Interface cable for Icom IC-7100 to a PK-232 Packet TNC

I was trying to interface the Icom IC-7100 to a PK-232 MBX Terminal Node Controller (TNC).  On my Yaesu radios it is a pretty simple matter to put a 6 pin mini DIN connector on the end of the PK-232 cable and have everything working in a very short time.  However, it wasn’t that easy on the IC-7100.  The IC-7100 is a great little radio, covers just about DC to daylight in a very compact package.  But I wanted to have the ability to use it on VHF packet radio, so interfacing the PK-232 was a requirement.

After trying the data port and the accessory port I realized what the problem was. There was no squelch on the audio from these two outputs. I found that information on using this new radio with a vintage TNC was very hard to find. Reading the manuals supplied with the transceiver didn’t help much.  After some additional investigation I saw that audio output from the receiver was available at the mic jack I then knew how to make the cable.  Since that was from the speaker it would be squelched.

Here is the connections to operate the PK-232 Terminal Node Controller with a Icom 7100 all mode all band radio.  Below is the cable details for creating your own interface cable.   On the left is the rear view of the RJ45 microphone connector on the IC-7100 matched up to the wire colors of a “standard” PK-232 radio cable as supplied by Timewave.  If you are using a Kantronics TNC look up the pin outs for it’s connector in the manual or on the web.  It should work just as well, although I don’t have a Kantronics TNC to test here.  If anyone out there tries the Kantronics drop me a note and let me know how it worked.

Click on image to expand

To enable the audio output to the microphone jack, you need to turn on “Speaker Out” in the function menu.   Press <SET> then select <Function> on the main menu, then scroll down to <Speaker Out> and set that on “ON.”

Set Speaker Out ON in the Function Menu

The law what allows the President to ban immigration

I went to look for myself that the law says about the President being allowed to ban certain people from immigrating to the US.  The clause is in U.S. Code  Title 8, Chapter 12, Subchapter II, Part II, § 1182. Here is a link to where I found this statute:

https://www.law.cornell.edu/uscode/text/8/1182

Scrolling down, very far down in this text you will see this clause:

(f) Suspension of entry or imposition of restrictions by President

Whenever the President finds that the entry of any aliens or of any class of aliens into the United States would be detrimental to the interests of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or nonimmigrants, or impose on the entry of aliens any restrictions he may deem to be appropriate. Whenever the Attorney General finds that a commercial airline has failed to comply with regulations of the Attorney General relating to requirements of airlines for the detection of fraudulent documents used by passengers traveling to the United States (including the training of personnel in such detection), the Attorney General may suspend the entry of some or all aliens transported to the United States by such airline.

That’s it folks. Says the President can do what Trump has done for as long as he wants to. Jimmy Carter did it, Bill Clinton did it, and the darling of the left, Barack Obama did it. But for some reason the Left has decided that President Trump can’t do it.

Really?

Noise Burst?

I see these bursts of noise from time to time on 40 meters. I have expanded the spectrum display and it is fairly broad band but it varies in amplitude across the spectrum. It doesn’t look like typical noise and sometimes I wonder if it is a sampling Phenomenon in the SDR as a reaction to a noise input. Has anyone else seen this. Today when I saw it I logged into my buddies system, a Flex 6700 in North Carolina to see if it was wide spread. Didn’t see it at all on his Flex. I have uploaded a short video from my phone camera.

Does anyone have an idea what this might be?

K9AY Receiving Loop Antenna

I have an acre lot and that sounds like a pretty good size, but actually space for antennas is at a premium. The the house sits fairly far back on the lot and the lot is fairly long and narrow, almost a pie slice shaped, coming to a point in the backyard. Further complicating the issue is the arrangement of the trees that make for little room for low band antennas. I was able to squeeze a 40 Meter Double Extended Zepp fed with open wire feeders. Even in an Inverted VEE configuration it goes from lot line to lot line. It does a very good job on most bands, particularly 10 Mhz and below, I generally get pretty good signal reports but the antenna is noisy.

Non-resonant antennas tend to be noisier than resonant antennas, and dipoles tend to be noisier than loops, at least in my experience.  This antenna confirms my experience.

