HF Station Systems Engineering Part 1 of 2: Planning and DESIGN by Drew Vonada-Smith K3PA 1 Dec 2017, All rights reserved

Systems Engineering? Do we need it? This looks simple enough to me. HF Transceiver Dipole Key Mic

Do we need it? I’d like a better station. It’s still fairly simple. HF Transceiver Dipole Key Mic Amplifier Triband Yagi Switch Computer Digital Interface Rotator

Do we need it? I’d love a good contest station. Single Op Two Radio (SO2R) sounds fun! HF Transceiver 1 80M 4 Square Paddle Mic Amplifier 1 40M Yagi Switch Computer Digital Interface 20M Yagi HF Transceiver 2 Amplifier 2 Keyer DVK 160M Vertical 15M Yagi 10M Yagi RX Ants Band Filters Panadapter Rotator Ø Control

Do we need it? Yikes! Maybe we should think this through? Panadapter 160M Vertical 80M 4 Square 40M Yagi 20M Yagi DVK Computer Digital Interface Ø Control Rotator Rotator Keyer Paddle RX Ants 20M Yagi HF Transceiver 1 Amplifier 1 Band Filters Rotator Mic Switch HF Transceiver 2 Amplifier 2 10M Yagi 15M Yagi Band Filters Rotator Rotator

Hell yes, we need it! What are some of the issues we face? This is a lot of complexity to maintain. This is a lot for the operator to set and keep track of. Distracting! There are a lot of connections here. How do we cable it all? How do I choose all this equipment? Can I even fit it all on the desk and reach the controls?

How do we start? What are some of the issues we face? This is a lot of complexity to maintain! It sure is. Let’s think it through, design it, and document it. There are a lot of connections here. How do we cable it all? Design it. Label it. Lay it out neatly. How do I choose all this equipment? Learn which specifications matter, and which do not. What about antennas? A major topic! Let’s discuss the basics. This is a lot for the operator to set and keep track of. Distracting! You want the operator focused on making QSOs, not the station. Automate! Can I even fit it all on the desk and reach the controls? Put the most critical devices within reach. Automate the rest, or bring to a hub.

Design This is a lot of complexity to maintain! It sure is. Let’s think it through, design it, and document it. You are going to forget later. Draw diagrams. Visio is nice! Computer port configurations get complex. Write them down. Design, document, and implement. Don’t implement first. Don’t document last. Simple block diagrams are a good starting point. Keep copies of configuration files, or take pictures of setup screens. You WILL need them.

Design There are a lot of connections here. How do we cable it all? Design it. Label it. Lay it out neatly. Buy a P Touch labeler. Label both ends of *every* cable. Use good cable. LMR240 is flexible nice for shack RF interconnections. Use good connectors. *GOOD* PL-259 crimp types are very reliable. Check tightness twice. Don’t forget the PL-259 tooth alignment problem! Standardize on a control signal connector. I like 9 pin D (DE9) connectors. Use the capture screws! Have a permanently mounted power strip with plenty of spare outlets Consider a cable raceway, cable tie anchors, or some method of neatening things.

Equipment Selection How do I choose all this equipment? For your transceiver(s), learn which specifications matter, and which do not. Every serious transceiver made since the 1970s probably has sufficient sensitivity and (SSB) selectivity. Yes, most transceivers are not up to the job for use on large antennas or for SO2R service. Why? Poor overall dynamic range (basic design issue) Poor close in dynamic range (roofing filters) Excessive phase noise (synthesizer) Bad AGC characteristics (designers who don’t operate) Dirty transmitter, either poor IMD (SSB) or key clicks (CW) (no marketing demand) CW is a more critical application for the best transceivers, due to the nature of SSB signals

Equipment Selection How do I choose all this equipment? How do I learn more about specifications that matter? The “Sherwood List” http://www.sherweng.com/table.html is a good guide for receiver performance. But it isn’t gospel. Use it as a guide, and understand it. So, what receivers seem the best? Some currently offered proven winners are: Elecraft – K3 & K3S. Also has one of the cleanest transmitters. Yaesu – FTDX5000. Icom – 7851. 7610 soon. 7300 is not bad for relatively low cost, perhaps not SO2R. Kenwood – TS-990 & TS-590. TS-590 is a particular bargain! Flex – 6500, 6700 and others. Very different approach. TenTec – Orion & Orion II Many other older radios. Ask your local contester!

