top loaded vertical (80 ft of rohn 25 insulated from ground  
     phili guys and 8-17 foot far end skirted wires for top       
     loading)  2 miles of ground radial. This antenna is located  
     far west from the hf towers.
80-  inverted vee @ 150 ft. slopers/phased verticals, misc crap.
40-  3 ele Telrex at 190 ft. No other antennas on this tower.

But its still fun to call and every now and then someone will
answer. Sometimes we are loud on 160/80 and even get pile-ups. Okay
not often. But the worst of times is when VY1JA, VE8CE and myself
listen to VE7CC and KL7Y (who are NOT far north stations) work a
pile of people we can't even start to hear. 

Rich  KL7RA at icefog.gcgo.nasa.gov 

>From es at mvuss.att.com (Edward S Parsons +1 508 960 6722)  Mon Dec  5 16:38:00 1994
From: es at mvuss.att.com (Edward S Parsons +1 508 960 6722) (Edward S Parsons +1 508 960 6722)
Date: 5 Dec 94 16:38:00 GMT
Subject: Autek RF-1 Measurements
Message-ID: <9412051644.AA19824 at ig1.att.att.com>

In measuring R + jX use the SWR and Z results and cal R and X
from

         (Z*Z + 2500)(SWR)
    R =  ----------------
          50(SWR*SWR + 1)

     Z*Z = R*R + X*X, for inductive reactance
     Z*Z = R*R - X*X, for capacitive reactance

Yes the above equations are good. The problem is that the SWR is
measured to tenths and the Z to 1 ohm, so there is some error but
its a lot better than R at resonance and then cal X.

I have found no problem with using it to measure verticals as K0SF
mentioned. 

One problem I do find is that it does not measure 1/4 wave resonance
frequencies with accuracy. If 50 KHz error at 3.5 MHz is within your
expectations then it will do fine. My tracking generator arrangement works
to within 2 KHz at 3.5 MHz so I dont find the RF-1 useful for this 
measurement.

The other problem is that half the display disappears at times for
no good reason. Its not battery voltage or temperature effect as far
as I can tell. But all in all its a great little device.  

73, Robye W1MK
lr at mvuss.att.com

>From Henri Molhuizen (PA3DUA)" <H.Molhuizen at derma.AZN.NL  Tue Dec  6 07:55:20 1994
From: Henri Molhuizen (PA3DUA)" <H.Molhuizen at derma.AZN.NL (Henri Molhuizen (PA3DUA))
Date: Tue, 06 Dec 1994 08:55:20 +0100 (MET)
Subject: CQWW LOG SUBMISSION VIA INTERNET?
Message-ID: <01HKBFREM2768ZED5M at DERMA.AZN.NL>

Maybe I missed it, but could someone please inform me if it is possible to submit my modest CQWW CW entry via Internet. If so, what kind of files should I
submit?? I used CT 7.14, so generating the right files should not be much
of a problem I guess...

Thanks in anticipation!

73 de Henri, PA3DUA
H.Molhuizen at derma.azn.nl

>From Henri Molhuizen (PA3DUA)" <H.Molhuizen at derma.AZN.NL  Tue Dec  6 07:55:52 1994
From: Henri Molhuizen (PA3DUA)" <H.Molhuizen at derma.AZN.NL (Henri Molhuizen (PA3DUA))
Date: Tue, 06 Dec 1994 08:55:52 +0100 (MET)
Subject: No subject
Message-ID: <01HKBFVHN21K8ZED5M at DERMA.AZN.NL>

review

>From p_casier at eunet.be (Peter Casier)  Tue Dec  6 08:59:19 1994
From: p_casier at eunet.be (Peter Casier) (Peter Casier)
Date: Tue, 6 Dec 1994 09:59:19 +0100
Subject: EU CONTESTERS: ARRL 10m score net
Message-ID: <199412060859.JAA06227 at box.eunet.be>

European contesters, 
let's gather on Sunday 11/12 at 20:00z on 3.775 +- QRM
to exchange 10M ARRL scores.

If I do not show up, this means our first baby is one week early, so I trust
someone else will run the score net!

PS: US GUYS: do not forget to try for EU beaming over AF or SA! Last year
the only openings we had, was over this skewed path.