K9AY Loop May Be the Answer

I have been looking for a good solution to the noise problem on receive and had heard about the K9AY loop antenna. It is a relatively small receiving loop that works well from 10 Mhz and down. I talked to with several hams about their experiences with the K9AY. N4IQ, Bill, is South Carolina was a great source. He has the K9AY and several beverage receiving antenna and had high praise for the performance of the K9AY.

When I saw a Array Solutions K9AY loop controller on QRZ’s swap page, I jumped on it. I had the controller in a week and started collecting the other bits and pieces for the loop. I measured off a space in one of the pine straw islands in the back yard.  I found a good place to put it, but need to get some professional clean up of trees and low limbs.  After the clean up the XYL was pleased with the  the yard too. Little did she know what was coming!

What is a K9AY loop and why did I want one?  The K9AY is a receiving loop antenna that works well on the lower frequency bands.  It resembles a Delta Loop, but is a very good directional receiving antenna.  Comprised of a 85 foot loop with a switching box located at the bottom feed point.  Below is the basic K9AY Loop.  You can click on the photos for a larger view:

Basic K9AY Loop Configuration

The loop is supported at the top, usually by a fiberglass pole, and fed at the bottom.  One side of the loop is coupled to the feed line with an impedance matching transformer and the other side of the loop is returned to ground through a terminating resistor.  This makes the loop directional in the direction of the feed line side, somewhat like a Beverage antenna.  The K9AY now produced by Array Solutions, there are two loops, set at 90 degrees from each other and a control box with relays switches the feed and termination side of the loops.

Setting the corners of the loops to the NW, SW, NE, NW directions and using the control box to select the proper feed and terminations gives a 4 directional antenna.  The relays are controlled by a controller in the shack, that also includes a preamp.  Since this is a small loop, there is a bit of loss of signal strength.  The preamp helps bring the signals back up to about the same as a large antenna.

Array Solutions K9AY Loop Control

My K9AY Loop

My implementation was to hang the top of the Loop from rope at strung between two trees in the pine straw island and then tie off the ends to stakes in the ground.  At the feed point of the antenna there is a relay box.  The relay box is a waterproof 4 inch electrical box with a plate attached that allows it to be mounted to a round post using a U-Bolt.  I used a 30 inch section of 1 inch galvanized water pipe driven into the ground for the relay box mount.  I made a strain relief / insulator for the loops out of a piece of 1/4″ PVC sheet.  I cut a hole in the center that it would fit over the 1 inch pipe, and used a hose clamp below and a pipe cap on top of the PVC sheet.  I drilled 4 snug holes in the corners to bring the loop wires through and wrapped them down to the relay box.  I drove a 8 ft. ground rod beside the mounting post and tied the ground connection to the rod.

K9AY Base Detail Photo

To hold the top of the loop I made an insulator out of a small piece of PVC pipe with three sets of holes drilled through it.  The top hole is for the support rope, another pair holes for the SW/NE loop to go through the insulator, and another pair of holes at 90 degrees from the first set for the NW/SE loop.

Top Insulator Detail

Finally, to hold then ends I used simple dog bone antenna insulator tied off to the ground stakes.

Dog Bone corner insulator

Ok, the ground stakes didn’t work all that well.  Because the stakes were too close in from the center of the loop, the ends of the loop were too low.  I just happened to have 4 trees that were off the ends of the loops, so I used some 1/8 inch rope around the trees at about 36 inches above the ground. That brought up the ends of the loops to a good height.  It is hard to see, but in this photo looking across a loop, you can see the ends tied off to the trees.

Loop End View

Not that I was actually trying to hide this antenna, but with the black top rope and the black insulated wire for the loops the stuck back in the trees, the antenna is just about invisible from the yard.  You can see the insulators and the florescent orange tie ropes for the ends, but otherwise it is very hard to see.  If you are in a place that you have to hide your antennas, this arrangement will work great for a hidden antenna.

Results

I have had a few days now to work with the antenna.  I love it!  For some reason it is very noisy at my QTH.  This antenna drops the noise level about 15 dB on 40 meters.  My day for NCS on the Sunrise CW net gives me a good opportunity to evaluate the antenna.  I can hear stations much better, and using the directionality of the antenna to reduce the noise and QRM I can copy stations much better than with the vertical or my Zepp.

I find that the loops pattern is a very broad front lobe with a very sharp notch off the back of the antenna.  It works better at notching out a signal off the back of the antenna than bringing up a signal off the front.  However, it still works very well.  As you might expect, it doesn’t do much for very strong signals, other than notching them down off the back, but it will bring the noise down and the signal up on weak signals and make them very easy copy.

