New Elecraft ax1 Antenna

I received an email from Wayne N6KR Yesterday related to a new antenna system that will be offered by Elecraft later this year. It was announced at Pacificon today

The AX1 is a dual-band (20 and 17 meter) compact antenna system based on an optimized 2-piece whip. It intended for use with lightweight transceivers such as the Elecraft KX2 an KX3 that are equipped with an internal antenna tuner. The AX1 can be configured for HT-style or right-angle use as shown below.

it should be able to be used also with other qrp rigs and an antenna tuner

This makes for an interesting anteena for field ops and SOTA work.

no idea on price but lets assume $60-$80

Its a 4 foot base loaded whip.

This will make an nice addition to the kx3 for portable operations.

see attached

Elecraft AX1 FAQ, rev. F

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County Comm GP-5 SSB Travel Radio

The guys at County Comm have an excellent shortwave portable that offer lw/mw/sw/fm coverage in a nice small form factor. It come well equipped and makes a great travel or hand held monitoring radio. It runs off 3 AA batteries and can charge nicads with a 5v jack just like on your cellphone.

I am very pleased with the purchase and do wish it had a keypad but that may be in a newer model but with the ETM tuning it may not be a big deal but is more so for ham listening.

I did some quick tests with the AN-200 loop antenna when i got home and that worked well along with the loop antenna accessory for MW.

As promised i would blog for county comm stickers (hi hi )

No need to read for 7 pages when you just go buy one and enjoy the radio for monitoring signals especially SSB.

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case, mw loop, earbuds and longwire antenna complete the go kit.

picks up cw like its designed to do and it does it well

WWV and WWVH on 15. I also heard the 25Mhz signal blasting in as well

SOTA Summit W6/NC-298 Vollmer Peak Summit Report- 581 Meters Elevation

SOTA Summit W6/NC-298 Vollmer Peak Summit Report-  581 Meters Elevation

After activating San Bruno and a trip to the Oakland HRO I made my way through heavy Friday traffic to Tilden Regional Park. I found out later I could have driven up (which would have saved me some time) but due to another hiker giving me false information I ended up hiking from the parking lot. The summit is on the left side of the Seaview trail as you make your way up. You will see the commercial antenna towers as you walk up. The hike was wonderful with views of Mount Diablo to the East across the valley and I could feel the elevation gain.

Again, I used my Yaesu FT-817, Elecraft T1, Chameleon MPAS Antenna and my Icom 92AD. I had the ability to toss a water bottle up into the trees and run a IPS Marconi NVIS configuration.

I made 2m FM simplex contacts using the handheld and the FT817 using the 5/8 whip.

A repeat contact with Dave WB6DTB who patiently was monitoring 52 waiting for me to summit and start the round of CQ calls.

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Mount Diablo in the East

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The Chameleon Hybrid Micro MPAS

I had the wonderful chance to work another SOTA summiteer Steve WD4CFN for a contact over 400 miles using 5 watts SSB who was at Combs Peak W6/SD-011.

Lesson learned was that the Mountain Topper radio needs to be on a set up like the SotaBeam FlightDeck and that some sort of antenna throw bag is needed in case you drink the water in the water bottle that is used to get the wire in the air. Better yet the Canadian antenna launcher aka Hockey Puck would have been ideal. Also, RF from the nearby commercial radio equipment could be a factor and in my case, it did not seem to be an issue.

Wire antennas are a problem if if there is no support so a vertical could start to make sense. Antenna efficiency is key when running SSB as many hams don’t bother with weak signals as intelligibility is an issue where with morse code its not a problem.

Due to the traffic of a Friday afternoon in the valley and the evacuation of the forest fires in the Santa Rosa area (there were 4 complex fires causing damage and loss of life) I chose to skip the Mount Davidson Summit and instead make the 1-hour trip to Pacifica beach instead and hope that traffic would not be an issue.

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A great memorable summit and another chance to play radio out in the wild.

vollmer peak sota log

SOTA Summit W6/CC-072 San Bruno Mountain Summit Report – 401 Meters Elevation

SOTA Summit W6/CC-072 San Bruno Mountain Summit Report – 401 Meters Elevation

It dawned on me that California is blessed with a lot of SOTA Summits all do-able and accessible by car. The plan was to attempt San Bruno, the HRO store, Vollmer Peak, Mount Davidson and Mount Tamalpais then low tide at Pacifica Beach then fly out of SFO.

I had the good fortune to activate this previously activated summit as a shake-out test to try out various set ups. It is also close to San Francisco and is an easy drive up to the summit which can simplify things when on a tight schedule.

