kidphc

The Antenna. I really wanted a Laird CWB270b. Well guess what they don't make it anymore. Couldn't find coil numbers or anything. It seemed ideal about 65" and wide banded. So I started searching. Found an article from the ORF/3730 Group in Canada. Apparently, they wanted something similar. Hence, a Larsen NMO30 with 64" whip for 11m/CB and NMO34 with 64" whip for 10m. I have those now. REALLY BIG CON This combo wiggles more then jello. At about 70 MPH the whole thing is canted back almost 30 degrees. Simply getting in and out of the truck the SWR was all over the place on the nano vna, from the jiggling. When tuning for 10m. I couldn't get the SWR lower then 1.6 at 28.540 or so. After talking to folks at MYGMRS and others. I probably went as short as I could with the coil in question. So I ran around with this for a while. I really wanted 1(one) antenna for both bands. I really took Marc's words about the antennas being too short now a days into consideration. Part of the reason the antenna is not center line roof was due to height. The NMO30/34 64" whip combo put it after tuning about 4 inches higher then my Larsent2/70b. In comes my birthday in a couple of days. Wife has been hounding me for weeks as to what radio I want. Well the THD74a is like a gazillion dollars now, due to the shortage. So that is out. I asked for an MFJ 1610T 10m Hamstick and Hustler quick disconnect on top of a Tram NMO to 3/8 adapter. Below here she is tuned in at CH20 on the with a beautiful SWR around 1.14. On 10M tuned in at 28.400 at with an SWR of 1.09. Pretty close to under 1.6 across the band width in both bands depending where I have it set on the whip. Interesting enough, the marks between 10m and 11m are only about 2 inches. Overall height? Under a couple inches below 13'. So objectives met.

THE ANTENNA MOUNT I choose to go with an NMO mount. I wanted to be able to repurpose the mount if necessary. Never know when I like to put another radio in. So I ended up with a Walcott radio hood fender mount. This particular one was expensive (same style on Amazon $28 this one was $70) but Walcott sold it with an NMO so at first I thought it was close to a wash. Long story short it came in. I found out why it was expensive. It came with the NMO and coax, the mount, and a 3/8 stud Fire Ring style coax. both Coax are terminated with an FME connector and PL259 adapter, pretty slick if you ask me. Pulling the cable was crazy easy. Even better the Coax for the NMO mount is wait? LMR200???? REALLY!!! AWESOME!!!. Wait it also comes with a nylon centering isolator (the 3/8 stud still needs to be able to go through, but the hole is too big for the NMO to self center)? The 3/8 mount is RG58U. Con The antenna had a backwards rake and outwards tilt. Some grinding and re-tightening sorted that out. Really no space under the mount for the NMO or stud coax. Be real care with cable routing] Because of the shoulder NMOs don't seal well. Just not enough material. Come on a 1/4 of steel isn't going to kill your profits. NO INSTRUCTIONS. Install was kinda straight forward and not. Attach the ground lead Mount the NMO/Stud Grind the crap (paint) off the location where the mount will come in contact with the body trust me a single braided strap isn't what you want for the ground plane connection. Install into the hole in the fender. Prepare for cussing, cuts and the likes Mount the antenna Check angle Finish routing coax and ground strap

ITS IN ITS IN !!!!! OMG So here is a shot of it installed. FTM400 using a Lido ball mount. FTM400 mic comes out the side with a Magnetic Mic mount for the mic. I wanted to adjust the angle of the radio. AT6666 mounted below it. Button in the top right is a Magnetic Mic Mount. THEY ARE AWESOME. The RS-70 HF inline SWR meter is off center and didn't go all the way left due to the way the SO239 connections are on it. I had to use to 90 degree SO239 adapters so it could clear things without really stressing out the coax. The front face comes off. That was important for me to be able to access the USB hub as well as swap SD cards out in the FTM400 for when we head up into Canada. RS-70 can be powered by USB. (the reason I started the Delta Fox thread) Which I did with this one. It is constantly on same with the NOTE 3. Remember it is hooked up to an Auxiliary (housekeeping battery) Negative. No Peak hold (not great for a mobile situation) Doesn't work real well with SSB (no carrier, so it is a bit iffy in readings) Positive Can be powered by USB All Metal Casing (basically the MFJ-844 Who are we kidding it is probably the same device. The Chinese manufacturer just doing the copyright thing. Light goes out till RF is detected. NOTE 3 is for the APRS DROID OSM This is connected to the FTM 400 via Bluetooth. HOW? Via serial to Bluetooth Adapter and a Yaesu SCU-20 cable with gender changer male-male serial adapter. Again thank you AMAZON!!. All USB power is provided by a Hundy QC3.0 USB hub. I clipped the power leads, ran some test. Installed Power Poles into the distribution box. On the side, not pictured is a Microtek SD media center. So I can play about 300 different videos on the Kenwood which relays it to the rear television.