Equipment Selection How do I choose all this equipment? For your peripheral equipment, look at the big picture Buying the “best in class” item for each function is not always the best approach. Consider how the devices interconnect and play together. A family line can have advantages. Can the various devices communicate on a buss? This may eliminate a lot of connections. Does the company have a history of stability? You are going to need driver support for a long time. When you have to change configuration, can it be done in software? Or will it need to be re-cabled? …more later

Antennas What about Antennas? Antenna Design and selection is a topic worthy of its own presentation, but some basic design of an approach can be addressed here. How is antenna switching to be arranged? How many antennas will you have? How high should the antennas be? What feedline should be selected? What connectors should be used? If you need multiple bands at once (SO2R), how will you accomplish this?

Antennas What about Antennas? How is antenna switching to be arranged? Method 1: Run every antenna feedline to the shack, and switch them there This is the most flexible method. All connection schemes can be changed later. All switching equipment is inside and protected from the weather All those cable runs can be expensive! If you add another antenna, you may will have to run (and bury?) another cable Dipole Yagi Wall Antenna Switch Yagi Yagi Coax Vert

Antennas What about Antennas? How is antenna switching to be arranged? Method 2: Switch the antennas at the source, and run one or feedlines to the shack You must carefully think through what you will need Fewer cables will reduce cost, or make more expensive hardline feasible You can add antennas later, within the capability of your switch Waterproofing of the switching equipment will be important Both methods have their place! Dipole Yagi Wall Antenna Switch Control Signals Yagi Yagi Coax Vert

Antennas What about Antennas? How many antennas will you have? What can you afford and fit on your lot? I recommend somewhere between one and infinity! A multiband dipole can make plenty of contacts A very effective compromise is a tribander on upper bands plus dipoles on 40M and 80M Modern interlaced (non-trap) multiband Yagis can be almost as effective as mono band beams If you need every band (i.e. WARC), a Log Periodic beam can be a good compromise A Yagi on 40 meters is a great upgrade, if you have the room and height needed Verticals will generally outperform low horizontal antennas for DX on the low bands A four square array is a great step up from a vertical and can be built inexpensively Big stations use Yagis on every band 10M through 40M, and a four square on 80M Really big stations use more than one Yagi per band, stacked, or fixed on prime locations 160M has unique requirements. An Inverted-L is a great compromise performer. Verticals rule! Consider dedicated receive antennas for 80 and 160 meters

Antennas What about Antennas? How high should the antennas be? As high as you can! Not always true, but a pretty effective guideline for most of us. Rohn 25 and similar towers can be pretty cheap, and often available for sweat equity. Low horizontal antennas are not the best DX performers. A good rule of thumb is ½ wavelength, minimum. If you cannot raise your horizontal wire or beam to ½ wave height, consider a vertical If you have lots of really high Yagis, and no stacks, consider adding a low Yagi Some ideal height ranges for dipoles and Yagis are: 40M – above 60 ft. 90+ ft. is far better. Otherwise, go vertical. 20M – above 35 ft. 65 to 130 ft. is ideal. 15 and 10M – above 25 ft. 50 to 100 ft. is ideal. For big spenders, using a stack can get you the best of low and high heights!

Antennas What about Antennas? What feedline should be selected? What connectors should be used? Semi rigid coax (a.k.a. “hardline” or “Heliax”) is always your best choice where feasible ½ and ¾ inch sizes are often available surplus There is not much need for sizes above ¾”, except VHF/UHF and extremely long runs Rigid aluminum 75 ohm cable can sometimes be found nearly free. The 75 ohm rating is no big deal. Hard line cables normally use “Type N” connectors, often available surplus. They can be easily reused. For flexible rotor loops, Davis RF “Bury-Flex” or other 0.400” RG8/RG213 type coax is suitable Crank up towers will also require flexible coax. Bury Flex or LMR400 is flexible enough for this. LMR400 Superflex is NOT RECOMMENDED for outdoor use PL-259 “UHF” connectors are typical for coax. There is no electrical superiority of “N” connectors below UHF. Quality modern crimp connectors are reliable when applied with proper tools. Some still do not like them. I do. Hard line can be direct buried. Coax varies widely, some types can be buried. Many can not.