I was concerned about the air quality due to the Santa Rosa fires North of the site but it did not seem to be a problem. I could easily see the intense smog/haze due to the smoke and ash particles from the fires. I realized later when I was at HRO that there was indeed ash in the air at street level. However, higher up the air was cleaner as ash would settle towards the lower elevations. After a week in the Bay area I didn’t smell the smoke as I had gotten used to it.

I was not able to connect with a Santa Rosa ham on 52 who was calling out but he did get a relay and had some traffic regarding the forest fires that destroyed that city this week. I chose to make quick contacts and allow long gaps for any break ins with emergency ARES traffic.

I already knew from Rex’s report (KE6MT) and his expert guidance that placing an antenna without trees was going to be an issue and my taped up doweling I got from the local store was too flimsy but you can see a sign post did the trick. The height still sucked but I still managed a contact on HF but ended up focussing on 2m FM. I could hear them on 20m and 40m but the 5 watts was still weak on a band that was acting like a yo yo with lots of QSB. The A index was 9 and the K index was 2. The best approach was to try to check into the west coast nets among the kilowatters. I had success but when they called out the QSB hit and the band started sliding. They were all pounding in on 20m and 40m. I hoped to make more contacts on SSB but that will need better band conditions and a vertical antenna to get some skip distance. The antenna right now was a sad NVIS configuration.

I still enjoyed the summit and had a chance to learn valuable lessons in being better prepared and organized. The somewhat obscured views of the Transamerica building were great but alas I could not see Alcatraz island or the Golden Gate bridge.

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I used my Yaesu FT-817, Elecraft T1, Chameleon MPAS Antenna and my Icom 92AD. I did not have time for the Mountain Topper Radio and the Emtech ZM-2 for cw contacts.

I made 2m FM simplex contacts using the handheld and the FT817 using the 5/8 whip.

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The longest was to San Jose at about 40 miles line of site using 5 watts

I gave up trying to use the Mountain Topper radio with the newly acquired Emtech ZM-2 (thanks to Steve WG0AT).

I couldn’t spot myself either as I needed an account password. (Lesson Learned)

This summit also offers views of planes landing and taking off at SFO with many Dreamliner’s making the trek between SFO and APAC airports.

Bob W7TE running the net

As a bonus the State Park also qualifies for a Parks on The Air (POTA) KFF-1196 activation.

Ok off to HRO in Oakland for lunch and picking up some items.

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John Leonardelli VE3IPS/W6

san bruno sota log

 

New Japanese DMR Radio – Alinco DJ-MD40

Excellent news for the DMR community with the release of a Japanese ham radio manufacturer supporting DMR with a new radio.

I had a chance to demo the Alinco radio at the Oakland HRO store. It has good solid feel and some great features worthy of purchase. This would be a great way for a Tytera user looking to upgrade their radio to something that is more robust.

As the growth of DMR continues so does the choice of radios which is an excellent story. The other digital modes lock the buyer into single brands with few choices where in DMR one has many choices to choose from. The radio offers a recording function that I did not try out but the display was crisp and the radio had the rugged feel to it. Take note this is built to commercial standards and is available at a ham friendly price.

alinco dmr

alinco dmr2.jpg

Motorola = Vertex

Jan 1, 2018 Motorola Solutions and Vertex Standard will join forces under the Motorola Solutions brand.
Vertex Standard models rebranded as Motorola Solutions: VX-260 Series, VX-450 Series, VX-2100 and VX-2200 mobiles, EVX-261 and EVX-S24

No word on the 6550 being released with a japanese manual

Yaesu Ft-101 E pricing 1977 – WOW a G Note?

When i got licensed back in the 70s the FT-101E was the popular radio until Kenwood released their excellent TS-820s (owner of both). The Yaesu was market leader because you were able to add a crystal and get on 11m for Freeband and 100w CB action.

The optional fan was the key item to add and most used the 4 pin Turner 3 or D104 mic.

You had a couple of choices of where to buy it : Hamtraders or VE Amatuer radio sales.

Canadian Yaesu Prices Apr.77

Hiker Go Kits for QRP Action in the Field

Here are some go kit ideas for qrp

I am still working on a tuner-less set up for the mtr3b set up but I did find the correct pelican box for it. I am looking at the St Louis series of antennas or will go with the Altoids L-Tuner. I am not kidding a couple of 9v work like a charm. About 2 watts output on 40 or 20m – no problemo. It was this or an icom 5100…icom lost

LMR qrp go kit.jpgsota kit

Learn How Transceiver work using the BITX40

This adds some effort by Goran VE6GPO to put a block diagram together that in conjunction with the schematic and the Ashhar’s description will give you some excellent information on how transceivers work.

42 years ago when i was licensed you had to know this stuff plus the morse code to get your ticket. I know that things have changed over the years but I am still excited when other hams start building stuff and figuring out how things work.

To really delve into this deeper you should buy one as they are cheap and support local labour efforts. Its amazing how you can make contacts with 5-7 watts with a dipole.

