DVB-T Dongle SDR Radio activation

On the 26 Feb I wrote that I had ordered a DVB-T Dongle in order to try out this dongle as an SDR radio as suggested in a QST article entitled 'Cheap and Easy SDR' in QST January 2013 page 31. This using the Realtek RTL2832U and Elonics tuner.

Yesterday I received the dongle and am delighted to report that I had it operational using the SDR# Software Radio App and associated custom drivers after about 30 minutes of starting to configure the drivers and software radio. I followed the directions in QST without hitch. I am not a software guru so this is saying something! I attached a wire to the dongle and immediately was able to receive local FM stations loud and clear!

Here are the steps I followed and articulated in 'software config for dummies' kind of language.

FOR WINDOWS 7 PC's/laptops. Sound card working and volume turned up.

1. Download the install script from sdrsharp.com/downloads/sdr-install.zip into the Windows download folder. Move the zip folder (SDR-install.zip) to the desktop and open it.
2. Open the SDR-install folder and extract the httpget.exe, install.bat, and unzip.exe to your desktop.
3. Double click on the install icon on your desktop and you will see the install taking place. Give it time and after a while it will say 'install successful'
4. Delete the install files (ref 2,3 above) from your desktop since you will not need them any longer.
5. Look around on the desktop for a new folder now on your desktop called SDRSharp.
6. Open SDRSharp and scroll down until you see an icon called ZADIG
7. Plug in the dongle to a spare USB port
8. Double click on ZADIG to open it
9. In the window that appears you should see a box with 'Bulk-In, Interface (Interface 1) shown'
10. Click on the 'install driver' box and give it a bit of time. Eventually you will see a 'driver installed successfully' box appear. This is all good. Close the window.
11. Open the Device manager view in Control Panel.
12. Look down the list and you should see something called LibUSB. Under this 
1. Bulk - In, Interface (Interface 0)
2. Bulk - In, Interface (Interface 1)
13. Close the Device manager since the above indicates that the drivers have been installed successfully.
14. Open the SDRSharp folder (it may already be open). Scroll down until you see an 'EggBeater' icon. This is the executable. Double click on this exec to run SDRSharp.
15. You should now see the GUI for SDRsharp appear. This is good!
16. Press the config button and select the SDR radio called RTL-SDR/USB from a list of supported SDR radios.
17. Click WFM (wideband FM)
18. Stick a piece of random wire a few feet long into the dongle antenna PAL socket
19. Press PLAY and presto your world will light up with the sound of static coming through the laptop speakers.
20. Click on a signal and the static will turn to music! Well done!
21. Now fool around to your hearts content with the settings.
22. Go to tinyurl.com/blsg2or and look around for a manual on SDR# written by W9RAN.

If the above sequence does not work for you then please refer to the QST article where much more detail is given.

I really am enjoying my first exploits into the world of SDR Radio. Now I need a decent antenna.

Dongle from EZCAP. DVB-T FM DAB

SDR on the cheap. Showing SDRSharp + Dongle + Test Antenna

EFHW field test idea & tuning an EFHW

I am recording here an email I received from Monk ZS4SF who is in Welkom and a keen cw op on 40meters and my response:

"Hello Dick ,

Thanks  for  the  mail.  Thought  I  would let you know that I will be monitoring  the freq. on 40 meters on Sat.and Sun. mornings. I have put together  a  small fm tx that I plug into the hf rec.( ear socket )and tx  into  the  house.  RX on a portable fm receiver. On Sundays I will monitor only until 1 PM.

Okay  on  the efhw antenna, the day we worked I was using full power (100  watts,  but  even with 1 watt the chaps in Durban and Jhb give me over  the  9  reports.  I  would  love  to  build a qrp rig that I can attenuate  down  to 50Mw and less. I have the circuit for it but can't obtain the toroids in this country.

Do  you  cut  your  efhw  for the lowest freq. and then tune the other bands  ?  This  I  have  not tried.  In your blog you mention that you touch the rig and observe the swr to see if you have any rf around. I  have found that this does not really work.You must grab the coax at a  voltage  point. I have my wife run her hand up the coax while I key and look at the meter. With Qrp I don't think it matters.

CU on the band

Regards.

Monk

Hi Monk,

many thanks for the response and very excellent on the monitoring project.

