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Monday, September 12, 2016

40-6 Meter Inverted L Off Center Fed Dipole

                                            40-6 Meter Inverted L Off Center Fed Dipole

Here is what I came up with after ruining a few hundred feet of wire experimenting.
Its not the best OCF ever made but it was cheap takes up very little space and gives me 100% of the 40 meter band without too much compromise. If you only have a small yard this is a amazing antenna for 50 foot of space.

Sunday, September 11, 2016

I accidently came across a post on radioreference and thought this lone post was very interesting. Maybe a good idea for someone with very little real estate. thanks Hertzian!

  End-Fed OCFD

I wanted to put some items that weren't being used to good use, and came up with a general purpose end-fed OCFD for hf. I'm currently using it for rx-only.

Essentially, it is a 4:1 UNUN in the center of the ocfd dipole, and at one end of the transmission line, is an 1:1 RF choke balun, and after that another run of coax into the shack. Being basically a non-resonant antenna, I'd keep jumper 2 no longer than about 50 feet to help keep the swr losses down.

Schematically it looks like this:

[ Receiver ] ----- jumper 2 ----- [1:1 RF Choke] ---- jumper 1 ------ [4:1 UNUN] ------------- wire -----------------

*The coax jumpers are 50z LMR200. Jumper 2 is about 25 feet from the receiver to the choke just to get it outside.
* The 1:1 RF choke is an MFJ 915
* Jumper 1 is 12 feet lmr200. (serves as transmission line AND antenna element)
* The 4:1 UNUN is from LDG. Nothing connected to ground side.
* The end wire is 22 feet long, a little less than twice the length of jumper 1. Attached to ant connector of the UNUN.

Essentially all I'm doing here is utilizing the common-mode of jumper 1 to serve as one side of an off-center dipole, and as a transmission line at the same time. This is a non-critical antenna for me, so I just make the end wire twice the length of jumper 1. Jumper 2 just gets it from the antenna to the shack.

Subsitute your own components if you like. Critical however is the RF choke. The MFJ was sufficient for now, although I'll probably end up with some stuff from Balun-Designs LLC.

The antenna is relatively broadband, and matching is not critical, although if you want to, you could use a tuner. I found no need for this non-critical application. Works well from 10mhz up to 28. If I wanted better low-band coverage, I'd increase the length of both jumper 1 and the end wire - but generally trying to keep a 1:2 ratio (about 1/3 off center) to make it easy on the 4:1 unun. Again, not entirely critical.

Mount it any way you like, and see what the reception lobes are like. In my case, I needed an impromptu stealth single-wire antenna mounted away from the house using only a wooden garden lattice for support. Jumper 2 runs out the house, jumper 1 runs along the ground, and the wire is run up vertically along the lattice for about 8 feet high, and the rest horizontal. Envision an inverted-L with only 1 radial wire on the ground. Mount yours any way you like.

Not the best, BUT it is outdoors, away from my shack noisemakers, and the rf-choke help prevent rf-ingress from those noisemakers, as well as making jumper 1 do double-duty as a transmission line and one side of the ocfd.

I'm not going to over-analyze this thing. I put it up, and let the lobes fall where they may. From about 10 to 30 mhz, my swr as read on an antenna analyzer is about 4:1, which is ok for reception, BUT swr is not the whole story!

Fun for sure. It goes into my antenna bag of tricks notebook.

Saturday, September 10, 2016

Decided to experiment with an off center fed 40 meter inverted L dipole. the short side is around 17 feet long and represents the vertical portion of the OCF dipole. My antenna is so low because I do not have room for a much more extensive design. the long side is around 48-49 feet long (I eyeballed it sorry. The antenna is 25%/75%) and I used the balun design posted by PU2YYP on his blog. the SWR is decently low on every resonnant band and the tuner has no issue tuning everywhere 6-40 meters. I consider this very worthwhile to build for a ham with very little space and it is very forgiving if you decide to slope the antenna down or bend the ends a little.

Tuesday, March 11, 2014

Dear W6ABJ about that 150 watt PSK31 transmission on a CB linear.

psk31 does not need an amplification device so please stop.............. the mode requires very little power to be efficient so please dear GOD stop using 150 watts on a Messenger 400 CB amplifier with psk31! your ic-7000 sound like a chainsaw at a daycare and noone likes it. so keep the ALC low and operate correctly as per FCC rules and regulations. A Messenger 400 CB Amp is not a type acceped device and splatters like a wolf eating pancakes!  Thank you and dear lord stop! 73

Sunday, March 9, 2014

Multiband HF longwire Balun!