MOCKING THINGS UP & INSTALLING So after a week of cussing my father under my breath and multiple visits to Home Depot, Harbor Freight etc. To replace missing (taken) or destroyed tools. Won't get into it anymore. I was ready for placement mock ups. I cut out holes for the Uniden external speaker, and Yaesu MLS 200 speaker. In retrospect I should of gone with 2x MLS 200s. The Uniden is a nice speaker, with noise suppression circuit be requires 12v power. I just wasn't sure at the time if the Anytone AT6666 could handle a non-powered speaker. FTM 400 mounted up top and the AT6666 down below. I am using the same cheap Amazon Power pole distribution block at home so this got added to the mix to handle auxiliary power. All the power to the center console is supplied via an Auxiliary battery, circuit breaker and isolator setup in the passenger front firewall area. So how do I access the fuse box and other things after installation. In come cheap Amazon 3mm neodymium magnets. they are mounted on a lip around the cutout where the cigarette lighter I added. The cigarette lighter port act as a handle to remove the door. Complete pain in the but to wire with power poles. You can see in the lower left the 0 gauge to 4-12 gauge stereo power distribution block I added. The power pole distribution block is behind it. The radios are directly wired to the distribution blocks, sniped the glass fuses off and on went ATC fuse holders with power poles. Again thank god for Amazon.

THE B*@TCH CONSOLE So lets start off the stock front center console. It is a slanted "U' shape. With an uneven floor. didn't realize how non-symmetrical it was till it was too late. I would of gone with the expensive police/ems console I had known how bad it really was. I use to build sub woofer cabinets for me, my brother and friends. So why not go with something I knew. Console was built with 3/4 MDF for the sides and 1/2 MDF for the front face. Not going to show the template, as it was just a dismantle of the console and tracing on paper. For the initial mock up. Nor am I going to show the first failed attempt. The space I had to work with. Showing backside of the console to be used as a template. NOtice the bracket and how skewed it is.e At this point. The WTF moment hit and I realized oh. This is not going to be fun.

Long Preface Sorry. I hope to say you time and money with my pain. So almost 2 years ago I got my FTM400XDR. Found as small as the body of the radio was I had no where to install it in my 2002 Suburban. The center console when dismantled because of the odd shape didn't have enough room as planned for the radio and additional things I wanted. So a custom front console came into mind. So in, came a year of procrastination. Well a year later and I got the bright idea for road trips it would be nice to listen to channel 19 on a CB radio. Ham buddy said, might as well do a 10/12m rig if really all you are going to do is listen on 11m/cb. After looking at Harris consoles and the like. It became quite apparent just the console was going to cost me nearly $800 with the mounts. Even in the used market, they were priced for just the console in excess of $200 for a banged up one. So that idea got tossed quickly. So I choose to start the nightmare project of a custom front center console. I say nightmare because, first it is not a square although it looks like it. More of lopsided "U" and all my wood tools, my dad had taken secretly or destroyed and left behind.

Another great video on theories and why we do what we do.

Saw that video a while ago. He was an incredible lecturer, some of other videos are just as informative. For me at least that video help conceptualize SWR. Another awesome video on antenna concepts in reality.

So here are my thoughts on the radio. My take on the Anytone At6666. Found another poster and it about sums my experience. -SSB receive distortion. (Not bad but, sometimes have to play with the clarifier more then I like) -Impotent NB (really doesn't do much) -Barely touch the RF gain pot and it maxes out -Only 6 memory channels (come on! Really?) (really has 400 memory in frequency mode) -Mode not saved in memory (yeah wtf) -Programming software failure out of the box (really no really controls, minus saving some memories and turning features off, for me turning of FM since it is outside of license. -The VFO is a click digit then dial each digit in. Royal pain in the ass. The plus, clarifier works well. Better then I expected. Wish there was a way to adjust ALC. Wish there was an eq for sound out. This thing is tinny. Same speaker I use at home for the HRI, which is bass heavy. Too the point where HI-Cut has to be on for some conversations or you can't hear anything becuase of the tinniness. It is sensitive, a bit too much. Can pull signals out of the noise floor. However, even with an external speaker (noise filter on), NB on the radio the fricking thing half the time you barely hear anything due to cosmic hash. When you get a strong signal it blows your ear drums out. It's either too quiet (background static/cosmic hash) or way too loud. Constantly, fiddling with the volume. The VFO is a click digit then dial each digit in (did I mention I hate this? For a mobile radio bit of a pain unless stopped way to much time staring at the screen)

Damn it. That was what I was looking for. I am looking for the lowest log? Sent from my SM-G975U using Tapatalk

Its a Larsen NMO34 coil. Unfortunately, no information on capacitance. Might have to go old school and break out a mult-meter to measure it out. Thanks for the information it is a start.