I will add the block diagram before the schematic. This block diagram is the key to understanding how the radio works.

BITX40 – Circuit Description

– Ashhar Farhan, VU2ESE

The original BITX was published on the Internet in the year 2003. In the last 13 years, it has grown to become one of the most popular rigs among radio amateurs around the world. The BITX40 board is this very classic now available as a fully tested board that is easy to hookup, modify and operate. You can read the original article that described the BITX at http://phonestack.com/farhan/bitx.html.

bit40x

Download the circuit diagrams »

What’s special about this version of the BITX?

  • Uses a 12 MHz IF and a Si5351 at 5 MHz as a rock solid local oscillator
  • The entire transceiver fits into a single large and easily accessible PCB
  • Though it works on 40 meters, it is easy to change coils and work it on other bands (details to be released soon)
  • It has a separate power line for the PA. By increasing the PA power voltage, the transmit power can be increased
  • The components supplied with the board will get you up on air without any special skill
  • Read the Wire Up to understand how it is hooked up

Development Notes

Almost all modes of radio communications share a natural principle that the receivers and transmitters use the same line-up of circuit blocks except that the signal direction is reversed. The CW direct conversion transceiver is the simplest illustration of this principle. A more complex example is the bidirectional SSB transceiver.

Bi-directional SSB transceivers have been quite common in amateur literature. A transceiver was described in the ARRL SSB Handbook using bipolar transistors. W7UDM’s design of bidirectional amplifier (as the basis of bidirectional transceiver) is referred to by Hayward and DeMaw in their book Solid State Design. The bidirectional circuitry is often complex and not approachable by the experimenter with modest capability.

The Raduino

The Raduino is a very powerful, hackable, easy to program board that comes loaded with the BITX40 software. The lower side OSCILLATORS connector has 16 pins. A 5 pin header that sits on it takes 12v, ground, and also provides the DDS output to be connected to the main board’s DDS connector. An 8 pin CONTROLS connector on the top connects to the tuning pot and future switches and controls. The tuning system is very precise and easy. The tuning pot covers 50 KHz of the band and the edge of the tuning pot’s range allow you to scan up and down the rest of the band in 10 KHz steps.

The broad band bi-directional amplifier

My interest in bidirectional transceivers arose after looking at an RC coupled bidirectional amplifier in the book Experimental Methods in RF Design (p. 6.61). An easily analyzed circuit that was simple and robust was required. It began its life as an ordinary broad-band amplifier:

There are some interesting things about this circuit:

  • The power gain, and the input and output impedances are all related to the resistor values and do not depend upon individual transistor characteristics. We only assume that the transistor gain is sufficiently high throughout the frequencies of our interest. The precise value of the transistor characteristics will only limit the upper frequency of usable bandwidth of such an amplifier. This is a useful property and it means that we can substitute one transistor for another. You can use 2N3904, BC547, 2N2222, etc. Just about any transistor will do!
  • The power gain is not a function of a particular transistor type. We use much lower gain than possible if the transistor was running flat out. But the gain is controlled at all frequencies for this amplifier. This means that this amplifier will be unconditionally stable (it won’t exhibit unusual gain at difference frequencies).

In order to make bidirectional amplifiers, we strap two such amplifiers together, back to back. By applying power to either of amplifiers, we can control the direction of amplification. This is the topology used in the signal chain of this transceiver. The diodes in the collectors prevent the switched-off transistor’s collector resistor (220 ohms) from loading the input of the other transistor. A close look will reveal that the AC feedback resistance consists of two 2.2K resistors in parallel, bringing the effective feedback resistance to 1.1K. All stages of amplification in this transceiver work this principle.

Diode mixers

The diode mixers are inherently broadband and bidirectional in nature. This is good and bad. It is good because the design is non-critical and putting 8 turns or 20 turns on the mixer transformer will not make much of a difference to the performance except at the edges of the entire spectrum of operation.

The badness is a little tougher to explain. Imagine that the output of a hypothetical mixer is being fed to the next stage that is not properly tuned to the output frequency. In such a case, the output of the mixer cannot be transferred to the next stage and it reflects back into the mixer. Ordinarily, if the mixer was a FET or a bipolar device, this reflected power just heats up the output coils. In case of diode ring mixers, you should remember that these devices are capable of taking input and outputs from any port (and these inputs and outputs can be from a large piece of HF spectrum), hence the mixer output at non-IF frequencies reflects back in the mixer and mixes up once more creating a terrible mess in terms of generating whistles, weird signals and distorting the original signal by stamping all over it.