Yes I heard you qso with Andy ZS6ADY last sunday morning on this initiative to monitor the 7020Khz freq. I can tell you that I don't have a set up here at the apartment (yet) but any chance I can get to take a walk in the park and set up I will definitely do it. 

I am very interested in trying some experiments using the efhw. I reckon it may be very value-add to those interested in field operations. Here is the idea I had in a nutshell:

I would set up my ZS6TJS 7metre high mast at suitable locations around Region 6 in the clear. I would then erect an efhw on 7020KHz to the full mast height (7m) with the wire broadside to the receiving station (for example ZS4SF...) then transmit at 5W, 500mW and 50mW cw signal. Obtain signal reports. I would then lower the efhw to 4m and obtain signal reports. Then lower it to 2m and obtain signal reports for the 3 power levels. Then I would orient the efhw so that it is pointing straight at the receiving station and then repeat the tests.

Repeat the above tests a few times during the day. Say 7am, 11am, 2pm and 4pm.   Then if it yields interesting results I could try different locations and path lengths over the course of time.

The objective of such a test would be to see what the limits on height, power per time of day/year on 40meters are for field stations in region 6 South Africa. Of course one could go crazy and do it for different frequencies. Night tests would be really interesting..... One could also try different configurations. I find that invariably here I am sitting under a tree and have the wire strung across to another tree. So I am mostly in practice using an inverted L type config. This seems to work very well.

Do you think this type of experiment would be interesting? Perhaps it has all been done before? 

Ok on the need for a small QRP rig and agreed 100% on the need for 50mW for the reasons shown above. Please let me know what parts you need? I will be able to get them from W Land for you no problem. I have people coming across from the USA from time to time who can carry a small bag of stuff. In fact I may also join you and build one of these rigs. Must have a built in attenuator. Can be rockbound on 7020KHz for this purpose. Let me know and I will work with you on this one.

Interesting on the efhw and the voltage point. In practice I really only use a very short piece of coax to connect the tuner to the rig. I suppose I had assumed that by touching anywhere there I was in fact at a voltage point. I will definitely try to connect a long piece of coax and see the effect of touching at different points.

Here is the way I tune the efhw if I really want to do it 'properly and according to the book'. First I connect a 5K resistor across the tuner (link coupled parallel circuit). I then tweek the capacitor to minimum swr dip. Then I disconnect the 5K resistor and connect the efhw to the tuner and tweek the length of the wire until I achieve minimum SWR.  

In practice I have realized that there are several flaws with this method. The most obvious is that the literature stated impedance of 5Kohms at the end of the wire is not the case in practice since the lower-end is likely coupling to surrounding objects.... I have experimented with raising and lowering the fed-end closer and nearer the ground and have noticed significant differences in the resonant point etc. This is why I am a bit curious regarding the use of a fixed component tuner in the field such as the PAR END FEDZ. How much does the SWR vary? There is huge room for experimentation in this area.  In practice I simply sling a 66 foot piece of wire into a nearby tree and tweek the parallel tuned circuit for minimum SWR. Seems to work FB. Seems to work far better here than at my home QTH in the USA where the soil is clay and verticals are not popular. There I get reports of deep QSB and a few s points inferior to a field dipole. Here in SA the signal level seems to hold much steadier. Why is this?

Yes as you mention below I have tried to tune a 66 foot piece of wire for operation on 20m and 15m and 10m using the same tuner. Obviously now it is not behaving as an efhw. I am able to get a resonant point on those bands. However not surprisingly the SWR is now not 1:1 as per 40m since the turns ratio for the link coupling has not been changed. I have not recorded the SWR but I am able to use my internal K2 Elecraft ATU to obtain a 1:1. What I have not tried is to use an efhw on these higher bands with the same tuner. I imagine it would work but would not be matched optimally.

  Many thanks Monk for your comments and questions. I can tell that this subject is of interest to you. Thanks for setting up the FM TX. Sounds like fun! I will be sure to be one of the regular call ins. 

