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41
Antennas / Re: Double Bazooka antenna plans
« Last post by KE7TRP on July 24, 2013, 07:42:54 PM »
I got my 75 meter DBZ up today.  Mine is made from RG11 coax.  I am not getting the bandwidth I wanted.  I can go from 3715 to 3915 under 2 to 1. Not the whole band.  I am using 100ft of Brand new LMR400 for the feedline that then runs into 100 FT of half inch hard line.  Tomorrow I will run the LMR into shack so I will remove 100 FT of feedline. 

The tests ran tonight where back to back. It took me 2 minutes running to lower 80 meter Open wire line antenna and put up DBZ.

The setup:


55ft crank up tower set at 40 ft due to monsoon season.
Antenna 1 = 126ft open wire line doublet (True ladder line dot com) to a Johnson matchbox balanced tuner. 40 ft
Antenna 2 - Double bazooka made from RG11 coax fed with LMR400. 35 ft

5 stations on the air ranging from 15 miles to 400 miles..  NOBODY knew which antenna I was on. Only Antenna 1 and antenna 2.

In all cases the DBZ BEATS the Doublet.  I am in shock.  I would have bet money the open wire doublet would win.  Reports are 3 to 6 DB.  I see 6 DB lower baseline noise on my band scope with the DBZ. But 3 to 6DB higher RX. 

Keep in mind I ran out and switched the antennas back and forth and did the tests 4 times.

NOT one station said Antenna 1 was better.  NOT one station was higher on RX then Antenna 2.

The DBZ on these state side contests wins with out question.  Now to ponder why.  There nothing much more efficient that 600 ohm open wire line to a doublet with a balanced tuner.

Tomorrow I will remove the 100 Ft section of hardline and run just the LMR400.  I will also put the DBZ at 40 ft.  Then, I will adjust it for 75 meters. The Low point is 3800 where I would like 3900.

The best part of all of this?

With the Open wire line doublet, If I ran 100 watts, I would blast over the Home theater.  With the DBZ, I can run 100 watts and not cover over the theater at ALL.  In fact, I can run up to 500 before I just start to hear my signal over the speakers. 

Hmmm.   I had a lot of fun with these tests.   More to come.

42
General discussion (QSO) / A tour of WLW 500,000 watt AM radio station from the mid 1930s
« Last post by KE7TRP on July 21, 2013, 01:28:45 PM »
http://www.youtube.com/watch?v=CbHjcwIoTiY

Enjoy!
43
General discussion (QSO) / HAARP shuts down
« Last post by KE7TRP on July 21, 2013, 12:39:43 PM »
No more HAARP.  Article from ARRL:


http://www.arrl.org/news/haarp-facility-shuts-down
44
Antennas / Re: Antenna options for those living in apartments
« Last post by KE7TRP on July 21, 2013, 08:29:20 AM »
Quote from: KB9MBP on June 30, 2013, 09:40:49 PM
I live in an apartment with outside garage.  I have few grounding options, and desire ideas.  Thanks! :)


What bands where you planning to use?    I recently tested an end fed antenna called the "end fed easy tenna".  I got the 54 ft version.  I ran battery power with an FT450 yaesu.  I worked pages and pages of contacts on 10, 15,17,20 and even talked to state side friends on 80 meters.  All with 30 watts or so.

C
45
AM Transmitters / Re: WA2ROC Studio A
« Last post by KE7TRP on July 20, 2013, 01:53:32 PM »
Very nice station!   I love that combo. I used to have a decent NC300 with the outboard Converter and speaker. I sold it off. Maybe I will find a very nice one some day or maybe a 303.

Good info on the loop. I wish I had room here.  That sounds like the way to go.  I do have some pines but the loop would be closer to all the neighbors so I think for now, I will keep the doublet. I enjoy trying antennas and testing them. I plan to try a couple different antennas soon. Its just so darn hot outside here in the summer!
46
Antennas / Re: RV HF antennas, whats the best?
« Last post by W5LZ on July 17, 2013, 05:39:39 PM »
Of the two choices you give, I'd pick the screwdriver antenna.  It's at least tunable, that 'marine' antenna isn't.
 - 'Doc
47
Antennas / RV HF antennas, whats the best?
« Last post by KB9OPW on July 17, 2013, 03:55:31 AM »
I'm in the process of installing a station in my 5th wheel RV. Now I know that opinions are just like noses...everybody has one, but I'm interested in finding out what you all think is best. I'm looking at the Shakespeare Marine SSB fiberglass antenna or a TarHeal screwdriver, but I'm open for other suggestions.
48
General discussion (QSO) / Re: How do I hookup rig and computer to run PSK31 ?
« Last post by W6DPS on July 16, 2013, 11:33:13 AM »
Quote from: KB9CDM on July 13, 2013, 11:45:16 AM
... It does not have a serial port so I am going to have to have some sort of gaget to  hookup between Yaesu 857-D and computer. Anyone got the answer ?

I have a great "gadget" called a SignaLink USB, from Tigertronics.  Works great, has a built in sound card and VOX circuitry.  It works with any sound card software, so PSK, RTTY, SSTV, etc. I use an Icom IC-718, and connect through the DIN connector on the back.  Many radios have these digital connectors built in that make the process much easier.  I believe there is a digital DIN connector on your 857.

I like having a separate sound card so you just set your digital software to use that sound card, and leave everything else going to the default sound card.  That way you don't transmit system sounds, music, etc.

As I was getting started I used the old "acoustic coupling" method to listen around the bands.  Just put your computer microphone near the radio speaker, and you will be surprised how well it can receive digital modes.  A little annoying because you also have to hear the digital audio, but not bad while you are checking things out.

For software, check out Digipan for PSK, MMTTY for RTTY, and MMSSTV for Slow-Scan Television.  Manyothers around, but I like these.

My two cents worth, refunds available on request.

Dave, W6DPS
49
AM Transmitters / Re: WA2ROC Studio A
« Last post by WA2ROC on July 16, 2013, 10:08:53 AM »
Here's Studio B.  Johnson Viking II, Viking 122 VFO, National NC-300, MFJ Differential T tuner and an Electro-Voice 664, replaced recently with an Astatic 10C for less bass response.
50
AM Transmitters / Re: WA2ROC Studio A
« Last post by WA2ROC on July 16, 2013, 10:02:10 AM »
My loop is basically 300 feet of #14 house wire (black, but RF is color blind) and it is strung between 7 trees in almost a triangular shape.  Why 7 trees, you ask?  Because that's where 300 feet of wire would fit between.  Altitude varies but is about 40 feet up.  That's as far as I could reach with a borrowed ladder.

It is insulated using ceramic dogbone insulators and UV proof cords in each tree.  The trees are tall so I felt that no 2 of them would swing in opposite directions at any one time.  So far, I have been correct.

It is fed with about 50 feet of 450 ohm window line from the middle of one of the longer sections directly to a Tucker T-3000 antenna matching box with an adequate balun inside to handle the balanced load.  It will tune SWR down to 1:1 on all bands, 80 through 10 and I may try it on 160.

Loops are notoriously quiet, noise-wise.  Much less static and local QRN than other antennas I have used here.

It really works well on the Monday Night 20 Meter AM Net too.

I also have a 100 foot doublet, a G5RV in earlier life, but without the hokey twin lead and coax, fed with more 450 ohm window line to an MFJ Differential T Tuner in Studio B, a Johnson Viking II and NC-300.  But an HQ-170 is in the works to replace that 300.  I do have a second NC-300 as backup on the shelf. 

This doublet is actually inside the perimeter of the loop, so there's no telling what kind of interaction is happening.  All I know is both antennas work very well.
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