A simple LC band pass filter that immediately follows the diode ring mixer will do a good job only at the frequencies it is tuned to. At other frequencies, it will offer reactive impedance that can cause the above mentioned problems. It is a requirement that the diode mixer’s input and output ports see the required 50 ohms termination at all the frequencies. In other words, they require proper broadband termination. Using broad-band amplifiers is a good and modest way of ensuring that. A diplexer and a hybrid coupling network is a better way, but it would be too complex for this design.

Circuit Description

Although simple, every effort was made to coax as much performance as was possible given the limitations of keeping the circuit simple and affordable.

The Receiver

The RF front-end uses a high performance 3 section band-pass filter for strong image and IF rejection. The three poles of filtering provide for a no-tune bandpass filter that needs no adjustment.

The 7 MHz bandpass filter. Each vertical division is 5 MHz

The RF Amps

An RF amplifier follows the RF band pass filter (Q1). There is 8mAs through the RF amplifier and the post-mix amplifiers to keep the signal handling capacity of the circuit above average. The Post-mix amplifier (Q2) does the job of keeping the crystal filter as well as the diode mixer properly terminated. The crispness of the receiver is more due to this stage than anything else. An improper post-mix amplifier easily degrades the crystal filter’s shape and introduces spurious signals and whistles from the diode mixer.

The Optional VCO

The BITX40 is supplied with the Raduino to make drift free, precise tuning easy. For the purists, a voltage controlled oscillator that covers 4.8 Mhz to 5 Mhz to cover the 7.0 Mhz to 7.2 MHz is an alternative. Just plug out the Raduino and solder the supplied yellow VFO coil. A varactor was chosen over a variable capacitor as it is easier to tune. Mounting a VFO capacitor properly is difficult. Good quality tuning capacitors are nolonger available. Those who like slower tuning rates with the VCO could use a multiturn 10K linear pot instead of a regular potentiometer. The VCO is fed via a broad-band amplifier into the doubly balanced mixer. The trimmer provides exact band covereage. This oscillator has low noise though it does drift a little like all analog oscillators. It settles down to a very imperceptible drift within 10 minutes of warm up. Tip: Turn the BITX40 on for a few minutes before actual use to avoid the warm up drift. The receiver withe the VCO takes just 90 mA current.

The Crystal filter

 The 12 Mhz crystal filter follows a Cohn topology. All the capacitors around it are 100pf. We use just 4 crystals to keep the ringing down and side-band suppression is 40 db. The receiver sounds exceptionally clean because of this crystal filter and the low noise oscillators.

BFO, Detector and Audio

The BFO is a plain RC coupled crystal oscillator with an emitter follower. The emitter follower has been biased to 6V to prevent limiting. The detector also doubles up as the modulator during transmit mode; hence it is properly terminated with an attenuator pad. It has no impact on the overall noise figure as there is enough gain before the detector. The Q13 audio pre-amplifier is a single stage audio amplifier. The 100pf capacitor across the base and collector provides for low frequency response. The receiver does not have an AGC. This is not a major short-coming. Manual gain control allows you to control the noise floor of the receiver and I personally find it very useful when searching for weak signals or turning it down to enjoy the local ragchew.

Transmitter

The microphone amplifier has a DC bias for the mic. This is required for the electret microphone that is supplied with the kit. The common Personal Computer type of headset too need this bias voltage. If your microphone does not require any bias, then insert a 1uF in series with the microphone. The microphone amplifier is a simple single stage audio amplifier. It does not have any band pass shaping components as the SSB filter ahead will take care of it all. One 0.001uf at the microphone input and another at the modulator output provide bypass for any stray RF pickup.

The two diode balanced modulator has a simple balance control. The attenuator pad at the output was found necessary to properly terminate the diode modulator and keep the carrier leakage around the IF amplifier to a minimum.

Rest of the transmission circuitry is exactly the same as the receiver. There is an extra stage of amplification (Q13) to boost the very low level 7 MHz SSB signal from output of the bandpass filter to 1V level : enough to directly drive a driver stage.

Inductor data

The inductors used on the board as follows:

  • L1, L2, L3 : 6uh, 40 turns on T30-6 core
  • L4 : Only needed the analog VFO, 9uh, 50 turns on T30-6 core
  • L5 : just a jumper on the standard bitx40, you will have to an inductor of a few uh to pull the BFO down for upper-sideband
  • L6, L7 : 1.1 uh, 17 turns on T30-6 core
  • L8 : 10 turns on FT37-43
  • T1,T2,T4,T5,T6,T7 : 10 turns trifilar on FT 37-43 core

The L1,L2,L3,L4 need a wire gauge thin enough for the large number of turns. We use 36swg enamelled copper wire, you can use thinner wire if you have any. The rest of the transformers and inductors have use 28 swg.

Note: The L4 is not required with the Raduino or any other digital VFO. The L5 is needed only if you want to operate USB (to pull the BFO to the lower slope of the crystal filter).