That kinda was the question to begin with. How to see resonance frequency not using SWR.

If you are using the repeater memory slot. Which should be memory 15-22. Then no worries with the frequencies it should automatically listen to 462.xxx and transmitting on input 467.xxx. Make sure it is the right frequency. As far as your DCS codes that sound about right. Program it and clunk away to see if you break the repeater's squelch.

I have seen the video before and it was no help. Michael thanks for the input. I guess this antenna coil combination wants to stay resonant at 28.59 or so. Uncut it seamed to be resonant at 29 mhz, with the swr at 1:1.7. Currently, it's 2.0 swr at the band edges and at 1:1.7swr at 28.450, 1:1.66 at 2.58. I guess next step is to check the impedence values at those frequencies. When the nmo30 and hamstick comes in about a week I will have to rerun the sweeps. The 1:1.7 swr I started to think was due to the terrible ground plane interactions. Bending the antenna away from a pillar resulted in an swr that dropped a few hundreths. I will never recommend a hood mount that close to the pillar as an even remotely acceptable mounting location. May have to get another mount that mounts the antenna closer to the center of the fender. Should be intresting to compare the two locations and their respective swr values. Sent from my SM-G975U using Tapatalk

I have a nanovna ver h4. Kinda why I am asking how you would look for the resonance. It certainly has way more ability then the user to do many functions at this point. Sent from my SM-G975U using Tapatalk

That is one way. But a rigg expert will have to wait. Was hoping for something like with the nanovna like at lowest reactance and inductance. Actually might have found something on those lines. From: https://www.electronics-notes.com/articles/antennas-propagation/antenna-theory/resonance-bandwidth.php Basically, the lowest impedance value. --- This is the frequency where the capacitive and inductive reactances cancel each other out. At this point the antenna appears purely resistive, the resistance being a combination of the loss resistance and the radiation resistance. Well kinda. For a pre-engiered antenna generally 1.5 swr is where the antenna is resonant. But an antenna can be resonant t frequency and have a really high swr say like 1:5, example folded dipoles. ---

So building out my system for the truck. Finally, after a year of laziness I am building a center console (well the front half) to house a FTM400xdr and an Anytone at6666 10/12m radio (code for illegal cb radio for those that don't know). It will be used for 10m work as well. STAY TUNED FOR A BUILDOUT POST. So the antenna is mounted to the hood in front of the a pillar. Using a NMO34 with a 64" whip (10m) and a NMO30 with 64" whip(11m).This is going away. The whip is .100 and it flexes to 45 degrees above 30 mph and much more at 70. Incoming MFJ 10m hamstick. Should be tunable for both bands. I was trying to hold to Marc's talk about every commercial antenna for 11m is too short even with a spring. SIDE NOTE: I DID FIND SOME ONE THAT MAKE CUSTOM EXTENDERS TO GET A 102" TO 115" OR SO. Now back on track. The nmo34/30 combo the lowest I could get was a SWR of 1:1.6 or 1:1.7 with trimming. I gave up because the SWR started climbing back up. Lowest frequency for the 10m set up was 28.594 (VSWR OF 1:1.6). Just a hair away from the target of 28.400. It started making me think of antenna resonance and how to calculate it. So in order to find the resonant frequency of an antenna I am looking for an impedance of about 75 ohms purely resistive? This the value I gather for a dipole in free space. So the question is how the hell do I find resonance of a custom, less then ¹/4 wave whip with a bottom loaded coil? Sent from my SM-G975U using Tapatalk

Might have to go with a hood mount by the windshield with a s much antenna as you can get to clear the windshield and roof. Outside of that you may be stuck with a mag mount. Depending on the shape of the trunk a lip mount on the side of the trunk. Similar to the link below. https://hamradioschool.com/wp-content/uploads/2014/07/GetStarted-bands.jpg

Nano vna is easy peezy. Not a turn on and good to go device. But close. Buy it. Buy it... only if you are constantly tweeking or building antennas. The other swr meters you need to provide an input. Aka key up.