Antennas What about Antennas? If you need multiple bands at once (SO2R), how will you accomplish this? Antenna switching needs to accommodate this. A “8 x 2” switch is a common choice. Remote antenna switching will require at least two runs to the shack, one for each radio. Output of Transmitter X into Receiver Y must be limited, both for damage and good RX performance. Such isolation can be achieved by antenna spacing, band filters, and coax stubs. Antenna isolation is normally not sufficient, especially at high power Multiband Yagis can be used on more than one band simultaneously using a Triplexer. Be careful! Band switched low power band filters can be placed between each transceiver and amplifier For this case, coax stubs can be added to improve harmonic interference Or, high power band filters can be placed on each single band antenna Front end protection for receivers is advised to avoid expensive mistakes There is much, much more to this topic!

Automation of Controls The operator should be focused on making QSOs, not running the station. Automate! What can be automated? For General Use Antenna selection Amplifier tuning Logging Antenna rotation For Contests Sending CW Voice messages For SO2R Which radio is connected to the headphones, mic, keyer, digital interface Band filter selection

Automation of Controls What can be automated? Antenna Selection & Band Filter Selection One of the easiest and most helpful upgrades for stations with multiple antennas Use with a remote antenna switch, located inside or outside Most transceivers have a band selection output. BCD, Analog V, or CI-V An inexpensive hardware interface can be used with Yaesu, Elecraft, Icom radios More complex devices can control multiple devices like band filters and sequencers Programmable devices can control multiple antennas per band, and change configuration via software Consider solutions by microHAM (Station Master), 4O3A (Antenna Genius), and Hamation (BandMaster)

Automation of Controls What can be automated? Amplifier tuning Expensive, but very helpful Vacuum tube amps are complex and motor driven. Cost > $6000. ex. ACOM 2000, Alpha 9500 Solid state amps use relays for band switching and use broadband output circuitry. Many available. Both have advantages and disadvantages Solid state amps at less than legal limit are becoming affordable. 1500W is still expensive. Features to consider: Power? Duty cycle? 6M? QSK? Remote control head?

Automation of Controls What can be automated? Logging For contesting, consider N1MM, WinTest, or WriteLog For everyday use, more choices than you can name! Most modern products integrate transceiver control, USB or serial Consider LOTW upload, DXCC tracking, Packet Cluster features There is no one best solution for everyone

Automation of Controls What can be automated? Antenna Rotation Computer interfaced rotators permit automated or manual logger control; one less thing to reach for! Hygain and other rotator OEMs offer serial or USB interfaced rotator control boxes Automation can also be added to popular manual control boxes For flexibility, consider a universal control box that works with any rotator. Green Heron rules this roost.

Automation of Controls What can be automated? Sending CW A simple transistor interface can do the job A Winkey interface is inexpensive and eliminates PC timing issues Voice messages A simple transformer interface can do the job Sending RTTY Both FSK and AFSK options have their advantages FSK interface is similar to CW AFSK interface is similar to SSB and also useful for other digital modes Commercial products integrate these functions and others Both manual and programmable computer based devices are available

Automation of Controls What can be automated? Which radio is connected to the headphones, mic, keyer, digital interface SO2R products can switch TX interfaces and RX output between two transceivers Serious products are fully programmable and support advanced switching modes Consider solutions from microHAM (MK2R+, u2R) and 4O3A (Interface Genius)

Centralization of Controls Can I even fit it all on the desk and reach the controls? Put the most critical devices within reach. Automate the rest, or bring to the PC. Keep transceivers within easy reach. It should be comfy to tune all weekend. Keep key paddles at comfortable arms length. Consider headset mics Place automated amps, switches, and rotators out of the way Route everything you can through the PC so your logger can control it For Elecraft, consider the remote tuning pod (K-Pod) Xkeys or another macro key solution can be very helpful

Centralization of Controls Xkeys or another macro key solution can be very helpful The author’s Xkey bar. No control keys need to be memorized for major contest functions. One key press can: Turn the rotator to the bearing for the station entered in the log Move to the CQ frequency Move to the last Search & Pounce frequency Change RX and TX to the second radio Swap frequencies of the two radios Listen to radio #2 while radio #1 is calling CQ Change to alternating CQs on two bands Listen to both radios in stereo ...and more

Centralization of Controls An neat SO2R Layout at 4O3A!

Centralization of Controls The Author’s Station – Small But Efficient

Questions? Any Questions?

Thank you for your interest! Conclusion Thank you for your interest!