73 Dick 

The 5K calibration resistor can be seen near the blue efhw wire

A simple parallel tuned circuit designed to load into 5kohms

River Cottage at Malelane Mpumulanga

I started writing this blog while sitting under an acacia tree at the river lodge in Malelane on the southern border of the Kruger National Park. Berry and I plus Chaiya (we  have been here since Thursday lunch time). Really a pleasant spot. Of note we saw four rhino, a huge croc, a lone buffalo and three hippos out tussling on the bank. All this from the comfort of the front lawn at river cottage. No driving. We stayed in a small self catering cottage, number 14. This was the last available by the time we booked and is not the best at river cottage. Now we are back in Jozi and relaxing before the start of another week.
I was able to set up a 40m dipole at about 6 meters high in the center and strung between a palm tree and a mango tree. It was tough getting the launch rope to slide over the palm tree branch since it is quite 'sticky'. The good news about palm trees is that you can get the wire in the clear. The bad news is their roughness. I experimented yesterday with 40m, 20m, 15m and 10m dipoles facing E-W. 15m was the best although I was unable to make any QSO's. My dipole was definitely working and was directional. India and Indonesian stations broadside on were S9, however Europe was just above the noise for me. I was surprised to find 20m very noisy in the evening. I believe it was local QRM.
On Saturday morning I called CQ on 7020KHz and was able to have two excellent rag chews with John ZS6JBJ in Witbank and Monk ZS4SF in Welkom. Both gave me 579/599 reports. Monk came on at about 7am local and indicated that the band was just opening to him. I was able to copy John at 599 with no problem on his QRP signal. Monk kindly sent me an email and pic showing his EFHW on 10m. He is simply using a small length of coax to provide the needed capacitance for resonance with a toroid wound coil on 10m.
On Saturday afternoon I did not show up for the net due to us being in the middle of a wonderful piri piri chicken braai with our friends, however today Sunday I called CQ at about 8am and was able to enjoy an excellent regchew with Andy ZS6ADY in Benoni. Andy gave me a 599+ report with a bit of QSB. I was really delighted by this. Not bad for a 430km distance. I now have high confidence in my ability to QSO using QRP and my EFHW throughout ZS6 region albeit perhaps an S point down on a traditional dipole.

Observations from this trip:

1. I can  deploy an EFHW on 40m during daylight hours QRP with a high degree of confidence that I will make a QSO.
2. Persistence calling CQ on 7020Khz in the mornings over the weekend will eventually pay off although there seems to only be a small group of enthusiasts on this CW frequency.
3. Try building EFHW's for all bands. 
4. Use more slippery cord for the antenna launcher. When launching up to 30foot a longer launch cord is needed.
5. Next trip book room 3 or the large boma cottage. Better trees there than room 14.
6. If you start a braai at noon then likely you will not make it to the 2pm AWA net hi hi.

Buffalo & croc. Crocodile river Malelane opposite river cottage

Friends and a braai, river cottage Malelane

The deck restaurant Malelane

My radio gear packed for this trip

Moxon Measurements & Adjustments

I wanted to understand how sensitive the Moxon is to wire size and frequency in terms of it's physical elements. I also wanted to adjust my prototype moxon to resonate within the 10m band which it is not currently doing.

I set up a test system in my front yard for this purpose. The antenna was located about 2.3metres off the ground which is roughly a quarter wavelength at 10m. It  i snot a perfect environment since the antenna is about 1.5meters from nearby walls and foliage. However I noted that the resonant frequency was about the same as what I had observed in the field.

The following measurements were obtained using my SWR meter built into the K2 and about 500mW of power:

F (MHz)     SWR

27.6            2.3

27.7            2.0

27.8            1.8

27.9            1.8 

28.0            1.8

28.1            1.9

28.2            2.0

28.3            2.1

As expected at this low height, the SWR is somewhat high but the Fo should be about correct at around 27.9MHz. At this height I have a 2:1 bandwidth of 300KHz. This should increase as I raise the antenna in a field deployment.

 Ok so how do I raise the resonant frequency to the target frequency of 28.2MHz? The design frequency for this moxon was in fact 28.2MHz using dimensions derived from the Moxon calculator by AC6LA. So I have a difference between actual resonant frequency and theoretical resonant frequency of 28.2-27.9 = 300KHz.

So if I input 28.2+0.3 = 28.5 into the calculator as my theoretical frequency than I should see the desired frequency of 28.2MHz in the field?