CU in the test, as OS6TT, single op phone only 
(I got to be crazy doing this)

Peter
ON6TT

p_casier at box.eunet.be

>From ni6t at ix.netcom.com (Garry Shapiro)  Tue Dec  6 09:05:28 1994
From: ni6t at ix.netcom.com (Garry Shapiro) (Garry Shapiro)
Date: Tue, 6 Dec 1994 01:05:28 -0800
Subject: 3-500Z Recommendations
Message-ID: <199412060905.BAA26775 at ix2.ix.netcom.com>

You wrote: 

>
>I need to purchase several sets of 3-500Z to get L4 and a L4B linears 
ready 
>to sell.  I've noticed that there are less expensive alternatives to 
the 
>EIMAC 3-500Z's, 3-500Z's with "graphite plates", and versions from 
Amperex.
>
>My initial reaction is to stick with the EIMAC tubes; however I thought 
it 
>might be worthwhile to ask the net for positive and negative 
experiences 
>with alternate manufacturers.  I'd then post the results of the survey 
back 
>to the net.
>
>So .... please share any experiences you have - good or bad - with the 
>non-EIMAC suppliers of 3-500Z's.
>
>
>Thanks .... Dave, W9ZRX    (zephd at iquest.net)
>
>
>

Funny you should mention that...

Cuppla years ago, the 20 year-old Eimacs in my L4B went to their 
reward--or at least one did. A friend was tight with Richardson and I 
got a pair of the Amperex "Super Z's", which had gotten a "super review" 
in CQ, from Dave Ingram, I believe. Richardson owns the Amperex factory 
in France that makes the "Super-Z's".
The tubes are beautiful, rugged and efficient. They also have a bit less 
power gain. Although Richardson marketed them with a data sheet whose 
specs were identical to Eimac's, I believe they are not quite the same.

I obtained replacements from Richardson: no difference. I innocently 
inquired about it, and talked to their "expert", who turned out to be a 
salesman who knew the buzzwords, and little else. I persisted, and was 
stonewalled. I was supposed to get a call from the factory; I never did. 
Since I had gotten a good price as a "favor" and was embarrassing my 
friend, I backed off.

Since this is a technical crowd, I will be more specific. 120 watts 
drive (checked with a Bird) from a tweaked TS930S nets 1000-1200 watts 
out on 80 thru 20.(I get less on 15 and 10 because I compromise-tune the 
input tanks to get the WARCs.) 80m output is 1000-1100 watts with the 
grid bypassing substantially increased (60's amp designs often had less 
grid bypass capacitance to reduce the possibility of overdrive on the 
lower bands from 150-250W tube exciters and to and provide some 
degenerative feedback.) 

The input SWR is less than 1.5:1 80-20m. Presuming normal efficiency in 
the input tank, more than 100W is finding its way into the tube 
cathodes. 

The data sheet says 2x46=92W drive should provide 2x600=1200W output 
from the TUBES with 2500V on the plates and 2x400=800mA plate current 
and 2X120=240mA grid current (zero bias). (Yes, I know these are 
"typicals", but the Eimacs meet them.) One subtracts tank-circuit loss 
and gets real power output. In my case, over 110W drive yields 1150W 
out, but with 720mA plate current at 2350V and 180mA grid current. The 
low plate and grid currents suggest insufficient drive: I cannot 
overdrive these tubes! On the other hand, the tubes appear to have good 
plate efficiency (1150-80)/(.72*2350)=64%. (The "80" is roughly the 
fed-through driver power). This suggests to me that the Amperex 3-500Z 
has a bit larger grid-cathode spacing and a lower mu and power gain--but 
I am not a tube engineer.

Is this good or bad? If your transceiver struggles to put out 100W, you 
may be disappointed when you find lower power output. Bypassing the hell 
out of the six grid pins will get some of that back on 80 and 40. On the 
other hand, if the grid-cathode spacing is indeed larger, the tubes will 
be less susceptible to the grid-cathode shorts that are a typical cause 
of death for these tubes. And they do run a bit cooler.

Don't forget to re-tweak the input circuits for your new tubes.

I have no experience with the Chinese cheapies. I am told you get 
shorter life, but they are a lot cheaper.

73 de Garry, NI6T

>From Warren Rothberg <wrothberg at mv.MV.COM>  Tue Dec  6 11:44:11 1994
From: Warren Rothberg <wrothberg at mv.MV.COM> (Warren Rothberg)
Date: Tue, 6 Dec 1994 06:44:11 -0500
Subject: OO reports during contest
Message-ID: <199412061144.GAA11826 at mv.mv.com>

>      Someone on the reflector related getting a citation or OO report.
>      I got one ÿOO report! for operating on a frequency too close to "the
>      approved SSTV frequency allocation..."  during SS Phone.  Any simila
>      occurrances?
> 
>      Dick, K4XU                   dfrey at harris.com

Yes, I got an OO notice for operating to close to the band edge during SS.
I was on 3752.5.  The OO was right.   I should have allowed 3 KHz operating
on LSB.

Warren, WB1HBB
wrothberg at mv.mv.com