Pan adapter for Elecraft K2 04/20/2012
My Elecraft K2 hasn’t seen the use that it really warrants since I bought it several years ago. With field day approaching in June and the revised rules allowing SDRs and skimmer I thought I would dust it off and try to finally get my software panadapter working. The set up is fairly simple. A K2 with Z10000 buffer board is attached to a cross country wireless SDR which has been re crystalled for 4.9125MHz. I am using an E-MU 0202 USB soundcard with the SDR, but as my PC is quite limited, I plan to only use it to read 48KHz of spectrum. From a software point of view I would like to run N1MM as my contest logger as well as skimmer and possibly NAP3 as a panadapter. This clearly put some real pressure on COM port usage, as all of those bits of software need access to the K2’s COM port. Fortunately, N8LP has developed LP-Bridge (LPB2) that handles all of this and I am trying to integrate all of this kit together using the information on Larry’s website. The problem I have now is that it only partially works. Larry’s documentation suggests that one should use Kenwood mode in NAP3 to connect to LPB2 on com port 99. This is where my first problem arises; there is neither com port 99 nor a generic Kenwood setting in NAP3, even when NAP3 is opened first as Larry has suggested to others on the LP-Pan forum. However, if I close LPB2 and choose Elecraft K2 in NAP3 with the appropriate com port (6 in my case) then I can connect to the radio and NAP3 tracks my VFOs no problem. Similarly, in Skimmer, if I choose IF mode, then Elecraft K2 in the CAT tab, then skimmer connects to the radio and tracks the VFO. The problem here is that I still haven’t told skimmer what my IF out frequency is so I don’t know if that is the correct way to do things. So a partial success? Clearly I need to get LPB2 working so that I can skim and contest log at the same time. The next issue is that I have a huge spike in the panadapter and skimmer waterfall. I thought the Z10000 should be taking this out? Or have I told NAP3 the wrong IF frequency? Add Comment Free amplifier parts 04/09/2012
I am sorting out my gear and have two old amplifiers available free to a good home, provided you collect from north London. Both are for 144MHz and are for single 4CX250s. There are two sets of PSU parts, a changeover relay and one blower. One was given to me by a club mate, so is of amateur construction. The other I bought for parts at a rally years ago and is nicely made in a blue case. I was told it was made as a project by apprentices at Marconi, but have no way to verify that. If anyone needs a used valve or two for the project I can raid my box - but you can't have them all. Please contact me by email to arrange collection from North London. Here are some pictures taken in my loft (where the amps have been for almost 6 years - hence the dust!) using my iphone, so excuse the poor picture quality: 
More tropo 03/17/2012
After watching the cluster on and off at work, I realized that the tropo had extended into a second day, but moving more to the South. After doing my domestic jobs at home I got back on the bands, this time looking at 2m. There were plenty of DLs around at 600Km and I spent a bit of time on the key, yielding two OKs both in a new square (#183). My 2m QSOs are mapped below. 
I also spent some time on 70cm, but didn’t hear much. I CQ’d for about 20 minutes but only worked DB6NT in JO50 with his typical rock crunching signal. Tropo on 432MHz 03/13/2012
There has been some high pressure over the UK for the last few days and I suspected that this evening's 432 UKAC would be blessed with some good conditions. I wasn't wrong and managed to work several OZs and one SM. Pretty good going as my amp isn't working right now so I had 50W and mmy 18 element yagi. GU6EFB and MW6OXO were both active from squares that would be new for me on 70cm, but nothing was heard from either of them - they are my worst directions! I did work the following stations though 13/03/2012 21:05 SK7MW JO65MJ 59 10 559 140 70 cm. SSB 963Km 13/03/2012 21:01 OZ9KY JO45VX 59 9 57 144 70 cm. SSB 808Km 13/03/2012 20:58 OZ9PZ JO46LC 53 8 53 64 70 cm. SSB 773Km 13/03/2012 20:45 OZ1DLD/P JO45SK 55 1 56 88 70 cm. SSB 764Km 13/03/2012 22:04 F8BRK IN99VF 55 17 57 102 70 cm. SSB 269Km were my best QSOs... Let's hope there is more to come Parallel dipole build 02/09/2012
I have tried a number of multiband wire antennas at GB2GP over the last year and have never been really happy with the results. The current antenna is a 1/3 2/3 split OCF dipole, which seems to work but still causes me a few problems. The main issue is that there is huge BCB breakthrough from Brookmans Park which is in LOS, so I am using a high pass filter at the transceiver to reduce this to a reasonable level. The filter is designed for 50 ohm impedance and the OCF is no where near that on all bands and even though the radio ATU can tune out any mismatch we toasted one of the filter torroids during JOTA due to the mismatch. The answer seems to be to use a resonant antenna for each band of interest. One of my neighbors, G0RPM, has had good results with a parallel dipole made by Alpha Delta. I called the UK importer Martin Lynch to enquire about these and was told by an unhelpful person they were out of stock and didn’t know when they would get any more in. As a result I have decided to stop being lazy and build one! The plan is to have an antenna for the 80-10m contest bands. This means four dipoles, 80m, 40m (which also works on 15m), 20m and 10m which I measured out in my hall from wire I had knocking about in my store. 
Measuring dipole wires
The next job was to build some spacers for the elements. A search on google suggests the spacing should be wide as possible to make tuning easier. I have a miniVNA which should simplify tuning so I decided to use only 75mm between wires. I picked up a length of PVC pipe from my local hardware shop cut it into pieces then 3mm drilled holes in my workshop (aka the kitchen). 