I was looking around and found this picture of a multiband HF balun and the website was closed so I took it to share. It seems to be a slightly different design and with a set capacitor value. I will make it  and use a variable capacitor and see how it works!

Wednesday, February 26, 2014

DM-780 Rare DX and callsign definition file/list/xml

I created a Rare DX etc etc list for my DM-780, I am sharing the list but I am still getting the list created a little at a time and I will upload a new one every now and then. Maybe we can find some rare DX! Enjoy!

Download Rare DX list here!

Monday, February 24, 2014

IC-746,IC-746pro etc etc power settings for digital modes. (and most other radios)

Recently I have spent more than a few hours getting a little mad at the overly abundant steaks of 1600k wide digital mode distortion ruining my hope for man on my psk31 waterfall......But that's OK we have all been there.

So I am going to attempt to try to explain how I set up my nice clean psk31 and other digital modes  without uttering all kinds of Tech garble.

Step one.......hook up all of your digital stuff right.....once again no tech mess here! Read the instructions its all in there! 

Step two.......check on step one again! 

Step three....after you check the installation of all your digital wire mess see step 4

Step 4..... turn the computer sound or whatever device you are using to about 45-50% that's all! NO MORE then turn the radio mic gain to ZERO and turn the RF gain up to 100% transmit and add mic gain on the radio until you get whatever power range you want. Watch the ALC and make sure to keep it on the bottom of the scale! Zero ALC! If your radio cannot do it check and make sure the sound card is not up too high and then take the mic to zero and slowly add again until you get to your power level. that's it! no more! let the mic drive the power level and life is easy! keep it under 40 watts and you will more than likely read no ALC at all!

Step 4 Answer 2

If you have no ALC because you are on an old radio just do the same thing but be aware of a nice steady power output. If the meter is jumping around..... that is bad.

Saturday, February 22, 2014

Ham Radio Deluxe Version 5.24.38 download

Decided I wanted to make sure the few download links left on the internet had a brother! 
This is a set of links to the last version of HRD that was free...........

Ham Radio Deluxe 5.24.38

Another link just in case!

Make sure if you love this software that much to go over to the site and grab a paid copy of the newer version.Until then enjoy!

Friday, February 21, 2014

HRD/DM-780 macros will not save fix!

now this one is easy! 1........First crank up Dm-780 and then look around......

2.......change from the default macro to set 3 or whatever you want......... right click set 3

4...........Hit the set title button and name it something you want! I like to use my call!

5................Now go to import and basically copy the default set of macros...........

Done! after all this is done your new macro set will save like a champ! Time for some digital DX!

Thursday, January 23, 2014

THE RADIO AMATEUR'S HAND BOOK A Complete, Authentic and Informative Work on Wireless Telegraphy and Telephony BY FREDERICK COLLINS

Here is a free ham radio read that you might find interesting.

KF-382 Coupler Controller! How to Tune a tank!

I have seen these antenna tuners every now and then at ham fests and was always interested in a way to make a tune control for one. Well now is here our excuse to find one of these tanks and put it into operation.