This yields the following dimensions from the calculator: (28.5MHz, 1mm diameter wire)

A: Rectangle long side long side = 3834mm

B: Driven Element short side = 583.8mm   

C: Between Element gap = 97.7mm  

D: Reflector short side = 712.8mm

E: Rectangle short side = 1394.2mm  

On retest at these new measurements I found that the Fo was about the same which was a big surprise. I did notice that the SWR varied from 1.8 to 1.6 depending upon the direction of the antenna leading me to think that there is more interaction than I had at first thought between the environment and the antenna. Dealing with this solid strand wire is a pain since it breaks all the time. Next I will rebuild the moxin using stranded wire.
-----------------------------------

The Moxon Antenna Project
Sensitivity analysis
Date: 3/17/2013
Author: R Hayter, ZS6RSH
Tool: The Moxon Triangle Generator by AC6LA
Wire size sensitivity
		Rectangle dimensions (mm)
F  (MHz)	Wire size (mm)	A	B	C	D	E
28.3	1.5	3855.9	581.5	104.9	719.7	1406.1
28.3	0.5	3868.9	595.9	89.6	714.6	1400.1
	0.5-1.5 =	13	14.4	-15.3	-5.1	-6
	% difference	0.3%	2.4%	-17.1%	-0.7%	-0.4%
A: Rectangle long side
B: Driven Element short side
C: Between Element gap
D: Reflector short side
E: Rectangle short side
Frequency Sensitivity
		Rectangle dimensions (mm)
F (MHz)	Wire size (mm)	A	B	C	D	E
28	0.75	3906.1	598.2	95.1	724.1	1417.5
29.4	0.75	3719.6	569.2	91.2	689.8	1350.2
-1.4	0	186.5	29	3.9	34.3	67.3
-5.0%	0.0%	4.8%	4.8%	4.1%	4.7%	4.7%

Moxon hub using 20mm PVC

Test bed in the garden. 2.3 meters high.

Cedar Lakes ZS0AWA net

I took a one kilometre walk down to the upper lake here in the Cedar Lakes property. A beautiful afternoon. Unfortunately kids were sitting at the picnic table I had earlier planned to use. I found a nearby tree and deployed the EFHW into a tree about 3 meters high. I then strung the wire over a branch and down to a spot at the bottom of the tree. Total deployment time was about 10 minutes.
The net was run by Andy ZS6ADY. QRV at 14:00hrs local. Also checked in was ZS6AJY Om Barrie. Barrie had problems copying me due to QSB. Both gave me a 559 signal report. My Antenna was working but not great. I enjoyed the net and ragchew with Andy lasting for about an hour. I also heard ZS1TTJ in CT and ZS3AOR slightly up the band. Their signals were down.
This trip I was able to carry all my gear in the K2 carrying case. But still room for improvement for sure.
Observations this trip:

1. Be prepared to deploy in a place where you had not planned to. Take a towel to sit on.
2. Even with the wire only 3 meters up I was still able to QSO in the net albeit with QSB

Upper lake deployment site @ Cedar Lakes, Fourways 

Saamrus Magaliesberg 'Piet-my-Vrou' 

Saamrus between mountains. Not good for radio!