Spacers cut and ready to drill
Feeding the wires through the holes was a simple job, but securing the spacers was more difficult. I tried hot melt glue, which was partially successful, but ended up using cable ties to produce my ladder effect. I had a spare commercial 1:1 balun which I put at the feed point and the antenna is ready to go in the air. Hopefully, installation will be an easy job, but I hope that I don‘t get too cold trying to tune the thing as the temperature here is not predicted to rise above freezing for a few days. Chinese desk microphone 02/07/2012
I usually use either a fist microphone or a headset when on the air, but my recent experiences at GB2GP have shown me that a desk microphone is useful when operating a special event station as it is easier for visitors to use on the air. GB2GP has two radios that don’t have microphones at the moment so I looked into building a couple of electret gooseneck desk mics from the ARRL handbook. Once I had costed up some parts that weren’t in my junk box this project felt too expensive until I saw PC desk mics on ebay for only £2 each. At that price I bought a couple and they arrived this morning. The external quality looked just fine - so far so good 
Like any good radio amateur, the first thing I did was take one apart to see how I could add a PTT. As expected the quality inside was only worth £2, but the thing that really surprised me was the bag of grit that had been inserted to add weight to the base! 
I guess it works, so why not stick with it, but I will be sealing the bag as I spilt half the contents on the floor when I tried to take it out of the microphone! Next job is to change the flex to some 4 core and add an 8 pin microphone so they can be used with the TS-711 and TS-690S at GB2GP which shouldn’t take long. Gilwell install 02/07/2012
Here are a few old photos of the team installing the radio cabinet at GB2GP. FIrst of all te antennas on the mast  Then the LDF5-50 run entering the LID building  30m of LDF 5-50 (for each of three antennas) runs inside the LID store room from the entry point to the celing over the radio cabinet. We installed cable tray to hold the weight of the run  Finally the radio cabinet after fitting with Frank, M0AEU testing things out.  At a loss 01/17/2011
At a loss I haven’t blogged for a while – mainly because I have been too busy building stuff to write anything down. The main focus of my activity has been rebuilding kit to install at Gilwell Park, the Scouts Association’s HQ which holds the special call sign GB2GP. I will write about antennas another day, but I have been rather stumped by some recent measurements I have made on co-ax runs. The main coax runs at GB2GP will be Andrew Heliax LDF5-50 which is great news. 5-50 is a rigid cable so you have to use a loop of flexible cable around the rotator and other joints. As a result I bought some Ecoflex 10 from Terry at Diode Communications to do that job. It isn’t cheap, but has a good price:loss ratio! Terry did a great job in rushing the cable to me in bad weather at his end and I made up three lengths to go from the antenna feed point, down the boom (where required), round the rotator and then to the main 5-50 run. These lengths were 13m, 11m and 2m. The antennas are being fitted on a commercial tower by professional riggers so I wanted to make sure the cable assemblies were perfect as there is no second chance to fix mistakes. Using mini db calculator I estimated the losses on the highest frequency that it would be used on and compared them to the losses measured using both my mini VNA and calculated from power read using a Bird 43 wattmeter. The table below shows the losses for each bit of cable (db) and one major issue:
0.86db loss from a 3m length of cable! Shocking! This was the only cable that used a PL259,so I immediately suspected this to be the problem. I called Henry Westlake and ordered some pressure fit PL259s to ensure that the braid was properly installed, but this made no difference at all. I then wondered if the co-ax itself was not to spec and tested all of the runs on 432MHz as this could highlight any problems:
I am prepared to accept 0.2db variations from spec I had to use some inter series adapters and I am not using calibrated measurement gear, but it looks like I have a problem with that short run. If the PL259 is good, then the N-type at the other end must be the problem! What else can it be? I am at a loss….. More new squares 10/12/2010
Some more tropo last night, so I spent time on 432 again looking for new stuff, but there wasn’t much around that I hadn’t worked before. I did manage a few OZs and DLs, but didn’t want to make too much noise with my little boy in bed. I had been hanging out on the ON4KST message system earlier in the day and during a chat with Martin GM6VXB he kindly agreed that we could try a sked if conditions looked promising. Around 9.30pm I stuck the antenna to the north and found the GB3ANG beacon at 559 – the first time I have heard it on 432. Back on KST Martin was good to his word and we had a quick QSO on 70cm followed by a more difficult one on 2m. A GM shouldn’t be a big deal, but Martin is in IO97aq and as the picture below shows, there isn’t much land in IO97 for a station to sit in!  So, Martin, thanks a lot for looking for me – IO97 was new on two bands. More to come in the 432 UKAC contest tonight? Tropo opening 10/11/2010
The weather here has been fine and dry over the weekend suggesting that we were under a high pressure weather system. High pressure can mean tropo openings on the VHF bands and a quick look at the Hepburn forecast on Friday suggested that there could be some fun ahead.  I realised that the radio station was untested since I changed from PLT to a wifi bridge between the operating position and radio shack, so I spent an hour on Saturday making sure everything worked and also reinstalled the amplifiers following VHF NFD (which was only 3 months ago!). Luckily for me most of the system worked first time and I only had to spend a few minutes with the soldering iron. I didn’t hear much activity on Saturday, but on Sunday morning 144MHz started to open between Northern G/GM and Northern Europe (SM/SP/DL) and by dusk I too had propagation. There wasn’t much new for me on 2m, so I concentrated on 432MHz, working 8 stations in SM, OZ, DL and SP.  ODX was SP1NQN at 1186Km, with four other contacts over 1000Km. I did briefly hear LY2WR at 1664Km, but he wasn’t strong enough with me for a QSO. It looks like there is a day or two of high pressure left so let’s hope for some more! | AuthorA few notes on recent radio activity by Steve, M0BPQ. ArchivesApril 2012 CategoriesAll | ||||||||||||||||||||||||||||||||||||
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