It works well on 160 meters through 40 meters, although the preamp in the Array Solution control box passband is about 1.5 to 4.5 Mhz, using it on 40 without the preamp works just fine.  It also works very well on the AM broadcast band.  I like listening to AM DX and this antenna works well.  I have seen several instances when listening on US Clear Channel stations that I can switch the antenna to the SW or SE and completely notch out a US station and hear a Caribbean or Mexican station 599.

What now?

Well, other than wearing out the direction selector switch playing with the antenna, I have read that ground radials under the Loop Array improves the performance.  So I will be getting some wire and put some radials under the array to see how that affects the performance.

Update

I recorded audio from the FT-1000MP on 40 meters switching between the K9AY loop and the inverted Vee antenna.  From the recording you can hear the superior signal to noise ratio on on the K9AY compared to the Vee.  The preamp in the Array Solutions control doesn’t cover 40 meters, so the signal strength drops a little, but the Signal to Noise ratio is still superior on the K9AY loop.

TRAM 1480 Dual Band Antenna

I was looking for an inexpensive dual band VHF/UHF antenna to use with my go box radios.  I came across a dual band antenna from TRAM on Amazon that was half the price of similar Diamond and Comet dual band antennas.

The specs for the Tram were advertised as follows:

Gain:                                    6 dB on 2m or 8 dB on 70 cm

VSWR:                                Less than 1.5:1

Frequency Range:             144-148 Mhz and 430-450 Mhz

Polarization:                      Vertical

Impedance:                        50 Ohm

Configuration:                   5/8 Wave 2 Element (2m) and 5/8 Wave 4 Element (70cm)

Power Capacity:               200 Watts

Connector:                         UHF Female

So I ordered one and in a few days I had it in hand.  It was 48 bucks and it was free shipping.  Not a bad price at all.

The antenna was packaged nicely and arrived in good condition.  The antenna was shipped in two pieces that were less than 54 inches long.  Assembled the antenna is just over 8 ft. at 98 inches long.  (Click on the thumbnails to enlarge the photo)

tramdualband-1

The antenna is very similar in design to the Comet antennas and uses the same mounting system as the Comet antenna with a aluminum sleeve at the bottom of the mount with extruded aluminum brackets and stainless steel U-bolts.  It was all neatly packaged and all the parts were there.

tramdualband-2The antenna requires assembling the two sections using a Allen setscrew.  The required Allen wrenches are supplied with the antenna and the assembly is very easy.  With a pair of needle nose pliers you pull the center radiator out of the top section and connect it to the pin on the bottom section.

The two sections are shown here, the bottom on the right and the top on the left.

tramdualband-3

Shown here with the two sections joined with the setscrew.

tramdualband-4

Then slide the innards back into the antenna and tighten the coupling nut that seals the two halves of the antenna.

tramdualband-5

Then add the radials, the mounting sleeve, and clamps and attach it to your mast.

tramdualband-6

The TRAM Dual Band Antenna assembled and ready for SWR testing.

I mounted the antenna on a tripod and attached a 50 ohm coax cable and the MFJ Antenna Analyser.  Below is the VSWR I measured at several frequencies across the bands:

Frequency SWR Note
144.0 2.3:1
144.5 2.1:1
145.0 1.8:1
145.5 1.6:1
146.0 1.4:1
146.5 1.3:1
147.0 1.3:1
147.5 1.2:1 Low SWR @ 147.4 mhz
148.0 1.3

 

Frequency SWR Note
440 1.4:1
441 1.3:1 Low SWR @ 441.4 mhz
442 1.4:1
443 1.5:1
444 1.5:1
445 1.6:1
446 1.7:1
447 1.7:1
448 1.7:1
449 1.7:1
450 1.6:1

Well, so much for the VSWR Spec!  The SWR reads a bit high on the MFJ.  The FM portion of the 2 meter band seems to be pretty useable and the lower section of the UHF where one transmits seems to be usable.  In a functional test with a FT-8900 there was no problems.  I could hit the repeaters just find and I could get into the 2 Meter packet nodes with no problem.  The rig didn’t show any issues with the antenna and it performed nicely.

All in all, not a bad antenna for 48 bucks.

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