Berry, our dog Chaiya and I spent a wonderful weekend at Saamrus, a guest farm nestled in the beautiful Magaliesberg area and only about an hour from our apartment in Fourways. The main attraction here being the fact that it is dog friendly, a huge plus for us, especially Chaiya. The road access was terrible to say the least. We kept touching down in our very low Toyota Corolla. I wished that I had a higher clearance vehicle for this trip. Our bags plus my radio gear, minus the moxon were man-carried the last 100m up a steep 4 wheel drive only road. The cottage, called  Piet my Vrou after a popular local bird, was beautiful. Very peaceful among nice shady trees. Extremely clean, neat and nearly new.
On friday evening I was able to erect an EFHW about 5 meters off an extremely steep slope behind the cottage. Upon orienting myself using my BB compass I was disappointed to see that mountains to the north behind the cottage and the Magaliesberg would completely block the path to Europe.
During the evening nothing heard and a lot of noise on all bands except a few stations on 40m in the noise. I tried connecting the EFHW tuner to the fence via a short lead but no real difference.
The next morning I was up early and was surprised to note that 40meters sounded better. I deployed a 40m dipole up about 10m and facing N-S. This involved a lot of scrambling around in dense bush, getting tangled on small aloe bushes and generally falling and stumbling over the steep rocky ground. Not fun and dangerous. But it sure was good practice for field operations! Since this was a new antenna I had to take it up and down to trim it to resonance. I noted about 1s unit improvement between the EFHW and the dipole for near in stations with a definite noticeable improvement in the dipole for Region 1 and 5 stations in the Cape and Natal. At around 8am I was able to QSO with om John in Witbank ZS6JBJ. John gave me a 579 report improving to 599. He was unable to hear any difference between the two antennas. I then had a nice chat with Andy ZS6ADY in Benoni and Pierre ZS6A also in Benoni. They both gave me a 599 report and Pierre noted a slightly better signal on the dipole. The results interested me and I assumed that the EFHW is a good antenna for NVIS work and is adequate for local contacts within Region 6 Gauteng, NW and Mapumulanga areas. I also assume that I was getting some benefit from the extreme slope behind the EFHW for propagation towards the south.
After a stiff and enjoyable 3 hour walk I was back on the air for the AWA net at 2 pm running 2 watts. The following stations checked into the net ZS0AWA/ZS6ADY, ZS5DM, ZS5CQD, ZS6AJY, ZS6JBJ. All stations in region 6 had no problem copying my 2watts. However the region 5 stations were having some difficulty. They were also experiencing heavy QRN at the time in Natal.
Later in the afternoon I erected a 15m dipole facing N-S. I was amazed at the difference between this antenna and my long wire (20meters). I could hear no stations on the long wire. On the dipole the band came alive although the signals were weak from Europe. No doubt due to the mountains blocking the low angle signals. It was very frustrating hearing all the G land stations on the air and participating in the BERA contest but they were barely above the noise. My log for BERA (Commonwealth contest) stations worked was as follows (UTC).
15:14 7Q7BP 599 599 177 15m 001 Malawi
15:20 5X1XA 599 599 214 15m 002 Uganda
16:27 5H3EE 599 599 285 15m 003 Tanzania
16:52 9X0NH 599 599 244 20m 004 Rwanda
04:05 5H3EE 599 599 585 20m 005 Tanzania
04:28 9J2BO 599 599 360 40m 006 Zambia
I am certain that given a better QTH that I would have been able to contact the UK and also the many Canada and Indian stations calling. Clearly I had  continental communications into East Africa.
My 15meter and 20meter dipoles also performed well. These were all antennas built in a hurry for this trip.
I could also hear that 10m was well opened and I kicked myself for not having a 10m dipole with me. I did contemplate shortening the 15m dipole but I ran out of time. Propagation appeared to be good with the SFI above 110. However the A index was high and thus the noise level was too high for good QRP conditions.
On Sunday morning I was on 20m by 6am local and worked 5H3EE before the band closed. I then deployed my 40m dipole and was surprised to hear the path to North America wide open. I believe I was copying via long path since there was flutter and echo on the signals. I am sure that I could have worked some of the big guns if I had been on top of the mountain. Once the band went short I called CQ for an hour between 7am and 8am local with no response. I guess Sunday morning is not the time for 40m CW in SA?
During our walk on Saturday we walked to the topmost point on the farm mountain. From there we could clearly see the Magaliesberg to the north and the Witwatersberg to the south. We scouted the area and found a good spot where I could deploy a field station in the future. However no tall skyhooks are up there. Still I reckon a low dipole would work given the clear take off in every direction. I need to look at a topo map of the area to see what the altitude difference is between the Magaliesberg and where we were at Saamrus.

Lessons and observations from this trip:

1. Get a topo map of the area
2. Re build the 20m and 15m antennas to strengthen the connection to the feeder hub
3. Build a 10m dipole
4. Buy more thin 'lacing cord' from Builders Hardware and build a new and better antenna launcher. This cord is nice and slippery and extremely light weight.
5. Remember the back pack!

Berry and I will definitely return to Saamrus. Recommended for all dog lovers who have social dogs. The end of another enjoyable adventure!

Berry and Chaiya taking a break

A picture of fitness and good looks :)

Berry and Chaiya with a beautiful stone fence post. (Note the  lichen).

A view of the 40m dipole and the cottage Piet-my-Vrou

Piet-my-Vrou from the steep hill where the EFHW was deployed

Far too many wires and too few QSOs!

Big Guns on 10m ARRL Intl. DX  cw contest

Below is a record of some of the stations I was able to work during the recent ARRL International DX cw contest. See my blog of this contest on Feb 16th and 17th 2013.

I obtained this information from the station descriptions found on QRZ.COM. Of course, I cannot verify exactly which antenna systems were used for my contacts with these stations.

