Magnetic Antenna Mounts - The Correct Installation | HAM RADIO

And don't forget it is on the roof, then drive into a multi-storey park or under a height barrrier - it makes one heck of a racket! 🙂

As someone new to the hobby and who has been struggling to tune my HF antennas on the roof of my (steel) narrowboat, this has been really, really useful and a few things to try! Thanks very much!

Good gold wisdoms, from wise & practical man.TNX and stay well Peter. 73,S51X

Nice explanation of use of mag mounts. Several things not considered before especially how it is an offset dipole! Thanks Peter, cheers!

Great explanation. Thank you for the excellent explanation.

Great video Peter,timing was perfect as im getting a cb magmount ready.Thank You.

Thanks for all the information

Good explanation as ever. Much appreciated.

Thanks for an interesting informative video young man.

May I add some thoughts Peter, from years past and the use of many magnetic bases and various whip aerials. I used to put the base in the centre of the roof with coaxial cable across same and in through a door jam or tail lift hatchback. But beware, that if you leave it on for a period of time, you ran the risk of scratches under the coax caused by dust road grime accumulation. This only happened once for me and I had learnt my lesson, so after that I would mount the magnetic base on the offside of the roof and where the coax did not contact same. I have to admit that I never used a line isolator and I would be rather concerned at having one close to the magnetic base as you show and decribe so admirably, and which would not be advisable in my opinion if the aerial installation was used for any high speed mobile operation, fine if static /M of course. And one final point and which I experienced with the magnetic bases having rubber boots, was the black circle left on the paintwork if the base had been on for a period of time, I think I spotted this on your car Peter? Another excellent video and a really good watch for newcomers and old timers like me! Never too old to learn more about our diverse hobby. And in passing, I still have the FDK Multi U11, purchased from you over 40 years ago, £249, paid for on hire purchase ;-) 73, Martin GW3XJQ

I mostly use vhf /uhf so these mounts are practically all I use other than a rubber ducky. If I ever get around to getting a general license I will have to try hf mobile (14 years as a technician) Thanks for the info on the line isolation for a mag mount! I can only add - Don't pinch the coax going through the door jam or through the window... 😉

Every days a learning day ta muchly.

A very good Friday morning to you sir from Wellington Somerset

Thank you for sharing , it's very interesting as always . A line isolator is not required if the transceiver is earthed to ground via an earth electrode stake ,the common mode current is then slugged straight to ground via the earth electrode stake . If a line isolator is used , the line isolator will reduce the RF power output from the transceiver . There are difficulties using transceivers mobile or portable as there's generally no ground , a simple earth stake tapped into the ground should suffice on mobile & portable radio use. The home base transceivers are generally grounded through the negative terminal that is connected to the power supply as the negative terminal on the 13.8v power supply will also relate to the earth connector on the 13 amp mains plug , so there is a direct negative earth connection from the home base set up to the outside of the SO239 connector on the rear of the transceiver & again a line isolator will serve no purpose , however if the transceiver has no earth whatsoever , then perhaps a line isolator may suffice ?.

Hi Peter I think that the diameter of the torroid is measured in 1/100th inch segments. Therefor a 240-43 would be 240 hundredths of an inch. Or 2.4 inchs imperial.

Question: Why is not a line isolator built in as default. If it is a must it should be there when you buy the mag mount.

Very useful video!! You brought up some very interesting points, many thanks!! Robert K5TPC

I have long wondered why moving the mag mount around the top of the car changed the sir. Thanks

one for truckers pulling an empty full size forestry trailer.... you could string a full size moxon rectangle for 21MHz between the uprights on the back.... so when someone comes on trying to impress you with an ATAS on a mag mount you can go back with "& I'm using a full size 2 element beam mobile" (OK it is a sod when you go around a corner & you lose them as they drop out of the beamwidth but there are plenty of straights on the motorway good enough for a quick qso). Going to the opposite extreme when I first started I had a friend who had a bright yellow little Fiat 126 with a Revco 2m 5/8 on a magmount on the roof so it looked more like a dodgem car than anything else (& had a xtal Pye Vanguard in the boot). Good call about the line choke (type 61 material may be better for vhf/uhf... or just an ugly balun).

I keep it really simple and have fantastic results. No antemna analyser,.no isolator. Just put my Ampro whip onto Sirio magmount, see what SWR is at top and bottom of band, adjust accordingly like in the olden days before people they had to have an amalyser. Always get decent match and always work some great DX! 73 M3KXZ