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I have been lacking the ability to operate on the lower HF bands, while my small 'multi-band' OCFD could be used on 40m trying to use it on 80m was nigh on impossible with my ATU. As you would expect even if matched for a useable VSWR the actual performance has been compromised.

I needed a cheap and relatively unobtrusive solution and I found one in Len Paget's (GM0ONX) design for an inverted L. The full details were printed in the Practical Wireless magazine several years ago and PDFs are available for download from Len's website. The designs make use of coaxial traps, one for the 80m version, two if you want to add a top-band (160m) option.

Opting for the smaller 80m version I set about building one. Using an old fibre-glass fishing pole about 5m high at the far end of the garden tucked behind the summer house which I could collapse down and then retract the wire elements when not in use so hiding it from view.

The fun and interesting part was building the trap. They are formed by coiling some coax, in this case RG58, round a former such as plastic waste pipe. I had a bit of scrap pipe but it was 32mm not the 40mm diameter type described in the article, thinking it couldn't make 'that much difference' I built one using the same number of turns but the resultant antenna wasn't anywhere near resonant according to the analyser.

I decided I needed to test the trap's frequency response. I found a YouTube video by Dave Tadlock (KG0ZZ) where he demonstrates using a MFJ 'Grid Dip Meter' adapter on an MFJ antenna analyser to test coaxial traps.

The adapter consists of nothing more than a coil of wire on a suitable former so I made my own to use with my AW07A analyser. It worked a treat and I discovered my trap was way off frequency. In the mean time I had located a useful PDF document by David Reynolds (G3ZPF) which informed me I actually needed 180cm of RG58 round a 32mm pipe to make a suitable 7MHz trap, so I made another.

I made a small video showing the traps and how I tested them.


The resulting antenna seems to perform well, but it does sag a little due to the weight of the trap and wire and the flimsiness of the pole. But I have made a number of contacts on it and used it during the RSGB 80m CC Datamode contest a few weeks back. It was my first go at this contest but once I got the hang of operating it was great fun.


Andrew Garratt, MØNRD, is a regular contributor to AmateurRadio.com and writes from East Midlands, England. Contact him at [email protected].

I have been lacking the ability to operate on the lower HF bands, while my small 'multi-band' OCFD could be used on 40m trying to use it on 80m was nigh on impossible with my ATU. As you would expect even if matched for a useable VSWR the actual performance has been compromised.

I needed a cheap and relatively unobtrusive solution and I found one in Len Paget's (GM0ONX) design for an inverted L. The full details were printed in the Practical Wireless magazine several years ago and PDFs are available for download from Len's website. The designs make use of coaxial traps, one for the 80m version, two if you want to add a top-band (160m) option.

Opting for the smaller 80m version I set about building one. Using an old fibre-glass fishing pole about 5m high at the far end of the garden tucked behind the summer house which I could collapse down and then retract the wire elements when not in use so hiding it from view.

The fun and interesting part was building the trap. They are formed by coiling some coax, in this case RG58, round a former such as plastic waste pipe. I had a bit of scrap pipe but it was 32mm not the 40mm diameter type described in the article, thinking it couldn't make 'that much difference' I built one using the same number of turns but the resultant antenna wasn't anywhere near resonant according to the analyser.

I decided I needed to test the trap's frequency response. I found a YouTube video by Dave Tadlock (KG0ZZ) where he demonstrates using a MFJ 'Grid Dip Meter' adapter on an MFJ antenna analyser to test coaxial traps.

The adapter consists of nothing more than a coil of wire on a suitable former so I made my own to use with my AW07A analyser. It worked a treat and I discovered my trap was way off frequency. In the mean time I had located a useful PDF document by David Reynolds (G3ZPF) which informed me I actually needed 180cm of RG58 round a 32mm pipe to make a suitable 7MHz trap, so I made another.

I made a small video showing the traps and how I tested them.


The resulting antenna seems to perform well, but it does sag a little due to the weight of the trap and wire and the flimsiness of the pole. But I have made a number of contacts on it and used it during the RSGB 80m CC Datamode contest a few weeks back. It was my first go at this contest but once I got the hang of operating it was great fun.


Andrew Garratt, MØNRD, is a regular contributor to AmateurRadio.com and writes from East Midlands, England. Contact him at [email protected].

For those of you who read my BM-800 microphone, G4IZH modification Blog I wrote early April. A UK ebay seller is currently selling the BM800 at a silly price of £6.99 ($10) including UK delivery! These are branded Floureon BM-800 which are the same specification as the 48V ones I have already mentioned, making them ideal for conversion as the details on the link above or for using straight into an audiomixer.

The price proved so irresistable, I decided to purchase another pair and they arrived boxed with all the accessories within a couple of days of clicking the mouse: 





Really the price is so stupid, you could fill the cupboard with a load. If you make a mistake with the mods or a slip with the soldering iron you are not going to end up red faced or feel it on your pocket. The G4IZH project is now really viable for a club, to get your heads together, purchase a shed full and have a modification night.

Link to seller:

(3/7/16) The offer has now ended, so I have removed the sellers link. Hope you got yours? 

* Please note this is a UK seller and I don't know if they ship internationally? I have no connection with this company only to spread you Amateurs with the news.
Steve, G1KQH, is a regular contributor to AmateurRadio.com and writes from England. Contact him at [email protected].