K3OO (PA) - 10m beam on 45foot boom at 46feet agl.
K3LR (PA) - 10m 4 square and beam at 200feet agl.
K1RX (NH) - 10m 6 ele rotaryy at 32 meters agl, 10m 5 over 5 at 27 meters agl.
N8AA (OH) - 70feet agl - 4 full size elements on 10m.
N1UR (VT) - 10m 6ele KLM yagi on 26ft boom at 72 feet agl stacked over a homebrew 5 ele on 24 foot boom fixed NE. A 4 ele yagi on 20 ft boom South. 3 Homebrew, 5 ele yagis on a 70 ft tower -- each yagi can be rotated. An array of 2X5 elements plus some others.
K4RO (TN) - PRO 57 antennas, 7 ele on a 24ft boom at 60 ft and at 97 ft agl.
K3AJ (MD) - 3 ele Steppr at 50 ft agl.

This impressive list is humbling to say the least. Only the very biggest stations operated by top operators were able to work my station. Sometimes I forget who is doing the hard work in DX QRP contacts.

Cedar Lakes Gauteng end-fed-half-wave (efhw)

At 13:30 local, I walked out from our apartment a distance of about 500 metres to the upper corner of our Cedar Lakes gated community. There I located a nice tree to sit under which was right under the electric fence. Well lets see what I can hear! My Inventory for this trip consisted of the following:

1. Small backpack
2. K2 with internal battery, carried in purpose built case
3. mini-Palm paddles
4. 7.020Khz (20.32m) long 0.5mm pvc covered wire
5. EFHW antenna tuner
6. Coax connector from K2 to tuner
7. Antenna launcher consisting of a 10m long cord tied to a yogurt bottle filled with sand.
8. Leatherman
9. Earplugs
10. Electrical tape
11. Waterbottle
12. Notebook and pen
13. Hat (on my head)

Using my sand filled yogurt bottle antenna launcher, I was able to get my EFHW up into the tree about 8 metres after two throws. I then strung the wire across to a branch in my shade tree up about 2.5 metres and routed it down to the tuner which was sitting on the ground near the radio. After setting up the K2 and bypassing the internal ATU I was able to tune the wire to an SWR of 1:1 with ease using the efhw little tuner and about 400mW. Based on the marked spot on the tuner dial I could see that the system was operating correctly and there was no noticeable coupling to surrounding objects. I then touched the K2 chassis and noted no change in SWR. I figured that a counterpoise (other than the chassis and metre long connecting cable) was unnecessary. This antenna loves it when the rig is on the ground. I was QRV after a 15 minute set up time and turned the power up to 5 watts. I immediately heard ZS4SFon 7020KHz. I called om Monk in Welkom FS and had a wonderful 40 minute rag chew with him. We QSY'd down to 7015KHz due to a net starting up at 14:00hrs. He gave me a solid 599 report and he was 599+20dB. I was absolutely amazed at how good this efhw worked. I could hear the electric fence but was able to eliminate the QRM completely by using my noise blanker on setting 2. The wx was looking threatening so I packed up after making a few CQ's with no answer and walked the 500m back to the apartment. I reckoned this trip was a great success and I look forward to more QSO's with Monk in the future. It sure was nice to do a bit of qrp/field/cw on a lazy saturday afternoon!

Improvement opportunities:

Cerdar Lakes, Fourways, behind our apartment

1. I need a cw rig for 40m with built-in batteries. 2 watts. Rockbound on 7020khz.
2. Built in LED type swr meter in the tuner altoids tin.
3. The efhw wire can be much smaller gauge
4. Use a fishing weight as the launcher
5. Get a miniature notebook
6. Use smaller coax for the feeder line.
7. Try to tune the EFHW using the built in K2 tuner (however I will be surprised if it works since the EFHW exhibits an end impedance of about 5kohms??
8. A small towel to sit on to prevent 'ants in my pants!' 

40m EFHW + Antenna launcher. Too bulky!

EFHW tuner showing expected tune mark on 40meters

EFHW tuner. A parallel tuned circuit with 5K to 50 ohm transformer

 

DIPOLE LENGTHS MHZ - METRES

Ref: http://www.csgnetwork.com/antennaedcalc.html

28.060 - 5.084
28.250 - 5.049
21.060 - 6.773
21.150 - 6.745
14.060 - 10.146
14.150 - 10.081
7.0300 - 20.291
7.0200 - 20.320
7.1000 - 20.091
3.5600 - 40.069
3.7000 - 38.553