As you can see, there are no microprocessors! The active components are simple relays. What could be easier?
Here's how it works. You initiate a Tune Cycle (say you've switched from 40 to 20 meters) by pressing the momentary Tune Initiate switch.  This sends a Tune Pulse Request to the RF-382 coupler on Pin E of the 14 Pin connector. The coupler, in turn, sends a Tune Power Request back on Pin F. The Tune Power Request grounds the cathode of the 'Tuning' LED, lighting it up, and pulls in K1 the Pad Enable relay and K2 the Tune relay. K1 enables an external 6 DB RF pad to drop the RF output of the rig to 25 watts or so. K2 does two jobs. First, it opens the key line between the transceiver and the linear amplifier. Next, it keys the transceiver CW or Tune key line. All three of these actions take the amp off-line and key the transmitter and reduce the transmitter's power output so the coupler will have proper tune power to work with.
At this point, the coupler attempts to find a match. There are only two possible outcomes; either the coupler finds a match or it does not.
If the coupler finds a match, it toggles the Tune Power request off. This causes the 'Tuning' LED to extinguish and K1 and K2 to drop out. When K1 drops out it first unkeys the transceiver and then puts the amp back on-line. K2 disables the external 6-DB RF pad. You may now transmit into a glorious 1:1 SWR load with full power. Life is good!
If the coupler does not find a match it will toggle the Tune Power request off and will toggle the Match Fault line (Pin C) low. This causes the 'Match Fault' LED to light and pulls in K3, the Fault Relay. The fault relay opens the circuit for the Tune Relay preventing an endless series of tune cycles and opens the key line to the amp, taking it off-line.
Note that the key is still connected to the transceiver so you can still transmit into the poor load - you just can't apply full power.
Finally, note that there is another possible fault condition - a Thermal Fault (Pin N). A thermal fault will also take the amp off-line while allowing operation to continue.
And, that's about it! There is a switch that allows you to bypass the coupler entirely and another switch allowing you to select High Power or Low Power. This switch merely tells the coupler whether or not you are using an amp and, if so, the coupler will run it's internal fan to dissipate any heat generated internally.  (The older RF-351 coupler has this fan, I don't think the newer RF-382 does..)
The component values are obviously non-critical. The relays must be able to switch whatever voltage and current is on the key line between your transceiver and your amp as well as the transceiver CW key line. K1 is a Hamlin 721C12-10, K2 and K3 are Tyco-Axicom D3002 and K4 is a Zettler 820-2C-12DE. K4 is the only interesting relay in the circuit - it has a make time of 5 milliseconds and a break time of 2 milliseconds. The timing of K4 is altered by the addition of C1 (47 μF) to prevent hot switching the amp since RF from the exciter drops off relatively slowly. The associated 15 Ω resistor is to limit the current through K4's contacts while C1 charges in order to prevent damage to those contacts.
The LEDs need suitable current limiting resistors again, for whatever voltage you are using. Typically, a 1.2K Ω resistor will work for a 12 VDC supply. I found the LEDs to be too bright so I upped the current limiiting resistors to 10K Ω. Except for the limiting resistor in the Low/High power indicator. I upped that value to a whopping 57K Ω. That indicator is the only one that is on all the time and it drove me crazy it was so bright. The other LEDs indicate the coupler is tuning or is in a fault or a bypass condition and are rarely lit - I want those indicators to be bright!
The connector on the coupler is an Amphenol MS3102E20-27P so the mating cable connector at the coupler is an Amphenol MS3106F20-27S. The connector on the back of the KF-382 coupler controller is an Amphenol MS3102E20-27S so the mating cable connector in the shack is an Amphenol MS3106F20-27P.
For the front panel toggle switches I used some nice rocker switches I use on lots of projects. The Tune Initiate switch is a momentary pushbutton switch with integral LED indicator.
The 12 VDC supply needs to be able supply up to 4 amps while tuning (3 amps is typical). I found a cheap outboard switcher at Marlin P. Jones and Associates. Their part number is 18599 PS. The matching power jack for the rear panel is from Mouser, part number 163-MJ22-EX a Kobiconn 2.5 mm DC Power Connector.
The case is also from Marlin P. Jones and Associates and is their Part Number 17806BX. The case is just barely large enough to be able to mount the big Amphenol coupler control connector. It comes with a perf board already installed. The case, as received, seemed about twice as deep as it needed to be so I chopped mine in half - but if you don't have a metal cutting bandsaw handy you could just use the case as is. I used an external power supply but if you use the full size case you could probably build a supply into the unit. The perf-board made for quick and easy construction.
The tri-color LED indicators are from Marlin P. Jones and Associates, part number 17137 and I used the same part for all three indicators even if I didn't use all three colors. It was just simpler that way..

The full write up and design is by W7KF and here is the link I got this from

Thanks W7KF for the awesome idea!

Saturday, January 18, 2014

One more antenna that got Screwed!

Decided to add my Alpine antenna's Screwdriver to a modified 4-btv with a 102" whip added to the top instead of a resonator! Turns out it is rig tunable(IC-746) from 20 meters and up and flat SWR all day long on 40-160 meters! works really well for a quick slap together job and I can once again enjoy some 80 and 160. Take note that the screwdriver antenna is not attached to the ground rod electrically. I have a insulator seperating the antenna from the ground rod. And I do not use the coil on the bottom of the screwdriver as a ground point at all. I do have a whip on top of the screwdriver also but I am sure it just acts as a cage on the lower freqs. I do plan on making a section of the antenna from the base of the 4-btv to the bottom of the 10 meter coil a cage style antenna soon for no good reason other than experimentation.  Wes(KA6ELK) makes a really good antenna so go check him out!