For those of you who read my BM-800 microphone, G4IZH modification Blog I wrote early April. A UK ebay seller is currently selling the BM800 at a silly price of £6.99 ($10) including UK delivery! These are branded Floureon BM-800 and are the same specification as the 48V ones I have already mentioned, making them ideal for conversion as the details on the link above or using straight into an audiomixer.

The price proved so irresistable, I decided to purchase another pair and they arrived boxed with all the accessories within a couple of days of clicking the mouse: 





Really the price is so stupid, you could fill the cupboard with a load. If you make a mistake with the mods or a slip with the soldering iron you are not going to end up red faced or feel it on your pocket. The G4IZH project is now really viable for a club, to get your heads together, purchase a load and have a modification night.

Link to seller here.

* Please note this is a UK seller and I don't know if they ship internationally? I have no connection with this company only to spread you Amateurs with the news.
Steve, G1KQH, is a regular contributor to AmateurRadio.com and writes from England. Contact him at [email protected].

The bike all loaded up

I had Friday off and it was a beautiful sunny day so it was time to take my KX3 out on the trail to see how my new bike/ham radio setup works. My goal today was to see how to fit all I needed and find out what I really don't need to take on my bike and to make sure my antenna setup worked. I wanted to have an enjoyable ride and at the same time have all needed to setup for portable operations on the trail. The antenna was my mono band whip antennas from 10m-40m. I have them in a nice nylon roll up canvas bag I found they fit just perfect on the bikes horizontal support frame. I also have 2 canvas carry bags mounted on the rear of the bike that can be removed. While also loading the side bags I came to the conclusion that less is more! I had to trim down on what I was bringing. First off my KX3 was in a Pelican case and the case has to go as it takes up one side bag Since the KX3 is a trail rugged rig and I have a protective face cover ( from GEMS) for my next trip the KX3 is not going in the Pelican case. I also found the binder I use would not even fit in the side bags so that has to be re-thought out as well. The binder I have now is nice as I put a small metal plate in it for my Palm paddle to secure too via it's base magnets.
After loading up the bike the first thing I found out was the kick stand on the bike would not support the bike and the loaded side bags. It turned out to be a fine balancing act when it

Diamond K400 mount

came time for setup making sure the bike did not tip over. Since the bike is brand new and I told the bike store what I was doing he wanted to see if this bike stand would work as it is lower profile. I was told if it was not doable then to come back and a more robust kick stand will be installed free of charge.
Here is a list of the items I am packing:
KX3-on it's own with no Pelican case
Extra battery just in case- The Tracer battery pack
18 gauge counter poise- only for 20m at this time
Pens, paper and 3x5 cards with programming Kx3 instructions
Headphones- I don't use ear buds as my hearing is not that great and any noise around me tunes out CW.
Trunk lip mount base for antenna- Diamond K400 
Miscellaneous items- antenna connectors, adjustable wrench, tire repair kit for bike, hat, sunglasses and so on.
Lets get to the trail adventure..........I was able to bike to one of my pre picked spots down at the Lake where a nice size picnic table was available. The antenna mount setup worked great on the bikes rear rack which I mounted back at the condo in case there was issues. I attached the counter poise via a male female 14 gauge connectors. The rig setup was straight forward as I have done this many times in the past. I fired up the rig  and I wanted to see at this point if the counter poise was sufficient for a decent SWR and it was. BUT after

The setup

the tuning process had finished and my KX3 display returned it returned with an error message "ERR TXG D=114. Never had I seen this error before on my KX3 but then again Murphy is always close by to make things interesting. I was not able to transmit at all so I was dead in the water........and I was even picking up a G4 station calling CQ! I got the Iphone out and Googled the error code and it came back that possibly a TX gain calibration was needed to be done. That was not a big deal as the Elecraft software utility does this automatically but the rig has to be at home to do this. The trail/ham radio outing had come to a grinding halt but that was just fine as I really accomplished what I set out to do and that was see how things packed up, transported and how the rig operated using the bike to mount the antenna on. Back at home I did the TX gain calibration and the same issue persisted. I went online to the Elecraft reflector and was advised that it may be my internal AA batteries were low. They were just charged I thought.........Julie informed me it was about 3 months ago that happened. I

The surprise error code

charged the unit and all is well. So today it's another great day and it's off to the trails again to hopefully make a contact or two.    
Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

Amateur Radio Weekly is curated by Cale Mooth K4HCK. Sign up free to receive ham radio's most relevant news, projects, technology and events by e-mail each week at http://www.hamweekly.com.

Reports from Dayton are that Kenwood has a D-STAR tri-band handheld under glass in the booth, along with colorful brochures. None of my sources are reporting on price or availability, and the documents all show “Tentative”. Never the less, this news along with the development going on within the dv4 group are pretty exciting!

Kenwood APRS DStar ! @hamradio360 #hv2016live #dstar @kenwoodhamradio pic.twitter.com/vLNrdATtb4

— KF7IJZ (@KF7IJZ) May 20, 2016

UPDATE: Tom KJ9P on the ground in Dayton reports that the model name and number haven’t been published yet, but it should be available by year end with an MSRP between $500 and $700.

I also had a D-STAR conversation with Tony N8NNX as he was walking the floor at Hamvention regarding the dv4mobile product. His inquires came back also with a 2016 availability date and prices between $800 and $1000.

Michael Brown, KG9DW, is a regular contributor to AmateurRadio.com and writes from Illinois, USA. Contact him at [email protected].